柔性桩复合地基的沉降分析

Settlement of composite ground reinforced by deformable piles

为了分析柔性基础下柔性桩复合地基的沉降问题,提出了改进的单元体位移模型.通过假定的单元体竖向位移模式和纯摩擦桩桩侧摩阻力分布模式,利用桩土间无相对滑移、桩土界面处桩土压缩量相等和单元体边界处竖向切应力为零等边界条件,推导出复合地基纯摩擦桩桩侧摩阻力分布的具体表达式,以及加固区桩土压缩量的计算公式.随着荷载的增大,当桩体不再是纯摩擦桩时,计算方法同样适用于有桩端力或桩侧摩阻力达到极限值的情况.实例计算表明,理论公式计算结果与实测值比较接近.

An advanced unit cell model was put forward to evaluate the settlement of deformable pile under flexible foundation. Based on the assumed vertical displacement of the unit cell and the assumed distribution on the pile-soil interface of the pure friction pile, and using the boundary conditions that there was no relative slipping between pile and soil, the pile decrement was equal to that of soil on the pile-soil interface and that the vertical sheer stress of the unit cell＇s outer edge was equal to zero, the formula for the frictional distribution of the pure friction pile and the formulas for the displacement of pile and soil in the treated area were deduced. As the load increases, when the pile is no longer the pure friction pile, the method is also applicable for the cases that the pile has end support or the friction acting on the pile reaches limit. After computing and comparison, the result of the theory is close to the real value.