刚性桩复合地基地震反应机理分析

为研究刚性桩复合地基的抗震性能，用刚性桩复合地基振动台试验验证了所采用的等效线性方法及其参数取值，在此基础上针对实际问题进行了三维有限元分析，对地基分层、土体模量、桩径、桩长、垫层厚度和垫层模量等因素对复合地基地震反应的影响进行了分析讨论，对刚性桩复合地基在地震荷载作用下的工作机理进行了较详细的分析。结果表明，等效线性方法能较好地模拟结构-复合地基相互作用的特性；上部结构惯性力和自由场变形对复合地基桩身内力影响都较大；地基明显软硬分层的存在，会使桩身内力显著增大。

Mechanism analysis of earthquake responses of rigid pile composite foundation

Concerning the aseismic ability of rigid pile composite foundation, the equivalent linear method and its parameter values are verified by shaking table tests of rigid pile composite foundation; some practical cases are analyzed by means of 3D finite element method. The effects of layered foundation, soil modulus, pile diameter and pile length, cushion thickness and cushion modulus etc. on the earthquake responses of rigid pile composite foundation are discussed; and the aseismic mechanism of rigid pile composite foundation is studied. It is found that the equivalent linear method can adequately simulate the characteristics of the interaction between structure and composite foundation; the inertia force of the superstructure and the deformation of the free field have notable impact on the inner forces in piles; the inner forces in piles tend to remarkably increase for the existence of weak layers in soil.