碎石土边坡破坏机理的敏感性分析

在碎石土类边坡中常常发育稳定的地下水管网排泄系统,它们对控制地下水水位上升,保持边坡稳定十分重要。以官家滑坡为例,通过对滑坡稳定性系数有关的各因素敏感性分析,发现地下水是影响边坡变形破坏以及复发破坏的最主要因素。当坡脚开挖或坡体堆载时,会破坏管道状地下水排泄系统,降雨入渗导致地下水水位升高,从而引起坡体内孔隙压力比、水头高度和水力坡度增大,使潜在滑面上的孔隙水压升高,影响碎石土边坡的稳定性；同时,地下水位的升高降低了土体的内摩擦角,而因素敏感性分析发现,内摩擦角对边坡失稳具有极其重要的影响。在官家滑坡的后期治理中,治水作为主要工程措施的理念已经得到很好的贯彻,效果十分明显。

Sensitivity Analysis on Failure Mechanism of Debris Slope

Groundwater pipe drainage systems (GPDS) which are important in restricting groundwater level rising and in keeping slope stability are often found in debris slopes. With the example of Guan-jia landslide, through the sensitivity analysis which are related with stability coefficient, it is found that the rise of groundwater level leads to the landslide collapse and relapse. Cutting at slope toe or loading on slope surface may destroy the pipe seepage system and make groundwater level rise obviously which lead to the pore pressure ratio, head level and hydraulic gradient rise, and the pore-water pressure on a potential slip surface to rise. Also, the internal friction angle which is the most important factor in stability decreases when the level of groundwater rises. In the remedying design, the conception of descending the level of ground-water is emphasized, and the effect of it is quite obvious.