降雨入渗作用下膨胀土缓坡稳定性数值模拟

Numerical Simulation on Stability of Expansive Soil Gentle Slope under Rainfall Infiltration

降雨入渗是引起工程边坡破坏的一个主要因素。膨胀土是一种具有明显湿胀干缩特性的特殊土。膨胀土边坡表层土体在长期干湿循环过程中裂隙发育、雨水渗透通道增多,相对应地增大了其土层的渗透系数。该文运用强度折减法和有限元分析软件,对不同降雨工况下长、大、缓边坡的安全稳定性进行研究。结果表明:在不同降雨强度、不同降雨历时作用下,膨胀土边坡内部孔压、饱和度及边坡表面位移的变化与降雨程度成正比,但属非线性变化关系,即在降雨强度达到一定数值后,降雨强度的增加对于膨胀土边坡内部孔压、饱和度及边坡表面位移变化的影响微乎其微,安全系数的降低程度亦存在一定差异。

Rainfall infiltration is a major factor causing slope failure.Expansive soil is a special soil with obvious wet-swelling and dry-shrinking characteristics.During the long-term dry-wet cycles of the surface soil of the expansive soil slope,cracks develop and rainwater infiltration channels increase,correspondingly increases the permeability coefficient of its soil layer.In this paper,the strength reduction method and finite element analysis software are used to study the safety and stability of long,large and gentle slopes under different rainfall conditions.The results show that:under different rainfall intensities and durations,the changes in internal pore pressure,saturation,and surface displacement of expansive soil slopes are directly proportional to the rainfall degree,but the relationship is nonlinear,that is,the increase in rainfall intensity after reaching a certain value has little impact on the changes in internal pore pressure,saturation,and surface displacement of expansive soil slopes,and there are also some differences in the degree of reduction of safety factors.