地下水对碎石土类边坡稳定性影响分析

ANALYSIS OF GROUNDWATER'S EFFECT ON STABILITY OF DEBRIS SLOPE

在碎石土类边坡中常常发育地下水管网渗流系统,他们控制地下水水位上升,对保持边坡稳定十分重要。当坡脚开挖或坡体堆载时,会破坏管道状地下水排泄系统,从而导致地下水水位升高,使潜在滑面上的孔隙水压升高,最终导致滑坡的发生。本文综合分析了滑坡与水相互作用机理,并以官家滑坡为例,通过对滑坡稳定性计算中与地下水有关的各因素敏感性分析,发现地下水位变化对孔隙压力比、水头高度和水力坡度的影响极大的影响了碎石土边坡的稳定性;通过官家滑坡极限状态的塑性变形发现,碎石土边坡的变形破坏往往是在部分脆弱部位,通过长期蠕变积累首先展开,并逐渐扩展至整个滑面,由此得到在滑坡稳定性计算中,强度参数按照饱水面积比影响下经衰减的数值进行计算,所得到的稳定性系数更符合工程实际现状,对滑坡剩余推力的计算和治理设计具有积极的指导意义。

Groundwater pipe drainage systems （GPDS） which important in restricting groundwater level rising and in keeping slope stability are often found in debris slopes. Cutting at slope toe or loading on slope surface may destroy the pipe seepage system and make groundwater level rise obviously As a result, the pore-water pressure on a potential slip surface will rise and a landslide may take place. This paper analyses the mechanics between landslide and water. With the example of guanjia landslide, it find that the change of groundwater level affects the slope＇s stabilization because the pore pressure ratio,head level and hydraulic gradient act synthetically in the change. Though the plastic strain of slide mass of landslide in limiting state, it get that the distortion often occurs in some vulnerable position, and expands to all slide surface after some extent of creep. Then, the parameter must be faded which is related with saturation-area ratios in the stability calculation of landslide. Moreover, the stability coefficient from than is much more agree with practice, and rest thrust is more significant for remedying design.