中文摘要：

成层土在工程中很常见，研究降雨过程中成层非饱和土的渗流一变形耦合对非饱和土土力学的发展具有重要的意义。由流体质量守恒，Darcy定律和Lloret等的非饱和土本构模型可得成层非饱和土渗流．变形耦合的控制方程。采用Gardner的非饱和土的渗透系数公式以及Boltzman模型，基于Laplace变换得到耦合方程的解析解。解析及其参数分析表明，渗流和变形耦合是具有时间效应的。与吸力变化相关的土的模量F，对成层土的孔隙水压力分布有明显影响。两层土的F差异越大，孔隙水压力消散得越慢，耦合效应越不显著。增大表层土的F值有利于降低耦合效应。成层土饱和体积含水率变化对吸力变化产生有限的影响。

英文摘要：

Layered soil such as landfill and cracked soils are often found in engineering. Its coupled infiltration and deformation during rainfall is significant for development of unsaturated soil mechanics. Based on fluid mass conservation, Darcy＇s law, and the constitutive model proposed by Lloret et al., coupled governing equations for seepage and deformation in unsaturated soils are obtained. The unsaturated coefficient of permeability is expressed using Gardner＇s model and the water retention characteristics are expressed using Boltzman＇s model. The analytic solution to the coupled equation is developed by Laplace transformation. The analytic solution and parameter analysis results show that the effect of coupling between unsaturated seepage and deformation is related with time. The modulus related to suction changes F has a marked effect on the pore water pressure. The larger the F ratio values for two-layer soils are, the more slowly the suction dissipates. The results indicate that a large F for the top-layer soil can effectively reduce the coupling effect. Volumetric moisture content changes in two-layer soils play a limited role in the suction distribution.