降雨入渗作用下风积沙路堤边坡的稳定性分析

Stability Analysis of Aeolian Sand Embankment Slope under Rainfall Infiltration

以风积沙路堤边坡为研究对象,分析了不同降雨类型下,土体的体积含水量、孔隙水压力对边坡稳定性的影响及渗透规律。采用基于饱和-非饱和渗流理论的有限元软件,考虑基质吸力对滑动面抗剪强度的影响,对坡体在不同降雨类型下的渗透规律和对边坡的稳定性进行分析。结果表明:边坡在降雨入渗过程中,边坡表层体积含水量逐渐增大,基质吸力逐渐降低,在强降雨下边坡表层形成一个暂态饱和区,容易发生浅层滑动;连续降雨的边坡表层没有暂态饱和区,雨水全部下渗,在相同降雨量下连续降雨的渗入量和渗透深度都要大于短时强降雨;连续降雨相比短时强降雨对路基稳定性的影响更大,为了减小降雨对边坡稳定性的影响,坡面可采取防护措施起到阻水作用;在降雨量较大地区路基表层和边坡还要采用隔水措施,减少降雨入渗对边坡稳定性的影响。

In this paper, the aeolian sand embankment slope is taken as the research object, the effects of the volume water content of soil and pore water pressure on slope stability and the filtration law were studied and analyzed under different rainfall types. Adopting the finite element software based on saturated-unsaturated seepage flow theory, considering the influence of matrix suction on the shear strength of sliding surface, the permeability law of the slope under different rainfall types and the stability of the slope are analyzed and studied. The results show that during the rainfall infiltration process, the surface volume water content of the slope gradually increased, the matrix suction gradually decreased and a transient saturation zone was formed in the heavy rainfall on the surface of the slope, prone to shallow sliding. The slope surface of the continuous rain has no transient saturation zone and the rainwater is all infiltrated. The infiltration and infiltration depth of continuous rainfall under the same rainfall will be greater than that of short-term heavy rainfall. Continuous rainfall has a greater impact on the stability of the roadbed compared to short-term heavy rainfall. In order to reduce the impact of rainfall on slope stability, protective measures can be taken on the slope surface to play a role in water blocking. In the areas with large rainfall, the surface of the subgrade and the slope should also be adopted the measures of water diversion to reduce the influence of rainfall infiltration on slope stability.