考虑桩土相互作用的非饱和土复合地基固结理论研究

随着非饱和土问题的日益凸显，考虑非饱和土的复合地基沉降变形预测与控制是地基设计的关键问题。复合地基作为软土地基处理的有效方法之一，其理论发展滞后于工程实际。本项目拟系统研究非饱和土复合地基桩-土相互作用机理，建立考虑桩-土相互作用的非饱和土复合地基固结理论。首先，结合数值模拟、试验研究和理论分析等方法，揭示非饱和土复合地基桩-土界面的力学行为并探明非饱和土复合地基桩-土荷载分担比；在此基础上，推导出桩-土相互作用边界条件和初始条件；最后，建立考虑桩-土相互作用的非饱和土复合地基固结模型，给出单桩复合地基的理论解析解和群桩复合地基的数值解，并采用现场试验验证其可靠性，同时给出可用于工程设计和施工的计算方法。研究成果将丰富复合地基固结理论，对推动复合地基设计理论发展有着重要理论意义，且对预测和控制复合地基的沉降变形具有指导意义。

As the problem of unsaturated soil becomes more and more prominent, the prediction and control of settlement and deformation of composite foundation considering unsaturated soil is the key problem of foundation design. As one of the effective methods of soft soil foundation treatment, the theory development of composite foundation lags behind the engineering practice. In this project, the mechanism of pile-soil interaction of unsaturated soil composite foundation is studied systematically, and the consolidation theory of unsaturated soil composite foundation considering pile-soil interaction is established. First of all, combining with numerical simulation, experimental research and theoretical analysis, the mechanical behavior of the pile-soil interface in the composite foundation of unsaturated soil is revealed and the pile-soil load sharing ratio of the composite foundation of unsaturated soil is verified; on this basis, the boundary conditions and initial conditions of pile-soil interaction are derived; finally, the consolidation model of unsaturated soil composite foundation considering pile-soil interaction is established, and single consolidation model is given The reliability of pile composite foundation is verified by field test, and the calculation method which can be used in engineering design and construction is further given. The research results will enrich the consolidation theory of composite foundation, have important theoretical significance for promoting the development of composite foundation design theory, and have guiding significance for predicting and controlling the settlement and deformation of composite foundation.