金沙江某库区东爷庙滑坡成因分析及稳定性评价

Genetic analysis and stability assessment of a landslide in a reservoir area of Jinshajiang River

文章在对滑坡周界确定和滑坡体特征研究基础之上,从岩性条件、地质构造及地下水等方面详细分析了滑坡成因。该滑坡发生在侏罗系沙溪庙组(J2s)缓倾角红层中,地层岩性为河湖相紫红色泥质粉砂岩、泥岩和灰绿色粉砂岩互层,软硬相间,该套地层的岩性内在差异构成了滑坡产生的岩性条件。加上边坡呈顺向坡结构,顺坡向节理发育,坡角临空,岩体沿着软弱层发生滑移-拉裂破坏。通过对滑坡进行稳定性计算和分析,结果表明:该滑坡在天然状态、蓄水或地震等不利条件下,整体仍处于稳定状态,只是在相对较陡的滑坡体前缘和库水位附近地形较陡的局部部位,蓄水后可能会产生小规模失稳,但其方量不会太大,加上离坝址较远,所以不会危及工程安全。因此,通过对滑坡成因分析和稳定性评价,为工程建设和移民安置工作提供了重要的保证。

Based on the research of the perimeter and character of the landslide, this paper describes the cause of landslide from conditions of lithology, structure and groundwater. The landslide occured in interbeded red mud stone layer （J2 s）, whose dip angle is 15°and the rock strengthes are different. The combination of structure, joint and undercutting at bottom of the slope makes the slope slide along the weak structural plane. The stability assessment indicate that the whole landslide is stable in various condition, and the steep part at toe of landslide and where near the reservoir level are unstable, but the scale is small and have no effect on the dam. Therefore, the analysis of genetic cause and stability assessment provide important guarantee to engineering construction and people migration.