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VALUATION OF EARTH PRESSURES ACTING ON FOUNDATIONS DURING STRONG

强震期间作用于地基的土压力的评估

基本信息

批准号：
09450202
负责人：
TOKIMATSU Kohji
金额：
$ 4.54万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450202/
关键词：
Earth pressure Coefficient of Subgrade reaction Torsional shear test Earthquake Foundation Active earth pressure Passive earth pressure Pile

项目摘要

A torsion triaxial shear test system is developed with which earth pressures in between the active and passive states can be measured. The test results show that earth pressures of normally consolidated sand in between the active and passive states can be expressed in terms of the angle of internal friction of the sand and the strain rate between minor and major axial strains. Based on this finding static earth pressures in between the active and passive states are formulated by extending the theories presented by Rankine and Coulomb. Similarly, earth pressures in between the active and passive states during earthquakes are formulated and the methods to estimate dynamic earth pressures acting on buried structures and retaining walls are presented. The effectiveness of the proposed methods is confirmed based on the comparison with the results of previous studies.To examine the earth pressures acting on embedded foundations and piles in liquefied and laterally spreading ground, pseudo-static analyses are conducted for well-documented case histories of pile foundations and the scaling factors for the horizontal subgrade reaction of piles and for the maximum reaction force are back-calculated. The analytical results show that : (1) both the coefficient of the horizontal subgrade reaction of piles and the maximum reaction force of laterally-spreading soils are 0.05-0.2 times those of non-liquefied soils, and (2) the earth pressure acting on the embedded foundation varies from the active to passive state depending on the pile rigidity and relative displacement between the embedded foundation and the surrounding ground.

研制了一套能测量主动和被动状态之间土压力的扭转三轴剪切试验系统。试验结果表明，正常固结砂土在主动和被动状态之间的土压力可用砂土的内摩擦角和轴向小应变与大应变之间的应变率来表示。在此基础上，通过推广朗肯和库仑的理论，推导了主动和被动状态之间的土压力公式。同样，在主动和被动状态之间的土压力在地震期间制定和方法来估计动土压力作用在地下结构和挡土墙。为了研究液化和侧向扩展地基中作用在埋置基础和桩上的土压力，对已有的桩基工程实例进行了拟静力分析，并反算了桩的水平地基反力和最大反力的比例因子。分析结果表明：（1）桩的水平地基反力系数和侧向扩展土的最大反力均为非液化土的0.05-0.2倍，以及（2）作用在埋置基础上的土压力随桩的刚度和埋置基础与周围环境的相对位移而从主动状态变化到被动状态地上