考虑幂函数渗透压缩变化的双层砂井地基固结性状

采用Barron轴对称固结及大变形固结问题的某些简化与假定，推导建立了砂井地基大变形固结控制方程，利用建立的双层砂井地基大变形固结方程及编制的计算程序，通过引入软土渗透系数、有效应力与孔隙比之间的幂函数关系k =ced与e=a( )b，对瞬时加载下双层砂井地基固结性状进行算例计算。结果表明：（1）双层软土幂函数渗透关系及压缩关系中诸参数对双层砂井地基固结性状有重要影响：随着两层软土幂函数渗透关系中参数c1、c2的增加（渗透性增加）、或幂函数压缩关系中参数a1、a2的增加，各土层水平径向与竖向孔隙比减小更快，沉降发展速率与超静孔压消散速率也相应增加，且沉降发展速率快于孔压消散速率。（2）两层土在分界面处的孔隙比及平均超静孔压均出现明显的突变，将沿深度分布曲线分成形状不同的两段，表现出不同的固结性状。

Consolidation behaviors of double-layered vertical drains ground considering power function permeability and compressibility variation

Based on some simplification and assumption of one-dimensional finite-strain consolidation theory and Barron axisymmetric consolidation theory, a finite-strain consolidation governing equation for vertical drains ground is established. Based on the finite-strain consolidation equation for double-layered vertical drains in soft soil and the computing program in some literatures, the power function relationships of permeability coefficient-void ratio k=ced and effective stress-void ratio e=a( )b for soft soil are introduced; and some examples calculation of consolidation behaviors of double-layered vertical drains ground are carried out under instantaneous loading. The obtained results show that: (1) Some important influence on the consolidation behaviors of double-layered vertical drains ground of various parameters in power function permeability and compressibility relationships for double-layered soft clay soil are as follows. With the increase of parameters c1, c2 of power function permeability relationship (the increase of permeability), or parameters a1, a2 of power function compressibility relationship for soft soil, the void ratios in the radial and vertical directions decrease faster; and the dissipation velocity of excess pore water pressure and the settlement rate are also accelerated; the settlement development rate is faster than the dissipation velocity of excess pore water pressure. (2) The void ratio and average excess pore water pressure at the interface of double-layered soft soil present significant mutation, of which the distribution curve along the depth is divided into two sections with different consolidation behaviors.