EVALUATION OF DYNAMIC SOIL-PILE-STRUCTURE INTERACTION DURING SOIL LIQUEFACTION AND CYCLIC MOBILITY

土壤液化和循环流动过程中动态土-桩-结构相互作用的评估

基本信息

批准号：
07455216
负责人：
TOKIMATSU Kohji
金额：
$ 3.2万
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：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455216/
关键词：
Pile Interaction Ground displacement Whincler foundation Centrifugal model test Earthquake Bending moment

项目摘要

The conditions causing soil liquefaction and resulting damage to building foundations in the 1995 Hyogoken-Nambu earthquake are examined. It is shown that possible causes fo the foundation damage include : (1) horizontal forces and overturning moments imposed on the foundation from the superstructures, (2) kinematic forces acting on deep foundations due to shear deformation of soils, (3) reduction in bearing capacity due to ground failures including liquefaction, and (4) lateral spreading.Both failure and deformation modes are examined using a borehole camera and a slope-indicator for prestressed concrete piles of buildings that experienced liquefaction-induced ground displacement during the 1995 Hyogoken-Nambu earthquake. It is shown that the damage is concentrated at the interface between liquefied and non-liquefied layrs, suggesting the significant effect of ground displacement on pile damage.Centrifuge shaking table tests are conducted on a soil-pile-structure model to investigate the effects of ground displacement and inertia force from the superstructure on stresses in piles during soil liquefaction. It is shown that the ground displacement and inertia force are in phase if the natural period of the structure is less than that of the soil deposit, whereas they are out of phase if the natural period of the structure is greater than that of the soil deposit.An analytical model is then proposed in which a group of piles connected with the same foundation is subjected to lateral ground displacement and inertia force, and the stress and displacement of the piles are calculated. The computed failure and deformation modes agree reasonably well with the field observations, confirming that the proposed analytical model could be effectively used to estimate stresses in piles during soil liquefaction.

检查了导致土壤液化的条件，并在1995年的北南北地震中造成了建筑基础的损害。结果表明，基础损害的可能原因包括：（1）水平力和上层建筑的基础上施加的倾斜力量，（2）（2）由于土壤的剪切变形而作用于深基础上的运动力，（3）由于地面故障的轴承能力降低了轴承故障，包括液体和（4）次涂层的轴承，以及（4）befortion。预应力混凝土堆的坡度指示剂，这些建筑物在1995年的Hyogoken-nambu地震期间经历了液化引起的地面位移。结果表明，损害集中在液化和非木质层面之间的界面上，这表明地面位移对桩损伤产生了显着影响。对土壤核培养基结构模型进行了缩放摇桌测试，以研究土壤置换的影响，以研究地面位移和惯性作用的影响。结果表明，如果结构的自然周期小于土壤沉积物的自然时期，则地面位移和惯性力是相同的，而如果结构的自然周期大于土壤沉积的自然时期，则提出与土壤沉积物的自然时期。然后，提出了与同一基础相关的一组桩，将其与同一基础相连，以后地面地面的位移和惰性势力和屈服于PITRAUTS和PITRAUTS的压力。计算出的故障和变形模式与现场观测值非常吻合，证实了所提出的分析模型可以有效地用于估计土壤液化过程中桩的应力。