雅砻江右岸某巨型滑坡变形机理及稳定性分析

某滑坡位于雅砻江流域内拟建卡拉水电站水库右岸单斜构造带内,呈方形展布,为方量1.22×108 m3顺层巨型滑坡,主滑方向为NE向。滑坡变形表现在中下部的局部表层蠕滑变形,其机理为蠕滑-拉裂-滑移式。据野外调查和勘探成果,并结合该滑坡所处地质环境条件,运用弹性有限元方法对其进行数值模拟。结果表明,该滑坡在天然状态下稳定性较好,最大剪应力集中在滑带附近,其值约0.27MPa。滑体中下部主要为水平位移,且滑体在重力作用下对力的约束最为敏感;上部则表现为以竖向位移为主。

Deformation Mechanism and Stability Analysis of a Giant Landslide at the Right Bank of the Yalong River

A landslide is located in the monoclinal structural zone at the right bank of the proposed Kala hydropower station in the Yalong River Basin, and it has a square distribution and a volume of 1.22×108 m3with a main slide in NE direction. The local surface creep deformation occurs in the middle and lower parts of the landslide, and its deformation mechanism is the peristalsis~cracking~sliding type. Based on the field geological investigation and exploration results, the elastic finite element method was used to simulate the landslide deformation in consideration of the geological conditions of the landslide. The results showed that (1) the landslide is stable under natural conditions, and the maximum shear stress is located around the sliding zone with a value of about 0.27 MPa; (2) the horizontal displacement is dominated in the middle and lower parts of the landslide, and the landslide is sensitive to the constraints of force under the action of the gravity; and (3) the vertical displacement is dominated in the upper part of the landslide.