KINDAI UNIVERSITY


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KAWAI Katsuyuki

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FacultyDepartment of Civil and Environmental Engineering / Graduate School of Science and Engineering Research
PositionProfessor
Degree
Commentator Guidehttps://www.kindai.ac.jp/meikan/1373-kawai-katsuyuki.html
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Last Updated :2020/04/04

Research Activities

Research Areas

  • Social infrastructure (civil Engineering, architecture, disaster prevention), Geotechnical engineering

Published Papers

  • INSIGHTS FROM ROUND-ROBIN SEEPAGE ANALYSIS EXERCISE ON RIVER LEVEE WETTING DUE TO RAINFALL INFILTRATION, SHINSEI Akira, NISHIMURA Satoshi, FUJISAWA Kazunori, TAKESHITA Yuji, KAWAI Katsuyuki, SAKO Shunsuke, MORI Hirotoshi, YAMAZOE Nobutaka, OHTA Masayuki, Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering), Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering), 75(4), 398 - 414, 2019 , Refereed
    Summary:

     The stability assessment of river levee against intense rainfall and flooding involves predicting variations of the phreatic surface level and pore water pressure through unsaturated seepage analysis. This study is a summary of collective work conducted by JSCE River Levee Research Committee WG2, which was set up in 2012 to investigate the applicability of unsaturated seepage analysis to the levee wetting problems in practice, and to assess the accuracy and robustness of the analysis implemented with different numerical codes by different users. To this end, three levels of round-robin analysis exercise were conducted, in which different degrees of prescription were imposed to analysis conditions. Amongst the main findings from this exercise is that all the numerical codes, whether commercial or home-grown by the authors, output sufficiently accurate and practically identical solutions when same conditions are input, despite the differences in their discretisation methods, integration methods, etc. When the participants were given a total freedom in modelling the given levee's cross-section and material data, notable variations in the numerical results came out, confirming that each participant's engineering judgment in conditioning/modelling, not the sensitivity of numerical codes, is the main cause of the diverse outputs. Nevertheless, the variations are on the whole within a range which can be deemed acceptable for most levee engineering purposes.

  • Solute transfer during consolidation based on a solid-fluid-solute coupling model, Nomura, Shun, Kawai, Katsuyuki, Tachibana, Shinya, Iizuka, Atsushi, INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, 42(10), 1172 - 1196, Jul. 2018 , Refereed
    Summary:The migration of contaminant through soil is usually modeled using the advection-dispersion equation and assumes that the porous media is stationary without introducing a constitutive equation to represent soil structure. Consequently, time-dependent deformation induced by soil consolidation or physical remediation is not considered, despite the need to consider these variables during planning for the remediation of contaminated ground, the prediction of contaminated groundwater movement, and the design of engineered landfills. This study focuses on the numerical modeling of solute transfer during consolidation as a first step to resolve some of these issues. We combine a coupling theory-based mass conservation law for soil-fluid-solute phases with finite element modeling to simulate solute transfer during deformation and groundwater convection. We also assessed the sensitivity of solute transfer to the initial boundary conditions. The modeling shows the migration of solute toward the ground surface as a result of ground settlement and the dissipation of excess pore water pressure. The form of solute transport is dependent on the ground conditions, including factors such as the loading schedule, contamination depth, and water content. The results indicate that an understanding of the interaction between coupling phases is essential in predicting solute transfer in ground deformation and could provide an appropriate approach to ground management for soil remediation.
  • Behavior of the Air Phase within Embankment Due to Rainfall, Kawai, Katsuyuki, Hazama, Daichi, Nose, Ryunosuke, PANAM UNSATURATED SOILS 2017: APPLICATIONS, PANAM UNSATURATED SOILS 2017: APPLICATIONS, (302), 1 - 10, 2018 , Refereed
    Summary:In this study, air pressure behavior within an earth structure was investigated through a full-scale embankment test. The road embankment (2 m height) was constructed on low-permeability soil and measurement devices (tensiometers, air pressure meters, and soil moisture meters) were installed. The embankment was exposed to natural conditions, such as rainfall and evaporation, and vehicle weight was applied. Characteristic behaviors of water and air pressure were observed throughout the 1-year monitoring period. Water pressure increased under rainfall and kept decreasing due to evaporation without rainfall. The infiltrated rainwater flowed toward the slope toe. Consequently, water pressure at top of the slope increased due to rainfall and decreased soon after rainfall stopped; while pressure at the slope toe started decreasing after a period of time. Conversely, air pressure increased under only heavy rain. Moreover, it decreased to a point lower than atmospheric pressure following the heavy rain and recovered after a brief interval.
  • Simulation of saturation process in a transuranium disposal facility, Takayama, Yusuke, Iizuka, Atsushi, Kawai, Katsuyuki, ENVIRONMENTAL GEOTECHNICS, ENVIRONMENTAL GEOTECHNICS, 4(5), 339 - 352, Oct. 2017 , Refereed
    Summary:Bentonite materials have been considered as a candidate material for engineered barriers in transuranium (TRU) waste disposal facilities due to their physical and chemical characteristics. Bentonite materials will be initially compacted and unsaturated. After closing the cavern, the bentonite material will become saturated through exposure to a percolating groundwater. It is therefore important to understand the behaviour of bentonite during saturation, which provides an initial condition of the disposal facilities. This paper explains a mathematical model which can express the saturation process. Subsequently, a series of numerical simulations were carried out. First, the swelling pressure of buffer and backfill was examined to verify the numerical model. It was confirmed that the simulated swelling pressure rises with water absorption, and swelling pressure test results from the literature are shown to be satisfactorily predicted by the numerical model, although these were slightly overestimated. Next, the mechanical behaviour of bentonite materials in a TRU waste disposal facility during the saturation process was examined using soil/ water/ air coupled finite-element method. Although it is difficult to examine the validity of analysis results because of the difficulty of an extremely long-term measurement, the qualitative behaviour of the saturation process could be inferred.
  • Influence of soil moisture and stratigraphic structure on actual evaporation, KAWAI KATSUYUKI, Proc. 19th Int. Conf. on Soil Mechanics and Geotechnical Engineering, Proc. 19th Int. Conf. on Soil Mechanics and Geotechnical Engineering, 1167 - 1170, Sep. 2017 , Refereed
  • AIR PRESSURE DISTRIBUTION INDUCED BY RAINFALL INFILTRATION IN SOIL/WATER/AIR COUPLED SIMULATION, Kawai, Katsuyuki, Kawakatsu, Takuya, Teraoka, Ayumi, INTERNATIONAL JOURNAL OF GEOMATE, INTERNATIONAL JOURNAL OF GEOMATE, 12(32), 63 - 69, Apr. 2017 , Refereed
    Summary:Recently, the frequency of torrential rainfall has increased due to global climate change, and these events cause sediment potential failure. It is difficult to predict when and where a slope failure will occur because of the concentration of heavy rain. Knowing precursory phenomena, however, is effective for disaster reduction. Nonetheless, some of these phenomena have not been explained in the framework of geotechnical engineering. Organic smells and strange sounds, known as precursory signs of slope failure, propagate through the atmosphere. Therefore, it is important to monitor air movement within earth structures. This study focuses on pore air behavior within the ground due to rainfall infiltration. Here, the infiltration column test combined with monitoring smell, as conducted by Tsuchida et al., was first simulated using the soil/ water/air coupled finite element code, DACSAR-MP. Next, a sloping earth structure exposed to rainfall was simulated. Consequently, it was found that distribution of pore air pressure was dependent on drainage conditions of air, and that pore air behavior influenced rainfall infiltration behavior.
  • Constitutive modeling for compacted bentonite buffer materials as unsaturated and saturated porous media, Takayama, Yusuke, Tachibana, Shinya, Iizuka, Atsushi, Kawai, Katsuyuki, Kobayashi, Ichizo, SOILS AND FOUNDATIONS, SOILS AND FOUNDATIONS, 57(1), 80 - 91, Feb. 2017 , Refereed
    Summary:Bentonite has remarkable swelling characteristics and low permeability that enhance the stability of the buffer materials in repositories for the geological disposal of radioactive waste. It is necessary to apply reliable numerical simulation techniques to assess the safety and mechanical stability of repositories over a long period of time. Having a constitutive model that can describe the mechanical behavior of bentonite is key to such numerical simulations. This paper proposes an elasto-plastic constitutive model to describe the changes in the mechanical properties of bentonite due to saturation in the progress of a repository becoming submerged under groundwater. In the proposed model, the swelling index is formulated as a function of the degree-of-saturation to express not only the swelling behavior, but also the dependency of the degree-of-saturation on the dilatancy characteristics. The montmorillonite content is used as a material parameter to determine the normal consolidation line. The experimental results of swelling volume and swelling pressure tests in previous literature are shown to have been satisfactorily predicted by the proposed model. (C) 2017 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society.
  • Effects of stress conditions on B-value measurement, Sugiyama, Yuri, Kawai, Katsuyuki, Iizuka, Atsushi, SOILS AND FOUNDATIONS, SOILS AND FOUNDATIONS, 56(5), 848 - 860, Oct. 2016 , Refereed
    Summary:The B-value, measured after setting up a specimen for triaxial testing, is used for evaluating the degree of saturation of a specimen. However, the stress conditions used when measuring the B-value have not been standardized. Although some experimental approaches have been pursued, no detailed analyses have evaluated the effects of the measurement conditions on the B-value results. In this study, the B-values of nearly saturated specimens under various stress conditions were investigated, using a smart triaxial test apparatus capable of elaborate stress control, and comparisons among measurement results were conducted. Moreover, by applying Henry's law, which governs the dissolution of the gas phase into the liquid phase, to an existing constitutive model for unsaturated soil, a new soil model was proposed. This new model accurately represents the behaviors of pore air even under nearly saturated conditions. In addition, the effects of the stress conditions on the B-values were investigated through numerical simulations of B-value measurements. (C) 2016 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V.
  • Explanation of Dry Density Distribution Induced by Compaction through Soil/Water/Air Coupled Simulation, Kawai, Katsuyuki, Phommachanh, Viradeth, Kawakatsu, Takuya, Iizuka, Atsushi, ADVANCES IN TRANSPORTATION GEOTECHNICS III, ADVANCES IN TRANSPORTATION GEOTECHNICS III, 143, 276 - 283, 2016 , Refereed
    Summary:Most onshore earth structures, such as earthen dams, embankment, and river levees, are constructed by compaction. Transportation geotechnics also includes construction of compacted earth structures, such as road and railway embankment. Optimum compaction can increase shear strength, while decreasing compressibility and permeability of earth structures. For this reason, compaction has been used for earthworks since the dawn of times. Generally, a series of lab compaction tests is conducted to obtain a compaction curve before constructing these structures. The shape of the compaction curve, which determines the maximum dry density at the optimum water content, is very important in the design and construction of structures. However, it is difficult to control compaction quality on the basis of lab tests alone, as soil materials are inhomogeneous. Furthermore, there are differences in the compaction methods used in lab tests and at construction sites. Therefore, it is necessary to explain the mechanisms of compaction in the framework of soil mechanics. In this study, compaction of earthworks is simulated in a similar way. The effect of compaction layer thickness and the number of compaction layers on the distribution of dry densities in an earth structure was investigated through soil/water/air coupled simulation. Consequently, it was found that multi-layered compaction can create a gap in the dry density between two layers and that this gap can be reduced by thinner layer compaction. On the other hand, though the average dry density in a compacted earth structure can be increased by increasing the number of compacted layers, some gap between compaction layers was inevitable. Through these findings, this study contributes to the performance design of compacted earth structures.
  • Soil/water/air coupled F. E. simulation of phreatic surface generation process within a river levee, Kawai, K, V. Phommachanh, A. Iizuka, Japanese Geotechnical Society Special Publication, Japanese Geotechnical Society Special Publication, 2(49), 1714 - 1717, Nov. 2015 , Refereed
  • ワイブル分布による被災者数のベイズ推定, 小谷稔, 飯塚敦, 河井克之, 土木学会年次学術講演会講演概要集(CD-ROM), 土木学会年次学術講演会講演概要集(CD-ROM), 70th, ROMBUNNO.IV-043, Aug. 01 2015 , Refereed
  • STUDY ON THE DEPLOYMENT MODEL OF DMAT IN ACUTE DISASTER MEDICAL, KOTANI Minoru, IIZUKA Atsushi, KAWAI Katsuyuki, Journal of Japan Society of Civil Engineers, Ser. F6 (Safety Problem), Journal of Japan Society of Civil Engineers, Ser. F6 (Safety Problem), 71(1), 32 - 45, 2015 , Refereed
    Summary: In recent years, enormous damage has been caused by natural disasters. Disaster Medical Assistance Team (DMAT) play an important role in minimizing human suffering. However, since factual information is intermingled with disinformation in the event of a disaster, it is difficult to obtain correct information, such as where and to what extent medical care is required, in order to dispatch DMAT appropriately. In this study, using a victims estimation formula empirically derived from the cumulative death toll data with the passage of time in past seismic hazard, an optimization problem was addressed to minimize the number of deaths.
     Consequently, it was found that early dispatch of DMAT would be effective, and DMAT should be dispatched according to the circumstances (number of DMAT, conditions of affected areas) in order to minimize the cumulative death toll. And, by setting the conditions of the affected area, it was possible to consider the way of reasonable DMAT dispatch. Thus, it has become possible to suggest the way of effective dispatch of finite DMAT, to use limited DMAT resources efficiently, and to help make decisions.
  • THEORETICAL AND EXPERIMENTAL STUDIES OF STRESS DISTRIBUTION IN WEDGE-SHAPED GRANULAR HEAPS, Pipatpongsa Thirapong, Matsushita Tadaki, Tanaka Maho, Kanazawa Shinichi, Kawai Katsuyuki, ACTA MECHANICA SOLIDA SINICA, ACTA MECHANICA SOLIDA SINICA, 27(1), 28 - 40, Feb. 2014 , Refereed
  • Experimental and numerical studies on the effect of rainfall on triggering shallow landslides, Binod Tiwari, Katsuyuki Kawai, Adam Lewis, Phommachanh Viradeth, Landslide Science for a Safer Geoenvironment: Volume 2: Methods of Landslide Studies, Landslide Science for a Safer Geoenvironment: Volume 2: Methods of Landslide Studies, 123 - 128, Jan. 01 2014 , Refereed
    Summary:© Springer International Publishing Switzerland 2014. Rainfall is considered one of the major triggering factors for shallow landslides. The effect of rainfall in causing landslides depends on the intensity and duration of rainfall, the type of soil, the inclination of the slope, and ground water conditions. The majority of slope stability problems in shallow slides involve partially saturated soils. Although experimental modelling of slopes subjected to various intensities and durations of rainfall are ideal to evaluate the effect of rainfall on slope stability, it is time consuming and expensive. Numerical simulation of such experimental modelling can save a great deal of time and cost. In this study, slope models were prepared at angles of inclination of 30º and 45º with double washed construction sand, at a void ratio of 0.7. The slopes were subjected to 30 mm/h of rainfall for 3 h. Spatial variation of suction during the rainfall and depth of water front with time were measured for the entire rainfall period. The depth of water front and spatial variation of suction were also calculated through the finite element model (FEM) that was developed based on a hydro-mechanical model developed for the partially saturated soil. The numerical and experimental results provided identical results. The numerical result was extended to predict the spatial variation of suction, depth of water front and deformation of slope subjected to higher intensity of rainfall.
  • THEORETICAL INTERPRETATION OF THE PORE PRESSURE COEFFICIENT B WITH SOIL/WATER/AIR COUPLED MODEL, SUGIYAMA Yuri, KAWAI Katsuyuki, TANAKA Hiroyuki, IIZUKA Atsuhi, Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 70(2), I_145 - I_153, 2014 , Refereed
    Summary:The pore pressure coefficient B, which is measured on triaxial test, is useful for evaluating degree of saturation of specimen. However, the influential factors on this B value other than degree of saturation have not been investigated in detail up to now. In this study, first, Henry's law that indicates dissolved air in pore water was applied to the existing constitutive model for unsaturated soil in order to express the behavior of pore air on unsaturated soil extremely close to fully saturated state. Next, the influential factors, such as degree of saturation, confining stress and back pressure, were investigated through numerical simulations with using newly obtained model. Consequently, it was found out that B value depends on not only degree of saturation but also stress state.
  • An interpretation of mechanical properties of bentonite as a non-linear elastic material, Y. Takayama, S. Tsurumi, A. Iizuka, K. Kawai, S. Ohno, International Journal of GEOMATE, International Journal of GEOMATE, 3, 357 - 362, Jan. 01 2012 , Refereed
    Summary:Bentonite is usually modeled as a geo-material with elasto-plastic isotropic compression/expansion and plastic dilatancy characteristics. In this paper, fundamental considerations of elasto-plastic constitutive modeling for fully saturated bentonite are investigated. According to uniaxial compression test data by Sasakura et al. (2003), where lateral earth pressure was measured, it was found that the hysteresis response between loading and unloading processes does not appear. It suggested that bentonite is an elastic material in which the swelling line corresponds to the normally consolidated line in the 'e-logp' relationship. Also, according to triaxial CU test results of bentonite, it was seen the effective mean stress remains almost unchanged during shearing. This implies that bentonite does not have dilatancy characteristics as defined by the critical state theory. Similar interpretation can be derived from the experimental results obtained from a series of triaxial CD tests by Cui et al. (2006). © 2012, International Journal of GEOMATE.
  • Consideration of influences of soil parameters on compaction behavior with soil/water/air coupled F. E. code, KAWAI Katsuyuki, SAKAMOTO Satoshi, PHOMMACHANH Viradeth, IIZUKA Atsushi, Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 68(2), I_299 - I_306, 2012 , Refereed
    Summary:Compacted soil is widely used for earth structures. However, the mechanism of compaction has not been explained, so it is difficult to grasp distributions of stress, void ration, and soil moisture within compacted earth structure. Therefore, estimation of safety and stability of compacted earth structures exposed to natural disaster is complicated. Compaction is decreasing void ratio by applying stress under certain water content and pushing air out of soil mass. Thus, the mechanics of unsaturated soil, which includes air within void, is needed for understanding of compaction. In this study, we regarded compaction as compression and expansion phenomenon of unsaturated soil under drained air and undrained water conditions and formulated it in initial-boundary-value problem. Here, the influences of permeability and soil water retention characteristics on compaction were considered and static compaction tests were simulated. Moreover, multi-layered compaction was examined.
  • Analysis of the mechanical behavior of compacted soil with F.E. method, KANAZAWA Shin-ichi, TOYOSHIMA Takuma, KAWAI Katsuyuki, TACHIBANA Shinya, IIZUKA Atsushi, Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 68(2), I_291 - I_298, 2012 , Refereed
    Summary:Compacted soil is widely used to build earth structure. Although construction management of the soil progresses day by day, it is said that mechanism of compaction effect isn't fully made clear. This is due to the complication of compaction mechanism of unsaturated soil. Recently, some constitutive models for unsaturated soil and SWCC models were proposed and advanced the study on unsaturated soil. In this study we regarded compaction as the consecutive cycle of compression and expansion of unsaturated soil under undrained condition, and simulated it with unsaturated soil/water/air coupled finite element analysis. In this study, we expressed the characteristics of the mechanical behavior of compacted soil, which has not been explained for a long period of geotechnical engineering. And we considered the difference of compaction procedure affected the quality of earth structures. The achievement can be managed reasonably the compaction of earth structure.
  • Growth environment estimation of the monumental pine in Rikuzen Takada with mass transfer simulation, KAWAI Katsuyuki, SUGIYAMA Yuri, Nomura Shun, IIZUKA Atsushi, Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 68(2), I_345 - I_352, 2012 , Refereed
    Summary:The coastal area of eastern Japan was hit by Tsunami due to the gigantic earthquake on March 11th 2011. Tsunami gave serious damage to Rikuzen Takada and drowned out famous pine forest, called “Takadanomatsubara”. However, only one of 70,000 pines could survive miraculously without falling down. People decided to preserve this pine as the monumental pine for the symbol of recovery. However, there are some problems, groundwater rise due to land sinking and salt concentration from seawater. These factors can kill root system. In this study, the current situation around the monumental pine was simulated with soil/water/air coupled F. E. code applying the mass transfer equation first. Next, the alternative preservation methods were examined. Consequently, it was found that pumping up from deep inside of sheet pile is effective for inhibiting salt diffusion and flashing is effective for washing salt away from ground.
  • Modeling of coal fly-ash with self-hardening property and simulation of water body reclamation, PHOMMACHANH Viradeth, MAEGAWA Futoshi, KAWAI Katsuyuki, IIZUKA Atsushi, Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 68(2), I_307 - I_315, 2012 , Refereed
    Summary:Coal fly-ash is a product of the coal-burning process in thermal power plants. Coal fly-ash has self-hardening property and increases its stiffness with time. Therefore, it has been reused as a concrete aggregate in the production of concrete up to now. Recently, coal-fly ash is mixed with dredged soil from construction waste and reused for reclamation. In order to reuse coal fly-ash in the geotechnical engineering field, the self-hardening property in the framework of the constitutive model needs to be expressed. In this study, the self-hardening property is assumed as increases of the frictional angle and the yield stress. Our model is formulated for the initial-boundary problems with finite element method. Triaxial tests and the self-weight consolidation test are simulated with soil/water coupled F. E. code.
  • Theoretical Evaluation of the Mechanical Behavior of Unsaturated Soils, Michinori Honda, Shintaro Ohno, Atsushi Iizuka, Katsuyuki Kawai, Hideki Ohta, Geotechnical and Geological Engineering, Geotechnical and Geological Engineering, 29, 171 - 180, Mar. 01 2011 , Refereed
    Summary:An evaluation method for the mechanical behavior of unsaturated soils is studied in this paper. Although the mechanical behavior of unsaturated soils is complicated, a simple modeling is preferable in practice. This is because the soil properties are not homogeneous and ground data is limited when structures are being designed. In addition, in order to evaluate the reliability of the design, the physical meanings of the parameters applied in the prediction model should be clear. Firstly, the authors study the relationship between compaction curves and compression indexes in the unsaturated state that is used in the proposed constitutive model. Based on the constitutive model, the stress paths for constant volume shear tests are formulated under a constant void ratio condition and the stress paths for undrained shear tests are calculated under a constant water content condition. In the case of unsaturated specimens, the volume of these specimens changes with the shear deformation and the stress paths depend on the initial degree of saturation. The results of the calculation qualitatively describe the test results by considering the changes in effective confining pressure in the undrained condition and the water retention curves. © 2010 Springer Science+Business Media B.V.
  • Transfer model of water-soluble material in saturated/unsaturated ground, NOMURA SHUN, KAWAI KATSUYUKI, KAKUI SHUNSUKE, TACHIBANA SHIN'YA, KANAZAWA SHIN'ICHI, IIZUKA ATSUSHI, Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 67(2), I_231 - I_240, 2011 , Refereed
    Summary:The ground pollution is one of the most serious environmental issues all over the world now. Industrial wastes discharged from various human activities infiltrate to the ground, diffuse and damage to plants and animals indirectly. Therefore, it is strongly requested to know the transfer behavior of contaminant movement in the ground. In this study, continuous equations and advection-dispersion equation are derived from mass conservation laws in soil, water, air and dissolved material phases. These governing equations are applied to the constitutive model for unsaturated soil and formulated in the framework of the initial boundary value problems with the finite element method The soil/water/air coupled analysis program, DACSAR-M_ad, applied mass transfer equation to is coded. Here, the mass within the ground due to loading is simulated with this code.
  • 築堤シミュレーションにおける設定条件が盛土内応力分布に及ぼす影響, 田中麻穂, 河井克之, 金澤伸一, 橘伸也, 大野進太郎, 飯塚敦, 竹山智英, 応用力学論文集(CD-ROM), 応用力学論文集(CD-ROM), 13, 423 - 430, 2010 , Refereed
  • 締固め方法の違いが締固め土構造物の品質に及ぼす影響, 柴田昌輝, 河井克之, 尾崎早希子, 金澤伸一, 橘伸也, 飯塚敦, 応用力学論文集(CD-ROM), 応用力学論文集(CD-ROM), 13, 363 - 370, 2010 , Refereed
  • Impacts of plant-induced uptake on the stability of the earth structure, K. Kawai, A. Iizuka, S. Tachibana, S. Ohno, Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 1, 526 - 529, Dec. 01 2009 , Refereed
    Summary:It is empirical knowledge that vegetation can influence the behavior of earth structure. It prevents surface failure and erosion due to rain and wind, and contributes to the stability of earth structure. Moreover, it encourages water circulation with transpiration, fixes atmospheric nitrogen and carbon via photosynthesis, and improves the environment. Therefore, surface seeding is purposely performed when an earth structure, such as an embankment or an earth dam, is constructed. Typically, vegetation grows on unsaturated soil. Consequently, a constitutive model for unsaturated soil is needed for understanding the effects of vegetation on the ground. In this study, we focus on the effect of vegetation-induced water uptake. The effect of water uptake due to evapo-transpiration can be regarded as reduction of water content within soil and appropriately represented in simulation studies. The constitutive model proposed by Ohno et al. (2007) is used for the simulation. In this model, the effective degree of saturation is treated as a parameter expressing hardening/softening. Moreover, the 'root element,' where the reduction of water content occurs, is applied to the soil/water coupled analysis with unsaturated soil mechanics. To verify the applicability of this model, the accident in Poland where non-uniform settlement and building damage were caused by water uptake of vegetation was simulated. The results show that water uptake increased suction and induced non-uniform settlement. This method is effective for understanding the effects of vegetation on the ground. © 2009 IOS Press.
  • 盛土の設計と締固め 不飽和土の力学理論から見た土の締固め, 河井克之, 金澤伸一, 飯塚敦, 基礎工, 基礎工, 37(7), 032 - 035, Jul. 15 2009
  • A finite element simulator for mechanical behavior of unsaturated earth structures exposed to evaporation and moisturization, Kanazawa, S, Kawai, K, Iizuka, A, Ohno, S, Tachibana, S, Pipatpongsa, Proc. 4th Asia-Pacific Conf. on Unsaturated Soils, Proc. 4th Asia-Pacific Conf. on Unsaturated Soils, 2009 , Refereed
  • Simulations of static compaction with unsaturated soil/water coupled F. E. code, 河井克之, 柴田昌輝, 金澤伸一, 橘伸也, 大野進太郎, 飯塚敦, 本田道識, 応用力学論文集, 応用力学論文集, 12, 429 - 436, 2009 , Refereed
  • Study of the stratigraphic architecture resistant for salt damage and the method to purify salty ground, 河井克之, 野村瞬, 大野進太郎, THIRAPONG Pipatpongsa, 橘伸也, 金澤伸一, 飯塚敦, 応用力学論文集, 応用力学論文集, 12, 421 - 428, 2009 , Refereed
  • Laboratory hydraulic testing in unsaturated soils, Farimah Masrouri, Kátia V. Bicalho, Katsuyuki Kawai, Geotechnical and Geological Engineering, Geotechnical and Geological Engineering, doi:10.10007(s10706-008-9202-7), 691 - 704, May 23 2008 , Refereed
    Summary:This paper synthesizes the state-of-the art of the various laboratory testing techniques presently available for measuring the water hydraulic constitutive functions of unsaturated soils. Emphasis is on the laboratory testing techniques for measuring the soil-water retention curves and the water hydraulic conductivity functions of unsaturated soils. The significant recent advances in the investigation of the hydraulic behaviour of unsaturated swelling soils, are also presented. Comprehensive recent references on each measurement method are listed and discussed. © Springer Science+Business Media B.V. 2008.
  • Influence of vegetation uptake on the deformation of ground, KAWAI Katsuyuki, YAMADA Ryotarou, IIZUKA Atsushi, TACHIBANA Shinya, OHNO Shintaro, Journal of Applied Mechanics, JSCE, Journal of Applied Mechanics, JSCE, 11(11), 443 - 450, 2008 , Refereed
    Summary:Empirically, it is known that the vegetation influences on the earth structure. Kawai et al. focused on the effects of water uptake induced by the vegetation. They regarded it as an effect of decreasing soil moisture and applied the effect to unsaturated soil/water coupled F. E. analysis. In this study, the soil/water coupled F. E. analysis code is rearranged with the constitutive model for unsaturated soil proposed by Ohno et al.. In their model, the effective degree of saturation are applied as a parameter expressing stiffness of unsaturated soil to enable application of unsaturated soil mechanics to actual problem in geotechnical engineering site. To verify the applicability of soil/water coupled analysis, the accident that the vegetation uptake work brought about the non-uniform settlement of the ground and damaged the building in Poland are simulated. Consequently, it was found that the uptake increased suction and encouraged non-uniform settlement of ground surface. Its effects appeared prominently in a dry ground having low groundwater level and much uptake. This method is effective to understand the effects of vegetation.
  • Study of spatial discretization scheme in unsaturated soil/water coupled analysis, KANAZAWA Shinichi, TACHIBANA Shinya, KAWAI Katsuyuki, OHNO Shintaro, IIZUKA Atsushi, Journal of Applied Mechanics, JSCE, Journal of Applied Mechanics, JSCE, 11(11), 331 - 338, 2008 , Refereed
    Summary:Many of earth structures on the ground keep stability in unsaturated state. Moreover, these structures are exposed to drying and wetting conditions and changes in soil moisture always occur. Therefore, the constitutive model with unsaturated soil mechanics is needed for predicting the elasto-plastic behavior of the earth structures for a long term. The objective of this study is developing soil/water coupled F. E. analysis with unsaturated soil mechanics. In this study, the constitutive model proposed by Ohno et al. is used. Their model can express typical behavior of unsaturated soil, such as shrinkage on drying process, collapse on wetting process, and the effects of hysteresis on soil-water retention characteristic curve, and have the flexibility for dependencies on soil properties. Moreover, isoparametric element is applied on spatial discretization to preventing the dependency on mesh, which can be seen in the Akai and Tamura's method. This simulation method allows us precise prediction of the behavior of unsaturated earth structures.
  • Numerical investigation on the failure criterion of normally consolidated clays, Tachibana, Shinya, Iizuka, Atsushi, Kawai, Katsuyuki, Kobayashi, Ichizou, Pipatpongsa, Thirapong, Ohta, Hideki, INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, 31(6), 809 - 833, May 2007 , Refereed
    Summary:In this paper, a series of numerical simulations of conventional laboratory experiments on normally consolidated clays under undrained condition subject to uniaxial compression/extension loading at constant applied rate of strain in axisymmetric and plane strain conditions was performed in rectangular and octagonal modelled specimens in order to investigate failure behaviours of clays. The soil/water coupling finite element technique formulated under finite deformation theory based on the updated Lagrangean scheme were applied for the numerical simulations. Herein, the Cam-clay material with von Mises type failure criterion, which is independent of the Lode angle, is used to describe constitutive behaviour. It can be seen that the stress states at failure of the specimens obtained from the numerical simulations do not show the von Mises shape on the pi-plane but rather more closely resembles the Lade-Duncan model, which is dependent of Lode angle. The result suggests that Lode angle dependence consistently observed in the laboratory at failure is not a constitutive behaviour but is instead a result influenced by applied boundary conditions and material imperfections. Copyright (c) 2006 John Wiley & Sons, Ltd.
  • Non-uniform settlement of compacted earth structures caused by the deformation characteristics of unsaturated soil on wetting, Kawai, Katsuyuki, Iizuka, Atsushi, Hayakawa, Eiji, Wang, Weichuan, SOILS AND FOUNDATIONS, SOILS AND FOUNDATIONS, 47(2), 195 - 205, Apr. 2007 , Refereed
    Summary:The soil/water-coupled analysis for unsaturated soil mechanics with the finite element method is used to express the behavior of compacted earth structures exposed to rainfall. The constitutive model, which is proposed by Karube et al. (1996, 1997) and modified by Karube and Kawai (2001), is formulated for initial and boundary problems and coded as DACSAR-U (lizuka et al., 2000). A deep fill, which consists of compacted, unsaturated soil, was analyzed with DACSAR-U. Different patterns of rainfall were applied to deep fills in finite element simulations. As a result, non-uniform settlement of deep fill can be calculated and the magnitude of settlement of deep fills is dependent on the amount of collapse, namely, the compression due to the decrease in suction. Moreover, delayed settlement due to rainfall and an accumulation of an irreversible settlement due to cyclic rainfall was observed.
  • ELASTO-PLASTIC CONSTITUTIVE MODEL FOR UNSATURATED SOIL APPLIED EFFECTIVE DEGREE OF SATURATION AS A PARAMETER EXPRESSING STIFFNESS, OHNO Shintaro, KAWAI Katsuyuki, TACHIBANA Shinya, Doboku Gakkai Ronbunshuu C, Doboku Gakkai Ronbunshuu C, 63(4), 1132 - 1141, 2007 , Refereed
    Summary:To predict the long term elasto-plastic behavior of unsaturated earth structures, the constitutive model, which can express the following typical behavior of unsaturated soil, is needed. One is shrinkage and stiffness increase due to suction increase, second one is collapse with stiffness decrease due to suction decrease, and the last one is the influences of suction history relating to the hysteresis of soil-water retention characteristics. In this study, a constitutive model of unsaturated soil applied the effective degree of saturation as parameter expressing stiffness was proposed. The model showed good agreement with the experimental results and the appropriateness of the model was demonstrated.
  • The influences of uptake of vegetation on the ground, KAWAI Katsuyuki, IIZUKA Atsushi, SHIMONAGA Katsuyuki, TACHIBANA Shinya, Journal of Applied Mechanics, JSCE, Journal of Applied Mechanics, JSCE, 10(10), 375 - 381, 2007 , Refereed
    Summary:It is known that the vegetation is effective in preventing slope failure. In this study, we focus on the vegetation uptake from ground and show the way to estimate its effects on the ground quantitatively. The effect of uptake can be regarded as reduction of water content within soil. The ‘root element’, where the reduction of water content occurs, is applied to the existing code of soil/water coupled finite element analysis with unsaturated soil mechanics. To estimate the effects of uptake, three kinds of conditions, such as the amount of uptake water, the initial degree of saturation of the ground, and groundwater level are provided. Consequently, it was found that the uptake increased suction and encouraged non-uniform settlement of ground surface. Its effects appeared prominently in a dry ground having low groundwater level and much uptake. This method is effective to understand the effects of vegetation.
  • The Mathematical Modeling of Unsaturated Soil-Water Coupled Problem Considering Mass Transfer and its FE formulation, FUJIKAWA Kazuhiko, IZUKA Atsushi, KAWAI Katsuyuki, PIPATPONGSA Thirapong, Journal of applied mechanics, Journal of applied mechanics, 9(9), 377 - 384, 2006 , Refereed
    Summary:This paper proposes a new mathematical formulation for the unsaturated soil-water coupled stress-deformation problem in which the advection and dispersion phenomena are taken into consideration. The conventional mathematical formulation for advection and dispersion phenomenon cannot take account of influence arising from the stress change and deformation of the ground. Therefore, if some construction works such as irrigation facilities and wells are planed as measures for some contamination damage, their influence on the advection and dispersion phenomena of the contaminant cannot be quantitatively examined by the conventional mathematical formulation. Then, in this paper, a new mathematical formulation for the advection and dispersion phenomena is rebuilt and a set of governing equations coupled with the soil deformation is presented. This new formulation is capable of introducing any constitutive model for unsaturated and saturated soil. In this paper, an elasto-plastic constitutive model for unsaturated and saturated soil proposed by Kawai et al. is employed together with the water retention model for the unsaturated soil considering the hysteresis response under wetting and drying processes. Finally, the performance of this new formulation for advection and dispersion phenomena is demonstrated through a numerical simulation of salt damage in an imaginary ground.
  • A STUDY OF THE EVALUATIION METHOD FOR DEFORMATION CHARACTERISTIC OF COMPACTED SOIL, HONDA Michinori, IIZUKA Atsushi, OHNO Shintaro, KAWAI Katsuyuki, WANG Weichuan, Doboku Gakkai Ronbunshu, Doboku Gakkai Ronbunshu, No.806(806), 33 - 44, Dec. 21 2005 , Refereed
    Summary:This paper discusses the volume change characteristics of compacted soil based on the oedmeter test results. Each of the specimens was made under different water content, different compaction loads and different methods representing static and dynamic compaction, and the compression tests were conducted in soaked condition and unsaturated condition. The effect of the conditions of compaction for the compression curve is discussed.
    The evaluation method for deformation characteristic of compacted soil is discussed and the constitutive model for the compacted soil is proposed. Using the derived equations, the oedmeter test results were simulated. The calculation results simulate the compression curve of compacted soil well, by using the parameters of suction, water content and yield stress.
  • Modeling of the confining effect due to the geosynthetic wrapping of compacted soil specimens, Atsushi Iizuka, Katsuyuki Kawai, Eun Ra Kim, Masafumi Hirata, Geotextiles and Geomembranes, Geotextiles and Geomembranes, 22, 5, 329-358, 329 - 358, Oct. 01 2004 , Refereed
    Summary:This paper presents the modeling of the composite soil-geosynthetic structure and discusses the effect of the reinforcement arising from the confining of the deformation of the soil by geosynthetics. A series of compressive shear tests for compacted sandy soil specimens, wrapped in geosynthetics, is carried out for the purpose of quantitatively examining the effect of the geosynthetic reinforcement arising from the confining of the deformation of compacted soils during shearing. Furthermore, an elasto-plastic modeling for compacted soil and a rational determination procedure for input parameters, needed in the elasto-plastic modeling, are presented. In this paper, the subloading yielding surface is introduced to the elasto-plastic modeling in order to describe the irreversible deformation characteristics of compacted soil during shearing. Since compacted soil is essentially unsaturated and its mechanical behavior is influenced by the suction working in the compacted soil media, the suction effect is taken into account in estimating of the degree of compaction. Finally, an elasto-plastic finite element simulation is conducted and the geosynthetic-reinforcement effect is presented. © 2004 Elsevier Ltd. All rights reserved.
  • Interpretation of existing constitutive models for unsaturated soil and the general expression of the constitutive model considering hysteresis of the water retention characteristic curve, KAWAI Katsuyuki, WANG Weichuan, IIZUKA Atsushi, Journal of applied mechanics, Journal of applied mechanics, Vol.7,No.1,pp.505-513(7), 505 - 513, 2004 , Refereed
    Summary:There are some constitutive models for unsaturated soil. However, their mathematical structures, particularly for expression of collapse phenomenon, are essentially the same. Therefore, it is possible to unify the constitutive models which were proposed in the past. In this paper, a generalized constitutive model for unsaturated soils is presented. First, we outline existing constitutive models for unsaturated soil and, next, we propose a comprehensive constitutive model for unsaturated soils in terms of the effective stress for unsaturated soils. To this new elasto-plastic model, it is easier to introduce sophisticated methods such as a rotational hardening, a subloading surface and so forth. This model is formulated in the form of incremental general stress and strain relationship and is incorporated into a finite element code, DACSAR-U, for unsaturated soils. The performance of the new constitutive model is demonstrated by comparing with the models proposed by Karube et at and by Honda et al
  • Numerical si-adon of a geo-dome excavation for CAES conidering construction sequences, NISHIDA Hirofumi, IIZUKA Atsushi, KAWAI Katsuyuki, ITOH Fumio, Journal of applied mechanics, Journal of applied mechanics, 6(6), 1131 - 1139, 2003 , Refereed
    Summary:The mechanical behavior of soils is essentially dependent on the stress/deformation history in the past. It implies that the choice of construction sequence influences on the quality of the soil structure. This paper describes the numericalsimulation of a geo-dome excavation for CAES, which is an energy store system originally proposed by Hayashi. Throughout examining the deformation of ground and effective stress change with the construction sequence in representative elements, the crucial points not only in the construction stage but also in the long term use are tried to find. Herein, two dimensional soil/water coupled elasto-viscoplastic finite element technique is employed in the computation. Thefinal target is to develop a new method enabling to positively evaluate the total life-cycle-cost
  • THE MECHANICAL BEHAVIOR OF UNSATURATED SOILS AND WATER RETENTION CHARACTERISTICS ON UNDRAINED TRIAXIAL COMPRESSION TEST, KAWAI Katsuyuki, KARUBE Daizo, KADO Yoshitane, KATO Shoji, Doboku Gakkai Ronbunshu, Doboku Gakkai Ronbunshu, 715(715), 287 - 296, Sep. 21 2002 , Refereed
    Summary:A series of triaxial compression tests is carried out on the unsaturated silty kaolin clays. Specimens are subjected to undrained compressive shear under the conditions of constant air pressure. The pore water pressure and volume change during shear are monitored. The pore water pressure develops with compression and then turns to decrease with expansion when the degree of saturation is relatively high. On the contrary to it, when the degree of saturation is low, the pore water pressure monotonically increases independent of volume change. These experimental facts can be explained from the effects of the bulk stress. Thus, throughout experimental investigations, it is revealed that the behaviors of unsaturated soils are consistently explained in terms of the meniscus and the bulk stresses. Particularly, it is found that the failure criterion on unsaturated soils can be uniquely described using the suction stress, which is defined as the summation of meniscus and bulk stresses.
  • The expression of hysteresis appearing on water characteristic curves and the change of stresses in unsaturated soils, KAWAI Katsuyuki, WANG Weichuan, IIZUKA Atsushi, Journal of applied mechanics, Journal of applied mechanics, Vol.5,pp.777-784(5), 777 - 784, 2002 , Refereed
    Summary:The mechanical behavior of unsaturated soils strongly depends on the pore water distribution as well as the suction. The water characteristic curve (W. C. C) specifying the pore water content and the suction value plays a very important role in describing the mechanical modeling for unsaturated soils. However, the W. R. 0 shows the hysteresis loop in the wetting/drying processes. This paper emphasizes the importance of considering the hysteresis of W.C.C in the modeling. The accumulation of irreversible strains in the soil structures caused by rainfalls cannot be explained well without considering the hysteresis of W. C. C. An existing model of W. C. C is modified so as to express the accumulation of irreversible strains as the cyclic suction loading. Finally, it is shown that the modified model well explains the experimental results.
  • 施工履歴の違いを考慮した人工島の品質評価に対する検討, 飯塚敦, 西田博文, 河井克之, 井内崇也, 応用力学論文集, 応用力学論文集, 5, 767 - 775, 2002 , Refereed
  • Soil/water coupled dynamic F. E. analysis using an elasto-plastic constitutive model with a subloading surface, IIZUKA Atsushi, OHNO Shintaro, KAWAI Katsuyuki, TATEYAMA Kazuyoshi, Journal of applied mechanics, Journal of applied mechanics, 5(5), 601 - 610, 2002 , Refereed
    Summary:This paper describes the development of soil/water coupled dynamic finite element computation technique considering irreversible deformation characteristics of porous media such as soils. Incremental governing equations taking into account of the effect of acceleration, first, are summarized and discretized in spatial and time domain. Thus obtained discretized equations are formulated based on the finite element technique so that the acceleration and the total pore water head are unknown values that should be solved under imposed boundary and initial conditions. The finite element code newly developed in this paper is verified by comparing some strict solutions for solid/water coupled problems and is examined whether the seismic responses of soil/water coupled media can be explained. Fina ly, the vertical settlement due to the horizontal seismic external force is successfully simulated.
  • A simple method to predict the consolidation yield stress of compacted soils considering suction effects in unsaturated soil media, KAWAI Katsuyuki, KIM Eunra, NAGARETA Hiroyuki, IIZUKA Atsushi, HONDA Michinori, Journal of applied mechanics, Journal of applied mechanics, 5(5), 785 - 792, 2002 , Refereed
    Summary:The objective of this study is to apply mechanics of unsaturated soils to prediction of compacted soils behavior. First, we performed static compaction tests with monitoring the change of applied stress and suction of specimen during compaction. Next, we carried out compression tests for the statically compactedsoil specimen and measured consolidation yield stress of them. As a result, it was found that suction of compacted soil depends on the dry density as well as the water content. Moreover, compression lines of compacted soil retaining samesuction converged into on unique compression line. Finally, we proposed the simple method to predict consolidation yield stress of compacted soil using simplified model of unsaturated soils.
  • The role of pore water in the mechanical behavior of unsaturated soils, Daizo Karube, Katsuyuki Kawai, Geotechnical and Geological Engineering, Geotechnical and Geological Engineering, 19, 211 - 241, Dec. 01 2001 , Refereed
    Summary:Deformation and failure of soils are governed by the stresses acting on the soil skeleton. The isotropic stress acting on the soil skeleton can be divided into two components. One is the stress component which is transmitted through the soil skeleton. This skeleton stress is influenced by the pore water ("bulk water") in the soil. The other is the internal stress component which does not contribute to equilibrium with a given external force. The internal stress is induced by the capillary tension of meniscus water clinging to the contact point of soil particles and acts so as to connect the soil particles tightly. Therefore, in modeling the stress and strain relations for unsaturated soils, it is of much importance to quantitatively evaluate how the pore water exists in the soil. This paper discusses the role of pore water on the mechanical behaviour of the soil. In particular, the significance of the water retention curve is emphasized from a mechanical viewpoint. Essential features required in modeling of the constitutive relations for unsaturated soils are discussed and presented.
  • EFFECTS OF SUCTION ON STRENGTH CHARACTERISTICS OF UNCONFINED COMPRESSION TEST FOR A COMPACTED SILTY CLAY, KATO Shoji, YOSHIMURA Yuji, KAWAI Katsuyuki, SUNDEN Wataru, Doboku Gakkai Ronbunshu, Doboku Gakkai Ronbunshu, 687(687), 201 - 218, Sep. 2001 , Refereed
    Summary:Using the silty clay specimens that were compacted in the constant energy under various water contents, unconfined compression test, in which suction and volume change of specimen were measured, was carried out. The obtained stress-strain relations showed the tendency that depends on the initial degrees of saturation of the specimens. The measured relation between the suction stress and suction at failure showed similar tendency with the predicted ones based on the water content characteristic curve. This result means the possibility of estimating the suction vs. the adhesive force relation by unconfined compression test. And. when the suction stress was taken into account as a confining net stress, the stress state at failure followed the failure criterion for unsaturated soil proposed by Fredlund, Morgenstern & Widger. This result of silty clay means that the undrained strength follows the failure criterion based on the test results test under drained condition.
  • The behavior of anisotoropically consolidated unsaturated soil, Kastuyuki Kawai, Daizo Karube, Proc. 15th Int. Conf. on Soil Mechanics and Geotechnical Engineering, Proc. 15th Int. Conf. on Soil Mechanics and Geotechnical Engineering, 589 - 592, Aug. 2001 , Refereed
  • AN EVALUATION OF THE LONGTERM SETTLEMENT OF OFFSHORE MAN-MADE ISLANDS, KARUBE Daizo, FUKAGAWA Yoshitaka, HONDA Shuji, KAWAI Katsuyuki, Doboku Gakkai Ronbunshu, Doboku Gakkai Ronbunshu, 665(665), 1 - 18, Dec. 20 2000 , Refereed
    Summary:大水深の海域に大規模な埋立地を造成すると, 大きな荷重増加が海底地盤の深所にまで及ぶことになる. このことが造成地の沈下挙動の予測に幾多の問題を引き起こしている. 本論文は, 神戸ポートアイランドおよび六甲アイランドの多くの地点や構造物について続けられている長期沈下測定記録の一部を埋立経歴とともに整理したものである. それによれば, プレローディングは, その撤去後の地表面沈下の軽減に有効であり, このことは, 地震時沈下にも当てはまる. また, 双曲線法の長期沈下予測への適用性も詳しく検討され, その限界が示された.
  • DEFORMATION CHARACTERISTICS OF A COMPACTED CLAY IN COLLAPSE UNDER ISOTROPIC AND TRIAXIAL STRESS STATE, KATO Shoji, KAWAI Katsuyuki, Journal of the Japanese Geotechnical Society, Journal of the Japanese Geotechnical Society, 40(5), 75 - 90, Oct. 15 2000
    Summary:Deformation behavior of an unsaturated soil in collapse was studied using a modified triaxial test apparatus. Three kinds of wetting test were conducted on compacted clay specimens. (i) wetting tests under isotropic stress state, (ii) wetting tests under constant shear stress, and (iii) repeated wetting during shear test under a constant mean net stress. Collapse occurred later in comparison to isotropic stress state conditions under triaxial stress state when shear stress was kept constant. This phenomenon is due to the decrease of the coefficient of permeability, which relates to the changes associated with bulk water to meniscus water. The relationship between void ratio change and increase in water content observed under the different stress states tested showed similar behavior. In the repeated wetting during shear test, a continuous decrease in void ratio was observed with water absorption and drainage. This phenomenon is also related to the change of the bulk water to meniscus water. The secondary wetting process is observed in the experimental testing program discussed in this paper. The presently available constitutive models do not take into account the secondary wetting process. The research studies presented in this paper provide more insight into the collapse behavior.
  • Modeling of Water Retention Curves with Effects of Void Ratio., KAWAI Katsuyuki, KARUBE Daizo, ASHIDA Wataru, KADO Yoshitane, Doboku Gakkai Ronbunshu, Doboku Gakkai Ronbunshu, 2000(666), 291 - 302, 2000 , Refereed
    Summary:The water retention curve, which represents the relation of water content and suction value of soils, cannot be uniquely specified even in the same material. It shows the hysteresis loops between the drying and the wetting process. And also it varies depending on initial conditions. In this paper, the dependency of the water retention curve on void ratio is examined. The void ratio dependency dominantly influences the air and the water entry characteristics of unsaturated soils. Finally an attempt to quantitatively express the water retention curve is made considering the void ratio dependency. The model proposed in this paper can be applied to prediction of unsaturated soil behaviors.
  • Stress-Strain Relationship for Unsaturated Soil., HONDA Michinori, IIZUKA Atsushi, KAWAI Katsuyuki, KARUBE Daizo, Doboku Gakkai Ronbunshu, Doboku Gakkai Ronbunshu, 2000(659), 153 - 164, 2000 , Refereed
    Summary:The stress-strain relationship for unsaturated soil is discussed in this paper. Based on the Karube's theory, two types of the suction stress are used, and a new concept on the plastic yield condition and hardening parameter is proposed. The stresses used are called bulk stress pb and meniscus stress pm. Effects of pore water composition for mechanical behavior are presented by using two types of suction stress. As a result, constitutive model is derived by associated flow rule is proposed. Using the derived equations, triaxial compression test and consolidation test with suction change are simulated. The calculation results simulate two types of the test data well.
  • Soil/Water Coupled Analysis Considering Unsaturated Pore Water Distribution., IIZUKA Atsushi, HONDA Michinori, NISHIDA Hirofumi, KAWAI Katsuyuki, KARUBE Daizo, Doboku Gakkai Ronbunshu, Doboku Gakkai Ronbunshu, 2000(659), 165 - 178, 2000 , Refereed
    Summary:This paper presents a soil/water coupled formulation for unsaturated soil mass as an initial-boundary value problem, in which the constitutive equation for unsaturated soils proposed by Karube et al. is employed. This model is characterized in terms of bulk stress and meniscus stress. And also the water retention curve plays an important role to specify their inner stress components in the theoretical formulation of constitutive modeling. A soil/water finite element code is examined throughout comparison with some analytical solutions. Finally, in this paper, the F. E. code is applied to an initial-boundary value problem and the stress/deformation developing inside the domain is examined. The importance of considering mechanical characteristics of unsaturated soils is emphasized in the case of analysis of soil structures such as the core of rock fill dam.

Misc

  • 猪名川町大規模盛土の調査事例, 宮田和, 河井克之, 立石亮, Kansai Geo-Symposium論文集(CD-ROM), 2019, ROMBUNNO.2‐5,   2019 10 , https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201902241564907102
  • 和歌山市北部造成地の常時微動特性と造成年代, 鍋島康之, 大島昭彦, 河井克之, 遠藤信之, 福塚健次郎, 豊福恒平, Kansai Geo-Symposium論文集(CD-ROM), 2019, ROMBUNNO.2‐4,   2019 10 , https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201902244564416587
  • Study on stability evaluation of steel slag as road embankment material focused on the improvement effect of low quality soil, Satsuki Kataoka, Satoru Shibuya, Katsuyuki Kawai, Ryo Matsuo, AIP Conference Proceedings, 2157,   2019 09 18 , 10.1063/1.5126568, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85072679123&origin=inward
    Summary:© 2019 Author(s). In this study, based on field measurements conducted during the period from the start of embankment launch to dismantling, based on the results of the indoor tests on the sampled samples, the deformation and strength characteristics of the embankment receiving the traffic load and rainfall Etc., the performance of the steel slag mixed soil as an embankment material was evaluated by paying attention to the hydraulic characteristics of the embankment. As a result, by mixing and stirring the steelmaking slag and the earth at an appropriate ratio and properly compacting, it is possible to withstand deformation even under traffic load, and it is possible to suppress leaching of high alkaline water from the embankment by rainfall to some extent It could be confirmed. Therefore, it was found that there was no practical problem concerning the concern factor when slag was used as the embankment material.
  • 水溶性物質含有盛土の降雨浸透シミュレーション, 有西海飛, 河井克之, 片岡沙都紀, 土木学会年次学術講演会講演概要集(CD-ROM), 74th, ROMBUNNO.III‐441,   2019 08 01 , https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201902262591232124
  • 鉄鋼スラグ混合盛土における降雨浸透シミュレーション, 有西海飛, 河井克之, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2019, ROMBUNNO.III‐9,   2019 04 22 , https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201902212714586009
  • Triaxial compression tests on unsaturated soils under undrained condition, K. Kawai, D. Karube, S. Kato, ISRM International Symposium 2000, IS 2000,   2018 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85053900754&origin=inward
    Summary:© 2018 ISRM International Symposium 2000, IS 2000. All rights reserved. Pore water distribution in the unsaturated soil can be classified into two forms. Those are “bulk water” and “meniscus water”. Though it is known that the suction greatly affects on behavior of unsaturated soil, its effects depend on the forms of the pore water. When only the bulk water exists, the effects of suction act like Terzaghi's effective stress, the role of which is the same as negative pore water does. However, when only the meniscus water exists, the effects of suction act as cohesion at contact points of soil particles, and it increases stiffness of soil skeleton. We must take not only suction but also pore water distribution into consideration in order to predict behavior of unsaturated soil. In this paper, we carried out triaxial compression test on kaolin specimen under undrained condition. From the test results it is found out that the pore water pressure increased with compression and decreased with expansion, however that when the expansion increased, the pore water pressure increases again regardless of volume change. We can explain this phenomenon with the different effects caused by the bulk water and the meniscus water. According to shear strength, it is found out that, by application of the suction stress, we could use similar failure criterion with that for the results of drained shear test.
  • Estimation of cohesion in unsaturated soil with unconfined compression test, S. Kato, Y. Yoshimura, K. Kawai, ISRM International Symposium 2000, IS 2000,   2018 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85053940958&origin=inward
    Summary:© 2018 ISRM International Symposium 2000, IS 2000. All rights reserved. Estimation of the cohesion in shear strength under unsaturated state is an important problem when stability analysis is undertook for some natural slopes. In this paper, one simple method to estimate the cohesion is proposed. This method is based on the unconfined compression test in which suction of the specimen is measured. The unconfined compression test was carried out on compacted silty clay specimen in various water contents. Effects of the cohesion on the behavior of unsaturated soil studied through “suction stress” that corresponds to the cohesion. It is found out that relationships between the unconfined compressive strength and the suction stress are arranged uniquely, and that a prediction for the relationships between suction and the suction stress using the water characteristic curve show similar tendency with the relationship using the unconfined compression test results. These results mean an applicability of the unconfined compression test for estimating the relationship between the suction stress and suction.
  • 不攪乱粘性土に対する室内ベーンせん断挙動のX線CTスキャン観察, 川口貴之, 川尻峻三, 平林弘, 河井克之, 田中政典, 地盤工学研究発表会発表講演集(CD-ROM), 53rd, ROMBUNNO.0175,   2018 , https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201802217310440356
  • 飽和手法の異なるセラミックの内部密度分布傾向, 河井克之, 菊井慎也, 吉川直輝, 麓隆行, 地盤工学研究発表会発表講演集(CD-ROM), 53rd, ROMBUNNO.0354,   2018 , https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201802270188451028
  • 水理・変形特性に着目した実物大スラグ混合土盛土の長期挙動 その2 水理特性, 山里拓也, 石原朱莉, 片岡沙都紀, 澁谷啓, 河井克之, 佐藤厚子, 地盤工学研究発表会発表講演集(CD-ROM), 53rd, ROMBUNNO.0566,   2018 , https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201802273712914700
  • 交通荷重を受ける鉄鋼スラグ混合盛土の長期変状に関する研究, 澁谷啓, 河井克之, 片岡沙都紀, 白濟民, 環境助成研究成果 概要集 第36回・2015年度分:3件 第37回・2016度分:24件 平成30年, 45‐46,   2018 , http://jglobal.jst.go.jp/public/201802252279001629
  • 砂分含有率の異なる粘性土における室内ベーンせん断挙動のX線CTスキャン観察, 猶原有希子, 川尻峻三, 田中政典, 河井克之, 川口貴之, 平林弘, 中村大, 山下聡, 地盤工学会北海道支部技術報告集(CD-ROM), 58, 213‐216,   2018 01 , http://jglobal.jst.go.jp/public/201802243507253050
  • 降雨時の盛土内浸透流と空気圧分布について, 河井克之, 硲大智, 能瀬龍之介, 片岡沙都紀, 澁谷啓, Kansai Geo-Symposium論文集(CD-ROM), 2017, ROMBUNNO.5‐5,   2017 10 , http://jglobal.jst.go.jp/public/201702227924373277
  • 不透水性基盤を有する傾斜地盤内の降雨時間隙空気挙動, 寺岡歩美, 河井克之, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2017, ROMBUNNO.III‐23,   2017 05 01 , http://jglobal.jst.go.jp/public/201702260699629749
  • 耐震性に優れ環境に優しい鉄鋼スラグ混合土盛土の開発に向けた現場検証実験, 松尾遼, 田口未由希, 片岡沙都紀, 澁谷啓, 河井克之, 井上健, 松元弘昭, 太田哲郎, 水田智幸, 地盤工学研究発表会発表講演集(CD-ROM), 52nd, ROMBUNNO.0453,   2017 , http://jglobal.jst.go.jp/public/201702270912118438
  • 南海トラフ巨大地震に関する関西の地盤特性と被害予測, 大島昭彦, 三村衛, 岡二三生, 遠藤信之, 甲斐誠士, 春日井麻里, 河井克之, 河崎和文, 川下光仁, 北田奈緒子, 後藤浩之, 佐川厚志, 清水将之, 住武人, 豊福恒平, 永井久徳, 中嶋勲雄, 鍋島康之, 南部啓太, 日置和昭, 平井孝治, 平井俊之, 深川良一, 深井晴夫, 福塚健次郎, 藤原正明, 地盤工学研究発表会発表講演集(CD-ROM), 52nd, ROMBUNNO.NANKAITORAFUKYODAIJISHIN,OSHIMA,   2017 , http://jglobal.jst.go.jp/public/201702284134886853
  • 傾斜地盤における災害時前兆現象としての空気挙動の把握, 寺岡歩美, 河井克之, 日本道路会議論文集(CD-ROM), 32nd, ROMBUNNO.4005,   2017 , http://jglobal.jst.go.jp/public/201802234923394826
  • 交通荷重を受ける鉄鋼スラグ混合盛土の長期安定性に関する現場検証実験, 片岡沙都紀, 河井克之, 澁谷啓, 植松尚大, 田口未由希, 平嶋裕, 井上健, 戎剛史, Kansai Geo-Symposium論文集(CD-ROM), 2016, ROMBUNNO.4‐6,   2016 11 , http://jglobal.jst.go.jp/public/201602228734635783
  • Expression of air pressure distribution using soil/water/air coupled analysis, Kawai, K, T. Kawakatsu, A. Iizuka, Proc. of 6th Int. Conf. GEOMATE 2016, 233, 238,   2016 11 , Refereed
  • 鉄鋼スラグ混合土を用いて造成した実物大道路盛土の水理・力学挙動について, 植松尚大, 片岡沙都紀, 戎剛史, 河井克之, 井上健, 松本弘昭, 太田哲郎, 水田智幸, 澁谷啓, 地盤工学研究発表会発表講演集(CD-ROM), 51st, ROMBUNNO.0573,   2016 , http://jglobal.jst.go.jp/public/201602272736399371
  • Influence of stress release after sampling on shear characteristics, Sugiyama, Y, K. Kawai, A. Iizuka, N. Nakatani, Proc. of Int. Conf. on Soft Ground Engineering, 553, 559,   2015 12 , Refereed
  • 大阪地域の表層地盤モデルを用いた揺れやすさマップの作成, 平井俊之, 堤杏紗, 大島昭彦, 新井瞬, 濱田晃之, 北田奈緒子, 後藤浩之, 河井克之, 中嶋勲雄, Kansai Geo-Symposium論文集(CD-ROM), 2015, ROMBUNNO.7‐2,   2015 11 , http://jglobal.jst.go.jp/public/201602237331268980
  • 耐震性に優れ環境に優しい鉄鋼スラグ混合盛土の開発に向けた室内および現場施工試験, 片岡沙都紀, 澁谷啓, 植松尚大, 河井克之, 戎剛史, Kansai Geo-Symposium論文集(CD-ROM), 2015, ROMBUNNO.1‐4,   2015 11 , http://jglobal.jst.go.jp/public/201602246416628870
  • Development of high-capacity tensiometer using berthelot method, 松尾 直人, 飯塚 敦, 河井 克之, 神戸大学都市安全研究センター研究報告, 19, 59, 66,   2015 03 , 10.24546/81011469, http://www.lib.kobe-u.ac.jp/handle_kernel/81011469
  • Evaluation of a capillary barrier system with the soil/water/air coupled F.E. code, 中村 翔一, 河井 克之, 飯塚 敦, 神戸大学都市安全研究センター研究報告, 19, 67, 74,   2015 03 , 10.24546/81011470, http://www.lib.kobe-u.ac.jp/handle_kernel/81011470
  • Study of the method of removing the soil particles adsorbed material that focuses on particle size distribution, 西門 優, 飯塚 敦, 河井 克之, 神戸大学都市安全研究センター研究報告, 19, 75, 84,   2015 03 , 10.24546/81011471, http://www.lib.kobe-u.ac.jp/handle_kernel/81011471
  • Identification of parameters for elast-plastic dynamic ground model, 吉富 力, 妹川 賢司, 飯塚 敦, 河井 克之, ロハニ タラニディ, 神戸大学都市安全研究センター研究報告, 19, 85, 100,   2015 03 , 10.24546/81011472, http://www.lib.kobe-u.ac.jp/handle_kernel/81011472
  • Expression of the pore-pressure coefficient B with numerical simulation, Y. Sugiyama, H. Tanaka, K. Kawai, A. Iizuka, Computer Methods and Recent Advances in Geomechanics - Proceedings of the 14th Int. Conference of International Association for Computer Methods and Recent Advances in Geomechanics, IACMAG 2014, 403, 408,   2015 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84907346356&origin=inward
    Summary:Undrained shear strength is used for estimating the bearing resistance of foundations and the safety factor of a slope. For this test, the pore-pressure coefficients, namely A and B as proposed by Skempton, are available. These coefficients can be obtained from the undrained triaxial test. According to Terzaghi's effective stress theory, the B-value must be 1.0 in a saturated soil. Therefore, a B-value of 1.0 is used as the target for saturating a specimen. However, it is difficult to achieve a B-value of 1.0 in the triaxial test. Because of this, a specimen with a B-value greater than 0.95 is regarded as saturated. The relationship between saturation and the B-value is still not clear. In this study, the factors influencing the B-value were numerically investigated with a soil/water/air coupled model that considers the solvability of pore-air to pore-water. Consequently, the pore-water pressure behavior, which depends on the initial degree of saturation and initial stress conditions, could be expressed. © 2015 Taylor & Francis Group, London.
  • Numerical simulation of saturation process in TRU disposal facility, Y. Takayama, R. Hino, A. Iizuka, K. Kawai, Computer Methods and Recent Advances in Geomechanics - Proceedings of the 14th Int. Conference of International Association for Computer Methods and Recent Advances in Geomechanics, IACMAG 2014, 409, 414,   2015 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84907303194&origin=inward
    Summary:Due to its low permeability and excellent expansion characteristics, bentonite materials are considered to be the engineered barrier in Trans-Uranium (TRU) disposal facility. It is necessity to predict the mechanical behavior of bentonite using numerical simulation to evaluate the long-term performance of TRU disposal facility. In this paper, we simulated the saturation process of bentonite materials inTRU disposal facility from an initially unsaturated state. And we examined the mechanical behavior of bentonite buffer during the saturation process. This simulation result shows that Disposal waste is moved upward due to the difference of swelling pressure between buffer and backfill. And the facility existed in unsaturated state even under steady state conditions due to the entrapped air. © 2015 Taylor & Francis Group, London.
  • Soil/water/air coupled F. E. Simulation of phreatic surface generation process within a river levee, Katsuyuki Kawai, Phommachanh Viradeth, Atsushi Iizuka, 15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability, 1714, 1717,   2015 01 01 , 10.3208/jgssp.JPN-078, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84971452257&origin=inward
    Summary:In this study, the generation process of the phreatic surface within a river levee is investigated through soil/water/air coupled simulation. Here, the effects of river level fluctuation and rainfall on changes in soil moisture distribution within a river levee are considered. The constitutive model proposed by Ohno et al.1) is formulated to the initial and boundary value problems in accordance with Borja's multi phases' concept and is used for simulation. Consequently, it is first found that high groundwater level is maintained for ground consisting of low permeability and high soil water retentivity. Moreover, it is found that the fluctuation of river level directly influences the phreatic surface, and that, in contrast, the effect of rainfall appears after a time lag.
  • スメクタイトの変質作用がデコルマ帯におけるせん断特性に及ぼす影響, 佐々木陽亮, 杉山友理, 戎健次, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.186,   2015 , http://jglobal.jst.go.jp/public/201502202626497456
  • 応力履歴がB値発現に及ぼす影響(実験), 玉井三友紀, 杉山友理, 田中博之, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.347,   2015 , http://jglobal.jst.go.jp/public/201502202924235480
  • 覆土工における排水能力の評価, 岡田真理子, 生田勇輝, 飯塚敦, 河井克之, 坂尾亮太, 小原義之, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.32,   2015 , http://jglobal.jst.go.jp/public/201502203980123489
  • 応力履歴がB値発現に及ぼす影響(解析), 田中博之, 杉山友理, 河井克之, 飯塚敦, 玉井三友紀, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.348,   2015 , http://jglobal.jst.go.jp/public/201502204200574960
  • 気相の影響を考慮した河川堤防の外水位変動シミュレーション, 織田裕至, 川勝拓哉, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.535,   2015 , http://jglobal.jst.go.jp/public/201502204296592140
  • 粒度分布に注目した土粒子吸着物質の除去法の検討, 西門優, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.1148,   2015 , http://jglobal.jst.go.jp/public/201502204521643310
  • 地層処分におけるベントナイト緩衝材の変質挙動評価, 神藤卓哉, 樋野隆太, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.1188,   2015 , http://jglobal.jst.go.jp/public/201502205564891062
  • Albany硅砂の弾塑陸構成パラメータの同定, 吉富力, 河井克之, 飯塚敦, LOHANI Taran Nidhi, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.224,   2015 , http://jglobal.jst.go.jp/public/201502207733253871
  • 降雨時の傾斜地盤内における空気圧の挙動について, 川勝拓哉, 大川紀郁, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.1051,   2015 , http://jglobal.jst.go.jp/public/201502208363756573
  • 海底地盤からのサンプリングに伴う応力変化が強度特性に及ぼす影響, 中谷奈央, 杉山友理, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.356,   2015 , http://jglobal.jst.go.jp/public/201502209442342497
  • ベンダーエレメントを用いた不飽和供試体のせん断弾性定数, 妹川賢司, 吉富力, 飯塚敦, 河井克之, LOHANI Tara Nidhi, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.368,   2015 , http://jglobal.jst.go.jp/public/201502211309954492
  • 深海底デコルマ帯の変質を考慮したせん断破壊モデル, 戎健次, 杉山友理, 佐々木陽亮, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 50th, ROMBUNNO.185,   2015 , http://jglobal.jst.go.jp/public/201502220634254706
  • ワイブル分布を用いた災害死亡者数のベイズ推定モデル, 小谷稔, 飯塚敦, 河井克之, 河井克之, 日本災害情報学会研究発表大会予稿集, 17th, 184, 185,   2015 , http://jglobal.jst.go.jp/public/201502220920955274
  • 廃砂たい積場の覆土設置による沈下の評価, 佐々木陽亮, 飯塚敦, 高山裕介, 河井克之, 生田勇輝, 坂尾亮太, 瀧富弘, 土木学会年次学術講演会講演概要集(CD-ROM), 69th, ROMBUNNO.III-364,   2014 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402276004007929
  • 土の粒度分布に注目した放射性物質吸着土壌の減容化に関する検討, 吉井大貴, 飯塚敦, 西門優, 河井克之, 土木学会年次学術講演会講演概要集(CD-ROM), 69th, ROMBUNNO.CS9-010,   2014 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402276535592834
  • Representation of seepage face formation on reiver dike, 坂本 諭, 河井 克之, 神戸大学都市安全研究センター研究報告, 18, 54, 65,   2014 03 , Refereed, 10.24546/81011443, http://www.lib.kobe-u.ac.jp/handle_kernel/81011443
  • Mechanical model of Bentonite buffer considering long term chemical alternation, 鶴見 修平, 飯塚 敦, 河井 克之, 神戸大学都市安全研究センター研究報告, 18, 23, 31,   2014 03 , 10.24546/81011439, http://www.lib.kobe-u.ac.jp/handle_kernel/81011439
  • Mathematical modeling of unsaturated soils in consideration of dissolved air, 杉山 友理, 田中 博之, 飯塚 敦, 河井 克之, 神戸大学都市安全研究センター研究報告, 18, 32, 39,   2014 03 , Refereed, 10.24546/81011440, http://www.lib.kobe-u.ac.jp/handle_kernel/81011440
  • A study on volume reduction of radioactive material adsorption soil with a focus on the particle size distribution of the soil, 吉井 大貴, 西門 優, 飯塚 敦, 河井 克之, 神戸大学都市安全研究センター研究報告, 18, 40, 43,   2014 03 , 10.24546/81011441, http://www.lib.kobe-u.ac.jp/handle_kernel/81011441
  • Examination of technique to control salt damage with Finite Element analysis program of soil-water-airdissolved material, 田中 琢, 飯塚 敦, 河井 克之, 神戸大学都市安全研究センター研究報告, 18, 44, 53,   2014 03 , 10.24546/81011442, http://www.lib.kobe-u.ac.jp/handle_kernel/81011442
  • Numerical modelling of deformation for partially saturated slopes subjected to rainfall, Binod Tiwari, Katsuyuki Kawai, Phommachanh Viradeth, Landslide Science for a Safer Geoenvironment: Volume 2: Methods of Landslide Studies, 281, 285,   2014 01 01 , 10.1007/978-3-319-05050-8_44, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84949449571&origin=inward
    Summary:© Springer International Publishing Switzerland 2014. Rainfall is one among the most common contributing factor and trigger for landslides. In the majority of the cases, slopes are at partially saturated condition when they are subjected to rainfall. While analysing stability of those slopes, deformation analysis is performed in a conservative way assuming the slope to be in a fully saturated condition. In this research, a fully coupled hydro-mechanical finite element model is described based on the constitutive model developed for partially saturated soil condition. A 1.2 m long and 0.6 m high sandy slope was modelled in laboratory and was subjected to 30 mm/h of rainfall for 3 h. Values of suction measured after 3 h were very close to the numerically calculated values based on the finite element method developed by the authors. This model was used to calculate deformation of slope for different intensities of rainfall and at different angles of slopes in order to predict the amount of deformation or failure condition when a slope is subjected to a continuous rainfall of different intensities and durations.
  • TC106. Unsaturated Soil(2)(18th International Conference of Soil Mechanics and Geotechnical Engineering), 河井 克之, 地盤工学会誌, 62, 3, 45, 45,   2014 , http://dl.ndl.go.jp/info:ndljp/pid/10422228
  • 降雨浸透シミュレーションにおける浸透能の影響について, 川勝拓哉, PHOMMACHANH Viradeth, 家永康平, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.448,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402206205253113
  • 液相への間隙空気溶解を考慮した室内要素シミュレーション, 田中博之, 杉山友里, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.352,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402207883113298
  • 土/水/空気連成有限要素解析を用いた河川堤防における浸潤面形成過程の再現(1), 戎健次, 坂本諭, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.348,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402213795525675
  • 土/水/空気連成モデルによる降雨浸透解析, 中谷奈央, PHOMMACHANH Viradeth, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.447,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402236658068232
  • ベイズ推定を用いた災害時の被災者数予測, 小谷稔, 飯塚敦, 河井克之, 日本災害情報学会研究発表大会予稿集, 16th, 64, 65,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402238204892774
  • タイ東北部における塩害抑制手法の検討, 田中琢, 杉山友理, 野村瞬, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.445,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402246601775841
  • 土/水/空気連成有限要素解析を用いた河川堤防における浸潤面形成過程の再現(2), 坂本諭, 戎健次, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.347,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402256424210737
  • 化学変質を考慮したベントナイト緩衝材の力学モデル, 森本晃樹, 高山裕介, 鶴見修平, 飯塚敦, 河井克之, 大和田仁, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.1051,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402263278520385
  • 長期化学的変質を考慮したベントナイト緩衝材の力学モデルと境界値問題の定式化, 鶴見修平, 飯塚敦, 高山祐介, 河井克之, 生田勇輝, 地盤工学研究発表会発表講演集(CD-ROM), 49th, ROMBUNNO.1052,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402283518689120
  • 締固めメカニズムに着目した道路盛土の効率的な施工および維持管理計画, 河井克之, 高速道路と自動車, 56, 11, 53, 55,   2013 11 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302252523063964
  • 土壌種類に起因する塩類の移動性の違い, 杉山友理, 野村瞬, 飯塚敦, 河井克之, 土木学会年次学術講演会講演概要集(CD-ROM), 68th, ROMBUNNO.III-187,   2013 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302221553496170
  • 廃砂たい積場の覆土設置による沈下及び覆土の排水機能の評価, 生田勇輝, 飯塚敦, 高山裕介, 河井克之, 鶴見修平, 瀧富弘, 市川康明, 坂尾亮太, 土木学会年次学術講演会講演概要集(CD-ROM), 68th, ROMBUNNO.III-189,   2013 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302234953736654
  • ベントナイト材料の実験結果から得た構成モデルを用いた各種室内試験の解析, 前田圭介, 飯塚敦, 河井克之, 高山裕介, 土木学会年次学術講演会講演概要集(CD-ROM), 68th, ROMBUNNO.CS11-030,   2013 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302249978563565
  • 土質力学から見たベントナイト材料の特異性と構成モデル化, 高山裕介, 前田圭介, 飯塚敦, 河井克之, 小林一三, 土木学会年次学術講演会講演概要集(CD-ROM), 68th, ROMBUNNO.CS11-029,   2013 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302259888334198
  • 長期的化学変質作用を考慮するためのベントナイト緩衝材の力学モデル化, 高山裕介, 鶴見修平, 飯塚敦, 河井克之, 小林一三, 大和田仁, 土木学会年次学術講演会講演概要集(CD-ROM), 68th, ROMBUNNO.CS11-021,   2013 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302287824374530
  • Deformation characteristic of a capillary barrier system, and various factors influencing on the performance of it, 檜達也, 野村瞬, 河井克之, 神戸大学都市安全研究センター研究報告, 17, 61, 68,   2013 03 , Refereed, 10.24546/81011409, http://www.lib.kobe-u.ac.jp/handle_kernel/81011409
  • Elucidation of specific properties of bentonite and derivation of constitutive model, 前田圭介, 飯塚敦, 河井克之, 高山裕介, 神戸大学都市安全研究センター研究報告, 17, 39, 48,   2013 03 , 10.24546/81011407, http://www.lib.kobe-u.ac.jp/handle_kernel/81011407
  • Verification of argillic normally consolidated to rely on softening due to water absorption of overconsolidated clay, 安原昇平, 吉富力, 河井克之, 飯塚敦, 神戸大学都市安全研究センター研究報告, 17, 49, 60,   2013 03 , 10.24546/81011408, http://www.lib.kobe-u.ac.jp/handle_kernel/81011408
  • Quality evaluation of an earth structure compacted under various water contents with soil/water/air coupled F.E. analysis, 佐藤武斗, PHOMMACHANH Viradeth, 河井克之, 飯塚敦, 神戸大学都市安全研究センター研究報告, 17, 31, 38,   2013 03 , Refereed, 10.24546/81011406, http://www.lib.kobe-u.ac.jp/handle_kernel/81011406
  • 降雨強度および勾配,層厚がキャピラリーバリアの性能に及ぼす影響, 檜達也, 野村瞬, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.531,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302204149159419
  • 土/水連成有限要素法を用いた降雨時斜面安定に関する各種要因の検討, 松尾直人, 家永康平, PHOMMACHANH Viradeth, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.980,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302205267583531
  • 粒度分布を考慮した土粒子のイオン吸着試験, 西門優, 吉井大貴, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.1080,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302211464992028
  • 締固めによるサクション発現傾向の把握とその理解, 坂本諭, 余西佐知子, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.431,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302214212051122
  • Salt Damage and Soil Contamination induced by the East Japan Earthquake Tsunami, Iizuka Atsushi, Sugiyama Yuri, Nomura Shun, Kawai Katsuyuki, Tachibana Shinya, Kanazawa Shin-ichi, Takeyama Tomohide, NCTAM papers, National Congress of Theoretical and Applied Mechanics, Japan, 62, 0, 110, 110,   2013 , 10.11345/japannctam.62.0.110.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302251476106653
    Summary:This paper reports the investigation of ground contamination resulting from Tsunami due to the Great East Japan Earthquake.  We visited sites at suburbs of Sendai and Ishinomaki and took soil samples at the sites to analyse heavy metal contamination.  Herein, the sites st suburbs of Sendai were chosen as a typical area where any industrial facilities did not exit and the sites at Ishinomaki as a typical area where many industrial facilities were destroyed due to the Tsunami.  As conclusion, heavy metal contamination were not found resulting from destroyed industrial facilities but contaminated soils that had been settled under the sea were brought by Tsunami and covers the sites at Ishinomaki.
  • キャピラリーバリア内浸透流が変形に及ぼす影響, 野村瞬, 檜達也, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.530,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302275320864600
  • 構造物に近接する埋立て工事に対するロバスト制御アプローチの適用, 綿地規文, 田中琢, 佐藤毅, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.115,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302283270652359
  • 過圧密粘土の三軸繰返しせん断による変形強度特性の変化, 吉富力, 安原昇平, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.233,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302287110320479
  • 数値計算による異なる含水比で締固め度の等しい締固め地盤の品質評価, 佐藤武斗, VIRADETH Phommachanh, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 48th, ROMBUNNO.196,   2013 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302290976305356
  • Expression of self-hardening property of coal fly-ash with the constitutive model, V. Phommachanh, F. Maegawa, K. Kawai, A. Iizuka, 5th Asia-Pacific Conference on Unsaturated Soils 2012, 2, 424, 429,   2012 11 27 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869837401&origin=inward
    Summary:Thermal power plants burn oil and coal to generate electricity. Coal fly-ash is a product of the coal-burning process. Coal fly-ash has a self-hardening property and becomes extremely stiff over time. For this reason, it is being reused as a concrete aggregate in the production of concrete. Recently, coal-fly ash is being mixed with soil from construction waste for reclamation projects. To be able to reuse coal fly-ash in such a way, in the field of geotechnical engineering, the associated self-hardening properties must be incorporated in the framework of the constitutive model. It is generally known that cemented soil, such as fly-ash, behaves similar to unsaturated soil. In the constitutive model for unsaturated soil, hardening due to desaturation is expressed as the increase in yield stress. Here, changes in parameters used in the Cam-Clay model, generated by this self-hardening property, are studied by comparing the simulation results obtained from a soil/water coupled analysis with triaxial test results on two kinds of coal fly-ash. Consequently, the self-hardening property is expressed as an increase in the yield stress and an increase in the frictional angle, dependent on time. Differences between the two methods of producing fly-ash are reflected in the parameter set.
  • Mathematical model of soil/water/air coupled problem for unsaturated soils considering mass transfer within pore-water, S. Nomura, K. Kawai, A. Iizuka, S. Tachibana, S. Kanazawa, 5th Asia-Pacific Conference on Unsaturated Soils 2012, 1, 267, 272,   2012 11 27 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869836248&origin=inward
    Summary:Soil contamination caused by industrial activity has become a serious environmental problem causing ground deterioration. Since soil decontamination is expensive and its efficiency is difficult to estimate, the contaminated ground areas are often abandoned without purification. To encourage the reuse of land, the methods for predicting contaminant transfer, induced by changes in external forces and water levels are required. In this study, the mass transport equation was applied to the existing unsaturated soil/water/air coupled F. E. analysis code for expressing the advection and dispersion behavior of dissolved material within pore-water. First, the continuity condition equations and advection-dispersion equations were developed from mass conservation laws of soil, water and dissolved materials. These governing equations, including the constitutive model for unsaturated soil, were formulated as initial and boundary values problems and coded as DACSAR-Mad. Assuming the ground to be polluted, the effect of external forces on the ground surface was simulated. It was found that the external forces contribute to mass transfer. This analysis code is effective in describing the complications of the mass transfer problem including the effects of external force and water level. © 2012 IEEE.
  • The role of unsaturated geomechanics in desertification due to salt damage, A. Iizuka, K. Kawai, S. Nomura, S. Tachibana, S. Ohno, T. Pipatopongsa, 5th Asia-Pacific Conference on Unsaturated Soils 2012, 1, 30, 43,   2012 11 27 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869745705&origin=inward
    Summary:Desertification poses a serious problem to the global environment. A reported 7.2% of the world's land area is affected by desertification, with 35.8% of this figure located in Asia. Major causes of desertification include excessive deforestation, overgrazing of cattle and damage due to salt, all of which are the results of water cycle disorders relating to the geosphere and atmosphere. Through hierarchization (structurization) analysis, this paper discusses the issue of desertification as it pertains to issues threatening the health of the global environment. The key issues to be taken into consideration with regard to desertification have been extracted and examined from a geotechnical viewpoint. The authors focus on the role that geotechnical engineering can play in the prevention of desertification and in its restoration process. The paper highlights a northeastern area of Thailand where salt damage is likely to result in desertification. In order to numerically simulate what is happening there, a set of mathematical models based on unsaturated geomechanics is formulated, taking into account key issues revealed through a hierarchization analysis. The paper also includes a discussion on the applicability of these models for addressing the salt damage problem affecting this northeastern part of Thailand. The importance of unsaturated geomechanics is demonstrated in this paper, particularly as it pertains to prevention and restoration of salt-damaged areas that finally lead to desertification. © 2012 IEEE.
  • Elasto-plastic constitutive model for expansive soils with a concept of fully saturation curve, S. Tachibana, Y. Takayama, A. Iizuka, K. Kawai, S. Ohno, I. Kobayashi, 5th Asia-Pacific Conference on Unsaturated Soils 2012, 1, 303, 308,   2012 11 27 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869747381&origin=inward
    Summary:This study presents a new constitutive model for expansive soils. Under any arbitrary state of degree-of-saturation, the mechanical void ratio predicted by the elasto-plastic constitutive models, i.e. EC model and Se-hardening model are combined with the additional void ratio in order to characterize the typical swelling behavior of expansive soil. Herein, the fully saturation curve which derived from compaction and consolidation experimental tests are taken into consideration. The proposed model is examined by simulating the typical experimental test on expansive soil, i.e. normally consolidation and swelling pressure tests. © 2012 IEEE.
  • 締固めメカニズムに着目した道路盛土の効率的な施工および維持管理計画, 河井克之, 高速道路と自動車, 55, 9, 50, 51,   2012 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202271327087003
  • 東日本大震災における津波由来土壌汚染調査, 杉山友理, 野村瞬, 飯塚敦, 河井克之, 橘伸也, 金澤伸一, 竹山智英, 土木学会年次学術講演会講演概要集(CD-ROM), 67th, ROMBUNNO.VII-066,   2012 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202254962703584
  • Analysis of the effect of geotexstile reinforcement with unsaturated soil mechanics, 藤原鉄也, 飯塚敦, 河井克之, 神戸大学都市安全研究センタ-研究報告, 16, 45, 53,   2012 03 , Refereed, 10.24546/81011372, http://www.lib.kobe-u.ac.jp/handle_kernel/81011372
  • Long-term subsidence of foundation according to fluctuation of groundwater level, 籠橋慶太, 飯塚敦, 河井克之, 神戸大学都市安全研究センタ-研究報告, 16, 23, 31,   2012 03 , 10.24546/81011370, http://www.lib.kobe-u.ac.jp/handle_kernel/81011370
  • Modeling of coal fly-ash with self-hardening property, PHOMMACHANH Viradeth, 前川太, 河井克之, 飯塚敦, 神戸大学都市安全研究センタ-研究報告, 16, 63, 73,   2012 03 , 10.24546/81011374, http://www.lib.kobe-u.ac.jp/handle_kernel/81011374
  • Quality Evaluation of Kobe Airport, Manmade Island, 荒金延明, 宮本郁美, 飯塚敦, 河井克之, 神戸大学都市安全研究センタ-研究報告, 16, 33, 43,   2012 03 , 10.24546/81011371, http://www.lib.kobe-u.ac.jp/handle_kernel/81011371
  • Explanation of the condition within soil in the case of unsaturated tests with soil/water/air coupled F.E.analysis, 後藤浩司, 家永康平, 河井克之, 神戸大学都市安全研究センタ-研究報告, 16, 55, 62,   2012 03 , Refereed, 10.24546/81011373, http://www.lib.kobe-u.ac.jp/handle_kernel/81011373
  • 神戸空港島の経年沈下解析, 荒金延明, 宮本郁美, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 47th, ROMBUNNO.374,   2012 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202218993979832
  • 沈降海浜部地盤内の塩分移動予測及び一本松保護, 杉山友理, 河井克之, 野村瞬, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 47th, ROMBUNNO.19,   2012 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202221277245730
  • 不飽和土三軸圧縮試験におけるせん断速度の妥当性, 家永康平, 後藤浩司, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 47th, ROMBUNNO.329,   2012 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202233297501692
  • 土/水/空気連成有限要素解析プログラムによる締固め施工を考慮した築堤シミュレーション, PHOMMACHANH Viradeth, 河井克之, 佐藤武斗, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 47th, ROMBUNNO.11,   2012 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202255186118320
  • 締固めシミュレーションに及ぼす土質物性の影響, 坂本諭, PHOMMACHANH Viradeth, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 47th, ROMBUNNO.12,   2012 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202264835398972
  • 東日本大震災の津波による地盤塩害の調査・分析, 野村瞬, 河井克之, 杉山友理, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 47th, ROMBUNNO.983,   2012 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202276379894936
  • TRU廃棄物処分場における緩衝材の力学・化学連成解析, 鶴見修平, 飯塚敦, 高山裕介, 河井克之, 地盤工学研究発表会発表講演集(CD-ROM), 47th, ROMBUNNO.977,   2012 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202297976793110
  • Changing the water content of a compacted Embankment simulation with Soil/Water/Air Coupled Finite Element Analysis Program, Phommachanh Viradeth, Kawai Katsuyuki, Sato Taketo, Iizuka Atsushi, NCTAM papers, National Congress of Theoretical and Applied Mechanics, Japan, 61, 0, 101, 101,   2012 , Refereed, 10.11345/japannctam.61.0.101.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302220869509641
    Summary:Although compacted soil is widely used to construct earth structures, the mechanism of compaction has not been explained with soil mechanics. Therefore, we cannot help using the empirical method to design and construct such structures. Our research group defined the compaction soil as the exhaust un-drained compression and expansion of unsaturated soil with soil/water/air coupled finite element code (DACSAR-MP). And we could express the suction changes during the compaction and the shape of compaction curve, where the maximum dry density appears on the optimum water content. In this study, we will perform simulation on the full scale of embankment with closer step to actual construction phase and compaction method, to understand the non-uniformity of the internal embankment such as void ratio, stress, water content that occurred during the construction period. In addition changing the initial water content to study how differences in the quality of the embankment.
  • Study of stratification resistant to salt damage, S. Nomura, K. Kawai, S. Kanazawa, A. Iizuka, S. Ohno, P. Thirapong, S. Tachibana, Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils, 2, 1133, 1139,   2011 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859950443&origin=inward
    Summary:Desertification due to salt damage has recently become a serious problem throughout the world. Salt damage is a phenomenon where salt in the groundwater gets concentrated at the ground surface and kills vegetation. In this study salt damage due to disequilibrium of water balance was simulated with unsaturated soil/water coupled simulation code, as applied the material transport equation. Evaporation and precipitation cycles were applied to a model of ground that contained salty groundwater in its deep region. This allowed the successful reproduction of the phenomenon of salt accumulation on the ground surface. Additionally, identical climatic conditions were applied to model grounds consisting of two types of soil, different in terms of their soil-water retention characteristics. It was found that two methods of overlay and insertion of a layer of coarse-grade material, known as 'mulching', are effective in the prevention of salt accumulation. © 2011 Taylor & Francis Group, London.
  • Mechanical behaviors and water retention characteristics of micro-porous ceramic particles produced by burning sludge, J. Kawazu, K. Kawai, S. Kanazawa, A. Iizuka, Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils, 1, 277, 282,   2011 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859987778&origin=inward
    Summary:Shortage of landfill capacity in areas where industrial waste materials are dumped is a serious environmental problem. In this study, the mechanical characteristics of two kinds of soil samples, produced by burning sludge, were examined. In order to grasp some key fundamental mechanical properties of these soil samples, a series of laboratory tests were performed. It was found that the stress-strain characteristics and the permeability of these soil samples were very similar to those of standard sandy materials. In addition, particles in the soil samples were easily crushable and exhibited high water retentivity. Next, the applicability of the unsaturated elasto-plastic constitutive model of Ohno et al. (2007), in reproducing the mechanical behavior of these soil samples, was examined. The results of this study will help in useful utilization of micro-porous ceramic materials, obtained from sludge burning, in the field of geotechnical engineering. © 2011 Taylor & Francis Group, London.
  • Banking simulation with a constitutive model for unsaturated soil, M. Tanaka, K. Kawai, S. Kanazawa, A. Iizuka, S. Tachibana, S. Ohno, T. Takeyama, Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils, 2, 1337, 1342,   2011 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859939716&origin=inward
    Summary:It is difficult to estimate the current stress state of existing embankments because of their inherent sloping geometric shapes. Therefore an elastic analysis is always carried out in advance and the calculated stress state, assumed as the current stress, is used as an input parameter in the deformation analysis of an embankment. However, the stress state of a banking material can be quite complicated since banking materials are elasto-plastic and unsaturated in most cases, and, their behavior strongly depends on the stress history. In this study, the banking process is simulated with an elasto-plastic constitutive model for unsaturated soil. Specifically, the effects of banking speed and initial suction within the banking material are considered. It is found that the post-banking stress state depends on the distribution of the initial suction due to soil-water retention characteristics. © 2011 Taylor & Francis Group, London.
  • Simulation of static compaction with unsaturated soil/water coupled F.E. analysis, M. Shibata, K. Kawai, S. Kanazawa, A. Iizuka, S. Tachibana, S. Ohno, M. Honda, Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils, 2, 965, 971,   2011 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859977892&origin=inward
    Summary:Although compacted soil is widely used for constructing earth structures, the mechanism of compaction has not been explained using principles of soil mechanics. Therefore, designing and constructing such structures depend on empirical methods. In this study, we considered compaction as un-drained compression of unsaturated soil, and have simulated the compaction process using principles of unsaturated soil/water coupling problem. The constitutive model proposed by Ohno et al. (2007) and the soil-water retention characteristic curve model proposed by Kawai et al. (2000) were used for these simulations. When compared with static compaction tests performed by Kawai et al. (2003), the simulation results showed good agreement. Consequently, the shape of the observed compaction curve could be explained. The results achieved in this study can be applied to construction management on geotechnical engineering sites. © 2011 Taylor & Francis Group, London.
  • A numerical interpretation of density homogenization of bentonite material in wetting process, Atsushi Iizuka, Yusuke Takayama, Shinya Tachibana, Shintaro Ohno, Ichizo Kobayashi, Katsuyuki Kawai, Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM, 949, 954,   2011 12 01 , 10.1115/ICEM2011-59153, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84882977226&origin=inward
    Summary:Due to its low permeability and excellent expansion characteristics, bentonite is an excellent candidate with potential use as a buffer in the disposal of nuclear waste. Its expansion characteristics, activated by wetting, can be interpreted based on the full saturation line, depicted as a unique line on the density and the confining pressure relationship as proposed by Kobayashi et al. (2007). In addition, its elasto-plastic constitutive relation can also be formulated by introducing additional irreversible strain component describing the expansion of the montmorillonite present in the bentonite material. A constitutive model can consistently express the mechanical behavior of the compacted bentonite material from the unsaturated to the fully saturated state. This paper describes the density homogenization process that was conducted through a series of soil-water coupled elasto-plastic finite element simulations. Specifically, bentonite specimens, with different initial densities, were permeated with a constant water head. Stresses and strains developing in bentonite, particularly the density change, were carefully examined. A series of numerical simulations, performed on the two specimens, showed that specimens did not homogenize to a unique value of density upon reaching the fully saturated state. To confirm the simulation results, we carried out a series of experiments. The experimental results also support our simulation results. Copyright © 2011 by ASME.
  • 不飽和三軸圧縮試験における供試体内不均一性, 後藤浩司, 河井克之, 門田美咲, 土木学会年次学術講演会講演概要集(CD-ROM), 66th, ROMBUNNO.III-146,   2011 08 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102220897649926
  • The influence of initial moisture conditions of embankment materials on the initial stress state, 田中麻穂, 河井克之, 金澤伸一, 飯塚敦, 神戸大学都市安全研究センタ-研究報告, 15, 29, 40,   2011 03 , Refereed, 10.24546/81011338, http://www.lib.kobe-u.ac.jp/handle_kernel/81011338
  • The triaxial compression tests with the smart triaxial apparatus, 河津次郎, 安原昇平, 河井克之, 飯塚敦, 神戸大学都市安全研究センタ-研究報告, 15, 41, 50,   2011 03 , 10.24546/81011339, http://www.lib.kobe-u.ac.jp/handle_kernel/81011339
  • Formulation and application for soil/water/air/dissolved material model, 野村瞬, 河井克之, 金澤伸一, 橘伸也, 飯塚敦, 神戸大学都市安全研究センタ-研究報告, 15, 21, 28,   2011 03 , 10.24546/81011337, http://www.lib.kobe-u.ac.jp/handle_kernel/81011337
  • The modeling of mechanical behavior of bentonite, 飯塚敦, 河井克之, 高山裕介, 前田圭介, 神戸大学都市安全研究センタ-研究報告, 15, 13, 20,   2011 03 , Refereed, 10.24546/81011336, http://www.lib.kobe-u.ac.jp/handle_kernel/81011336
  • Study of the compaction effect with soil/water/air coupled F.E. analysis, 柴田昌輝, 大槻剛瑠, 河井克之, 飯塚敦, 神戸大学都市安全研究センタ-研究報告, 15, 51, 58,   2011 03 , Refereed, 10.24546/81011340, http://www.lib.kobe-u.ac.jp/handle_kernel/81011340
  • 荷重載荷条件下における飽和/不飽和地盤内における溶解物質の移動表現, 野村瞬, 角井駿祐, 河井克之, 橘伸也, 金澤伸一, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 46th, ROMBUNNO.502,   2011 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102222640922527
  • 弾塑性構成理論に基づくベントナイトの吸水膨潤特性の表現, 高山裕介, 前田圭介, 飯塚敦, 河井克之, 大野進太郎, 橘伸也, 金澤伸一, 地盤工学研究発表会発表講演集(CD-ROM), 46th, ROMBUNNO.339,   2011 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102228691800459
  • 土/水/空気連成有限要素解析プログラムを用いた「締固め」の力学的説明, 柴田昌輝, 大槻剛瑠, 後藤浩司, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集(CD-ROM), 46th, ROMBUNNO.346,   2011 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102238976036294
  • 締固めメカニズムの解明および新しい締固め管理手法の提案, 河井克之, ひょうご科学技術協会学術研究支援事業研究成果報告書, 2009, 98(1),99-102,   2010 09 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002239180335582
  • X線CT法を用いた静的締固め試験の可視化, 寺島裕樹, 河井克之, 椋木俊文, 大谷順, 柴田昌輝, 後藤浩司, 土木学会年次学術講演会講演概要集(CD-ROM), 65th, ROMBUNNO.III-097,   2010 08 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002220905351870
  • 土/水連成有限要素解析プログラムを用いた締固め土の品質の検討, 尾崎早希子, 柴田昌輝, 河井克之, 金澤伸一, 飯塚敦, 地盤工学研究発表会発表講演集, 45th, 1, 699, 700,   2010 07 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002231935483829
  • 不飽和土の力学から観た締固めによって生じる供試体内部状況の把握, 後藤浩司, 河井克之, 寺島裕樹, 地盤工学研究発表会発表講演集, 45th, 1, 669, 670,   2010 07 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002251729515197
  • 土/水/空気連成有限要素解析による締固めシミュレーション, 山田竜太郎, 金澤伸一, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集, 45th, 1, 675, 676,   2010 07 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002265123754367
  • 地下水位変動による地盤挙動の解釈, 島本恵梨子, 籠橋慶太, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集, 45th, 1, 745, 746,   2010 07 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002295893328591
  • 下負荷面を用いた不飽和土における降伏面内の弾塑性挙動のモデル化, PHOMMACHANH Viradeth, 河井克之, 金澤伸一, 飯塚敦, 地盤工学研究発表会発表講演集, 45th, 1, 667, 668,   2010 07 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002298728591856
  • 地下水位変動に伴う経年的地盤沈下メカニズムの推定, 籠橋慶太, 島本恵梨子, 飯塚敦, 河井克之, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2010, ROMBUNNO.III-19,   2010 05 22 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002252812376014
  • Simulations of compaction with unsaturated soil/water/air coupling analysis, 河井克之, 山田竜太郎, 金澤伸一, 神戸大学都市安全研究センタ-研究報告, 14, 45, 59,   2010 03 , Refereed, 10.24546/81011310, http://www.lib.kobe-u.ac.jp/handle_kernel/81011310
  • Explanation of the heterogeneity within soil induced by compaction with unsaturated soil mechanic, 河井克之, 寺島裕樹, 後藤浩司, 金澤伸一, 大谷順, 椋木俊文, 神戸大学都市安全研究センタ-研究報告, 14, 23, 43,   2010 03 , Refereed, 10.24546/81011309, http://www.lib.kobe-u.ac.jp/handle_kernel/81011309
  • Stress-strain and water retention characteristics of micro-porous ceramic particles made with burning sludge, K. Kawai, A. Iizuka, S. Kanazawa, A. Fukuda, S. Tachibana, S. Ohno, Prediction and Simulation Methods for Geohazard Mitigation - Proceedings of the International Symposium on Prediction and Simulation Methods for Geohazard Mitigation, IS-KYOTO 2009, 339, 345,   2009 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859819417&origin=inward
    Summary:When troublesome sludge discharged from industries and purification plants are burnt by 1300 degree, they change to innocuous micro-porous ceramic materials. The authors are seeking for practical use of such micro-porous ceramic materials in the geotechnical engineering field, particularly for geohazard mitigation. Then, in order to grasp fundamental mechanical properties of the micro-porous ceramic particles, a series of laboratory tests, that is, triaxial compressive shear tests, permeability tests and water retention tests, were performed. It is found that the stress-strain characteristics and permeability of the micro-porous ceramic particles are very similar to those of standard sandy materials but they have very high water retention capability. Next, applicability of the unsaturated elasto-plastic constitutive model proposed by Ohno et al. (2007) to the mechanical behavior of micro-porous ceramic particles was examined in this paper. © 2009 Taylor & Francis Group.
  • 斜面形状による築堤時の発現応力の違い, 田中麻穂, 河井克之, 金澤伸一, 橘伸也, 大野進太郎, 飯塚敦, 土木学会年次学術講演会講演概要集(CD-ROM), 64th, Disk 1, ROMBUNNO.III-335,   2009 08 03 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902209885238430
  • 不飽和土弾塑性構成モデルを用いた築堤シミュレーション, 田中麻穂, 河井克之, 金澤伸一, 橘伸也, 大野進太郎, 飯塚敦, 地盤工学研究発表会発表講演集, 44th, 973, 974,   2009 07 13 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902216384811510
  • 多孔質セラミック粒状体の一次元圧縮特性と破砕性, 河津次郎, 河井克之, 金澤伸一, 飯塚敦, 地盤工学研究発表会発表講演集, 44th, 481, 482,   2009 07 13 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902241413577836
  • 気候条件に伴う塩害の被害及び対策, 野村瞬, 河井克之, 大野進太郎, PIPATPONGSA Thirapong, 橘伸也, 金澤伸一, 飯塚敦, 地盤工学研究発表会発表講演集, 44th, 913, 914,   2009 07 13 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902241441210824
  • 土/水連成有限要素解析プログラムを用いた締固め曲線の表現, 柴田昌輝, 河井克之, 金澤伸一, 橘伸也, 大野進太郎, 飯塚敦, 地盤工学研究発表会発表講演集, 44th, 655, 656,   2009 07 13 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902254266211850
  • 不飽和土/水連成解析による築堤シミュレーション, 河井克之, 田中麻穂, 金澤伸一, 橘伸也, 大野進太郎, 飯塚敦, 竹山智英, 神戸大学都市安全研究センタ-研究報告, 13, 13, 1, 9,   2009 03 31 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002277388926362
  • Stress-strain and water retention characteristics of micro-porous ceramic particles made with burning sludge, K. Kawai, A. Iizuka, S. Kanazawa, A. Fukuda, S. Tachibana, S. Ohno, Prediction and Simulation Methods for Geohazard Mitigation, 339, 345,   2009 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85056043003&origin=inward
    Summary:© 2009 Taylor & Francis Group, London. When troublesome sludge discharged from industries and purification plants are burnt by 1300 degree, they change to innocuous micro-porous ceramic materials. The authors are seeking for practical use of such micro-porous ceramic materials in the geotechnical engineering field, particularly for geohazard mitigation. Then, in order to grasp fundamental mechanical properties of the micro-porous ceramic particles, a series of laboratory tests, that is, triaxial compressive shear tests, permeability tests and water retention tests, were performed. It is found that the stress-strain characteristics and permeability of the micro-porous ceramic particles are very similar to those of standard sandy materials but they have very high water retention capability. Next, applicability of the unsaturated elasto-plastic constitutive model proposed by Ohno et al. (2007) to the mechanical behavior of micro-porous ceramic particles was examined in this paper.
  • Theoretical undrained shear behaviour of unsaturated soils, M. Honda, S. Ohno, A. Iizuka, K. Kawai, H. Ohta, 12th International Conference on Computer Methods and Advances in Geomechanics 2008, 2, 992, 997,   2008 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=79952039835&origin=inward
    Summary:Prediction method for undrained shear behaviour of unsaturated soils is discussed in this paper. Based on Original Cam Clay model, authors have proposed constitutive model for unsaturated soils that the effect of water content is incorporated into superloading surface concept. Firstly, stress path of constant volume shear test is formulated under constant void ratio condition. And relationship between water content, dry density and constant volume shear strength is also derived. Secondary, calculation method of undrained shear tests is studied. In the case of unsaturated specimen, volume of the specimen changes with shear deformation and stress paths depend on initial degree of saturation. The calculation results described the tendency of test results qualitatively by considering the change in effective confining pressure in undrained condition and water retention curve.
  • 汚泥焼成土の基礎力学特性, 渡瀬梓, AGUNG Djoko S, 河井克之, 飯塚敦, 橘伸也, 金澤伸一, 土木学会年次学術講演会講演概要集(CD-ROM), 63rd, Disk 1, ROMBUNNO.3-451,   2008 08 13 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902214043515316
  • 植生の吸水作用が地盤の変形に及ぼす影響, 山田竜太郎, 河井克之, 飯塚敦, 橘伸也, 金澤伸一, 地盤工学研究発表会発表講演集, 43rd, 2155, 2156,   2008 06 12 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902282074661782
  • 土/水連成有限要素解析を用いた各種外的要因による地盤内水分布変化, 寺島裕樹, 河井克之, 飯塚敦, 橘伸也, 金澤伸一, 地盤工学研究発表会発表講演集, 43rd, 715, 716,   2008 06 12 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902287605706320
  • 締固め曲線と圧縮曲線の関連性について, 本田道識, 大野進太郎, 飯塚敦, 河井克之, 太田秀樹, 地盤工学研究発表会発表講演集, 42nd, 737, 738,   2007 06 11 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902233587792741
  • 地球環境問題の階層的整理と砂漠化問題の位置付け, 杉田芙紗子, 飯塚敦, 河井克之, PIPATPONGSA Thirapong, 地盤工学研究発表会発表講演集, 42nd, 1, 2,   2007 06 11 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902277250746915
  • 数値シミュレーションによる地圏・気圏間水循環に影響を及ぼす地下ダムの影響検討, 大昇弘樹, 飯塚敦, 河井克之, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2007, III-27,   2007 05 26 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902253844746714
  • 境界端面の潤滑性に注目した粘土供試体のせん断シミュレーション, 三好絵里子, 橘伸也, 飯塚敦, 河井克之, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2007, III-37,   2007 05 26 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902276717588778
  • タイ東北部における塩害と地盤変状シミュレータを用いた国際協力の可能性, THIRAPONG Pipatpongsa, 飯塚敦, 河井克之, 神戸大学都市安全研究センタ-研究報告, 11, 11, 43, 50,   2007 03 31 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902226783617307
  • An evaluation method for the volume change characteristics of compacted soil, M. Honda, A. Iizuka, S. Ohno, K. Kawai, W. Wang, Geotechnical Special Publication, pp.837-848, 837, 848,   2006 12 21 , 10.1061/40802(189)66, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=33845520828&origin=inward
    Summary:This paper discusses the volume change characteristics of compacted soil based on oedometer test results. After making specimens with different water contents and under different compaction loads, compression tests are conducted under both saturated and unsaturated conditions. The effects of the compaction conditions on the compression curves are discussed. It is confirmed that the yield stress and the water content are important factors when evaluating a compression curve, while dry density and suction are important factors when evaluating the yield stress. Copyright ASCE 2006.
  • 上負荷面を用いた締固め粘性土の排気非排水せん断挙動の表現方法, 古村隆博, 大野進太郎, 本田道識, 飯塚敦, 河井克之, 太田秀樹, 地盤工学研究発表会発表講演集, 41st, 849, 850,   2006 06 20 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902217137816505
  • 上負荷面を用いた締固め粘性土の等体積せん断挙動の表現方法, 本田道識, 大野進太郎, 古村隆博, 飯塚敦, 河井克之, 太田秀樹, 地盤工学研究発表会発表講演集, 41st, 847, 848,   2006 06 20 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902255047309352
  • An Influence of Ground Investigation for Prediciting Behavior of Soft Ground, Iizuka Atsushi, Nishida Hirofumi, Kawai Katsuyuki, Memoirs of Construction Engineering Research Institute, 第47号,87-100, 47, 87, 99,   2005 11 28 , http://ci.nii.ac.jp/naid/110004084754
  • 締固め土の体積圧縮挙動に着目した応力ひずみ関係の定式化, 本田道識, 飯塚敦, 大野進太郎, 河井克之, おう偉川, 土木学会年次学術講演会講演概要集(CD-ROM), 60th, Disk 1, ROMBUNNO.3-124,   2005 08 20 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902223861068022
  • 締固め土の圧縮特性に関する評価方法, 本田道識, 飯塚敦, 大野進太郎, 河井克之, WANG W, 地盤工学研究発表会発表講演集, 40th, 899, 900,   2005 06 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902202290576699
  • 関口・太田モデルの圧密特性と粘塑性パラメータ, 西田博文, 飯塚敦, 河井克之, 太田秀樹, 地盤工学研究発表会発表講演集, 40th, 983, 984,   2005 06 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902240453161717
  • 植生による蒸発散量を考慮した不飽和地盤の変形挙動予測, WANG Weichuan, 小羽根憲司, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集, 40th, 941, 942,   2005 06 15 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902291765335945
  • 不飽和地盤への降雨のモデル化, 杉田芙紗子, WANG Weichuan, 飯塚敦, 河井克之, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2005, III-35,   2005 05 29 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902221078810791
  • 実験土槽における降雨浸透特性, 須谷元保, 飯塚敦, 河井克之, WANG Weichuan, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2005, III-34,   2005 05 29 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902271020180639
  • 初期値境界値問題における地表面水理境界による降雨表現の検討, 桜井健一, 藤川和彦, おう偉川, 河井克之, 飯塚敦, 土木学会年次学術講演会講演概要集(CD-ROM), 59th, Disk 1, 3, 328,   2004 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902203004507207
  • 降雨に伴う土槽内の飽和度サクション分布の変化, 藤川和彦, おう偉川, 桜井健一, 河井克之, 飯塚敦, 土木学会年次学術講演会講演概要集(CD-ROM), 59th, Disk 1, 3, 326,   2004 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902214561967085
  • 不飽和地盤に及ぼす植物の吸水作用の影響, 霜永勝之, 岸本康照, 河井克之, 飯塚敦, 土木学会年次学術講演会講演概要集(CD-ROM), 59th, Disk 1, 3, 052,   2004 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902260621825040
  • 正規圧密粘土の瞬間せん断剛性の軸圧縮履歴依存性, 高木智哉, 岸本鉄太郎, 飯塚敦, 河井克之, 橘伸也, 土木学会年次学術講演会講演概要集(CD-ROM), 59th, Disk 1, 3, 276,   2004 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902285655645884
  • Mises規準から見た境界非排水粘土供試体の破壊シミュレーション―Mises規準かMohr‐Coulomb規準か―, 橘伸也, 飯塚敦, 河井克之, 太田秀樹, 地盤工学研究発表会発表講演集, 38th, 293, 294,   2003 06 06 , 10.11512/jiban.JGS38.0.293.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902210456428076
  • 荷重履歴の違いによる過剰間隙水圧の発生, 西田博文, 和泉大祐, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集, 38th, 1351, 1352,   2003 06 06 , 10.11512/jiban.JGS38.0.1351.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902218415117962
  • 地下水位変動履歴が地盤内のサクション変化に及ぼす影響, 梅原久嗣, 桜井健一, 河井克之, 垣本徹, 地盤工学研究発表会発表講演集, 38th, 1201, 1202,   2003 06 06 , 10.11512/jiban.JGS38.0.1201.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902233799295454
  • 上・拡張下負荷面,回転硬化を導入した弾塑性構成モデルによる砂の再液状化特性の表現, 大野進太郎, 飯塚敦, 河井克之, 太田秀樹, 地盤工学研究発表会発表講演集, 38th, 495, 496,   2003 06 06 , 10.11512/jiban.JGS38.0.495.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902282785062865
  • The Effects of Water Level Fluctuation on Suction Distribution in Soil, Umehara hisatsugu, Sakurai Kenichi, Kakimoto Toru, Kawai Katsuyuki, Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 0, 1201, 1202,   2003 , 10.11512/jiban.JGS38.0.1201.0, http://ci.nii.ac.jp/naid/130004620593
    Summary:実地盤は地表面での外水位変化だけでなく、内部の地下水位変化の影響も受け、複雑な含水率もしくは間隙水分布を呈しているため、地盤内のサクションも異なると考えられる。これまで降雨による地表面からの浸潤による地盤の応答に関する研究は数多く報告されているが、地下水位の変動についてはその変動幅が小さいとみなされ、あまり重要視されてこなかった。本論分では、地下水位変動が内部含水状態の分布に及ぼす影響を明らかにすることにある。ここでは、室内土槽試験、土/水連成有限要素解析を行い、多方面から問題究明に取り組む。
  • Excess pore water development relating to loading histories, Nishida Hirofumi, Izumi Daisuke, Iizuka Atsushi, Kawai Katsuyuki, Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 0, 1351, 1352,   2003 , 10.11512/jiban.JGS38.0.1351.0, http://ci.nii.ac.jp/naid/130004620677
    Summary:従来,道路盛土および人工島などに挙げられる土構造物の設計は,施工(荷重)履歴の違いが与える構造物自身あるいは基礎地盤の品質の影響を考慮するには至らなかった.これに対し,最近では多次元土/水連成弾(粘)塑性有限要素解析のアプローチから,荷重履歴の違いにより土構造物の品質が異なることが報告されている.本報告では簡単な地盤モデルを想定し,二次元土/水連成弾・粘塑性有限要素解析を用いて荷重履歴の違いがもたらす過剰間隙水圧の発生形態に重点を置き,土構造物の設計において考慮すべき事項について再認識を行った.
  • Failure criterion of soil specimens obtained from Mise-type clay materials, Tachibana Shinnya, Iizuka Atsushi, Kawai Katsuyuki, Ohta Hideki, Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 0, 293, 294,   2003 , 10.11512/jiban.JGS38.0.293.0, http://ci.nii.ac.jp/naid/130004621317
    Summary:本研究の目的は,室内試験を境界値問題と捉え,正規圧密粘土の非排水三軸圧縮・伸張試験,平面ひずみ圧縮試験をシミュレーションし,供試体の破壊挙動を解析的に検討することである.計算を行う道具として,有限変形弾塑性理論に基づく土/水連成3次元有限要素プログラムを開発した.シミュレーションにはMises型のCam-clayモデルを用いているため,解析解として得られる破壊強度に圧縮側,伸張側あるいはその中間で違いがあれば,一般に実験で得られるMohr-Coulombの規準は粘土の材料としての性質ではなく,他の要因に起因するものと考えられる.
  • The re-liquefaction simulation introducing superloading and extended subloading surfaces, and rotational hardening concepts, Ohno Shintaro, Iizuka Atsushi, Kawai Katsuyuki, Ohta Hideki, Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 0, 495, 496,   2003 , 10.11512/jiban.JGS38.0.495.0, http://ci.nii.ac.jp/naid/130004621429
    Summary:砂の再液状化特性は、その内部構造と密接に関わっていると考えられている。本研究では、この砂の再液状化特性を数値解析により表すことを目的としている。本研究では、砂の粒子配列を応力の異方性(降伏面の傾き)と考える。さらに、砂の嵩高な構造を考慮するために、上負荷面の概念を導入する。また、繰返し載荷への適用性を考慮し、拡張下負荷面、回転硬化を弾塑性構成式に導入する。応力振幅一定繰返し非排水せん断シミュレーションを通して、本弾塑性構成モデルの再液状化現象への適用性を検討した。結果として、砂の内部構造を、応力の異方性と上負荷面としてモデル化することの妥当性を示すことができた。
  • Simulation of differential settlement on deep fills, Hayakawa Eiji, Shimonaga Katsuyuki, Kobane Kenji, Kawai Katsuyuki, Iizuka Atsushi, Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 0, 911, 912,   2003 , Refereed, 10.11512/jiban.JGS38.0.911.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902214006058681
    Summary:近年、谷地形に大規模な盛土を行った土構造物が多く見られるが、長期の雨水浸透により盛土の品質が劣化し、盛土表面に不同沈下が生じてしまうという事例が報告されている。締固め土のような不飽和土は水浸させることにより,水浸沈下(コラプス)が生じることがわかっている。長期にわたり降雨が繰り返されることにより地盤内に局所的で短時間の水浸状態が繰り返し発生していると考えられ、盛土内に局所的な変形が生じることで不同沈下が生じていると考えられる。そこで仮想の谷地形盛土を想定し、不飽和土/水連成有限要素解析によって、水浸沈下による盛土の不同沈下を表現した。
  • Influence of ground improvement on residual settlement, Izumi Daisuke, Nishida Hirofumi, Iizuka Atsushi, Kawai Katsuyuki, Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 0, 1353, 1354,   2003 , 10.11512/jiban.JGS38.0.1353.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902237528208136
    Summary:道路盛土および人工島などに挙げられる土構造物が供用後の不同沈下等により要求される性能(要求性能)が低下する事例がよく見られる.このため,初期投資だけでなく維持補修時に要するコストを含めたライフサイクルコストの低減できるような技術システムを構築が求められている.本報告はサンドドレーンによる地盤改良時期・場所の違いにより埋立地がどのように長期的に変状するかを二次元土/水連成弾・粘塑性有限要素解析により検討したものである.
  • 締固め土における圧密降伏応力の推定, 金銀羅, 河井克之, 飯塚敦, 谷内世衣子, 土木学会年次学術講演会講演概要集(CD-ROM), 57th, III-352,   2002 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902141981365717
  • 締固め土のサクション発生機構に関する考察, 流田寛之, 河井克之, 森田寿, 萩原正人, 土木学会年次学術講演会講演概要集(CD-ROM), 57th, III-802,   2002 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902162931476442
  • 非排水条件下での等方応力載荷による不飽和土の変形特性, おう偉川, 河井克之, 桜井健一, 土木学会年次学術講演会講演概要集(CD-ROM), 57th, III-338,   2002 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902195895910586
  • The relationship between the suction and the consolidation yield stress of compacted soils, Kawai Katsuyuki, Kim Eunra, Iizuka Atsushi[et al.], Report of Research Center for Urban Safety and Security, Kobe University, 第6号,pp.397-408, 6, 397, 407,   2002 03 , http://id.ndl.go.jp/bib/6664234
  • The relationship between the suction and the consolidation yield stress of compacted soils, 河井 克之, 金 銀羅, 飯塚 敦, 神戸大学都市安全研究センター研究報告, 6, 6, 397, 407,   2002 03 , 10.24546/00317653, http://www.lib.kobe-u.ac.jp/handle_kernel/00317653
  • Effect of Difference of Constructing Process on Quality of Artificial Island, Nishida Hirofumi, Iuchi Takaya, Iizuka Atsushi, Kawai Katsuyuki, Proceedings of the Japan National Conference on Geotechnical Engineering, 37, 0, 961, 962,   2002 , 10.11512/jiban.JGS37.0.961.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902114116171845
  • Soil/water coupled elato-plastic F.E. numerical simulation of soil media subjected to seismic external forces, Ohno Shintaro, Proceedings of the Japan National Conference on Geotechnical Engineering, 37, 0, 1885, 1886,   2002 , 10.11512/jiban.JGS37.0.1885.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902146964622244
  • Non-coaxiality of stress-plastic strain increments of N.C. clays, Tatsumi M., Takagi T., Iizuka A., Proceedings of the Japan National Conference on Geotechnical Engineering, 37, 0, 247, 248,   2002 , 10.11512/jiban.JGS37.0.247.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902160891437675
  • The water retention curve characteristics of unsaturated soil under isotropic loading with undrained condition, Wang Weichuan, Kawai Katsuyuki, Sakurai Kenichi, Proceedings of the Japan National Conference on Geotechnical Engineering, 37, 0, 947, 948,   2002 , Refereed, 10.11512/jiban.JGS37.0.947.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902189048579199
  • The Relationship between Expression of Hysteresis on Water Characteristics Curve and Stress Components effecting on Unsaturated Soil Behavior, Kawai Katsuyuki, Memoirs of Construction Engineering Research Institute, 43, 43, 187, 196,   2001 11 , http://ci.nii.ac.jp/naid/110000078117
  • Study for Effect of Suction on Shear Deformation and Strength of Unsaturated Sand Under Axi-Symmetric State, Kato Shoji, Hatanaka Norihiko, Kawai Katsuyuki, Memoirs of Construction Engineering Research Institute, 43, 43, 153, 160,   2001 11 , http://id.ndl.go.jp/bib/6021250
  • The Discussion about Yield Function of Unsaturated Soil under Isotropic Stress State, Kawai Katsuyuki, Kato Shoji, Morita Hisashi, Memoirs of Construction Engineering Research Institute, 43, 43, 197, 204,   2001 11 , Refereed, http://id.ndl.go.jp/bib/6021266
  • The Relationship between Expression of Hysteresis on Water Characteristics Curve and Stress Components effecting on Unsaturated Soil Behavior, Kawai Katsuyuki, Memoirs of Construction Engineering Research Institute, 43, 187, 196,   2001 11 , Refereed, http://id.ndl.go.jp/bib/6021262
  • 不飽和土の非排水等方圧縮試験による最乾燥水分線の定量化について, 河井克之, おう偉川, 小川圭亮, 土木学会年次学術講演会講演概要集 第3部, 56th, A, 294, 295,   2001 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902195720079582
  • 水分特性曲線に基づくサクション‐粘着力関係の推定方法, 加藤正司, 吉村優治, 河井克之, 寸田亘, 地盤工学研究発表会発表講演集, 36th, 2409, 2410,   2001 05 08 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902138747015965
  • 低拘束圧状態における不飽和土の強度特性, 寸田亘, 加藤正司, 河井克之, 吉村優治, 平川雄一, 地盤工学研究発表会発表講演集, 36th, 897, 898,   2001 05 08 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902161835622180
  • 中央遮水壁型ロックフィルダムの築堤および湛水シミュレーション, 吉牟田竜太, 本田道識, 早川英司, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集, 36th, 1399, 1400,   2001 05 08 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902184372946801
  • A Proposal for the Method of Formulation of Water Retention Curve for Unsaturated Soils, Karube Daizo, Kawai Katsuyuki, Memoirs of Construction Engineering Research Institute, 42, 1, 12,   2000 11 , http://id.ndl.go.jp/bib/5629430
  • A Proposal for the Method of Formulation of Water Retention Curve for Unsaturated Soils, Karube Daizo, Kawai Katsuyuki, Memoirs of Construction Engineering Research Institute, 42, 42, 1, 12,   2000 11 , http://ci.nii.ac.jp/naid/110000078066
  • The Behavior of Unsaturated Soil under Anisotropic Consolidation with Constant Suction, Kawai Katsuyuki, Seguchi Hitoshi, Nagareta Hiroyuki, Memoirs of Construction Engineering Research Institute, 42, 42, 151, 158,   2000 11 , Refereed, http://id.ndl.go.jp/bib/5629587
  • Influence of Suction Stress on Strength Characteristic of Unconfined Compression Test for a Unsaturated Soil, Kato Shoji, Yoshimura Yuji, Kawai Katsuyuki, Memoirs of Construction Engineering Research Institute, 42, 42, 121, 130,   2000 11 , Refereed, http://id.ndl.go.jp/bib/5629564
  • 不飽和粘性土の異方圧密によるせん断強度, 流田寛之, 河井克之, 瀬口均, 軽部大蔵, 土木学会関西支部年次学術講演会講演概要, 2000, III.42.1-III.42.2,   2000 06 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902167959997474
  • サクション制御下での不飽和土の異方圧密挙動, 河井克之, 瀬口均, 流田寛之, 軽部大蔵, 地盤工学研究発表会発表講演集, 35th, 1281, 1282,   2000 05 31 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902118375799050
  • 締固め土の圧縮特性に及ぼす供試体作成条件の影響, 瀬口均, 本田道識, 河井克之, 飯塚敦, 軽部大蔵, 地盤工学研究発表会発表講演集, 35th, 1283, 1284,   2000 05 31 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902192825276821
  • 非排水条件下での不飽和土のせん断挙動及び水分特性, 河井克之, 軽部大蔵, 加藤正司, 嘉戸善胤, 神戸大学都市安全研究センタ-研究報告, 4, 4, 231, 239,   2000 03 31 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902126256607757
  • Behavior of unsaturated soil and water characteristics in undrained shear, Kawai Katsuyuki, Karube Daizo, Kato Shoji, Kado Yoshitane, Report of Research Center for Urban Safety and Security,Kobe University, 4, 4, 231, 239,   2000 03 , 10.24546/00231324, http://id.ndl.go.jp/bib/5561955
  • 締固め土の圧縮挙動に対する弾塑性構成モデルの適用, 本田道識, 軽部大蔵, 飯塚敦, 河井克之, 神戸大学大学院自然科学研究科紀要, 18, 18, 51, 59,   2000 03 , http://id.ndl.go.jp/bib/5590148
  • Soil structure and compressibility of marine clay precipitated under high temperature condition., FUJIWARA TERUYUKI, YOSHIDA TAKAYUKI, MURATA NORIYUKI, KAWAI KATSUYUKI, KURUBE DAIZO, 地盤工学シンポジウム論文集, 44th, 63, 66,   1999 11 17 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902151351664630
  • Investigation of Factors Affecting on Water Retention Characteristic of Soils, Kawai Katsuyuki, Karube Daizo, Ashida Wataru, Kado Yoshitane, Memoirs of Construction Engineering Research Institute, 41, 41, 177, 184,   1999 11 , http://id.ndl.go.jp/bib/4957515
  • Effect of salinity on sedimentation behavior under the high temperature condition of clay., FUJIWARA TERUYUKI, YOSHIDA TAKAYUKI, MURATA SATOSHI, KAWAI KATSUYUKI, KARUBE DAIZO, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 376, 377,   1999 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902147907480456
  • Evaluation method for the effect of suction for mechanical behavior in uniaxial compression test of unsaturated soil., SUNDA WATARU, KATO SHOJI, KAWAI KATSUYUKI, YOSHIMURA YUJI, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 88, 89,   1999 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902166061416401
  • Unidimensional compression behavior of super soft clay which settles under high temperature., YOSHIDA TAKAYUKI, FUJIWARA TERUYUKI, MURATA SATOSHI, KAWAI KATSUYUKI, KARUBE DAIZO, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 378, 379,   1999 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902181122587432
  • Effect of constraint pressure on the shape of moisture characteristic curve., YOSHIMUTA RYUTA, KAWAI KATSUYUKI, SEGUCHI HITOSHI, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 592, 593,   1999 08 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902181366998795
  • The pore pressure change on clay sample which caused by temperature change., FUJIWARA TERUYUKI, YOSHIDA TAKAYUKI, MURATA NORIYUKI, KAWAI KATSUYUKI, KARUBE DAIZO, 地盤工学研究発表会発表講演集, 34th, 475, 476,   1999 06 18 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902124689507762
  • The formulation of the stress-strain relationship for unsaturated soil., HONDA MICHINORI, KARUBE DAIZO, IIZUKA ATSUSHI, KAWAI KATSUYUKI, 地盤工学研究発表会発表講演集, 34th, 747, 748,   1999 06 18 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902144703386729
  • The water retention modelwhich take the influence of void ratio to the consideration., KAWAI KATSUYUKI, SEGUCHI HITOSHI, YOSHIMUTA RYUTA, KARUBE DAIZO, 地盤工学研究発表会発表講演集, 34th, 727, 728,   1999 06 18 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902153391446876
  • The influence of temperature and salinity on settling behavior of very soft clay., YOSHIDA TAKAYUKI, FUJIWARA TERUYUKI, MORI DAISUKE, KAWAI KATSUYUKI, KARUBE DAIZO, 地盤工学研究発表会発表講演集, 34th, 473, 474,   1999 06 18 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902185579449170
  • 土の水分保持特性に及ぼす拘束圧の影響, 吉牟田竜太, 本田道識, 河井克之, 軽部大蔵, 土木学会関西支部年次学術講演会講演概要, 1999, III.37.1-III.37.2,   1999 05 22 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902199833595795
  • The Relationship between Mechanical Behavior and Soil-Water Characteristic Curve of Soils, Karube Daizo, Tanaka Yasuo, Kawai Katsuyuki, Ashida Wataru, Memoirs of Construction Engineering Research Institute, 39, 39, 25, 35,   1997 11 , http://id.ndl.go.jp/bib/4391536
  • Mechanical behavior of unsaturated soil in undrained conditions considering pore water distribution., KADO YOSHITANE, KAWAI KATSUYUKI, ASHIDA WATARU, KARUBE DAIZO, 土木学会関西支部年次学術講演会講演概要, 1996, III.17.1-III.17.2,   1996 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902162892089452
  • The soil-water characteristic curve of unsaturated soil and the formulation of it., ASHIDA WATARU, KAWAI KATSUYUKI, KADO YOSHITSUGU, KARUBE DAIZO, 地盤工学研究発表会発表講演集, 31st, 2-2, 2071, 2072,   1996 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902176022007966
  • Triaxial compression test on unsaturated specimen under the undrainage condition., KAWAI KATSUYUKI, ASHIDA WATARU, KADO YOSHITANE, KARUBE DAIZO, 地盤工学研究発表会発表講演集, 31st, 2-1, 825, 826,   1996 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902177283785580
  • The effect of pore water distribution for the shear strength of unsaturated soil., HONDA MICHISHIKI, KAWAI KATSUYUKI, KATO SHOJI, KARUBE DAIZO, 土質工学研究発表会発表講演集, 29th, 3-1, 627, 628,   1994 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902104867700996
  • 不飽和土の三軸圧縮強度に及ぼす間隙水分布の影響, 河井克之, 本田道識, 藤原照幸, 軽部大蔵, 土木学会関西支部年次学術講演会講演概要, 1994, III.45.1-III.45.2,   1994 05 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902138527212247

Research Grants & Projects

  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(若手研究(A)), Clarification of the mechanism generating salt disaster with geotechnical engineering and proposal of ground improvement resistant to salt disaster, Salt disaster, triggering salt disaster, is generated by man-made factor, such as exceeding irrigation, and natural factor, such as long-term repetition of preparation and evaporation. Therefore, the countermeasure considering complicated external impacts to the ground is needed. In this study, we developed the soil/water/air coupled F. E. simulator, which can express deformation of the ground, groundwater flow, and mass transfer within the ground. Moreover, monitoring of evaporation with lysimeter tests is conducted for improving analysis accuracy. Finally, the soil stratification resistant to salt disaster is proposed.