褥垫层对复合地基承载特性影响的试验研究

通过现场静载荷试验，研究了不同厚度、不同材料的褥垫层对夯实水泥土单桩及多桩复合地基承载特性的影响。试验结果表明，随垫层厚度的增加，桩身分担荷载的比例逐渐减小，而桩间土分担荷载的比例却逐渐增大，表现为桩土应力比随垫层厚度增加而降低的特点。另一方面，垫层材料性能越好，则调整桩土协调变形的能力越强，即要求设置的褥垫层厚度越薄。对试验的两种材料不同厚度的褥垫层，其最佳厚度为0.2～0.3 m。

Test study on influence of cushion on loading behavior of composite foundations

The influence of cushion on loading behavior of the composite foundation with compacted soil-cement pile was studied by static loading in-situ. The result of test shows that the thickness and character of the cushion have an important impact on the loading and deformation characteristics of composite foundation. With increasing of the cushion thickness, the loading ratio of the pile is decreasing, but the ratio of the soil is increasing. The pile-soil stress ratio reduces with the increasing of the cushion thickness. On the other hand, the more the character of the cushion is strong, the greater the ability of adjusting deformation, the thinner the cushion thickness. The test result of different thicknesses and two types of cushion shows that the best thickness is of 0.2-0.3 m.