中文摘要：

柔性基础下复合地基的受力及变形过程是柔性基础、垫层、复合地基以及桩端下卧层土体四者相互作用、应力和变形相互耦合的复杂过程。在分析柔性基础下复合地基的荷载传递机理的基础上;将柔性基础-垫层-复合地基-下卧层土体作为一个共同作用的整体,建立考虑上、下部共同作用的柔性基础下复合地基简化分析模型,考虑柔性基础、垫层、复合地基与下卧层土体之间应力、变形协调关系以及桩、土界面的相对滑移,推导出表征复合地基性状的沉降变形和桩土应力比的求解公式;最后通过与工程实测结果的对比分析,验证该方法的合理性和适用性。

英文摘要：

The behavior of the composite ground under a flexible foundation is a complicated problem, which includes the interaction and stress-strain coupling among the flexible foundation, the cushion, the composite ground and the underlying strata. The law of load transfer of composite ground under a flexible foundation is analyzed firstly. And then a simplified analytic model is presented, in which the flexible foundation-cushion-composite ground-underlying strata is considered as an interactive system. According to the compatibility of stress and deformation on the interfaces between these four components, and considering the relative movement between the pile and the soil, the formulas of settlement and stress ratio of pile to soil, which are used to characterize the behavior of the composite ground, are derived. Finally, the rationality and applicability of the analytic solution are proved by one engineering case.