1,721,058 research outputs found
Rank p ? 1 mod-p H-spaces
No full textDifferent constructions by Cooke, Harper and Zabrodsky and by Cohen and Neisendorfer produce torsion free finite p-local H-spaces of rank l < p ? 1. The first construction goes through when l = p ? 1 and we show the second does as well. However, the space produced need not be an H-space. We give a criterion for when an H-space is obtained. In the special case of rank 2 mod-3 H-spaces, we also give a practical test for when the criterion holds, and use this to give many new examples of finite H-spaces
On the Rothenberg-Steenrod spectral sequence for the mod 3 cohomology of the classifying space of the exceptional Lie group (Cohomology Theory of Finite Groups and Related Topics)
Full text linkEvaluation of Time-dependent Behavior of Osaka Pleistocene Clay by Elasto-viscoplastic Finite Element Analysis
Full text link過圧密領域においても洪積粘土の時間俵存性挙動が発生すると仮定した新たな圧縮モデルを提案し，長期圧密試験結果と大阪港舞洲洪積粘土地盤の沈下現象を弾粘塑性有限要素法によって解析した。その結果，過圧密領域でも正規圧密粘土と同様，時間の経過とともに圧縮が生じることになり，室内長期圧密試験結果，および従来モデルでは過小評価した大阪港舞洲埋立地下部洪積粘土層の沈下量を，精度良く表現できることがわかった。The most difficult problem is that a delayed compression of Pleistocene clayscontinues even when the total overburden remains less than pc. A new procedure isintroduced to describe the delayed compression of the Pleistocene clays. A series ofnumerical analyses in terms of the elasto-viscoplastic finite element method is conducted tosimulate those time-dependent behaviors. Furthermore, the procedure is also applied to thelong-term deformation that has been monitored at the Maishima Reclaimed Island in OsakaBay. The calculated results can also well describe the monitored long-term settlement of theeach Pleistocene marine clay layers.過圧密領域においても洪積粘土の時間俵存性挙動が発生すると仮定した新たな圧縮モデルを提案し，長期圧密試験結果と大阪港舞洲洪積粘土地盤の沈下現象を弾粘塑性有限要素法によって解析した。その結果，過圧密領域でも正規圧密粘土と同様，時間の経過とともに圧縮が生じることになり，室内長期圧密試験結果，および従来モデルでは過小評価した大阪港舞洲埋立地下部洪積粘土層の沈下量を，精度良く表現できることがわかった。The most difficult problem is that a delayed compression of Pleistocene clayscontinues even when the total overburden remains less than pc. A new procedure isintroduced to describe the delayed compression of the Pleistocene clays. A series ofnumerical analyses in terms of the elasto-viscoplastic finite element method is conducted tosimulate those time-dependent behaviors. Furthermore, the procedure is also applied to thelong-term deformation that has been monitored at the Maishima Reclaimed Island in OsakaBay. The calculated results can also well describe the monitored long-term settlement of theeach Pleistocene marine clay layers
ELASTIC BEHAVIOUR OF A SATURATED CLAY DURING UNLOADING OF SHEAR STRESS
No full textIt is one of the major problems in soil mechanics to describe the mechanical response ofsoils under cyclic loading conditions. The objective of this study is to clarify the stress-strainbehaviors when the loading direction is reversed. For the purpose conventional triaxialtests for a saturated clay were performed in which deviator stress was applied in compressionstate and unloaded to failure in extension state.Stress-strain behavior has been found to be elastic in some portion after the moment ofunloading of shear stress and beyond the portion the behavior begins to be elasto-plastic.Such a limit of elasticity can be determined in stress space and the variation with the defor-mation history having been given before unloading are discussed. On the other hand shearmodulus G can be determined as the slope of the linear portion of stress-strain relationship.The effects of deformation history on G are also discussed.A few of conclusions are summarized as follows:1) A parameter defined as a function of stress ratio at the start of unloading and stressratio at the limit of elasticity appears to be related to shear strain given before unload-ing uniquely in spite of both drainage condition and OCR.2) G is not influenced by the degree of the deformation history if effective mean stressis not altered during deformation history as in drained tests but it decreases in thecase when effective mean stress decreases with shear as in undrained tests for normallyconsolidated clays.It is one of the major problems in soil mechanics to describe the mechanical response ofsoils under cyclic loading conditions. The objective of this study is to clarify the stress-strainbehaviors when the loading direction is reversed. For the purpose conventional triaxialtests for a saturated clay were performed in which deviator stress was applied in compressionstate and unloaded to failure in extension state.Stress-strain behavior has been found to be elastic in some portion after the moment ofunloading of shear stress and beyond the portion the behavior begins to be elasto-plastic.Such a limit of elasticity can be determined in stress space and the variation with the defor-mation history having been given before unloading are discussed. On the other hand shearmodulus G can be determined as the slope of the linear portion of stress-strain relationship.The effects of deformation history on G are also discussed.A few of conclusions are summarized as follows:1) A parameter defined as a function of stress ratio at the start of unloading and stressratio at the limit of elasticity appears to be related to shear strain given before unload-ing uniquely in spite of both drainage condition and OCR.2) G is not influenced by the degree of the deformation history if effective mean stressis not altered during deformation history as in drained tests but it decreases in thecase when effective mean stress decreases with shear as in undrained tests for normallyconsolidated clays
ENVIRONMENT CONTROL IN A BURIAL CHAMBER BY COVERING WITH AN EARTH MOUND --EVALUATION OF TEMPERATURE AND DEW CONDENSATION IN A BURIAL CHAMBER ASSOCIATED WITH THE OVERLYING TUMULUS MOUND --
No full text内部の石室に装飾が施された古墳では，石室の室温変化やそれに伴う水分移動に由来した石材や装飾の劣化が問題となっている．こうした劣化を抑制する方法として，覆土を施して石室を断熱する方法が有効と考えられるが，覆土の仕様を決定する上で，周囲の土が石室環境にどのように影響するか明らかにする必要がある．そこで，本稿では，墳丘の層厚，乾燥密度，飽和度が石室環境に与える影響を調べた．一次元熱伝導方程式を解き，石室の温度と結露を評価したところ，石室環境は層厚に敏感である一方，乾燥密度や飽和度には実質的にあまり影響を受けないことがわかった．したがって，石室の温度環境が重視される古墳に覆土する場合，最も重要なパラメータは層厚であり，他のパラメータについては，力学的安定性や雨水浸透の観点から決定するのが適当である．The decorated burial chambers in tumuli have been deteriorated due to temperature change and moisture movement in the burial chambers. Heat insulation of a burial chamber by covering with an earth mound is one of feasible means to control the damage. In the present paper, the temperature and dew condensation in a burial chamber was evaluated by one dimensional equation of heat conduction to investigate the influence of the thickness, degree of saturation and dry density of the mound on the chamber environment. The calculated performance suggested that the thickness of the mound has larger influence on the environment in the burial chamber than other factors. Therefore, the thickness of the mound is a key factor for designing an earth mound storing a decorated chamber which requires hydrothermal environment control for preservation. On the other hand, the degree of saturation and dry density of the earth mound with less influence on chamber environment should be decided considering the mechanical stability and water infiltration of the mound
Contribution of Forensic Geotechnical Engineering in the Ground Disaster and Accident
No full text本稿は，京大防災研究所によって採択され，2011年に設立された一般共同研究プログラム"地盤事故災害における法地盤工学研究会"(委員長 岩崎好規・幹事長 三村衛)の活動を報告するものである。研究会では，既往の事例を収集・整理し，問題点の指摘や今後のあり方を考究し，災害や事故の分析と事故防止・紛争改善のための現状の整理と提言を行うことを，目的としている。2011年度においては，2011年7月に法地盤工学国際シンポジュウムを開催し，さらに，2012年1月に法地盤工学ワークショップを開催した。This paper describes the activity of the general cooperative research program "Research Committee on Forensic Geotechnical Engineering"(chair Y.Iwasaki and manager M.Mimura), which was funded by Disaster Prevention Research Institute from 2011 to 2012. In 2011, we have organized an international symposium in Osaka and adapted a Resolution. The topics of the symposium cover various such accidents as slope failure by heavy rain, and failure of retaining wall. Special attentions are paid to "Rain induced slope failure, " Nicole's Highways Collapse in Singapore, " and Failure of bridge girder at Can Tho Bridge, Vietnam. The Research committee aims to collect case histories of the forensic geotechnical engineering and summarize the cases and proposes the direction to go in the future. At the symposium, a recommendation was adapted to cooperate with technical committees under the international society of soil mechanics and geotechnical engineering. At present, we have concluded that the most of the failed case did not use observational method. Monitoring was not properly fed back into the running field conditions. In January 2012, we have organized a workshop on forensic geotechnical problem and construction dispute. Citizens who are in active for legal attempt to construction of a housing structures on an active faults have joined the workshop as well as layers.本稿は，京大防災研究所によって採択され，2011年に設立された一般共同研究プログラム"地盤事故災害における法地盤工学研究会"(委員長 岩崎好規・幹事長 三村衛)の活動を報告するものである。研究会では，既往の事例を収集・整理し，問題点の指摘や今後のあり方を考究し，災害や事故の分析と事故防止・紛争改善のための現状の整理と提言を行うことを，目的としている。2011年度においては，2011年7月に法地盤工学国際シンポジュウムを開催し，さらに，2012年1月に法地盤工学ワークショップを開催した。This paper describes the activity of the general cooperative research program "Research Committee on Forensic Geotechnical Engineering"(chair Y.Iwasaki and manager M.Mimura), which was funded by Disaster Prevention Research Institute from 2011 to 2012. In 2011, we have organized an international symposium in Osaka and adapted a Resolution. The topics of the symposium cover various such accidents as slope failure by heavy rain, and failure of retaining wall. Special attentions are paid to "Rain induced slope failure," Nicole's Highways Collapse in Singapore," and Failure of bridge girder at Can Tho Bridge, Vietnam. The Research committee aims to collect case histories of the forensic geotechnical engineering and summarize the cases and proposes the direction to go in the future. At the symposium, a recommendation was adapted to cooperate with technical committees under the international society of soil mechanics and geotechnical engineering. At present, we have concluded that the most of the failed case did not use observational method. Monitoring was not properly fed back into the running field conditions. In January 2012, we have organized a workshop on forensic geotechnical problem and construction dispute. Citizens who are in active for legal attempt to construction of a housing structures on an active faults have joined the workshop as well as layers
Contribution of macroscopic permeability of sand/gravel layers to subsequent long-term settlement of the reclaimed marine foundation of KIA
No full text大阪泉州沖の大水深海域において埋立によって建設されている関西国際空港基礎地盤は，第四紀更新統の堆積層において大きな沈下を引き起こしている。本稿では，その主たる要因が，更新統粘土の擬似過圧密性と時間依存性，更新統砂礫層のマクロ透水能をであると考えた。既に著者らによって提案されている構造を有する粘土の新たな圧縮モデルを適用し，砂礫層の不連続性や細粒分による透水性低下を等価な透水係数を与えることによってマクロな透水特性をモデル化し，これらを弾粘塑性有限要素法に組み込むことによって，現地で起こっている現象を評価することを試みた。解析結果は，基礎地盤内の過剰間隙水圧分布，各更新統粘土層の沈下挙動の実測値を表現し得ており，提案している解析手法が妥当なものであることがわかった。A series of elasto-viscoplastic finite element analyses is carried out to simulate the stress and deformation of the reclaimed Pleistocene foundation due to construction of Kansai International Airport fill. The foundation ground at Senshu area consists of alternating Pleistocene clays and sandy gravel layers. The influential factor controlling the deformation of the foundation ground is high compressibility and strain rate dependency of the structured Pleistocene clays as well as mass permeability of the Pleistocene sandy gravel layers controlling the rate of consolidation. In the FE analyses, the equivalent permeability is introduced considering the discontinuity and/or change in thickness of permeable sand gravel layers and low permeability due to finer components. The calculated performance can describe the measured long-term settlement with time for each Pleistocene clay layer as well as the process of generation/dissipation of excess pore water pressure both in the Pleistocene clay and sand gravel layers very well.大阪泉州沖の大水深海域において埋立によって建設されている関西国際空港基礎地盤は，第四紀更新統の堆積層において大きな沈下を引き起こしている。本稿では，その主たる要因が，更新統粘土の擬似過圧密性と時間依存性，更新統砂礫層のマクロ透水能をであると考えた。既に著者らによって提案されている構造を有する粘土の新たな圧縮モデルを適用し，砂礫層の不連続性や細粒分による透水性低下を等価な透水係数を与えることによってマクロな透水特性をモデル化し，これらを弾粘塑性有限要素法に組み込むことによって，現地で起こっている現象を評価することを試みた。解析結果は，基礎地盤内の過剰間隙水圧分布，各更新統粘土層の沈下挙動の実測値を表現し得ており，提案している解析手法が妥当なものであることがわかった。A series of elasto-viscoplastic finite element analyses is carried out to simulate the stress and deformation of the reclaimed Pleistocene foundation due to construction of Kansai International Airport fill. The foundation ground at Senshu area consists of alternating Pleistocene clays and sandy gravel layers. The influential factor controlling the deformation of the foundation ground is high compressibility and strain rate dependency of the structured Pleistocene clays as well as mass permeability of the Pleistocene sandy gravel layers controlling the rate of consolidation. In the FE analyses, the equivalent permeability is introduced considering the discontinuity and/or change in thickness of permeable sand gravel layers and low permeability due to finer components. The calculated performance can describe the measured long-term settlement with time for each Pleistocene clay layer as well as the process of generation/dissipation of excess pore water pressure both in the Pleistocene clay and sand gravel layers very well
原位置試験による液状化危険度評価について
Full text link平成24年度京都大学防災研究所一般研究集会(24K-09)「浦安地盤調査一斉試験報告会」, 地盤工学会 地下大会議室, 2012/10/3
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