基于降雨入渗的非饱和土边坡稳定性影响因素分析

Analysis of Influencing Factors on Stability of Unsaturated Soil Slope Based on Rainfall Infiltration

针对降雨对边坡稳定性影响因素的研究多以改变降雨工况为主而对边坡初始渗流场和土体性质方面研究相对较少的问题,选定与其相关的年平均降雨量q、渗透系数异性k、地下水位高度h及吸力摩擦角φ~b等因素作为变量,保持降雨工况不变,利用Geo-Studio软件分析了降雨作用下边坡渗流场和稳定性。结果表明,降雨作用下坡顶孔隙水压力响应幅度大于坡底,q和k越大、h越高时,坡脚越容易饱和,其中q越大、h越高,边坡初始孔隙水压力越大,而k增大时,边坡初始孔隙水压力随之减小。q与边坡稳定性呈反比,当k=1,即土体各向渗透系数相同时,边坡最稳定,h对边坡稳定性的影响存在一个临界高度,φ~b作为土体抗剪强度参数对边坡稳定性影响最大。

The research on the influencing factors of rainfall on slope stability is mainly to change the rainfall conditions, and there were few studies on the initial seepage field and soil properties of the slope. Therefore, the annual average rainfall q, the anisotropy of the permeability coefficient k, the groundwater level height hand the suction friction angle φ, related to these two aspects were selected as variables. Under the condition of keeping the rainfall condition unchanged, the seepage field and stability of the slope under the action of rainfall were analyzed by using software Geo-Studio. The results show that the pore water pressure response at the top of the slope is larger than that at the bottom of the slope under action of rainfall. When the values of q, kand hincreases, the slope toe is more likely to be saturated. The initial pore water pressure of slope increases with the increase of q and h, but decreases with the increase of k. q is inversely proportional to slope stability. When k=1 makes the slope the most stable, which menas the permeability coefficient of soil in all directions is the same. hhas a critical height on the slope stability, and as the soil shear strength parameter, φhas the greatest influence on the slope stability.