雨水入渗下土体抗剪强度劣化时残坡积土边坡的稳定性及加固研究

Stability analysis and landslide reinforcement study for residual and diluvia soil slop under rainfall infiltration

云南属山地高原地形,地形地质条件复杂,分布有大面积的残积土和坡积物覆盖层,修建高速公路必将遇到大量高陡残积土边坡,而且有的裂隙发育,降雨入渗是影响此类边坡稳定性的主要因素。本文以某后缘大裂隙发育边坡为例,假设雨水入渗致使老滑动带复活,水沿顺坡方向渗流(忽略渗流力作用),土体抗剪强度发生劣化时,抗滑桩对此类边坡的加固效果。结果表明,抗滑桩能有效阻止土体下滑,但随着土体含水量和饱和度的增加,滑体位移及滑动带剪应力增加较大,加大了桩身结构安全的要求。特别是土体饱和度达到74%以上时,即使抗滑桩不被折断,但桩前面的滑体前缘也会出现滑坡。该实例分析为工程上滑坡的预测、初步分析和加固设计提供了相应的指导意义。

Yunnan province is located in YUNGUI highland.Most of the areas are characterized with high mountains and deep valleys.A large area of residual and diluvia soil covering the mountains region,and a large number of high slopes are associated with the construction of expressway.Rainfall infiltration is the main factor affecting the stability of such slop.In this paper,based on VG model and the shear strength theory,study the stability of residual soil slop under rainfall infiltration,focusing on the comparison of anti-slide pile reinforcement effect under different saturation of soil.The results show that the anti-slide pile can effectively prevent landslides,when the water content and saturation of soil is increased,not only the risk of landslides is increased,but also the structural safety of pile has been challenged.Especially when the saturation reaches above 74%,the front of slope will slide even if the pile is not broken.