路堤荷载下水泥土搅拌桩复合地基沉降分析

李永刚^{1, 2}，赵春风^{1, 2}，廖乾旭³，楼云³，潘维慧⁴

(1. 同济大学 岩土及地下工程教育部重点实验室，上海，200092；
2. 同济大学 地下建筑与工程系，上海，200092；
3. 浙江省交通运输厅工程质量监督局，浙江 杭州，311215；
4. 上海浦东发展置业有限公司，上海，200122)

摘 要：分析路堤荷载下水泥土搅拌桩复合地基的沉降问题，提出桩长小于临界桩长和桩长大于临界桩长2种计算模型。通过假定桩土竖向位移模式和临界桩长范围内桩侧摩阻力、桩土相对位移分布模式，并假定桩侧摩阻力与桩土相对位移之间满足理想弹塑性关系，推导出2种计算模型的桩顶沉降量和桩间土沉降量的计算公式。采用工程试验结果对推导所得的计算公式进行验证。研究结果表明：桩顶、桩间土沉降量的计算值与实测值比较接近，证实该计算方法的合理性。

关键词：路堤荷载；水泥土搅拌桩；复合地基；临界桩长；沉降分析

Settlement analysis of cement-soil mixed column composite foundation under embankment load

LI Yong-gang^{1, 2}, ZHAO Chun-feng^{1, 2}, LIAO Qian-xu³, LOU Yun³, PAN Wei-hui⁴

(1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,
Tongji University, Shanghai 200092, China;
2. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;
3. Construction Quality Supervision Bureau of Zhejiang Communication Department, Hangzhou 311215, China;
4. Shanghai Pudong Development Real Estate Co. Ltd., Shanghai 200122, China)

Abstract:Two kinds of calculation models, i.e. the pile length is shorter than and longer than critical length of pile were put forward to evaluate settlement of cement-soil mixed column composite foundation. Based on the assumed vertical displacement mode between pile and soil, the assumed distribution of side frictional resistance and the relative displacement between pile and soil in the range of critical length of pile, and the assumption of ideal elastic-plastic relation between side frictional resistance and relative displacement between pile and soil，the formulae of vertical displacement of pile and soil were deduced with two kinds of calculation models. The rationality of the formulae is confirmed compared with the test result of relative reference, which confirms the rationality of the method.

Key words:embankment load; cement-soil mixed column; composite foundation; critical length of pile; settlement analysis