川东南红层地区平推式滑坡成因机制研究

四川分布有大量的红层地区,在这些地区广泛发育有一种平推式类型的滑坡,这种类型的滑坡具有岩层倾角缓,后缘拉裂缝容易充水形成静水压力,砂泥岩互层的特点。以仪陇县的大山梁滑坡为例,研究该类型滑坡在强降雨条件下的稳定性。运用geostudio软件的seep模块分析其天然状态下与在降雨情况下地下水位线变化,并通过与slope模块进行耦合计算,以此分析降雨情况下地下水位变化以及引起的稳定性变化;并对其成因机制模式进行研究。研究结果表明,强降雨情况下滑坡后缘拉裂缝内会充水形成静水压力作用;并提升滑面处的扬压力,推挤滑体向前移动;并且随着降雨量的加大也影响了滑体内渗流场,导致滑体内孔隙水压力增大,致使后缘岩体在水的作用下软化崩解,进而加大后缘裂缝的深度与宽度。而滑体硬软硬的岩性组合迫使滑体整个的变形不一,使滑带土在雨水及推力作用下逐渐软化变形致使抗剪强度降低,最终使滑体沿砂岩与泥岩的层面交界处滑出。

The Formation And Mechanism Research of Horizontal Pushing Type Landslide In The Red Bed Region Of The East AND South Of Si Chuan

Abstract] Sichuan distribution have a large number of red bed region, There has the translational gliding landslide which extensively develop in these areas, this type of landslide has the characteristics of slow strata dip, trailing edge cracks easily filling water and form hydrostatic pressure, sand and mudstone placed over each other. The big mountain ridge landslide in the lion village of Yi Long county is based as an example in this article, and studying the stability of this landslide under the condition of heavy rainfall, By using geostudio,s seep module to inverse analyze the underground water level when it is under natural state and different rainfall conditions and through the coupling calculation with the slope module, to analyze the rainfall conditions of underground water level change and the stability of the change. Studying its genetic mechanism and model. The results show that the heavy rainfall will cases landslides trailing edge cracks filling water and form hydrostatic pressure, and promote the uplift pressure of sliding surface, push the sliding body moving forward.And with the increase of rainfall also affects the seepage field in the body, cause pore water pressure increasing in the body, the rock of trailing edge under the action of water get softening and disintegration, and increase the depth and width of trailing edge cracks. The combination of hard rock and soft rock which placed over each other have different forced deformation, and the soil of the sliding zone under the action of rainfall and thrust gradually get softening and deformation So cause the shear strength reducing, eventually make the slope start slide along the junction level of sandstone and mudstone.