四川省南江县下两中学滑坡成因机制分析与稳定性评价

Formation mechanism and stability of landslide at Xialiang middle school in Nanjiang county,Sichuan

巴中市南江县下两中学老滑坡由于强降雨作用出现大量拉裂缝和局部垮塌,通过对滑坡的区域环境和地质条件调查,结合滑坡工程地质特征及变形发育特征,分析了滑坡的地质成因机制。采用不平衡推力法计算评价了滑坡稳定性,并应用FLAC3D有限元软件模拟了滑坡在暴雨工况下的破坏模式。研究成果表明,工程建设开挖是导致滑坡复活的根本原因;滑坡前期两次强降雨是主要诱发因素;滑坡目前处于基本稳定,但在暴雨条件下为欠稳定,其变形破坏模式为牵引式。

A large number of tension cracks and partial collapses appeared on Xia Liang middle school landslide in the Nan Jiang county,city of Ba Zhong because of the heavy rainfall. Through field survey of the regional geological and environmental condition,combined with the engineering geological feature and development feature of the landslide,the deformation mechanism of the landslide was analyzed. In order to evaluate the stability of the landslide,the Imbalance Thrust Force Method was used. The failure mode of landslide under the rainfall was then simulated using the finite element software of FLAC3 D. The research results indicates that the free face formed in the front of the slope due to the construction excavation is the root cause of the landslides while the two previous long-term heavy rainfall is the main inducing factor; the landslide is now stable in natural condition,and will be unstable under the heavy rainfall,its deformation and failure mode is retrogressive.