中文摘要：

根据静载荷试验结果，研究褥垫层厚度对荷载在水泥土搅拌桩四桩复合地基中传递的影响规律。共完成四种厚度褥垫层的水泥土搅拌桩复合地基现场静载荷试验，在复合地基的不同位置埋设土压力盒，根据压力盒的读数算得桩和土中的应力。对桩、土应力的比较分析表明：随着褥垫层厚度的增大，桩侧负摩阻力增大，桩身最大应力位置下移，桩身应力随深度衰减速度减慢，桩身最大应力出现在距离桩顶2～4倍桩径范围；加载稳定期间桩土应力比n的变化表明了桩土间的荷载有协调重分配的过程，桩土应力比n随着荷载的增加先增大后减小，n值与褥垫层的厚度成反比。根据以上结论，对水泥土搅拌桩复合地基的设计提出几点建议，以提高水泥土搅拌桩复合地基的承载力。

英文摘要：

The load transfer mechanism of cement-soil pile composite foundations with dlllerent cushion heights were studied according to the results of static loading tests. Four types of static load tests of 4-pile composite foundation were carried out with different cushion heights. Using the data collected from the pressure cells, the stresses of the pile and the soil were calculated. Comparison and analysis of the data show that, with the increase of the cushion height, the negative friction of the pile increases, the location of the maximum stress of the pile shifts downwards, and the decreasing rate of the stresses of the pile is smaller. The location of the maximum stress of the pile is in the range of 2-4 times pile diameters distance from the top of the pile. During the period of stability, the change of the pile-soil stress ratio indicates the redistribution of load between soil and piles. With the increase of load, the pile-soil stress ratio first increases and then decreases, and it is inversely proportional to the cushion height. Suggestions are given for the design of composite foundation to increase its supporting capacity.