中文摘要：

在CFG桩复合地基中，褥垫层的设置厚度和模量对于复合地基的承载及变形特性有较大的影响。本文建立了CFG桩复合地基的三维弹塑性数值分析模型，研究了当采用不同厚度和模量的褥垫层时，复合地基沉降、桩端沉降、褥垫层压缩量和桩土应力等参数的变化规律。结果表明复合地基沉降和褥垫层压缩量随着垫层厚度的增加而增大，而随着垫层模量的增大而减小；垫层厚度和模量的变化对于桩端沉降的影响较小，从工程角度可认为桩端沉降不随垫层厚度与垫层模量的变化而变化；桩土应力比随垫层厚度的增大而减小，随垫层模量的增大而增大。

英文摘要：

For the CFG pile composite foundation, the setting thickness and modulus of cushion have a greater effect on the hearing and deformation characteristics of composite foundation. In this paper, the three- dimensional elastic-plastic numerical analysis model of CFG pile composite foundation is created, and the variation in the composite foundation settlement, settlement of pile, cushion compression and the pile-soil stress ratio and other parameters are examined when cushion of different thickness and modulus are used. The results show that the composite foundation settlement and cushion compression increase with the increase of the thickness of the cushion, decrease with the increase of cushion modulus; the effect of cushion thickness and modulus on settlement of pile is little; pile-soil stress ratio decreases with the increase of the thickness of the cushion, increases with the increase of cushion modulus.