降雨入渗条件下非饱和土边坡稳定性数值分析

Numerical analysis on stability of unsaturated soil slope under rainfall infiltration

应用有限差分软件FLAC2D中两相流分析模块建立了非饱和土边坡的数值模型,并进行了考虑降雨入渗影响的渗流场及稳定性分析。结果表明:降雨强度较大的情况下,雨水入渗主要引起边坡表层的饱和度增加;而降雨强度较小时,雨水更容易入渗到边坡的内部;降雨持时相同时,边坡的剪应变增量随着降雨强度的增大而增大;强降雨条件下,边坡的位移较大,其中边坡水平向位移随着高程的减小而增大,而竖直向位移随着高程的减小而减小;随着降雨持时的增加,边坡的位移不断增大,安全系数不断减小。

The paper built the numerical analysis model of the side slope along certain highway, using the two-phase flow analysis module of the finite difference software - FLAC2D. On this basis, seepage field and stability analysis was conducted with the consideration of rainfall infiltration influence. The result indicated that in case of heavy rainfall, the infiltration mainly resulted in a saturation increase of the slope surface ; while for light rainfall, the water is more likely to saturate into the internal structure of the slope. Also for the same rainfall duration, the shear strain increment of the slope rise with the growth of rainfall. The analysis also found that under heavy rainfall, the displacement of the slope is comparatively large, in which the horizontal displacement goes up, while the vertical displacement goes down, with the decrease of elevation. At the same time, the increase of rainfall duration enlarges the slope displacement, but brings down the safety coefficient.