Search Results 1-20 of 569

  • IMPROVEMENT OF PREDICTION ACCURACY ON RAINFALL-INDUCED SLOPE FAILURES USING A RAINFALL INDEX CONSIDERING MEASUREMENT RESULTS WITH A TENSIOMETER  [in Japanese]

    DANJO Toru , SAKO Kazunari , FUJIMOTO Masamitsu , ISHIZAWA Tomohiro , ITO Shinichi , FUKAGAWA Ryoichi

    <p> 本論文では,計測斜面近傍で表層すべり型崩壊が発生した時の降雨量とテンシオメータによる計測結果を用いて,現地計測結果を加味した雨量指標を提案するとともに,既往の雨量指標との比較を行うことでその有用性を検証した.その結果,本計測地点においては,計測地点で最初に飽和帯が形成されてからの継続時間とその間の平均降雨強度との関係を用いることで,計測期間(2004~2015年)における崩壊時 …

    Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) 77(1), 87-102, 2021

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  • Behaviors of rainfall infiltration and drainage characteristics of unsaturated soils under relatively high suction state  [in Japanese]

    KITAOKA Takafumi , OHTSU Hiroyasu , NONAMI Satoshi , PIPATPONGSA Thirapong , MATSUMOTO Atsushi

    <p>本研究では,マクロポアが発達した地盤条件における比較的高サクション状態の吸水・排水過程での体積含水率と間隙圧の変化を,Dual-Permeabilityモデルに準じてマクロポア部およびマトリックス部の挙動に分離し検討を加えた。その結果,原位置においても降雨開始時の体積含水率が圃場容水量を下回り,かつ間隙圧がそれに相当する値を下回る領域では,圃場容水量を最大値とするマトリックス流の …

    Japanese Geotechnical Journal 16(1), 35-47, 2021

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  • <International Research(Project No: 2019W-03)>Seismic Soil-Foundation-Structure Interaction in Unsaturated Soils

    Ghayoomi Majid

    京都大学防災研究所年報. A = Disaster Prevention Research Institute Annuals. A 63(A), 258-260, 2020-12

    IR 

  • Practical method to estimate parameters of elasto-plastic constitutive model for unsaturated soils from compaction curve

    Tachibana Shinya , Matsumoto Masayoshi , Iizuka Atsushi

    … The input parameters for the hardening law for the elasto-plastic constitutive model of unsaturated soils are generally fitting parameters that control the degree of hardening response and cannot easily be determined without the results of experimental tests in which the changes in suction, water content, and volume are measured or controlled. …

    Soils and Foundations 60(5), 1287-1298, 2020-10

    IR 

  • A theory of loosening earth pressure above a shallow tunnel in unsaturated ground

    Fang Xu , Kikumoto Mamoru , Cui Ying

    … A theory is proposed to evaluate the loosening earth pressure (vertical earth pressure after excavation) acting on a shallow tunnel in unsaturated ground with an arbitrary groundwater level. … The theory is developed based on the limit equilibrium theory, combining soil–water characteristic curves, Mohr–Coulomb failure criteria, and effective stress for unsaturated soils. …

    International journal for numerical and analytical methods in geomechanics 44(10), 1495-1508, 2020-03-26

    IR 

  • Leaching behavior of naturally-contained arsenic in marine sediment by the long-term column percolation test  [in Japanese]

    KATAYAMA Jun'ichi , INUI Toru , KATSUMI Takeshi , TAKAI Atsushi

    <p>自然由来の重金属等を含む堆積物を盛土材や埋立材として利用する場合,基準値以上の重金属等の溶出が懸念されることから,長期的な溶出挙動の把握が重要となるが,溶出挙動の長期的なモニタリング結果や広く用いられる溶出試験結果との比較結果は限られている。本研究では,自然由来の砒素を含む砂質海成堆積物を対象として,表層付近における降雨浸透による溶出挙動を再現する散水型カラム浸透試験を長期に渡っ …

    Japanese Geotechnical Journal 15(4), 675-682, 2020

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  • Estimating the Dielectric Spectrum of Unsaturated Soils with Different Moisture Contents  [in Japanese]

    UEMURA Masaaki , NAKAGAWA Kei , MIYAMOTO Hideki

    <p>本研究では,体積含水率(θ)の異なる豊浦砂の ε'<SUB>sand</SUB> スペクトルの態様を明らかにするために,2つの異なる手法,すなわち,ベクトルネットワークアナライザー(VNA)を利用した反復測定と,既往のモデルの改良・統合によって誘導した改良型誘電率混合モデルに基づく計算によって,θの異なる豊 …

    Shokubutsu Kankyo Kogaku 32(4), 201-207, 2020

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  • Dissipated energy verification on silica sand and volcanic sandy ash soil Shirasu with chemical grouting and compaction under triaxial cyclic behavior  [in Japanese]

    KIYOHARA Yukoh

    <p>繰返し三軸試験により,砂や火山灰質土であるしらす土,不飽和化を施した砂やしらす土,突固めやセメント改良,薬液改良などのしらす改良土の繰返しせん断挙動の把握を行ってきた。そのサイクリックモビリティーをもとに計算した基準化累積損失エネルギーの普通砂としらす土との比較,応力履歴,繰返し後の排水条件,飽和度の違いによる比較,対策工間の繰返しエネルギーに対しての耐液状化性能比較を定量的に行 …

    Japanese Geotechnical Journal 15(1), 15-24, 2020

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  • Analysis of applicability of SWRC equation to different types of soils and its prediction method considering initial dry density

    Zhang Ce , Zhang Xi-jun , Cai Guo-qing , Li Jian , Zhao Cheng-gang

    … <p>This paper is centered on the assessment of 3 soil-water retention curves (SWRC) equations for unsaturated soils, for its predictive capability with respect to different soil types. … The influence of different soils with different initial dry density on parameters in different equations is analyzed. …

    Japanese Geotechnical Society Special Publication 8(6), 194-199, 2020

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  • Semi-analytical solutions to one-dimensional electro-osmotic consolidation in unsaturated soils

    Wang Liujiang , Huang Penghua , Wang Yaoming , Liu Sihong

    … <p>This paper presents a 1D model for electro-osmotic consolidation of unsaturated soils. … The present solutions are more general and can be degenerated into conventional solutions to 1D consolidation of fully saturated soils and unsaturated soils without electro-osmosis. …

    Japanese Geotechnical Society Special Publication 8(4), 102-108, 2020

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  • Laboratory Test and Numerical Simulation about Unsaturated Liquefaction Characteristics of Volcanic Sandy Soil  [in Japanese]

    MATSUMARU Takaki

    <p>近年の地震では火山灰質土からなる斜面・土構造物に多くの災害が生じており,地盤が不飽和状態でありながら液状化のような現象が生じることが災害の要因の1つとなっている.しかしながら,火山灰質土を対象とした不飽和状態での繰返し載荷挙動はいまだ十分には解明されていない.本研究では,2種類の火山灰質土を用いて初期状態の異なる供試体の不飽和繰返し三軸試験を実施し,繰返し載荷挙動の評価を行うとと …

    Journal of Japan Association for Earthquake Engineering 20(1), 1_37-1_50, 2020

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  • Long-Term Leaching Behavior of Marine Sediment by a Large Column Percolation Test  [in Japanese]

    INUI Toru , HORI Mutsumi , KATSUMI Takeshi , TAKAI Atsushi

    … <p>Soils excavated in construction works often contain non-anthropogenic heavy metals and metalloids due to their geologic histories. … Evaluation of their leaching behaviors is essential to predict the environmental impact and achieve an optimum design when reusing such soils as construction materials. …

    Journal of the Society of Materials Science, Japan 69(1), 53-56, 2020

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  • Relationship between Compression Characteristics of Unsaturated Soils and Compaction Curves  [in Japanese]

    本田 道識 , 飯塚 敦

    地盤工学会誌 = Geotechnical engineering magazine : 土と基礎 67(9), 28-31, 2019-09

  • Current Status and Issues of Measurements for Soil Hydraulic Properties on Unsaturated Soils  [in Japanese]

    竹下 祐二

    地盤工学会誌 = Geotechnical engineering magazine : 土と基礎 67(9), 4-7, 2019-09

  • Extension of unsaturated soil mechanics and its applications

    Iizuka Atsushi , Tachibana Shinya , Takeyama Tomohide , Sugiyama Yuri , Nomura Shun , Ohta Hideki

    … Mechanical properties of unsaturated soils are phenomenologically integrated into the constitutive equation for a deformation problem, with effective stress expressed as a combination of partial stresses acting on each phase of the mixture. … and the liquefaction potential of unsaturated soil are presented. …

    Geotechnical Research, 1800004, 2019-05-07

    IR 

  • Numerical simulation of seepage failure by upward flow considering internal erosion

    Kimoto S. , Akaki T. , Kodama H.

    … 7th Asia-Pacific Conference on Unsaturated Soils (AP-UNSAT2019)In the present study, seepage failure by upward flow is numerically simulated using a seepage-deformation coupled method in which the internal erosion of fine particles and the transport of these particles are considered. …

    Japanese Geotechnical Society Special Publication 7(2), 654-659, 2019-04-30

    IR 

  • The migration experiment of Sr-90 in variable saturated soils and numerical simulation used Hydrus-3d (The 9th International Symposium on Radiation Safety and Detection Technology (ISORD-9))

    Deng Anchang , Zhu Jun , Shi Yunfeng , Chen Chao , Xie Tian , Li Ting , Zhang Aiming

    Progress in nuclear science and technology 6, 156-161, 2019-01

  • Influence of Initial Static Shear and Seismic History on Seismic Shear Behavior of Volcanic Clayey Soil at Residential Area Damaged by the 2016 Kumamoto Earthquake, Japan  [in Japanese]

    IZUMIYA Satoshi , KAMURA Akiyoshi , KIM Jongkwan , SATO Shingo , KAZAMA Motoki

    <p>2016年熊本地震では,斜面上の宅地地盤が大きく変形して甚大な被害をもたらした.本研究は熊本県益城町での宅地地盤の被害メカニズムを,火山灰質粘性土の変形特性から明らかにすることを目的として,現地で採取した火山灰質粘性土試料を用いた非排水繰返しせん断試験を行った結果を報告する.土試料は原位置の土被り圧に応じた拘束圧力で圧密し,斜面の傾斜に相当する初期せん断応力を与えて斜面の応力状態 …

    Journal of Japan Association for Earthquake Engineering 19(6), 6_1-6_15, 2019

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  • A Cyclic Cndrained Triaxial Test with Mean Principle Stress Constant for Estimation of Liquefaction Resistance of Improved Soils  [in Japanese]

    UEMURA Kentaro , NAGAO Koichi , SUEMASA Naoaki , ITOH Kazuya , SASAKI Takamitsu

    <p>固化改良砂および不飽和砂の液状化強度は,中空ねじり試験や側圧一定の繰返し非排水三軸試験から求めることが一般的であるが,固結供試体端部における局所破壊や不飽和砂における供試体のネッキングの発生が液状化による破壊に先行するため,液状化強度が低く見積もられていると考えられる.そこで,本研究では簡易的な側圧可変の三軸試験装置を試作し,固化改良砂および不飽和砂に対して平均主応力一定の液状化 …

    Journal of Japan Association for Earthquake Engineering 19(5), 5_146-5_155, 2019

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  • Cyclic Shear Behavior of Unsaturated Soil with Varying Pore Water and Pore Air Condition  [in Japanese]

    UNNO Toshiyasu , MIDORIKAWA Yusuke

    <p>地震時に発生する流動性崩壊の流下土砂は,飽和度が100%未満である場合が多く,メカニズムについて未解明な点が多い.不飽和土の力学挙動は,既知の通り間隙空気や間隙水の状態に応じてせん断強度や発生するせん断ひずみ等,せん断変形挙動が大きく影響を受けることから,メカニズム解明には水分状態と繰返しせん断変形挙動の関係について検討する必要がある.本研究では,空気連行剤(AE剤)を使用し強制 …

    Journal of Japan Association for Earthquake Engineering 19(5), 5_170-5_183, 2019

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