某滑坡破坏机理分析及治理方案的选择

Analysis of Landslide Failure Mechanism and Selection of Treatment Scheme

以某矿山露天采场西帮土体边坡为例,分析其滑坡事件的发生及勘察、治理方案的选择。结合以往勘察资料,通过对台阶土体边坡失稳前后稳定性系数的计算及破坏机理分析,排除本次边坡失稳并非是土力学方面的原因,得到其失稳主要原因是:土体边坡坡肩附近有地表水体的存在,地表水体通过具有液化性的粉质粘土与粉砂互层(俗称流砂层)的缓慢渗透,局部产生涌泥、涌水,最终产生管涌,导致土体边坡局部坍塌,并在地表水体的冲击作用下,进一步扩大边坡坍塌范围。基于滑坡破坏机理分析,从而否决"块石压坡、边坡再造"原方案,改以"填退水体,注浆改土"综合治理方案,为企业节约了治理成本。

Taking the soil slope in the west side of an open pit as an example,the occurrence of landslide and the selection of investigation and treatment scheme are analyzed. Combined with the previous survey data,and through the calculation of the stability coefficient before and after the instability of the soil slope on the step and the analysis of the failure mechanism,it is concluded that the instability of the slope is not caused by the soil mechanics. The main reason for the instability is:the existence of surface water near the slope shoulder of the soil slope. The slow infiltration of the surface water through the liquefied silty clay and silty sand interbed(commonly known as quicksand layer),locally generate mud breakout,water gushing,and finally piping,which lead to local collapse of soil slope,and further expand the scope of slope collapse under the impact of surface water. Based on the analysis of the landslide failure mechanism,the more economical treatment plan for landslide as "filling pond and grouting to replace soil" is proposed,instead of the original plan of "pressing slope with block rock and reconstructing the slope".