唐古栋滑坡成因机制研究

RESEARCH ON FORMATION MECHANISM OF TANGGUDONG LANDSLIDE

唐古栋滑坡位于楞古水电站拟选的上、中坝址和下坝址之间,且滑坡规模巨大,对水电站坝址的选择和水工建筑物的布置有决定性的影响,对滑坡成因机制的研究对于分析该河段类似斜坡的变形演化具有非常重要的意义。在对滑坡地质环境条件和滑坡体特征分析的基础上,采用物理模拟中的底摩擦试验方法和离散元数值计算对唐古栋滑坡的成因机制进行分析。研究结果表明,滑坡为沿强风化层内陡倾坡外和缓倾坡外结构面组合阶梯状滑面剪断层面滑动的滑移-拉裂式的巨型岩质滑坡。滑坡失稳过程为前缘坡体首先发生变形失稳破坏,然后中后部边坡不断蠕滑变形,最终前缘抗剪段失效导致中后部整个边坡的失稳破坏。

Tanggudong landslide which is huge lies among the pre-selected upper,middle and lower dam of Lenggu hydropower station. It has a decisive effect on the selection of hydropower station dam site and construction and layout. Studying formation mechanism of landslide has a very important influence on analyzing deformation and evolutionary of similar slopes in this river. On the basis of analyzing geo- environmental conditions and characteristics of landslide,the author analyzes formation mechanism of landslide by means of bottom friction test method and discrete element numerical calculation. The results show： Tanggudong landslide is a giant and rock landslide,of which the deformation and failure model is slipping-cracking. It cuts off layers and moves along theladder-like sliding surface which is composed of the steeply inclined outside joints and gently inclined outside joints in the strongly weathered layers. Instability and failure of these front slopes firstly occur,which is then followed by the continuous deformation of the upper slopes. Consequently,instability and failure of the whole upper slope in the rear part ultimately occurs.