Search Results 1-20 of 78

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

    Wang Liujiang , Huang Penghua , Wang Yaoming , Liu Sihong

    Pore-water pressure, pore-air pressure, and soil settlement are obtained in the Laplace domain. …

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

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  • A new explicit analytical solution to axisymmetric consolidation of vertical drain in unsaturated soils

    Qin Aifang , Li Tianyi , Sun Dean

    … In the derivation, the decoupling process is employed to convert the governing equations of excess pore-air and pore-water pressures into essentially the same homogeneous partial differential equations (PDEs). …

    Japanese Geotechnical Society Special Publication 7(2), 456-462, 2019

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  • Experimental investigation on two stress variables proposed by Fredlund from deformation, strength and moisture change under triaxial state of stress

    Zhang Long , Chen Zhenghan

    … In order to further verify the rationality of the two independent stress state variables for unsaturated soil, a triaxial apparatus for unsaturated soil was improved to control pore water pressure, confining stress and deviatoric stress. …

    Japanese Geotechnical Society Special Publication 7(2), 70-77, 2019

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  • Three-phase coupled seismic analyses of unsaturated/saturated grounds

    Uzuoka Ryosuke , Unno Toshiyasu , Matsumaru Takaki , Ueda Kyohei

    … <p>The role of pore air pressure on seismic behavior of unsaturated sandy soil is discussed through recent numerical simulations with three-phase and simplified two-phase coupled analyses. …

    Japanese Geotechnical Society Special Publication 7(2), 38-45, 2019

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  • Instrument for measuring the pore air pressure under the slope  [in Japanese]

    Iwagami Sho

    <p>近年,豪雨災害が顕著に増えており,その発生予測技術の開発は急務である.しかし水文学の降雨流出過程に関する研究においては,降雨に対する素早い流出応答を生じるプロセスは未だに説明しきれない部分があり,課題となっている.一般的な洪水予測モデルにおいては,降雨データを元にして流出の予測を行うが,本研究では降雨に加えて間隙空気(封入空気)が流出に影響を与える可能性に着目している.斜面内の空 …

    The Japanese Forest Society Congress 130(0), 393, 2019

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  • Basic Study on Use of Two-Phase Flow Method in Slope Stability Analysis  [in Japanese]

    ISHIDA Jumpei , SUGIMOTO Satoshi , JIANG Yujing

    <p>降雨時の斜面崩壊メカニズム解明のため,様々な解析手法による研究が行われているが,降雨時の斜面の安定性評価において,間隙空気の影響を考慮したものは少ない.地盤内で空気の閉塞が発生した際,水の円滑な浸透が妨げられることや,空気圧の上昇により地盤に破壊現象が生じる恐れがある.そこで本研究では,間隙空気の影響を考慮する気液二相流解析手法を用いて,室内模型実験の再現解析を実施した.その結果 …

    Journal of the Japan Society of Engineering Geology 59(5), 263-272, 2018

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  • NUMERICAL STUDY ON SEEPAGE FLOW IN SLOPE AT HEAVY RAIN CONSIDERING NON-UNIFORMITY AND PORE AIR FLOW  [in Japanese]

    SAITO Masahiko , MASUDA Ryuji

    豪雨時の斜面崩壊の誘因となる地盤内の水分量や水位・水圧分布については,浸透流解析による予測/推定がある程度可能であるが,通常は地盤物性値等は空間的に均一と仮定され,実際の斜面に見られる不均一性は考慮されない.本研究では,透水係数の空間分布モデルを用いて疑似的にばらつきと偏りのある不均一斜面を生成し,気液2相流解析によって間隙空気を考慮した豪雨時の斜面内浸透流の性質について検討した.その結果,均一場 …

    Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 74(4), I_7-I_12, 2018

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  • APPLICABILITY OF THE SIMPLIFIED THREE-PHASE ANALYSIS TO THE SEISMIC BEHAVIOR OF UNSATURATED LATERALLY LAYERED GROUND  [in Japanese]

    UEDA Kyohei , BAI Ke , IAI Susumu

    近年,降雨・浸透流に伴う盛土の崩壊メカニズムの究明等,不飽和土に関する研究が盛んに行われている.しかし,その多くは保水性やそのモデル化に主眼が置かれ,地震時の動的特性や耐震性能評価法に関しては,飽和土に比べて知見が不足しているのが現状である.そこで本研究では,水平成層地盤の地震時挙動に対する不飽和化の影響を調べるため,遠心模型実験と有効応力解析を実施した.実験の結果,不飽和地盤では加振時の過剰間隙 …

    Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) 74(2), 130-143, 2018

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  • SEISMIC RESPONSE ANALYSIS OF EMBANKMENT CONSIDERING BEHAVIOR OF PORE WATER AND AIR PRESSURE UNDER COLD SNOWY CONDITION  [in Japanese]

    MATSUMARU Takaki , KAWAJIRI Shunzo , KISHIDA Hisanori , TANAKA Yuki

    本研究では,積雪寒冷条件下にある盛土の地震時挙動を解明することを目的として,実際の盛土での各種計測と,数値解析による耐震性の評価を試みた.まず,実際に積雪寒冷環境にある盛土において,土壌水分量の測定や簡易動的コーン貫入試験により,凍結・融雪期における盛土の水理・力学挙動の把握を行った.その上で,観測された水分量の変化や<i>N<sub>d</sub></i …

    Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)) 73(4), I_642-I_654, 2017

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  • GROUND DETERIORATION DUE TO PORE AIR PRESSURE INCREASE IN SOIL

    MUSENERO Leah , KUWANO Reiko

    <p>地盤の表層が飽和している条件で地下水位が急激に上昇する場合,地盤内に空気が閉じ込められ,水の侵入に伴い空気圧が上昇し,地盤が局所的に破壊される可能性がある.カラム内の土供試体にこのような条件を与え,土供試体内の間隙空気が局所破壊に及ぼす影響を実験により検討した.上層の飽和層に非塑性の細粒土 (DL-clay) を,下部の不飽和層に珪砂を使用し,動水勾配を変化させ,浸透水量・間隙空 …

    SEISAN KENKYU 69(4), 191-194, 2017

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  • Evaluation of distribution of void ratio and degree of saturation in partially saturated triaxial sand specimen using micro x-ray tomography

    Kido Ryunosuke , Higo Yosuke

    … <p>Partially saturated soils are composed of three phases: soil particle, pore water and pore air. … The pore water forms menisci among soil particles at which suction works. … Suction is higher at the upper part of partially saturated soils due to the higher negative pressure head. …

    Japanese Geotechnical Society Special Publication 5(2), 22-27, 2017

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  • PORE AIR PRESSURE CHANGE OF SANDSTONE AND MADSTONE WITH WATER IMMERSION AND EVALUATION USING THE EQUIVALENT CHANNEL MODEL  [in Japanese]

    武藤 圭佑 , 長田 昌彦

    岩盤力学に関するシンポジウム講演論文集 44, 273-277, 2016-01-08

  • Instability on dike with scour due to surface flow and seepage

    Maeda Kenichi , Matsuda Tatsuya , Saito Hiroshi

    … The damage to a dike caused by high water levels from a localized torrential downpour over a long period is presumed to be related to dike saturation from the seepage water from the dike surface and the blow off of pore air following a movement in the seepage line in the dike. …

    Japanese Geotechnical Society Special Publication 2(29), 1065-1068, 2016

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  • Numerical studies on slope stability in torrential rainfall by using two-phase flow analysis

    Sugimoto Satoshi , Jiang Yujing , Omine Kiyoshi , Ishida Jumpei , Higashi Yukihiro

    … It may cause pore air occluding with rapid water flow in some cases. … Because natural slope is often unsaturated, it is required to consider effect of pore air pressure. … In this study, coupled stress-flow analysis is performed by calculating two-phase flow considered effect of pore air pressure. …

    Japanese Geotechnical Society Special Publication 2(27), 990-995, 2016

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  • Development of a temperature and pressure controlled triaxial apparatus and dissociation tests of carbon dioxide hydrate containing soils

    Iwai Hiromasa , Saimyou Kazuki , Kimoto Sayuri , Oka Fusao

    … These experiments require the high pressure and the low temperature conditions to form the carbon dioxide, and we have developed a new triaxial apparatus. … The dissociation results indicates that even a small percentage of hydrate saturation produced the large pore gas pressure and the sequential reduction of the effective confining pressure due to the hydrate dissociation, and extensive strain was observed. …

    Japanese Geotechnical Society Special Publication 2(13), 518-521, 2016

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  • Air-coupled effects on triaxial behavior of silty specimens under a constant confining pressure and various exhausted conditions

    Yoshikawa Takahiro

    … It is also necessary to take into account the flow and high compressibility of the pore air. … During rainfall, earthquakes, or other conditions under which air cannot be sufficiently exhausted, changes occur in the pore air pressure, causing changes in the pore air volume. …

    Japanese Geotechnical Society Special Publication 2(10), 435-439, 2016

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  • Measurement of pore-air pressure in the ground for landslide disaster prevention  [in Japanese]

    檀上 徹

    油空圧技術 54(12), 1-4, 2015-11

  • PORE AIR BEHAVIOR WITHIN A SLOPING EARTH STRUCTURE DUE TO RAINFALL INFILTRATION  [in Japanese]

    KAWAKATSU Takuya , KAWAI Katsuyuki , TIWARI Binod , IIZUKA Atsushi

    近年,地球規模での気候変動により集中豪雨が発生し,毎年のように土砂災害を誘発している.また,降雨の範囲がきわめて局所化しているため,いつどこで災害が起こってもおかしくない状況である.減災のためには,土砂災害の前兆現象を察知することが有益である.しかし,前兆現象のひとつである発災前の異音や異臭というのは地盤工学の枠組みの中で十分には説明されていない.本研究では異音,異臭が地盤内の空気の挙動によって発 …

    Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)) 71(2), I_171-I_180, 2015

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  • Collapse Due to Entrapment of Pore Air in Unsaturated Soil  [in Japanese]

    SATO Mari , KUWANO Reiko

    不飽和地盤における間隙空気挙動は浸透や強度に大きな影響を及ぼす.本研究では集中豪雨により多方向からの浸透流が発生した際に, 地盤内に空気が閉塞され間隙空気圧が上昇し表層地盤が破壊される可能性を一次元上方浸透流試験により検証した.実験では地盤内の空気圧, 水の流入速度, 地盤表層部変位を測定した.水の流入量に比例して間隙空気圧が上昇し, ある間隙空気圧を超えると表層部地盤が持ち上がり亀裂が発生し, …

    Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering 83(4), I_107-I_115, 2015

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  • Measurement of pore-air pressure in unsaturated soil and validation of influence on a tensiometer  [in Japanese]

    DANJO Toru , SAKO Kazunari , FUJIMOTO Masamitsu , FUKAGAWA Ryoichi , SAKAI Naoki

    地盤内の浸透挙動を把握するためにテンシオメータを用いた間隙水圧の計測がおこなわれてきた。テンシオメータの計測値には,間隙水圧と間隙空気圧の影響が含まれるが,地盤内の間隙空気圧をゲージ圧で0kPaと仮定しているため,間隙空気圧の影響については考慮していない。また,近年の研究により地盤内の間隙空気圧の上昇が降雨時の斜面崩壊,雨水浸透などに影響を及ぼす可能性があると指摘されている。そこで本研究では,異な …

    Japanese Geotechnical Journal 10(1), 81-92, 2015

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