考虑地表变流量的非饱和土渗流耦合的解析分析

Analytical analysis of coupled seepage in unsaturated soils considering varying surface flux

基于含水率和渗透系数是孔隙水压力的指数函数假设,通过Fourier积分变换,获取了降雨入渗过程中一维非饱和土渗流–变形耦合的解析解,该解能考虑地表降雨强度的变化。当降雨强度小于土体的入渗能力时,地表边界受流量控制;降雨强度逐渐增加,超过土体的入渗能力,地表边界为孔隙水压力。该解不仅能考虑地表变流量的边界,还可以分析压力边界条件,另外适用于任意的初始条件。算例计算结果表明,耦合对渗流产生影响;当渗流达到稳定时,非饱和土变形–渗流的耦合效应消失。

Based on the assumption that water content and permeability coefficient are exponential functions of pore-water pressure,the Fourier transform is used to obtain an analytical solution to one-dimensional coupled rainfall infiltration and deformation in unsaturated soils with varying surface rainfall flux.When the gradually increasing rainfall intensity is less than the saturated coefficient of permeability,a flux boundary condition is adopted.When the rainfall intensity is larger than the infiltration capacity of the saturated soils,a pore-water pressure boundary condition is used.The analytical solution can consider varying flux boundary conditions,pressure boundary conditions and arbitrary initial conditions.The calculated results of a case study show that the coupling effect has a markable effect on the pressure distribution for the transient unsaturated seepage.The coupling effect dissipates if the steady-state infiltration occurs.