疏桩的承载性能和土拱效应

疏桩在软土地区的应用可以分为两个方面：疏桩复合地基和疏桩基坑支护。本文针对疏桩基础中的摩擦桩，采用弹性力学中的Mindlin-Geddes解和Boussinesq解联合求解的方法，分析了疏桩基础的附加应力场。通过对比不同桩间距下的桩土荷载分担比的变化规律，分析了软土地区疏桩间距的合理范围。同时对疏桩水平方向上存在的土拱效应，采用三维有限元数值方法模拟了桩间距对疏桩成拱的影响，得出了产生土拱的最大桩间距范围在6～8d之间。针对疏桩复合地基的沉降控制计算方法，本文总结出应用Poulos弹性理论法计算单桩沉降和复合地基方法计算群桩沉降。

Research on Bearing Behavior and Arching Effect of Scattered Piles

The application of scattered piles in soft soil can be divided into two aspects：composite founda-tion and excavation pit supporting .This article analyzed the additional stress field of friction piles in sparse pile foundation with Mindlin and Boussinesq solutions .By comparing the load sharing percent of soil with different pile spacing, the reasonable range of pile spacing was recommended in soft soil region .Meanwhile, 3D finite el-ement method was adopted to analyze the horizontal soil arching effect of scattered piles influenced by pile spac -ing, concluding that the maximum pile spacing can reach 6~8d.While elastic theory methods were used in sin-gle pile settlement calculation , the designing method of composite foundation was adopted in pile group calcula-tion.