降雨入渗条件下边坡湿陷变形的数值模拟

降雨入渗是边坡发生失稳滑动破坏的主要因素之一为研究降雨入渗条件下边坡湿陷变形的基本特性，采用修正的巴萨罗那模型（BBM）和非饱和多孔介质力学理论，建立了基于弹垫性分析的非饱和流固耦合计算模型，开发相应的有限元程序，进行降雨入渗下非饱和土边坡渗流场和应力场耦合的数值分析，研究了降雨持时、降雨强度以及饱和渗透系数对边坡渗流和变形的影响．结果表明：该计算模型能够很好地反映边坡的湿陷变形特性，最大湿陷变形发生在坡面拐角及坡顶位置．降雨强度和土体饱和渗透系数的大小对边坡内孔压和位移影响显著：在降雨强度小于饱和渗透系数时，坡内孔压及位移随降雨强度的增大而增大；当饱和渗透系数小于且接近降雨强度时，坡内孔压和位移增量明显增大；而当饱和渗透系数远大于或小于降雨强度时，坡内孔压及位移变化量则较小．

Numerical Simulation on Wetting Deformation of Unsaturated Slope Under Rainfall Infiltration

Rainfall infiltration is one of the reasons for slope failures. In order to investigate the wetting deformation of slope under rainfall infiltration, an unsaturated flow-deformation coupling model was presented based on the improved basic Barcelona model and the mechanical theory of unsaturated porous media. Numerical simulations were conducted to examine the seepage field and wetting field of unsaturated slope during rainfall infiltration. The influences of rainfall duration, rainfall intensity and soil saturated permeability on seepage field and deformation were studied. The simulated results show that the presented model is reasonable in reflecting the actual behavior of slope under rainfall infiltration, and that the maximum wetting deformation occurrs at both the comer of slope surface and the top of slope. The relationship between rainfall intensity and saturated permeability also has a great influence on the variation of pore-water pressure and displacements. The pore-water pressure and displacements increase with rainfall intensity when the rainfall intensity is greater than the saturated permeability. The pore-water pressure and displacements increase more obviously when saturated permeability approaches rainfall intensity than those when the former is far greater or less than the latter.