固结和流变的饱和土—筏板—单桩共同作用分析

Analysis of saturated soil-raft-pile interaction with consolidation and rheology

根据Biot固结理论,采用Laplace和Hankel变换方法得到了半空间饱和土表面和土体内受垂直环形载荷作用下的变换域内基本解.再根据虚拟桩法,得出了土—筏板—桩的第二类Fredholm积分方程.求解积分方程并进行相应的数值逆变换可得单桩的变形、轴力、孔压以及筏板与土的接触正应力随时间的变化情况.数值结果表明:随着土体的逐步固结与流变,筏板与土的接触正应力将减小,而桩所分担的荷载比例增加;同时桩周孔压逐步消散;桩身位移随着时间的推移会增大.

Based on Biot＇s consolidation and rheology theory, the general solutions for a vertical ring load applied on the surface or the interior of a saturated soil are developed via the Laplace transform and Hankel transform. Utilizing fictitious pile method, the second kind of Fredholm integral equation describing the interaction among pile-soil-raft is obtained. By the numerical solution of the integral equation and the corresponding inverse integral transforms, the displacement, axial force and pore pressure along the pile axis as well as the contact normal stress between raft and soil are obtained. Numerical results show that the contact normal stress between raft and soil will decrease and more part of loading will transfer to the pile with the development of the consolidation and rheology in the saturated soil. Also, the pore pressure along the pile side will be dissipated and the vertical displacement of the pile will increase with the soil consolidated.