基于颗粒流的土质边坡失稳机理

为研究降雨工况下诱发土质边坡失稳过程及破坏机理,以泸州市古蔺县竹林沟滑坡为依托,通过PFC2D双轴压缩试验对滑坡体饱和状态下的强度参数进行标定,确定滑坡细观参数与宏观参数的内在联系,并引入接触黏结模型,对其破坏过程特征进行模拟研究,并对滑坡关键位置处的速度、孔隙率以及位移进行实时监测.计算结果表明:滑坡破坏的过程为:初期整体蠕滑变形,随着变形的发展,滑坡体向坡前临空方向发生剪切蠕变,后缘产生由坡面向深部发展的张拉裂缝,随着潜在滑面贯通,滑坡失稳破坏;通过监测不同位置的速度发现,0～10 s为加速阶段,坡体最大速度达到约14 m/s,最大颗粒速度达到约20 m/s,15～25 s坡体速度开始下降,滑坡最大位移约600 m,整体位移约450 m,并于25 s左右坡体停止滑动.通过对竹林沟滑坡的数值模拟,采用离散元颗粒流的方法去研究滑坡的运动过程有较好的应用性,也能为同类型滑坡的防灾减灾提供较好的参考意义.

Research on Instability Mechanism of Soil Slope Based on Particle Flow

To study the process of inducing soil slope instability under the working conditions of raining and its damage mechanism, in this paper, based on the Zhulingou landslide in Gulin County, Luzhou City, the strength parameter under the landslide mass saturation status was demarcated via PFC2D biaxial compression test, to determine the internal connection between the landslide microscomic parameters and macro parameters. In addition, contact adhesion model was introduced to carry out simulation study towards the features of destruction process, and make real-time monitoring for the speed, porosity factor and displacement at the key landslide position. According to the calculation result, it indicated: 1. The landslide destruction process was: the entire creeping and deformation at the initial stage, along with development of deformation, the landslide would have shear degradation in the direction facing the sky before the slope, with tensile fissure developing towards the deep part generated in the trailing edge, and along with potential landslide face connection, the landslide became instable and suffered destruction. 2. By monitoring speed at different positions, it was discovered that 0-10 s referred to the acceleration speed, the slope maximum speed reached about 14 m?s-1, and the maximum particle speed was up to about 20 m?s-1, during 15-25 s, the slope speed began to reduce, the landslide maximum displacement was about 600 m, and the entire displacement was about 450 m, and the slope stopped sliding at about 25 s. through numerical modeling for the landslide of Zhulingou, studying landslide movement process via the method of discrete element particle flow was of good application, and it could provide a good reference significance for disaster prevention and reduction of the similar landslide.