降雨入渗下残坡积土边坡的稳定性模拟研究

Research on the Residual Soil Slope Stability Simulation under Rainfall Infiltration

针对杭兰高速公路受降雨影响显著的非饱和残坡积土边坡,考虑降雨入渗的影响,通过对非饱和土水力特征参数的试验研究,用精度较高的Van Genuchten公式拟合土-水特征曲线,得出了非饱和渗透函数的特征参数;在此基础上,将饱和-非饱和非稳定渗流分析与有限元强度折减法相结合,进行了降雨入渗渗流场与应力场的耦合分析,模拟雨水入渗引起的暂态渗流场,并将计算所得到的暂态孔隙水压力用于考虑基质吸力影响的边坡稳定系数的计算;最后根据研究区的降雨气象资料,探讨了降雨强度、降雨持时对残坡积土边坡渗流场分布、发展和稳定性的影响。该研究可为滑坡地质灾害的预防提供依据。

Taking the fact that the Hang-Lan Highway is affected by the significant rainfall on the unsaturated residual soil slope and considering the effect of rainfall infiltration on unsaturated soil,this paper obtains the characteristic parameters of unsaturated permeability function by making the experimental research of hydraulic characteristic parameters of unsaturated soil and fitting soil-water characteristic curves with the high-accuracy Genuchten Van formula.On this basis,the analysis of unsaturated-saturated unstable seepage is combined with the finite element strength reduction method to make the coupling analysis of the seepage field and stress field of rainfall infiltration,simulate the transient seepage field caused by rain infiltration,and use the transient pore water pressure obtained from calculation to calculate the slope stability coefficient with the consideration of the influence of matrix suction.The paper also discusses the effect of rainfall intensity and rainfall duration on the distribution,development and stability of the slope seepage field of residual soil.