中文摘要：

根据路堤荷载下复合地基的荷载传递机理及变形特征,基于弹性理论,引入假定的桩间土位移模式,综合考虑路堤填土的土拱效应、复合地基加固区桩间土的成层性,建立了典型单元体的平衡方程,应用桩土位移协调条件及边界条件,得到了各层土范围内桩、桩周土竖向应力及桩侧剪应力的分布规律,从而推导出路堤荷载下复合地基加固区桩及桩周土压缩量计算的解析式,获得了表征复合地基工作性状的桩土应力比及沉降变形的解析表达式,并分析了加固区桩周土体层序对复合地基受力变形特性的影响。研究结果表明：当地基浅层土质较好时,复合地基加固区压缩量较其他情况下小,按本文建议的方法计算所得结果满足工程计算精度要求。

英文摘要：

Based on the load transfer mechanism and deformation characteristics of the composite foundation under embankment loads and elastic theory, hypothetic displacement modes between soil and piles are proposed. The soil arch effect and stratification of composite foundation are considered and equilibrium equations of typical unit are established. Combined with compatible equations of displacement and boundary conditions, the vertical stress of piles and soils as well as the distribution of shear stress along the piles are obtained. The analytical equations of compression of piles and soil in the reinforced zone are thereby deduced. Moreover, the analytical equations of pile-soil stress ratio and settlement representing the working condition of composite foundation are acquired. Thus the effects of the sequence of soil layers on composite foundation deformation are analyzed. The results show that when the shallow layers are of good quality, the compressibility of composite foundation is smaller than that in other cases. The calculation result with this method meets the need of engineering requirement, offering some reference for other projects.