CFG桩复合地基褥垫层的试验研究和有限元分析

针对CFG桩复合地基褥垫层效应问题，通过12根桩的单桩复合地基载荷试验，研究了不同厚度、不同材料的褥垫层对桩土应力比的影响。试验结果表明，褥垫层的厚度和刚度对CFG桩复合地基的桩土应力比均有影响，褥垫层过薄及过厚将使桩的承载力得不到有效发挥。利用有限元软件包ANSYS，建立了单桩复合地基有限元模型，分析了褥垫层厚度和变形模量对桩土应力比的影响，经与试验数据进行分析比较，得出了与试验结果相一致的结论。通过有限元分析结果与试验结果的对比分析，确定了CFG桩复合地基褥垫层的选用原则，从而为复合地基设计中褥垫层的设计提供了依据。

Experimental study and finite element analysis of cushion in CFG pile composite foundation

In light of the effect of cushion on the composite foundation，according to the single pile composite foundation load testing of 12 piles， influences of the cushion on the pile-soil stress ratio have been studied; the test result indicates that both the thickness and rigidity of the cushion have effect on the pile-soil stress ratio，either the excessively thinness or over thick load capacity can not function well. To verify the test data，the single pile composite foundation finite element model is established using ANSYS program; the influences of the cushion thickness and deformation modulus on the pile-soil stress ratio have been analysed. Analysis and experimental results show that the value analysis and test result are consistent. Comparing the finite element analysis and test result, the selection principle of the cushion has determined so as to provide the cushion design basis in the process of composite foundation design.