KINDAI UNIVERSITY


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河井 克之カワイ カツユキ

プロフィール

所属部署名理工学部 社会環境工学科 / 総合理工学研究科
職名准教授
学位博士(工学)
専門地盤工学
ジャンル科学・技術/建設
コメンテータガイドhttp://www.kindai.ac.jp/meikan/1373-kawai-katsuyuki.html
ホームページURL
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Last Updated :2018/06/15

コミュニケーション情報 byコメンテータガイド

コメント

    地盤構造物の強度や変形に関する研究をしています。特に、河川堤防や盛土、斜面など、陸上の地盤構造物が、降雨などによる含水率変化が生じた場合の、安定性評価,変形予測を専門としています。

報道関連出演・掲載一覧

    <報道関連出演・掲載一覧>
    ●2015/09/16
     産経新聞
     河川の堤防について。

研究活動情報

研究分野

  • 土木工学, 地盤工学

研究キーワード

  • 地盤工学 環境工学 防災工学

論文

  • Influence of soil moisture and stratigraphic structure on actual evaporation, Proc. 19th Int. Conf. on Soil Mechanics and Geotechnical Engineering, 1167, 1170,   2017年09月, 査読有り
  • AIR PRESSURE DISTRIBUTION INDUCED BY RAINFALL INFILTRATION IN SOIL/WATER/AIR COUPLED SIMULATION, Kawai Katsuyuki, Kawakatsu Takuya, Teraoka Ayumi, INTERNATIONAL JOURNAL OF GEOMATE, 12, 32, 63, 69,   2017年04月, 査読有り
  • 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, 57, 1, 80, 91,   2017年02月, 査読有り
  • Explanation of dry density distribution induced by compaction through soil/water/air coupled simulation, Kawai Katsuyuki, Phommachanh Viradeth, Kawakatsu Takuya, Iizuka Atsushi, Procedia Engineering, 143, 276, 283,   2016年09月, 査読有り
  • Expression of air pressure distribution using soil/water/air coupled analysis, Proc. of 6th Int. Conf. GEOMATE 2016, 233, 238,   2016年11月, 査読有り
  • Effects of stress conditions on B-value measurement, Sugiyama Yuri, Kawai Katsuyuki, Iizuka Atsushi, SOILS AND FOUNDATIONS, 56, 5, 848, 860,   2016年10月, 査読有り
  • Simulation of saturation process in a transuranium disposal facility, Environmental Geotechnics,   2016年01月, 査読有り
  • Influence of stress release after sampling on shear characteristics, Proc. of Int. Conf. on Soft Ground Engineering, 553, 559,   2015年12月, 査読有り
  • Soil/water/air coupled F. E. simulation of phreatic surface generation process within a river levee, KAWAI Katsuyuki, VIRADETH Phommachanh, IIZUKA Atsushi, Japanese Geotechnical Society Special Publication, 2, 49, 1714, 1717,   2015年11月, 査読有り
  • 弾塑性動的地盤モデルのためのパラメータの同定, 吉冨力, 妹川賢司, 飯塚敦, 河井克之, ロハニタラディ, 神戸大学都市安全研究センター, 19, 85, 100,   2015年10月
  • 粒度分布に注目した土粒子吸着物質の除去方法の検討, 西門優, 飯塚敦, 河井克之, 神戸大学都市安全研究センター報告, 19, 75, 84,   2015年10月
  • 土/水/空気連成解析によるキャピラリーバリアシステムの性能評価, 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報告, 19, 67, 74,   2015年10月
  • ベルセロ法を用いた高容量テンシオメーターの開発, 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報告, 19, 59, 66,   2015年10月, 査読有り
  • 深海底デコルマ帯におけるせん断破壊モデル, 戎健次, 杉山友理, 飯塚敦, 河井克之, 佐々木陽亮, 神戸大学都市安全研究センター研究報告, 19, 45, 58,   2015年10月
  • 深海底プレート境界デコルマ帯におけるせん断破壊モデル, 杉山友理, 戎健次, 飯塚敦, 河井克之, 佐々木陽亮, 土木学会論文集A2(応用力学), 71, 2, 605, 612,   2015年05月, 査読有り
  • 降雨時における傾斜地盤内空気の挙動について, 川勝拓哉, 河井克之, Binod TIWARI, 飯塚敦, 土木学会論文集A2(応用力学), 71, 2, 171, 180,   2015年05月, 査読有り
  • マルチング材料としての粉砕汚泥焼成煉瓦の有効活用について, 河井克之, 佐伯拓也, 野村瞬, 杉山友理, 飯塚敦, 骨材資源, 185, 13, 23,   2014年04月, 査読有り
  • 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, 27, 1, 28, 40,   2014年02月, 査読有り
  • A finite element simulator for mechanical behavior of unsaturated earth structures exposed to evaporation and moisturization, Kanazawa Shin-ichi, Kawai Katsuyuki, Iizuka Atsushi, Ohno Shintaro, Tachibana Shinya, Thirapong Pipatpongsa, Takeyama Tomohide, UNSATURATED SOILS: THEORETICAL AND NUMERICAL ADVANCES IN UNSATURATED SOIL MECHANICS, 711, +,   2010年, 査読有り

書籍等出版物

  • 理解を深める土質力学320問, 常田 賢一, 澁谷 啓, 片岡 沙都紀, 河井 克之, 鳥居 宣之, 新納 格, 秦 吉弥, 共著, 理工図書,   2017年04月01日, 4844608584
  • 基礎からの土質力学, 常田 賢一, 澁谷 啓, 片岡 沙都紀, 河井 克之, 鳥居 宣之, 新納 格, 秦 吉弥, 共著, 理工図書,   2017年04月01日, 4844608576

MISC

  • 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年05月01日, 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年, 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年, http://jglobal.jst.go.jp/public/201702284134886853
  • 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年11月, http://jglobal.jst.go.jp/public/201602228734635783
  • 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年, http://jglobal.jst.go.jp/public/201602272736399371
  • 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年11月, 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年11月, http://jglobal.jst.go.jp/public/201602246416628870
  • 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), 70th, ROMBUNNO.IV-043,   2015年08月01日, http://jglobal.jst.go.jp/public/201502211218331336
  • マルチング材料としての粉砕汚泥焼成煉瓦の有効活用について, 河井克之, 佐伯拓也, 野村瞬, 杉山友理, 飯塚敦, 骨材資源, 47, 185, 13, 23,   2015年06月20日, http://jglobal.jst.go.jp/public/201502215233112638
  • 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年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84907346356&origin=inward
    概要: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年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84907303194&origin=inward
    概要: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年01月01日, 10.3208/jgssp.JPN-078, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84971452257&origin=inward
    概要: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年, 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年, 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年, 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年, 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年, 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年, 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年, 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年, 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年, http://jglobal.jst.go.jp/public/201502208363756573
  • Theoretical and experimental studies of stress distribution in wedge-shaped granular heaps, Thirapong Pipatpongsa, Tadaki Matsushita, Maho Tanaka, Shinichi Kanazawa, Katsuyuki Kawai, Acta Mechanica Solida Sinica, 27, 1, 28, 40,   2014年02月01日, 10.1016/S0894-9166(14)60014-8, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84897746784&origin=inward
    概要:The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes with the mobilized state of stress along the slope surface is employed by imposing the orientation of principal stresses on the equilibrium equations. Comparisons were made with calculations based on the finite element method using an elastic model. Moreover, experiments on sand heaps deposited on a rectangular rigid base were conducted to validate the theoretical study. The measured pressure profile generally agreed well with theoretical results. © 2014 The Chinese Society of Theoretical and Applied Mechanics.
  • 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年01月01日, 10.1007/978-3-319-05050-8_44, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84949449571&origin=inward
    概要:© 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.
  • Numerical evaluation for performance of a capillary barrier system, Y. Sugiyama, S. Nomura, K. Kawai, M. Mimura, Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014, 1, 651, 658,   2014年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84901634645&origin=inward
    概要:With the remarkable increase in amounts of waste being generated recently, waste disposal has become a serious issue. There are various types of waste materials, some of which include substances that are harmful to humans and require proper handling for safe disposal. The infiltration of rainwater into a waste repository site can cause possible leakage of these harmful substances. The system for covering any repository site is therefore extremely important and now the use of a capillary barrier system is one of the more promising candidates for a suitable cover system. The capillary barrier system consists of two soil layers: a fine sandy upper soil layer and a coarse lower soil layer. The different water retention capabilities between the upper and lower layers are key to the performance of the capillary barrier system. Also by tilting these soil layers, the capillary barrier system can be made more effective because it prevents vertical infiltration and drain in the direction of the slope. In this paper, a series of parametric numerical computations were conducted using the soil/water/air coupling F.E. technique. The slope angle and thickness of the upper soil layer were changed in order to examine the performance of the capillary barrier system. The mechanism for the capillary barrier was then discussed. Throughout numerical computations, it was repeatedly shown that vertical water infiltration and retention in the soil layers decrease with an increase in the slope angle. The paper also reveals how the thickness of the upper soil layer influences the performance of the capillary barrier. © 2014 Taylor & Francis Group, London.
  • Numerical evaluation of a multiple soil barrier system preventing water infiltration, Y. Takayama, Y. Ikuta, A. Iizuka, K. Kawai, T. Taki, R. Sakao, Y. Ichikawa, Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014, 1, 659, 665,   2014年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84901611643&origin=inward
    概要:In this paper, a multiple unsaturated soil barrier system consisting of multiple layers of gravel, sand, decomposed granite soil, and bentonite mixture soil is considered as a hardly permeable covering to prevent rainwater from infiltrating into waste deposits. Water infiltration is prevented due to both the low permeability of the bentonite mixture soil layer and a capillary barrier with different water-retention capabilities. A series of numerical simulations was carried out to evaluate the performance of the barrier system using a saturated/unsaturated soil/water coupled FE computation technique. Impermeability of the barrier system is shown as a graphical chart with rainfall duration on the x-axis and rainfall intensity on the y-axis. The simulation results show that the capillary barrier is a key parameter in evaluating the long-term performance of the barrier system. Results also confirm that the barrier system can work well against the maximum intensity of the rainfall recorded in Nigyo-toge. © 2014 Taylor & Francis Group, London.
  • Compaction simulation with soil/water/air coupled FEA code and parametric study, K. Kawai, V. Phommachanh, S. Sakamoto, A. Iizuka, Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014, 1, 545, 552,   2014年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84901642908&origin=inward
    概要:In this study, in order to clarify the mechanism of compaction, the static compaction simulations are conducted by using soil/water/air coupled finite element code, which consists of the constitutive model for unsaturated soil, the soil water retention characteristic curve model and the gas state equation. Here, the compaction is assumed as an initial and boundary value problem, namely loading and unloading under drained air and undrained water conditions. Consequently, the shape of compaction curve could be successfully expressed. Moreover, parametric study is carried out to investigate the dependency of compaction curve on material properties. Here, compressibility, permeability and the soil water retentivity are considered as an influential factor. Consequently, the effects of material parameters on compaction quality can be theoretically explained. © 2014 Taylor & Francis Group, London.
  • 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, 123, 128,   2014年01月01日, 10.1007/978-3-319-05050-8_20, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84949437849&origin=inward
    概要:© 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.
  • Salt damage and soil contamination caused by the east Japan earthquake and Tsunami, Yuri Sugiyama, Shun Nomura, Atsushi Iizuka, Katsuyuki Kawai, Shinya Tachibana, Shin Ichi Kanazawa, Tomohide Takeyama, Theoretical and Applied Mechanics Japan, 62, 141, 148,   2014年01月01日, 10.11345/nctam.62.141, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84902185684&origin=inward
    概要:The East Japan Earthquake and Tsunami caused serious damages in the coastal area of eastern Japan. Many houses and cars on the road were swept away by the tsunami. Also, industrial facilities such as chemical plants in the coastal area were completely destroyed. Damage from saline seawater was not limited only to the rice field areas, and there were also serious anxieties regarding the possibility of ground contamination as a result of harmful heavy metals that leaked from destroyed chemical plants. In light of this scenario, we carried out a quantitative survey to examine these areas. This paper reports on the results of our survey. It was found that high salt concentrations were detected on the ground surface but predictions state that these concentrations can be diluted with rainfall. It was also revealed that serious ground contamination due to the harmful heavy metals was not detected.
  • Derivation of mass transfer model for unsaturated soil and its applications, S. Nomura, Y. Sugiyama, K. Kawai, A. Iizuka, Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014, 2, 1179, 1187,   2014年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84901607348&origin=inward
    概要:In this study, we use conservation laws to construct a method for describing the movement of dissolved material. This is then applied to a mathematical model. Recently, soil pollution, induced by toxic materials in the ground water, is spreading. The mobility modes for this dissolved material can be divided into advection, induced by distribution of fluid head, and dispersion, induced by distribution of concentration content. First, Darcy's law is derived from the momentum conservation law using Bear's theory. Secondly, the concept of total fluid head is extended for application to various fluids. Additionally, an infiltration equation and an advection-dispersion equation are derived from mass conservation laws. Coupling the two equations, we construct a mass transfer model for unsaturated/saturated ground. Using the model, the effect of density flow is considered assuming basic one-dimensional areas. The results show that mobility of the dissolved material depends on its density. We concluded that density flow dominates along the vertical rather than the horizontal direction and mobility of the fluid is dulled in the unsaturated area. © 2014 Taylor & Francis Group.
  • Application of soil/water/air coupled F.E. code to predict seepage and deformation on sandy slope, V. Phommachanh, N. Matsuo, K. Ienaga, K. Kawai, A. Iizuka, B. Tiwari, Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014, 1, 621, 627,   2014年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84901586728&origin=inward
    概要:In order to study the triggering factors for shallow landslides during rainfall, sandy soil slopes were prepared in laboratory angles of 30 and 45 degrees and those slopes were poured with rainfall intensities of 30 and 60 mm/hours through a specially developed rain simulator. Moreover, the rainfall on slope was simulated with using unsaturated soil/water/air coupled F.E. code, and the numerically calculated depth of water front and values of suction at different location in the slopes at various angles of inclinations matched well with the experimentally observed values. The combined results obtained with the numerical and experimental studies were utilized to predict the variation in the depth of water and values of suction at different intensities of rainfall as well as deformation of slopes during rainfall. © 2014 Taylor & Francis Group, London.
  • Expression of mechanical characteristics in compacted soil with soil/water/air coupled F.E. Simulation, K. Kawai, A. Iizuka, S. Kanazawa, 18th International Conference on Soil Mechanics and Geotechnical Engineering: Challenges and Innovations in Geotechnics, ICSMGE 2013, 2, 1129, 1132,   2013年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84907337346&origin=inward
    概要:Results obtained in a lab compaction test are difficult to apply to the design and compaction control at an actual geotechnical engineering site. This is attributed to the fact that the mechanism for compaction has not been explained using the principles of soil mechanics. The main theme of this study is interpretation of the compaction mechanism with unsaturated soil mechanics. Here, static compaction tests were simulated with soil/water/air coupled finite element analysis code DACSAR-MP. Consequently, the shape of the compaction curve was successfully expressed. Moreover, the effects of compaction on compressibility and permeability of compacted soil could be reasonably explained. Additionally, shear deformation was applied to the specimen obtained from static compaction simulations in soil/water/air coupled analysis. The relationships between shear strength and compaction curve showed good agreement with the actual behavior.
  • 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年11月27日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869837401&origin=inward
    概要: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年11月27日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869836248&origin=inward
    概要: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年11月27日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869745705&origin=inward
    概要: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年11月27日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84869747381&origin=inward
    概要: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.
  • 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, 3, 357, 362,   2012年01月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84905699789&origin=inward
    概要: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.
  • 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年12月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859950443&origin=inward
    概要: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年12月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859987778&origin=inward
    概要: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年12月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859939716&origin=inward
    概要: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年12月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859977892&origin=inward
    概要: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, PARTS A AND B, 949, 954,   2011年12月01日, 10.1115/ICEM2011-59153, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84882977226&origin=inward
    概要: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.
  • Theoretical Evaluation of the Mechanical Behavior of Unsaturated Soils, Michinori Honda, Shintaro Ohno, Atsushi Iizuka, Katsuyuki Kawai, Hideki Ohta, Geotechnical and Geological Engineering, 29, 2, 171, 180,   2011年03月01日, 10.1007/s10706-010-9340-6, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=79952036410&origin=inward
    概要: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.
  • 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年12月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84859819417&origin=inward
    概要: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.
  • Laboratory hydraulic testing in unsaturated soils, Farimah Masrouri, Kátia V. Bicalho, Katsuyuki Kawai, Laboratory and Field Testing of Unsaturated Soils, 79, 92,   2009年12月01日, 10.1007/978-1-4020-8819-3_7, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84889972084&origin=inward
    概要: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. © 2009 Springer Netherlands.
  • 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, 1, 526, 529,   2009年12月01日, 10.3233/978-1-60750-031-5-526, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84865166126&origin=inward
    概要: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.
  • 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年12月01日, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=79952039835&origin=inward
    概要: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.
  • The role of pore water in the mechanical behavior of unsaturated soils, Daizo Karube, Katsuyuki Kawai, Geotechnical and Geological Engineering, 19, 3/4, 211, 241,   2001年12月01日, 10.1023/A:1013188200053, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0035690303&origin=inward
    概要: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.
  • 不飽和土の応力〜ひずみ関係式, 本田 道識, 飯塚 敦, 河井 克之, 軽部 大蔵, 土木学会論文集 = Proceedings of JSCE, 659, 153, 164,   2000年09月21日, 10.2208/jscej.2000.659_153, http://ci.nii.ac.jp/naid/10004745413
  • 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年, 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年, http://jglobal.jst.go.jp/public/201502211309954492
  • 急性期災害医療におけるDMAT配置モデルに関する考察, 小谷稔, 飯塚敦, 河井克之, 土木学会論文集 F6(安全問題)(Web), 71, 1, 32, 45,   2015年, 10.2208/jscejsp.71.32, http://jglobal.jst.go.jp/public/201502213600138018
  • 海上埋立て地盤および立地建物の長期沈下挙動について, 軽部 大蔵, 深川 義隆, 本田 周二, 河井 克之, 土木学会論文集 = Proceedings of JSCE, 665, 665, 1, 18,   2000年12月20日, 10.2208/jscej.2000.665_1, http://ci.nii.ac.jp/naid/10005122012
  • 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年, http://jglobal.jst.go.jp/public/201502220634254706
  • 間隙比の影響を考慮した水分特性曲線モデル, 河井 克之, 軽部 大蔵, 芦田 渉, 嘉戸 善胤, 土木学会論文集 = Proceedings of JSCE, 666, 291, 302,   2000年12月21日, 10.2208/jscej.2000.666_291, http://ci.nii.ac.jp/naid/10005121938
  • 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年, http://jglobal.jst.go.jp/public/201502220920955274
  • 不飽和土の一軸圧縮試験時の強度特性に及ぼすサクションの影響, 加藤 正司, 吉村 優治, 河井 克之, 寸田 亘, 土木学会論文集 = Proceedings of JSCE, 687, 201, 218,   2001年09月21日, 10.2208/jscej.2001.687_201, http://ci.nii.ac.jp/naid/10007554918
    概要:一定エネルギーで締固めた, さまざまな飽和度のシルト質土供試体を用いて, サクションおよび体積変化を測定した一軸圧縮試験を行った. 得られた応力~ひずみ関係は初期飽和度に依存した傾向を示した. また, 破壊時のサクション応力~サクション関係の実測値は水分特性曲線より得られる予測値に近い傾向を示した. この結果はサクション~粘着力関係を一軸圧縮試験により予測できる可能性を示している. さらに, 破壊時の応力状態は, 破壊時のサクション応力を拘束応力とした場合, Fredlund, Morgenstern & Widger により提案されている不飽和土の破壊規準に従うことが判明した. このことは, 非排水状態で得られる一軸圧縮試験の強度が, 排水試験に基づいて得られた破壊規準に従うことを意味している.
  • 深海底プレート境界デコルマ帯におけるせん断破壊モデル, 杉山友理, 戎健次, 飯塚敦, 河井克之, 佐々木陽亮, 土木学会論文集 A2(応用力学)(Web), 71, 2, 605, 612,   2015年, 10.2208/jscejam.71.I_605, http://jglobal.jst.go.jp/public/201602202902086152
  • ワイブル分布を用いた被災者数情報のベイズ推定, 小谷稔, 飯塚敦, 河井克之, 土木学会論文集 F6(安全問題)(Web), 71, 1, 46, 57,   2015年, 10.2208/jscejsp.71.46, http://jglobal.jst.go.jp/public/201602204949457038
  • 降雨時における傾斜地盤内空気の挙動について, 川勝拓哉, 河井克之, TIWARI Binod, 飯塚敦, 土木学会論文集 A2(応用力学)(Web), 71, 2, 171, 180,   2015年, 10.2208/jscejam.71.I_171, http://jglobal.jst.go.jp/public/201602214872743810
  • 不飽和土の非排水三軸圧縮試験における変形強度特性および水分特性, 河井 克之, 軽部 大蔵, 嘉戸 善胤, 加藤 正司, 土木学会論文集 = Proceedings of JSCE, 715, 287, 296,   2002年09月21日, 10.2208/jscej.2002.715_287, http://ci.nii.ac.jp/naid/10009726893
    概要:不飽和供試体の非排水三軸圧縮試験を行い, 不飽和土の非排水変形強度特性および水分特性について調べた. 試験は, まず飽和状態にある供試体を加圧板法で不飽和化し, その後供試体の間隙空気圧を一定に保ち, 非排水状態で軸圧縮を行った. 比較的飽和度が高い供試体では, 間隙水圧は, せん断による体積圧縮とともに増加し, 膨張とともに消散した. しかしながら, せん断による体積膨張量が顕著になってくると, 再び間隙水圧は増加した. 一方, 飽和度が低い供試体では, 体積変化とは無関係に, 間隙水圧が増加するという傾向が現れた. これは, バルク水とメニスカス水の骨格変形に対する作用の違いとして説明できることが分かった. また, サクション応力を用いれば排水試験と同様の破壊基準を用いることができ, 飽和土の限界状態線と一致することがわかった.
  • マルチング材料としての粉砕汚泥焼成煉瓦の有効活用について, 河井 克之, 佐伯 拓也, 野村 瞬, 骨材資源, 47, 185, 13, 23,   2015年, http://ci.nii.ac.jp/naid/40020510581
  • TC106.不飽和士(国際学会TCワークショップ,<特集>第18回国際地盤工学会議(パリ)), 河井 克之, 地盤工学会誌, 62, 3,   2014年, http://ci.nii.ac.jp/naid/110009804454
  • 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 (平成24年度高速道路関連社会貢献協議会研究助成の概要(その4)), 河井 克之, 高速道路と自動車 = Expressways and automobiles, 56, 11, 53, 55,   2013年11月, http://ci.nii.ac.jp/naid/40019853179
  • 土/水/空気連成有限要素解析による締固め特性に及ぼす土質定数の影響の検討, 河井 克之, 坂本 諭, Phommachanh Viradeth, 飯塚 敦, 土木学会論文集A2(応用力学), 68, 2, I_299, I_306,   2012年, http://ci.nii.ac.jp/naid/130004557270
    概要: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.
  • 本号の編集にあたって, 河井 克之, 地盤工学会誌, 59, 12,   2011年, http://ci.nii.ac.jp/naid/110008798759
  • 不飽和土/水連成有限要素解析における空間離散化手法の検討, 金澤 伸一, 橘 伸也, 河井 克之, 大野 進太郎, 飯塚 敦, 応用力学論文集, 11, 331, 338,   2008年, 10.2208/journalam.11.331, http://ci.nii.ac.jp/naid/130004091245
    概要: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.
  • 植生の吸水作用が地盤の安定性に及ぼす影響, 河井 克之, 山田 竜太郎, 飯塚 敦, 橘 伸也, 大野 進太郎, 応用力学論文集, 11, 443, 450,   2008年, 10.2208/journalam.11.443, http://ci.nii.ac.jp/naid/130004091256
    概要: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.
  • 有効飽和度を剛性に関する状態量とした不飽和土の弾塑性構成モデル, 大野 進太郎, 河井 克之, 橘 伸也, 土木学会論文集C, 63, 4, 1132, 1141,   2007年, 10.2208/jscejc.63.1132, http://ci.nii.ac.jp/naid/130004943035
    概要: 不飽和地盤の長期挙動を高精度に予測するためには,不飽和土の特徴である,乾燥時の収縮および剛性増加,湿潤時の剛性減少に伴うコラプス沈下,乾湿履歴の影響を,表現する必要がある.本論文では,実務への適用を見据え,剛性を表す状態量として,簡易に測定可能な有効飽和度を用いた,不飽和土弾塑性構成モデルを提案する.提案モデルは,降伏面の設定に関して軽部らのモデルを参考にし,水分特性曲線モデルを設定すれば,乾湿履歴が変形特性に及ぼす影響を,変形および水収支に関して矛盾なく表現できる.また,有効飽和度の剛性への影響量を2つのフィッティングパラメーターで表すため,従来のモデルよりも柔軟性に富む.本研究では,締固め土のコラプス挙動を提案モデルと比較し,モデルの妥当性を検証している.
  • Deformation characteristics of a compacted clay in collapse under isotropic and triaxial stress state., 加藤 正司, 河井 克之, 地盤工学会論文報告集, 40, 5, 75, 90,   2000年01月01日, 10.3208/sandf.40.5_75, http://ci.nii.ac.jp/naid/130004247568
    概要: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.
  • 植生の吸水作用が地盤に及ぼす効果, 河井 克之, 飯塚 敦, 霜永 勝之, 橘 伸也, 応用力学論文集, 10, 375, 381,   2007年, 10.2208/journalam.10.375, http://ci.nii.ac.jp/naid/130004257904
    概要: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.
  • 物質移動を考慮した不飽和土/水連成問題の数理モデルと有限要素解析手法, 藤川 和彦, 飯塚 敦, 河井 克之, ピパットパンサー ティラポン, 応用力学論文集, 9, 377, 384,   2006年, 10.2208/journalam.9.377, http://ci.nii.ac.jp/naid/130004258414
    概要: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.
  • 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, 垣本 徹, 河井 克之, 地盤工学研究発表会 発表講演集, 38, 0, 1201, 1202,   2003年, http://ci.nii.ac.jp/naid/130004620593
    概要: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。
  • 荷重履歴の違い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, 38, 0, 1351, 1352,   2003年, http://ci.nii.ac.jp/naid/130004620677
    概要: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.
  • 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型かMohr-Coulomb型か-, 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, 38, 0, 293, 294,   2003年, http://ci.nii.ac.jp/naid/130004621317
    概要: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.
  • 上・拡張下負荷面,回転硬化を導入した弾塑性構成式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, 38, 0, 495, 496,   2003年, http://ci.nii.ac.jp/naid/130004621429
    概要: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。
  • 下負荷面弾塑性構成モデルを用いた土/水連成動的FE解析, 飯塚 敦, 大野 進太郎, 河井 克之, 建山 和由, 応用力学論文集, 5, 601, 610,   2002年, http://ci.nii.ac.jp/naid/130004258209
    概要: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.
  • 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, 5, 767, 775,   2002年, http://ci.nii.ac.jp/naid/130004258229
    概要:The deformation of soils is essentially dependent on the stress/deformation history in the past. The construction activity is nothing else but such a mechanical action given to foundation ground as the stress/deformation history. In this paper, considered is an imaginary construction of man-made reclamation land on soft ground foundation and examined is how difference of construction sequences effects on the final quality of the soil structure. Particularly, developments of inhomogeneous settlement, stress and pore water distribution after the completion of construction work are compared through a series of soil/water coupled elasto-viscoplastic finite element simulations. The final target of this study aims at specifying necessary maintenance works resulting in reducing the total life-cycle-cost (L. L. C.)
  • 不飽和土のせん断強度に与える間隙水分布の影響, 本田道識, 河井克之, 加藤正司, 軽部大蔵, 土質工学研究発表会発表講演集, 29th, 3-1, 627, 628,   1994年05月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902104867700996
  • 不飽和土の力学特性と水分特性曲線の関係について, 軽部大蔵, 田中泰雄, 河井克之, 芦田渉, 建設工学研究所論文報告集, 39, 39-A, 25, 35,   1997年11月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902100598302622
  • 不飽和土の力学を用いた締固め土における圧密降伏応力の簡易予測手法, 河井 克之, 金 銀羅, 流田 寛之, 飯塚 敦, 本田 道識, 応用力学論文集, 5, 785, 792,   2002年, http://ci.nii.ac.jp/naid/130004258231
    概要: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.
  • 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年05月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902138527212247
  • 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ー研究報告, 4, 231, 239,   2000年03月, http://ci.nii.ac.jp/naid/120000944769
  • 砂質土(強度2)(3.地盤材料,総括,<特集>第46回地盤工学研究発表会), 河井 克之, 地盤工学会誌, 59, 12,   2011年, http://ci.nii.ac.jp/naid/110008798800
  • 間隙水分布を考慮した非排水状態における不飽和土の力学挙動, 嘉戸善胤, 河井克之, 芦田渉, 軽部大蔵, 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年05月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902162892089452
  • 地盤工学会技術奨励賞を受賞して, ティラポン ピパットポンサー, 河井 克之, 地盤工学会誌 = / the Japanese Geotechnical Society, 56, 8,   2008年08月01日, http://ci.nii.ac.jp/naid/110006835793
  • 不飽和土の水分特性曲線とその定量化, 芦田渉, 河井克之, 嘉戸善胤, 軽部大蔵, 地盤工学研究発表会発表講演集, 31st, 2-2, 2071, 2072,   1996年05月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902176022007966
  • DEFORMATION CHARACTERISTICS OF A COMPACTED CLAY IN COLLAPSE UNDER ISOTROPIC AND TRIAXIAL STRESS STATE, 加藤 正司, 河井 克之, 地盤工学会論文報告集, 40, 5, 75, 90,   2000年10月15日, 10.3208/sandf.40.5_75, http://ci.nii.ac.jp/naid/110003946241
    概要: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.
  • 次世代を担う会員交流会 : 関西支部 第5回若手交流会の開催報告, 太田 里佳, 河井 克之, 倉橋 亜紀, 地盤工学会誌 = / the Japanese Geotechnical Society, 56, 8,   2008年08月01日, http://ci.nii.ac.jp/naid/110006835800
  • 非排水条件における不飽和供試体の三軸圧縮試験, 河井克之, 芦田渉, 嘉戸善胤, 軽部大蔵, 地盤工学研究発表会発表講演集, 31st, 2-1, 825, 826,   1996年05月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902177283785580
  • A Proposal for the Method of Formulation of Water Retention Curve for Unsaturated Soils, 軽部 大蔵, 河井 克之, 建設工学研究所論文報告集, 42, 1, 12,   2000年11月, http://ci.nii.ac.jp/naid/110000078066
  • モデル化,他(3.地盤材料-不飽和土,<特集>第43回地盤工学研究発表会), 河井 克之, 地盤工学会誌, 56, 12,   2008年, http://ci.nii.ac.jp/naid/110007005467
  • 締固め粘性土の等方およびせん断応力条件下におけるコラプス時の変形特性(『地盤工学会論文報告集』Vol.40,No.5 (2000年10月発行)掲載論文の概要), 加藤 正司, 河井 克之, 土と基礎, 48, 11,   2000年11月01日, http://ci.nii.ac.jp/naid/110003976570
  • 締固め土のサクションと圧密降伏応力の関係について, 河井 克之, 金 銀羅, 飯塚 敦, [他], 神戸大学都市安全研究センター研究報告, 6, 397, 407,   2002年03月, http://ci.nii.ac.jp/naid/120000944960
  • 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年05月22日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902199833595795
  • 温度変化に伴う粘土の間隙水圧挙動, 藤原照幸, 吉田高之, 村田識至, 河井克之, 軽部大蔵, 地盤工学研究発表会発表講演集, 34th, 475, 476,   1999年06月18日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902124689507762
  • 不飽和土の応力~ひずみ関係の定式化, 本田道識, 軽部大蔵, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集, 34th, 747, 748,   1999年06月18日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902144703386729
  • 水分特性曲線ヒステリシスと不飽和土力学挙動に影響を及ぼす応力成分, 河井 克之, 建設工学研究所論文報告集, 43, 187, 196,   2001年11月, http://ci.nii.ac.jp/naid/110000078117
  • 間隙比の影響を考慮に入れた水分特性モデル, 河井克之, 瀬口均, 吉牟田竜太, 軽部大蔵, 地盤工学研究発表会発表講演集, 34th, 727, 728,   1999年06月18日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902153391446876
  • 粘土の沈降挙動に及ぼす温度と塩分の影響, 吉田高之, 藤原照幸, 森大助, 河井克之, 軽部大蔵, 地盤工学研究発表会発表講演集, 34th, 473, 474,   1999年06月18日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902185579449170
  • 高温条件下における粘土の沈降挙動に及ぼす塩分濃度の影響, 藤原照幸, 吉田高之, 村田識至, 河井克之, 軽部大蔵, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 376, 377,   1999年08月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902147907480456
  • 土の水分特性曲線に及ぼす要因の検討, 河井克之, 軽部大蔵, 芦田渉, 嘉戸善胤, 建設工学研究所論文報告集, 41, 41-A, 177, 184,   1999年11月29日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902162349114935
  • 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-B, 51, 59,   2000年03月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902101784380575
  • Changes in the Instantaneous Shear Modulus of Normally Consolidated Clay with Shear History (IWS-ATHENS 2003「地盤力学における予測とシュミレーション手法」特集号), 飯塚 敦, 橘 伸也, 河井 克之, 太田 秀樹, 地盤工学会論文報告集, 45, 2, 135, 143,   2005年04月15日, 10.3208/sandf.45.2_135, http://ci.nii.ac.jp/naid/110003969746
    概要:Changes in the instantaneous shear modulus associated with the non-coaxiality of NC clay materials are presented. A series of hollow cylindrical shear tests was performed to measure the changes in the instantaneous shear modulus with shear history. After each normally consolidated clay specimen was compressively sheared until a prescribed shear level, it was continuously torsionally sheared under a constant volume to measure the instantaneous shear modulus. Coaxial constitutive relations, such as these of the conventional Cam-clay type of models, predict that the instantaneous shear modulus obtained, does not change regardless of the compressive shear history. On the contrary, it is known that non-coaxial constitutive relations theoretically bring about changes in the instantaneous shear modulus in relation to the compressive shear history. The test results supported the predictions made by the non-coaxial constitutive models. Finally, the proper formulation for the non-coaxiality between the stress and the incremental plastic strain is discussed.
  • 不飽和土の一軸圧縮試験時の力学的挙動に対するサクションの影響の評価方法, 寸田亘, 加藤正司, 河井克之, 吉村優治, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 88, 89,   1999年08月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902166061416401
  • 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年03月31日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902126256607757
  • 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, ピパットポンサー ティラポン, 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, 11, 43, 50,   2007年03月, http://ci.nii.ac.jp/naid/120000943174
  • 高温下で沈降した超軟弱粘土の一次元圧縮挙動, 吉田高之, 藤原照幸, 村田識至, 河井克之, 軽部大蔵, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 378, 379,   1999年08月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902181122587432
  • タイ東北部の塩害調査と「ジグソー・ピーシス作戦」(<小特集>国際貢献・交流), ティラポン ピパットポンサー, 飯塚 敦, 河井 克之, 土と基礎, 55, 3, 22, 24,   2007年03月01日, http://ci.nii.ac.jp/naid/110006239357
    概要:By a consequence of surveys on salt damage areas in the northeastern part of Thailand during October, 13-20, 2005 and November 26-29, 2006, a co-organized workshop on numerical method for unsaturated soil behaviors prediction was held in Bangkok on November 27, 2006. The sites and related organizations were visited to investigate the backgrounds of salt disaster. It was found that though each organization has clear different missions, there are some missing links among organizations to solve the salt disaster which is caused by multiple factors. It is expected that the workshop will be benefit to Thai experts while promoting mutual cooperation together.
  • 水分特性曲線の形状に与える拘束圧の影響, 吉牟田竜太, 河井克之, 瀬口均, 土木学会年次学術講演会講演概要集 第3部, 54th, A, 592, 593,   1999年08月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902181366998795
  • 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ー研究報告, 13, 1, 9,   2009年03月, http://ci.nii.ac.jp/naid/120002023100
  • 高温条件下で堆積した粘土の構造と圧縮性, 藤原照幸, 吉田高之, 村田識至, 河井克之, 軽部大蔵, 地盤工学シンポジウム論文集, 44th, 63, 66,   1999年11月17日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902151351664630
  • 不飽和土の力学理論から見た土の締固め (特集 盛土の設計と締固め), 河井 克之, 金澤 伸一, 飯塚 敦, 基礎工, 37, 7, 32, 35,   2009年07月, http://ci.nii.ac.jp/naid/40016746944
  • 間隙水分布の違いを考慮した不飽和土の土/水連成解析, 飯塚敦, 本田道識, 西田博文, 河井克之, 軽部大蔵, 土木学会論文集, 659, 165, 178,   2000年09月21日, 10.2208/jscej.2000.659_165, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902136319110543
  • 定サクション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, 建設工学研究所論文報告集, 42, 42-A, 151, 158,   2000年11月29日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902107013110728
  • 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年05月31日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902118375799050
  • 不飽和土の一軸圧縮強度に及ぼすサクション応力の影響, 加藤正司, 吉村優治, 河井克之, 寸田亘, 建設工学研究所論文報告集, 42, 42-A, 121, 130,   2000年11月29日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902112491966780
  • 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年05月31日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902192825276821
  • 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年06月05日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902167959997474
  • 間隙比の影響を考慮した水分特性曲線モデル, 河井 克之, 軽部 大蔵, 芦田 渉, 嘉戸 善胤, 土木学会論文集, 666, 291, 302,   2000年, 10.2208/jscej.2000.666_291, http://ci.nii.ac.jp/naid/130003983710
    概要:本論文では, 水分特性曲線に与える要因の検討を行うために, 3種類の試験方法でサクションによる脱水曲線と吸水曲線を得た. 一つ目は, 初期状態 (含水比, 間隙比, 飽和度) の異なる水分特性曲線, 二つ目に, サクション履歴の異なる水分特性曲線, そして, 拘束圧条件の異なる水分特性曲線である. 得られた水分特性曲線は, その形状を定量的に評価するために, Brooks and Corey 式で近似し, 算出されたフィッティングパラメーターの値を比較した. その結果, 水分特性曲線は間隙比に大きく依存することが分かった. その効果は空気侵入値, 水侵入値に現れ, それぞれ間隙比の関数で表される. この関係を Toll の提案するサクション~間隙比/等価間隙比面に適用した新しいモデルを提案する. このモデルによって, 任意の初期状態から描く脱水曲線, 吸水曲線を予測することができる.
  • 海上埋立て地盤および立地建物の長期沈下挙動について, 軽部 大蔵, 深川 義隆, 本田 周二, 河井 克之, 土木学会論文集, 2000, 665, 1, 18,   2000年, 10.2208/jscej.2000.665_1, http://ci.nii.ac.jp/naid/130003983674
    概要: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.
  • 不飽和土の応力~ひずみ関係式, 本田 道識, 飯塚 敦, 河井 克之, 軽部 大蔵, 土木学会論文集, 659, 153, 164,   2000年, 10.2208/jscej.2000.659_153, http://ci.nii.ac.jp/naid/130003801642
    概要:本論文は不飽和粘性土の応力~ひずみ関係式を提案している. Jennings らが Bishopの有効応力式の適用限界を実験的に明らかにして以来, 不飽和土に対してはサクションの作用を独立に取り扱うことで定式化した構成モデルを用いて力学挙動を表現する試みがおこなわれている. 本稿においては土塊内の間隙水分布状態を反映させた応力成分を用いて力学挙動を表現しているモデルに対して塑性降伏条件と硬化パラメータに新たな概念を適用し, 関連流動則にもとづいた応力~ひずみ関係式を定式化している. 計算結果と三軸試験結果との比較は良い一致を示している.
  • 軸対称応力条件下における不飽和砂のせん断時の変形強度特性に与えるサクションの影響, 加藤正司, 畑中憲彦, 河井克之, 建設工学研究所論文報告集, 43, 43-A, 153, 160,   2001年11月29日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902134364014919
  • 間隙水分布の違いを考慮した不飽和土の土/水連成解析, 飯塚 敦, 本田 道識, 西田 博文, 河井 克之, 軽部 大蔵, 土木学会論文集, 659, 165, 178,   2000年, 10.2208/jscej.2000.659_165, http://ci.nii.ac.jp/naid/130003801643
    概要:本論文では, 不飽和状態に置かれている土構造物を対象として, 有限要素法を用いた初期値・境界値問題として取り扱う手法を提示している. 不飽和土の力学特性を特徴づける水分特性曲線のヒステリシスを考慮した弾塑性構成モデルを用い, 土/水連成の有限要素プログラムを開発した. まず, 解くべき初期値・境界値問題を述べ, 用いた数理モデルを説明している. さらに, 有限要素プログラムの検証を行った後, 簡単な例題として仮想堤体の問題を取り上げ, 堤体上流側の水位変化による堤体内部の応力変化と変形を調べている.
  • 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年05月08日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902138747015965
  • 等方応力状態における不飽和土の降伏関数に関する一考察, 河井克之, 加藤正司, 森田寿, 建設工学研究所論文報告集, 43, 43-A, 197, 204,   2001年11月29日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902168076635382
  • 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年05月08日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902161835622180
  • 谷地形盛土の不同沈下シミュレーション, 早川英司, 霜永勝之, 小羽根憲司, 河井克之, 飯塚敦, 地盤工学研究発表会発表講演集, 38th, 0, 911, 912,   2003年06月06日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902214006058681
    概要: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。
  • 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年05月08日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902184372946801
  • 地盤改良時期および位置が残留沈下に及ぼす影響, 和泉大祐, 西田博文, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集, 38th, 0, 1353, 1354,   2003年06月06日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902237528208136
    概要: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.
  • 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年09月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902195720079582
  • 下負荷面弾塑性構成モデルを用いた土/水連成動的FE解析, 飯塚敦, 大野進太郎, 河井克之, 建山和由, 応用力学論文集, 5, 601, 610,   2002年08月28日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902172436071970
  • 水分特性曲線ヒステリシスと不飽和土力学挙動に影響を及ばす応力成分, 河井克之, 建設工学研究所論文報告集, 43-A, 187, 196,   2001年11月29日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902173914992994
  • 施工過程の違いによる人工島の品質への影響, 西田博文, 井内崇也, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集, 37th, 961, 962,   2002年06月17日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902114116171845
  • 土/水連成弾塑性動的有限要素解析手法の開発, 大野進太郎, 飯塚敦, 河井克之, 橘伸也, 地盤工学研究発表会発表講演集, 37th, 1885, 1886,   2002年06月17日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902146964622244
  • せん断に伴う応力‐塑性ひずみ増分の非共軸性, 辰巳雅俊, 高木智哉, 飯塚敦, 河井克之, 地盤工学研究発表会発表講演集, 37th, 247, 248,   2002年06月17日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902160891437675
  • 非排水条件下での等方応力載荷による不飽和土の水分特性, WANG W, 河井克之, 桜井健一, 地盤工学研究発表会発表講演集, 37th, 947, 948,   2002年06月17日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902189048579199
  • 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年09月01日, 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年09月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902162931476442
  • 8.メインテナンスの力学問題 施工履歴の違いを考慮したCAES地下空洞掘削シミュレーション, 西田博文, 飯塚敦, 河井克之, 伊藤文雄, 応用力学論文集, 6, 1131, 1139,   2003年08月28日, 10.2208/journalam.6.1131, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902246924846063
    概要: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
  • 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年09月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902195895910586
  • 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年06月06日, 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年06月06日, 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年06月06日, 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年06月06日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902282785062865
  • 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年09月01日, 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年09月01日, 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年09月01日, 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年09月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902285655645884
  • 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年05月29日, 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年05月29日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902271020180639
  • 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年06月15日, 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年06月15日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902240453161717
  • 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年03月31日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902226783617307
  • 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年06月15日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902291765335945
  • 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年08月20日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902223861068022
  • 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年06月20日, 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年06月20日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902255047309352
  • 植生の吸水作用が地盤に及ぼす効果, 河井克之, 飯塚敦, 霜永勝之, 橘伸也, 応用力学論文集, 10, 375, 381,   2007年08月29日, 10.2208/journalam.10.375, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902220238470198
  • 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年05月26日, 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年05月26日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902276717588778
  • 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年06月11日, 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年06月11日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902277250746915
  • 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年03月31日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002277388926362
  • 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年06月12日, 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年06月12日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902287605706320
  • 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年08月13日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902214043515316
  • 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年07月13日, 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年07月13日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902241413577836
  • 土/水連成有限要素解析プログラムを用いた静的締固めシミュレーション, 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, 12, 429, 436,   2009年08月19日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902283003347870
  • 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年07月13日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902241441210824
  • 耐塩害性地盤構造及び塩害地盤浄化手法の検討, 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, 12, 421, 428,   2009年08月19日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902287987135491
  • 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年07月13日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902254266211850
  • 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, 37, 7, 032, 035,   2009年07月15日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902230869879204
  • 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年08月03日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902209885238430
  • 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), 13, 423, 430,   2010年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102233367099849
  • 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), 13, 363, 370,   2010年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102238610488311
  • 飽和/不飽和地盤内における水溶性物質移動モデルの構築, 野村瞬, 河井克之, 角井駿祐, 橘伸也, 金澤伸一, 飯塚敦, 土木学会論文集 A2(応用力学)(Web), 67, 2, I.231-I.240 (J-STAGE), I_240,   2011年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202248812988408
    概要: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.
  • 不飽和土/水/空気連成解析を用いた締固めシミュレーション, 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年03月31日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302213769947971
  • 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不均一性の把握, 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年03月31日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302225695048366
  • 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年05月22日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002252812376014
  • 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年07月15日, 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年07月15日, 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年07月15日, 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年07月15日, 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年07月15日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002298728591856
  • 土/水/空気連成有限要素解析プログラムによる含水比を変えた締固め盛土施工シミュレーション, PHOMMACHANH Viradeth, 河井克之, 佐藤武斗, 飯塚敦, 理論応用力学講演会講演論文集(Web), 61st, 0, WEB ONLY OS11-06, 101,   2012年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302220869509641
    概要:河川堤防やアースダム等,陸上地盤構造物を建造する場合は,締固め土が多く用いられるが,締固め土はその強度発現メカニズムが解明されておらず,規格化された室内締固め試験結果を経験的手法で現場に適用する.本研究グループは,締固め土を不飽和土の排気非排水圧縮・膨張現象と捉え,土/水/空気連成有限要素解析プログラムDACSAR-MPを用いて,一次元室内締固め試験のシミュレーションを行い,山を持つような締固め曲線を描くことに成功した.これらを踏まえて,フルスケールの盛土構造物を模擬し,実際の手順に近い段階施工をならい,盛土の施工シミュレーションを行い,盛土施工の過程で発生する盛土内部の応力・間隙比・含水比などの不均一性を把握する.また,最適含水比及びその前後の含水比に対して,盛土の内部の変化を確認する.ここでは,敷き均しから放置まで,盛土を忠実に模擬することで,解析を通じて,締固め方法による盛土の品質の違いを検討することを目的としている.
  • 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年08月05日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002220905351870
  • 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年09月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002239180335582
  • 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年, 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年, 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年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102238976036294
  • 土/水/空気連成有限要素法を用いた締固め土の力学挙動の解析, 金澤伸一, 豊嶋拓馬, 河井克之, 橘伸也, 飯塚敦, 土木学会論文集 A2(応用力学)(Web), 68, 2, I.291-I.298 (J-STAGE), I_298,   2012年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402216954464975
    概要: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.
  • 盛土材料の初期含水条件が初期応力状態に及ぼす影響, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302211091923713
  • スマート三軸試験装置を用いた三軸圧縮せん断試験, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302243132379798
  • 土/水/空気/溶解物質連成問題の定式化とその応用, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302273421351474
  • 地盤内塩分移動シミュレーションによる陸前高田一本松の生育環境評価, 河井克之, 杉山友理, 野村瞬, 飯塚敦, 土木学会論文集 A2(応用力学)(Web), 68, 2, I.345-I.352 (J-STAGE), I_352,   2012年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402226356290607
    概要: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.
  • ベントナイト材料の力学挙動のモデル化, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302278807062932
  • 自硬性を考慮した石炭灰のモデル化及び埋立て模型地盤の解析シミュレーション, PHOMMACHANH Viradeth, 前川太, 河井克之, 飯塚敦, 土木学会論文集 A2(応用力学)(Web), 68, 2, I.307-I.315 (J-STAGE), I_315,   2012年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402260232408620
    概要: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.
  • 土/水/空気連成有限要素解析プログラムを用いた締固め土の強度発現メカニズムの検討, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302278926061146
  • 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年08月05日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102220897649926
  • 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年, 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年, 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年, 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年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202255186118320
  • 土/水/空気連成有限要素解析による締固め特性に及ぼす土質定数の影響の検討, 河井克之, 坂本諭, PHOMMACHANH Viradeth, 飯塚敦, 土木学会論文集 A2(応用力学)(Web), 68, 2, I.299-I.306 (J-STAGE), I_306,   2012年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402222811480791
  • 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年, 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年, 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年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202297976793110
  • 不飽和土の力学によるジオテキスタイル補強効果の検討, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302225883499766
  • 地下水位変動に伴う地盤の長期沈下, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302252719566875
  • 自硬性を考慮した石炭灰のモデル化, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302254307908898
  • 神戸空港島の経年品質評価, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302279794669758
  • 土/水/空気連成有限要素解析による不飽和土室内試験における供試体内部状況の把握, 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年03月, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302296863459932
  • 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年08月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202254962703584
  • 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年09月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202271327087003
  • 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年, 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年, 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年, 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年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302214212051122
  • 東日本大震災の津波による地盤塩害及び土壌汚染調査・分析, 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, 理論応用力学講演会講演論文集(Web), 62nd, WEB ONLY OS20-01,   2013年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302251476106653
  • 土/水/空気三相連成モデルによる間隙圧係数B値の解釈, 杉山友理, 河井克之, 田中博之, 飯塚敦, 土木学会論文集 A2(応用力学)(Web), 70, 2, 145, 153,   2014年, 10.2208/jscejam.70.I_145, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201502210737942574
    概要:三軸試験を行う場合に,供試体設置後に計測されるB値は,供試体の飽和化の度合いを知るために用いられる.しかしながら,このB値に及ぼす要因については,飽和度以外には詳細な力学的説明は加えられていない.本論文では,極めて飽和に近い不飽和状態でも,間隙空気の挙動を精緻に表現できるように,まず既存の不飽和土構成モデルの枠組みに,空気相の液相への溶解を規定するヘンリーの法則を適用し定式化した.次に,得られたモデルを用いて,供試体の飽和度や拘束圧,背圧がB値計測に及ぼす影響を数値シミュレーションによって検討した.その結果,同じ飽和状態であっても,応力条件によって計測されるB値が異なることが分かった.
  • 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年, 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年, 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年, 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年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302290976305356
  • 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年08月01日, 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年08月01日, 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年08月01日, 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年08月01日, 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年08月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302287824374530
  • 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年11月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302252523063964
  • 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年, 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年, 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年, 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年, 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年, 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年, 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年, 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年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402263278520385
  • 水分特性曲線ヒステリシスの表現と不飽和土の応力変化, 河井 克之, 江 偉川, 飯塚 敦, 応用力学論文集, Vol.5,pp.777-784, 777, 784,   2002年08月28日, http://ci.nii.ac.jp/naid/130004258230
    概要: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.
  • 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年, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402283518689120
  • 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年08月01日, 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年08月01日, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402276535592834
  • 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, 応用力学論文集, Vol.5,pp.601-610, 767, 775,   2002年08月28日, http://ci.nii.ac.jp/naid/40005574438
  • 不飽和土の力学を用いた締固め土における圧密降伏応力の簡易予測手法, 河井 克之, 金 銀羅, 流田 寛之, 応用力学論文集, Vol.5,pp.785-792, 785, 792,   2002年08月28日, http://ci.nii.ac.jp/naid/40005574440
  • 既存の不飽和土構成モデルの解釈および水分特性曲線ヒステリシスを考慮したモデルの一般的な表現方法, 河井 克之, 汪 偉川, 飯塚 敦, 応用力学論文集, Vol.7,No.1,pp.505-513, 1, 505, 513,   2004年08月23日, http://ci.nii.ac.jp/naid/130004091612
    概要: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
  • Modeling of the confining effect due to the geosynthetic wrapping of compacted soil specimens, Atsushi Iizuka, Katsuyuki Kawai, Eun Ra Kim, Masafumi Hirata, Journal of Geotextiles and Geomembranes, Elsevier, 22, 5, 329, 358,   2004年10月01日, 10.1016/j.geotexmem.2004.01.001, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=3142710897&origin=inward
    概要: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.
  • 軟弱盛土基礎地盤の挙動予測における地盤調査結果の差異の影響, 飯塚 敦, 西田 博文, 河井 克之, 建設工学研究所論文報告集, 第47号,87-100, 47, 87, 99,   2005年11月28日, http://ci.nii.ac.jp/naid/110004084754
  • Changes in the instantaneous shear modulus of normally consolidated clay with shear history, Atsushi Iizuka, Shinya Tachibana, Katsuyuki Kawai, Hideki Ohta, Soils and Founadtions, 45, 2, 135, 143,   2005年04月01日, 10.3208/sandf.45.2_135, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=18844448330&origin=inward
    概要:Changes in the instantaneous shear modulus associated with the non-coaxiality of NC clay materials are presented. A series of hollow cylindrical shear tests was performed to measure the changes in the instantaneous shear modulus with shear history. After each normally consolidated clay specimen was compressively sheared until a prescribed shear level, it was continuously torsionally sheared under a constant volume to measure the instantaneous shear modulus. Coaxial constitutive relations, such as these of the conventional Cam-clay type of models, predict that the instantaneous shear modulus obtained, does not change regardless of the compressive shear history. On the contrary, it is known that non-coaxial constitutive relations theoretically bring about changes in the instantaneous shear modulus in relation to the compressive shear history. The test results supported the predictions made by the non-coaxial constitutive models. Finally, the proper formulation for the non-coaxiality between the stress and the incremental plastic strain is discussed.
  • 締固め土の圧縮特性に関する評価手法の検討, 本田 道識, 飯塚 敦, 大野 進太郎, 河井 克之, 汪 偉川, 土木学会論文集, 806, 33, 44,   2005年12月21日, 10.2208/jscej.2005.806_33, http://ci.nii.ac.jp/naid/10016726648
    概要:本論文では締固め土における圧縮特性の評価手法を検討している. 現在の締固め施工では乾燥密度に着目した品質管理が主流であるが, 管理値と力学特性との関連性を明確化する上では検討の余地が残されている. 本論文では締固め土の圧縮挙動に及ぼす影響要因として乾燥密度, 含水比, サクションおよび締固め荷重に着目し, それぞれの組み合わせが異なる供試体の一次元圧縮試験結果から圧縮挙動との関連性を考察した上で, 降伏応力および圧縮曲線の評価方法を提案している.
  • 不飽和土の応力 ひずみ関係の定式化, 第34回地盤工学研究発表会講演集, pp.747-748,   1999年
  • 締固め土の圧縮挙動に関する弾朔性構成モデルの適用, 神戸大学大学院自然科学研究科紀要, Vol.18-B,pp.51-59,   2000年
  • 締固め土のサクションと圧密降伏応力の関係について, 河井 克之, 金 銀羅, 飯塚 敦[他], 神戸大学都市安全研究センター研究報告, 第6号,pp.397-408, 397, 407,   2002年03月, http://ci.nii.ac.jp/naid/110000074748
  • 下負荷面弾朔性構成モデルを用いた土/水連成弾朔性動的有限要素解析手法の開発, 応用力学論文集, Vol.5,pp.601-610,   2002年
  • 物質移動を考慮した不飽和土/水連成問題の数理モデルと有限要素解析手法, 藤川 和彦, 飯塚 敦, 河井 克之, 応用力学論文集, 9, 377, 384,   2006年08月25日, 10.2208/journalam.9.377, http://ci.nii.ac.jp/naid/40015305962
  • 施工履歴の違いを考慮したCAES地下空洞掘削シミュレーション, 西田 博文, 飯塚 敦, 河井 克之, 応用力学論文集, 6, 1131, 1139,   2003年, 10.2208/journalam.6.1131, http://ci.nii.ac.jp/naid/80016285151
  • Unsaturated Soils -Geotechnical and Geoenvironmental Issues-, TC6 of International Society of Soil Mechanics and Geotechnical Engineering,   2003年
  • Proceedings of the 2nd Asian Conference on Unsaturated Soils, Organizing committee of the 2nd Asian Conference on Unsaturated Soils,   2003年
  • An evaluation method for the volume change characteristics of compacted soil, M. Honda, A. Iizuka, S. Ohno, K. Kawai, W. Wang, Proc 4th International Conference on Unsaturated Soil, 147, 837, 848,   2006年12月21日, 10.1061/40802(189)66, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=33845520828&origin=inward
    概要: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.
  • Effect of suction on shear strength and deformation of unsaturated sand in triaxial test, Proceedings of the 2nd Asian Conference on Unsaturated Soils, 247-252,   2003年
  • Non-uniform settlement of compacted earth structures caused by the deformation characteristics of unsaturated soil on wetting, Katsuyuki Kawai, Atsushi Iizuka, Eiji Hayakawa, Weichuan Wang, Soils and Foundations, 47, 2, 195, 205,   2007年01月01日, 10.3208/sandf.47.195, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=72449146805&origin=inward
    概要: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 (Iizuka 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.
  • The deformation and the moisture characteristics of unsaturated soils under isotropic loading and undrained condition, Proc. 2nd Asian Conference on Unsaturated Soils, pp.171-176,   2003年
  • Estimation of the consolidated yielding stress of compacted soil considering the effects of suction, Proc. 2nd Asian Conference on Unsaturated Soils, pp.271-276,   2003年
  • Numerical investigation on the failure criterion of normally consolidated clays, Shinya Tachibana, Atsushi Iizuka, Katsuyuki Kawai, Ichizou Kobayashi, Thirapong Pipatpongsa, Hideki Ohta, International Journal for Numerical and Analytical Methods in Geomechanics, 31, 6, 809, 833,   2007年05月01日, 10.1002/nag.562, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=34247582246&origin=inward
    概要: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 π-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 © 2006 John Wiley & Sons, Ltd.
  • Computational soil/water coupled unsaturated soil behavior, Proc. 2nd Asian Conference on Unsaturated Soils, pp.299-304,   2003年
  • Suction change of compacted soil during static compaction test, Proc. 2nd Asian Conference on Unsaturated Soils, pp.429-434,   2003年
  • Influence of water level change on the behavior of unsaturated zone, Proc. 13th European Conference on Soil Mechanics and Geotechnical Engineering, Vol.1, pp.735-738,   2003年
  • The change of instantaneous shear modulus associated with non-coaxiality of normally consolidated clays, Proc. International Workshop on Prediction and Simulation Methods in Geomechanics, pp.21-24,   2003年
  • 施工履歴の違いを考慮したCAES地下空洞堀削シミュレーション, 西田博文, 飯塚敦, 河井克之, 伊藤文雄, 応用力学論文集, 6, 1131, 1139,   2003年, 10.2208/journalam.6.1131
  • A study of the relation between volume change characteristics of compacted soil and the condition of compaction, Proc. 2nd Asian Conference on Unsaturated Soils, pp.177-180,   2003年
  • Numerical assessment of long term non-uniform settlement of man-made island, Proc. 13th European Conference on Soil Mechanics and Geotechnical Engineering, Vol.1, pp.709-712,   2003年
  • タイ東北部の塩害調査と「ジグソー・ピーシス作戦」, THIRAPONG Pipatpongsa, 飯塚敦, 河井克之, 土と基礎, Vol.55,No.3,Ser.No.590,pp.22-24, 3, 22-24,1(2),   2007年03月01日, http://jglobal.jst.go.jp/public/200902285635139460
  • 不飽和土/水連成有限要素解析における空間離散化手法の検討, 金澤 伸一, 橘 伸也, 河井 克之, 応用力学論文集, 11, 331, 338,   2008年08月25日, 10.2208/journalam.11.331, http://ci.nii.ac.jp/naid/40016270015
  • Changes in the instantaneous modulus of normally consolidated clay with shear history, IIZUKA Atsushi, TACHIBANA Shinya, KAWAI Katsuyuki, OHTA Hideki, Soils and Foundations, 45, 2, 135, 143,   2005年, 10.3208/sandf.45.2_135
  • 植生の吸水作用が地盤の安定性に及ぼす影響, 河井 克之, 山田 竜太郎, 飯塚 敦, 応用力学論文集, 11, 443, 450,   2008年08月25日, 10.2208/journalam.11.443, http://ci.nii.ac.jp/naid/40016270026
  • Laboratory hydraulic testing in unsaturated soils, Farimah Masrouri, Kátia V. Bicalho, Katsuyuki Kawai, Geotechnical and Geological Engineering, 26, 6, 691, 704,   2008年05月23日, 10.1007/s10706-008-9202-7, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=56349145654&origin=inward
    概要: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.
  • The non-coaxiality induced by stress rate on the instantaneous shear modulus of clays, in the book of Dislocations, Plasticity, Damage and Metal Forming : Material Response and Multiscale Modeling, Key-note-lecture, Proc. Of PLASTICITY'05 : the 11th International Symposium on Plasticity and its Current Applications, edited by A.S.Khan an・・・, 265-267,   2005年
    概要:in the book of Dislocations, Plasticity, Damage and Metal Forming : Material Response and Multiscale Modeling, Key-note-lecture, Proc. Of PLASTICITY'05 : the 11th International Symposium on Plasticity and its Current Applications, edited by A.S.Khan and A.R.Khoei.
  • 有効飽和度を剛性に関する状態量とした不飽和土の弾塑性構成モデル, 大野進太郎, 河井克之, 橘伸也, 土木学会論文集, 63, 4, 1132, 1141,   2008年, 10.2208/jscejc.63.1132, http://jglobal.jst.go.jp/public/200902283812360837
  • Elasto-plastic constitutive equation to describe re-liquefaction phenomenon, Plasticity, Damage and Metal Forming : Material Response and Multiscale Modeling, Proc. Of PLASTICITY'05: the 11th International Symposium on Plasticity and its Current Applications, edited by A.S.Khan and A.R.Khoei., 286-288,   2005年
  • The effect of evapo-transpiration through vegitation on unsaturated ground deformation, Proc. of Symposium on Elasto-plasticity, Fukuoka, Feb.28, pp.37-46,   2005年
  • Influence of ground improvement on the quality of man-made islands, Proc. of 11th International Association for Computer Methods and Advances in Geomechanics, 327-332,   2005年
  • Influence of ground improvement on the quality of man-made islands,   2005年
  • 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,   2005年
  • 締固め土の圧縮特性に関する評価方法,   2005年
  • 関口・太田モデルの圧密特性と粘塑性パラメータ,   2005年
  • 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,   2005年
  • タイ東北部の塩害調査と「ジグソー・ピーシズ作戦」, 土と基礎, Vol.55, No.3, SerNo.590, pp.22-24,   2006年
  • 植生の吸水作用が地盤に及ぼす影響, 河井克之, 飯塚敦, 霜永勝之, 橘伸也, 応用力学論文集, 10, 375, 381,   2007年, 10.2208/journalam.10.375
  • A study on yield stress in unsaturated clay, Proc. 3rd Asian Conf. on Unsaturated Soils, pp.219-233,   2007年
  • The salt disaster problem and its mathematical modeling, Proc. 3rd Asian Conf. on Unsaturated Soils, pp.347-352,   2007年
  • The influences of evapo-transpiration on the ground, Proc. 3rd Asian Conf. on Unsaturated Soils, pp.359-364,   2007年
  • Inhomogeneous Deformation Developing in a Clay Specimen, Proc 16th Southeast Asian Geotechnical Conference, pp.289-296,   2007年
  • An application of performance-based design concept to design of compacted ground, Proc. 1st International Symposium on Geotechnical Safety & Risk,   2007年
  • 締固め曲線と圧縮曲線の関連性について,   2007年
  • 地球環境問題の階層的整理と砂漠化問題の位置付け,   2007年
  • 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,   2007年
  • 上負荷面を用いた締固め粘性土のせん断挙動の表現方法,   2007年
  • 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, 神戸大学都市安全研究センター研究報告, 第11号,pp.43-50,   2008年
  • 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,   2008年
  • 地球環境問題の階層的整理と砂漠化問題の位置付け,   2008年
  • 締固め曲線と圧縮曲線の関連性について,   2008年

受賞

  •   2001年, 土木学会論文奨励賞
  •   2003年, 前田工学賞
  •   2008年, 地盤工学技術奨励賞

競争的資金

  • 文部科学省, 科学研究費補助金(若手研究(B)), 締固め土構造物の変形挙動予測手法の開発, 河井 克之, 間隙に空気相と液相を含む不飽和土は、土構造物の設計の際に締固め土という形で材料として用いられる。本研究の目的は、従来の飽和土の力学ではなく、不飽和土の力学を用いて締固め土構造物の変形挙動予測を行うことにある。前年の、締固め土の圧密降伏応力算定手法の開発に続き、本年は水理境界条件が土内部の含水状態に及ばす影響を検討するために、模型土槽を作成し、土柱試験を行った。ここでは、特に地下水位以上の領域での、含水状態に焦点を絞っている。模型土槽は、直径20cm、高さ100cmの土柱内の水位が下部ポーラスメタルを介して連続するマリオット管を用いて制御できるもので、負の間隙水圧を測定できるようにテンシオメーターと含水率測定のためのADR水分計を設置した。水位変動履歴の影響を検討するために、3種類の水位変動パターンを与えた。また、既存の不飽和土/水連成解析プログラムDACSAR-Uを用いて、解析を行い試験結果との比較を行った。一般的に、地下水位以上の間隙水圧を計測することはまれであるため多くの場合、地下水位以上の飯域に対して、静水圧分布に準じた負の間隙水圧を仮定するが、試験結果は静水圧分布ほどの大きな負の水圧は見られなかった。しかし、時間とともに水位変動とは独立に静水圧分布へと接近していく様子が伺えた。解析でも同じ結果が得られたことから、不飽和化によって土の透水係数が劇的に小さくなるため、容易に静水圧分布を呈することができなくなっていると考えられる。実現場では、地表面の乾湿などさらに境界条件が複雑になることから、間隙水圧分布はさらに複雑になっていると考えられ、本研究は、現場計測の必要性を問うている。しかし、測定される負の間隙水圧と含水率の関係は、別途試験によって得た水分特性曲線と一致しており、負の間隙水圧が測定できれば、含水率は算出可能であることを示した。
  • 文部科学省, 科学研究費補助金(若手研究(B)), 不飽和地盤の保水特性に及ぼす地下水位変動および降雨の影響, 河井 克之
  • 文部科学省, 科学研究費補助金(若手研究(B)), 不飽和地盤における各種水理境界変動の影響, 河井 克之, 自然,人工問わず地盤構造物の多くは土粒子間隙に水と空気を含む三相構造で存在している.間隙が水で満たされている場合を飽和状態と呼び,空気が存在する一般的な不飽和状態とは区別する.しかしながら,地盤工学の発展は飽和状態にある土の挙動を表現することで発展してきたため,未だに不飽和土の力学が実問題へ適用されることは少ない.本研究は,申請者らが究明してきた不飽和土の力学体系を初期値境界値問題として定式化し,実用化するために実現象における各種水理境界変動の解析上の表現法を確立し,その影響を明確にすることを目的としている.前年度,行った土柱試験により地下水位変動と降雨による地盤内含水率変化を実験により求め,解析結果との比較を行った.今年度は,蒸発と外力が地盤内含水率分布に及ぼす影響を検討した.蒸発に関してはモニタリング法という水分特性曲線を求める方法が提案されており,蒸発時の含水率低減とサクション変動が水分保持特性に一致するのは明らかにされている.ここではその影響深度に関して,模型実験と解析の結果を比較した.その結果,地盤表面が乾燥してくると,実蒸発量が低下するため土内部での含水率低下がかなり抑制されることが明らかとなった.また初期の含水率分布によって,地盤のサクション増加挙動が大きく異なることが分かった.外力に関しては,シミュレーションによる検討を行った.非排水条件下で不飽和状態にある地盤に外力を加えると,外力や初期含水状態に依存した,異なる含水率分布を呈することが分かった.この結果は,締固めなどの外部との水収支がない状態で外力が作用する条件で,締固厚さや外力の大きさによって,品質が異なる可能性があることを示唆している.以上,本研究で得られた知見は,不飽和土の力学を地盤工学上の問題へ適用するための一助となったと思われる.今後は,定量的な表現において解析精度を高めていくことを目的とする.
  • 文部科学省, 科学研究費補助金(若手研究(A)), 塩害メカニズムの解明への地盤工学的アプローチ及び高塩害抑制地盤の提案, 河井 克之, 沙漠化の主要因の一つである塩害は,不適切な灌漑などの人為的要因と長期の乾湿繰り返しといった自然要因によって起こるため,地盤に及ぼす複雑な外的要因を考慮した対策が必要となる.本研究では,地盤の変形,地下水流れ,物質移動を同時に表現できるシミュレータの開発を行った.また,解析精度の向上を図るため,ライシメーターを用いた地盤からの蒸発量計測も行い,塩害抑制地盤の提案も行っている.
  • 文部科学省, 科学研究費補助金(基盤研究(C)), 物質移動を考慮した土/水/空気連成解析による汚染土砂締固め管理手法の確立, 河井 克之, 東日本大震災によって発生した福島原子力発電所事故によって,大気に放出された放射性物質は拡散しながら降下し土壌を汚染するだけでなく,各用水,農畜水産物への混入が予想され,早期の除染が社会的に焦眉の問題となっている.今後,大量の放射能汚染土砂を含有放射性物質の漏出を抑制しながら,特定の限られた領域内に力学的に安定した状態で保管するために,広範な地盤工学の知見を結集した締固め施工による,盛土建設が必要となることは明らかである.これまで,土壌汚染問題は浸透拡散問題として扱われ,地盤の変形の影響は考慮されることはなかった.しかしながら,地上で地盤材料を保管するには,体積を小さくし,力学的安定性を確保できる締固めによる盛土施工が必要であり,材料の変形は無視できない.ここでは,理論,解析,実験を駆使し,自然環境(降雨浸透,蒸発散など)の中で汚染物質の漏出を抑制し得る,安全な盛土構築手法の確立を目指す.まず,既往の土/水/空気連成有限要素解析コードに物質輸送方程式を適用し,土/水/空気/溶解物質連成有限要素解析コードを開発した.締固めを模擬する際には,締固め層内での含水率の局所的な分布が生じる可能性があり,同時に物質移動を表現する本研究においては,精緻な空間離散化を行う必要がある.研究者らがこれまで有していた物質輸送を表現し得る解析コードは,応力~変形に関する変数四角形要素の各節点で,水頭や状態量は要素中心で代表していたため,解析精度に問題があった.本研究では,新たにアイソパラメトリック要素を用いた空間離散化を行った.その結果,解析精度が向上するとともに,濃度フラックスが卓越する条件での解析の不安定化を抑制できるようになった.
  • 不飽和地盤の挙動評価
  • 植生が地盤に及ぼす影響
  • 塩害と砂漠化
  • 締固めメカニズムの解明