基于多场耦合的膨胀土边坡非饱和降雨入渗分析

膨胀土非饱和渗流的过程伴随着膨胀应变的产生。探明多场耦合作用下膨胀应变对膨胀土边坡非饱和降雨入渗的变化规律至关重要。基于有限差分渗流理论、降雨入渗模块的二次开发和膨胀应变的施加,采用C++和FISH语言编制程序,将膨胀应变引入非饱和土的流-固耦合模型,提出了一种综合考虑膨胀应变和应力应变的非饱和膨胀土多场耦合分析法,通过算例实现了降雨入渗条件下膨胀土边坡非饱和渗流的数值模拟,并探讨了膨胀应变对饱和度和暂态面积比的影响规律。研究表明,膨胀应变对膨胀土边坡非饱和降雨入渗的过程影响显著,其降雨入渗深度、湿润锋扩展速度和暂态饱和区时空分布受膨胀应变的控制,考虑膨胀应变时暂态面积比变化的雨后时间滞后性强于不考虑膨胀应变时。

Unsaturated Seepage Analysis of Expansive Soil Slope under Rainfall Infiltration Based on Multi-field Coupling

The process of unsaturated seepage in expansive soils is accompanied by the generation of expansion strains. The expansion strains under the coupling of multiple fields are crucial for investigating the variation of unsaturated rainfall infiltration in expansive soil slopes. By applying C++ and FISH language to programming, we introduced expansion strain into the fluid-structure interaction model of unsaturated soils, and proposed a multi-field coupling analysis method for unsaturated expansive soil considering expansion strain and stress strain. By using this model, we simulated numerically the unsaturated seepage flow of expansive soil slope in the presence of rainfall infiltration, and furthermore explored the influences of expansion strain on saturation degree and transient area ratio. Research results suggest that expansion strain has an evident impact on the process of unsaturated rainfall infiltration in expansive soil slopes. The depth of rainfall infiltration, the expansion speed of wetting front, and the temporal and spatial distribution of transient saturation region are controlled by the expansion strain. After rainfall, the time lag of transient area ratio is extended when expansion strain is considered.