混凝土芯砂石桩（CCSG）桩复合地基是一种新型多元复合地基。通过引入地基土体的e-lgσ和e-lgk对数模型，考虑地基土体固结过程中压缩模量和渗透系数非线性变化的特征，推导出基于等应变假设的CCSG桩复合地基非线性固结解析解，且现有的考虑土体非线性的砂井固结解和碎石桩复合地基固结解均是文中解的特例。根据该解析解得到桩土模量比、土体压缩指数与渗透指数比、荷载增量等无量纲参数变化时，CCSG桩复合地基的固结度曲线。分析结果表明，按应力和按变形定义的两种固结度不相等，通常按变形定义的固结速度较快；土体压缩模量和渗透系数的非线性变化对固结影响较大。最后通过和由实测数据获得的固结度曲线对比，验证了解析解的正确性。

Concrete-cored sand-gravel(CCSG) pile composite foundation is a new multi-type composite foundation. By incorporating the logarithm models of e-lgσ and e-lgk of soil, the characteristics of the nonlinear variation in the soil’s compressive modulus and the soil’s permeability during consolidation are considered. Based on equal strain assumption, the analytical solution is developed for CCSG pile composite foundation, which combined with itself characteristics and stress concentration effects. The existing consolidation solutions of sand drain foundation and gravel pile composite foundation under nonlinear characteristics of soil are special cases of this solution. Curves of the average consolidation degree of the composite foundation were observed based on the theoretical formula under the variation of various non-dimensional parameters such as the ratio of pile-soil modulus and soil compression index and penetration index, and load increment. The analytical results show that the average degree of consolidation in terms of stress is not equal to that in terms of deformation; in addition, the average degree of consolidation in terms of stress is greater than that in terms of deformation; the nonlinear characteristics of soil have a large affect on consolidation. The analytical solution is finally validated with the actual measurement data.