贵州省岑巩县大榕滑坡特征及形成机制研究

2012年6月29日，岑巩县思旸镇大榕村突发大型滑坡灾害，约310104m3。大榕滑坡为古滑坡堆积区失稳。基于滑坡破坏特征分析和地质原型分析，定性判断滑坡失稳模式为蠕滑-拉裂-牵引式滑移。滑坡启动区在不合理人工填土及强降雨作用下，坡脚蠕滑并发展为失稳，由此导致主滑区坡脚支撑作用明显减弱，主滑区中下部因此滑移失稳，并牵引右侧主滑体中上部坡体逐步失稳。滑带主要位于下伏强风化基岩中。主滑体左侧向西滑移，右侧主体向SW向滑移。基于渗流场-应力场耦合数值分析，再现了滑坡失稳过程及发生机理。大榕滑坡形成机制深入研究对于西部山区类似滑坡分析及识别具有重要的参考价值。

CHARACTERISTIC AND MECHANISM OF DARONG LANDSLIDE IN CENGONG NTY,GUIZHOU PROVINCE

A large-scale landslide disaster of about 3.1 million m3 happened in Darong village of Siyang town,Cengong country on June 29,2012. Darong landslide is in the accumulation zone of ancient landslide. Based on the analysis of failure characteristics and geological prototype of landslide,the failure mode is qualitatively judged as creep sliding-fracturing-traction sliding. Under the action of unreasonable artificial filled soil in landslide promoter region and heavy rainfall,the base of slope had creep deformation and became unstable,which weakened the supporting force in the base of slope of the main slide area. Consequently,sliding and instability happened in the lower part of the main slide area,which thus induced the upper right side of the main slide to be gradually unstable. Slip zone is located in highly weathered bedrock underlying. The left side of the main body slipped to west,and the right one slipped to southwest. Based on coupled numerical analysis of stress field and seepage field,the instability process and generation mechanism of the landslide are reappeared. The study on formation mechanism of Darong landslide provides an important reference for analogous landslide analysis and identification in western mountains.