（1 淮阴工学院建筑工程系，淮安 223001； 2 南京工业大学土木工程学院，南京 210009）

［摘要］利用ABAQUS软件对常规桩筏基础（3d桩距）和复合桩基（6d桩距）进行了三维弹塑性分析。利用无厚度接触面单元模拟筏板-桩-土的非线性接触特性，采用Mohr Coulomb弹塑性本构模型描述土的非线性特性，桩取为弹性。得到了沉降、桩土荷载分担比、桩周土体水平位移变化情况。分析结果表明，6d桩距群桩中基桩的承载能力很快发挥到极限，后续荷载交由承台下土体承担，有更多的天然地基承载表现，6d桩距群桩的桩间土绕桩滑动的趋势较3D桩距群桩的要强。分析结果基本反映了桩-土-筏的实际工作性状，验证了复合桩基理论的正确性。

［关键词］桩筏基础；非线性；数值分析；沉降

Numerical analysis of behavior of pile-soil nonlinear interaction to composite pile foundation

Chen Yadong1，2, Zai Jinmin2, Qi Kejun2

(1 Department of Civil Engineering, Huaiyin Institute of Technology, Huaian 223001, China;

2 College of Civil Engineering, Nanjing University of Technology, Nanjing 210009, China)

Abstract:ABAQUS is used to give a 3d elastoplastic finite element analysis to piled raft foundation of 3d and 6d pile spacing. No thickness contact element is employed to simulate the nonlinear behavior of interaction of pile-soil. Mohr-coulomb elastoplastic constitutive model is used to represent nonlinear behavior of soil, and the pile is assumed to be elastic. Settlement, load sharing percent and horizontal displacement of the soil around the pile are got from the analysis. The analysis results indicate the load capacity of 6d spacing pile group quickly got the limit, then the other load was taken by the cap, which present more behave of nature ground. Sliping trend around pile of 6d spacing pile group is more strong than 3d spacing pile group. Analysis results reflect the practical work properties of pile-soil interaction, and validate the correctness of composite pile foundation.

Keywords:piled raft foundation；nonlinear behavior；numerical analyses；settlement

*国家自然科学基金资助项目（50578122）。