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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.

对1995年兵库县南部地震中引起土壤液化的条件和由此引起的建筑物地基破坏进行了研究。分析表明，地基破坏的可能原因包括：（1）上部结构施加在地基上的水平力和倾覆力矩，（2）由于土壤剪切变形而作用在深基础上的运动力，（3）由于地基破坏（包括液化）而导致的承载力降低，和（4）侧向扩展。使用钻孔照相机和坡度指示器对1995年兵库县地震期间经历过地震引起的地面位移的建筑物的预应力混凝土桩的破坏和变形模式进行了检查。南部地震。通过土-桩-结构模型振动台试验，研究了地基液化过程中地基位移和上部结构惯性力对桩身应力的影响。当结构的自振周期小于存款的自振周期时，地面位移与惯性力同相;当结构的自振周期大于存款的自振周期时，地面位移与惯性力异相.并计算了桩的应力和位移。计算的破坏和变形模式同意合理以及与现场观测，证实了所提出的分析模型可以有效地用于估计在桩土液化过程中的应力。