南江县石板沟滑坡特征、成因及演化过程研究

摘要

石板沟滑坡是南江县2011年“9.18”洪灾期间降雨诱发的大型顺层基岩滑坡.通过野外调研,详细研究了石板沟滑坡的地质环境和滑坡特征,并从多方面论述了其发生的地质成因机制及变形演化过程.研究表明:原三沟环绕的地形特征为石板沟滑坡的发生提供了非常大的汇水条件,超强度降雨引起斜坡所蕴藏的高势能、极高的静水压力、浮托力以及滑带土的液化,是致使石板沟滑坡高速滑动的主要原因；滑坡的变形演化过程大致经历基岩斜坡原生节理裂隙充水张开、初期短距离拉槽起动、中期槽谷缓慢扩张、后期槽谷充水剧烈滑移4个阶段.最后建议在地质调查详查工作中应注重对斜坡微地貌及风化卸荷带的调查,对预测预报这类具有隐伏性的顺层基岩滑坡具有重大意义.%The Shibangou landslide was a rainfall-induced large-scale bedding bedrock landslide during the "9.18"floods in 2011 in Nanjiang county.Through field survey and detailed study on the geological environment and geological features of Shibangou landslide,we discussed its geological formation mechanism and deformation evolution in details.It's found that the surrounding three channels provided a very large catchment,The hidden potential energy caused by super heavy rainfall,the high static water pressure,uplift pressure,and the liquefaction of sliding soil are main causes of the high-speed sliding of the landslide.The landslide experienced four phases:the original jointed fissures in the bedrock were filled with water and then opened,and troughs initiated in short ranges,then the trough valleys slowly expanded,and finally the water-filled trough valleys slid violently.It' s suggested that during the geological survey,investigation of the microrelief of slopes and the weathered unloading areas should be focused on.It is of great significance for the forecast of such potential bedding bedrock landslide.