西安金盆水库放水塔附近滑坡特征及成因分析

FEATURES AND CAUSES OF A LANDSLIDE NEAR DISCHARGE WATER TOWER OF JINPEN RESERVOIR IN XI′AN

放水塔附近滑坡是金盆水库右岸原1号滑坡体下游边界段的残留体，受短期强降水因素的诱发导致坡体变形、失稳滑动。滑坡体具顺层牵引滑动特征，且平面上，不同区段变形破坏程度不同，其表现形式与坡体平面旋转有一定的相似性。坡体滑动主要受4组结构面的控制，其中的软弱片理结构面（产状150°～170°∠35°～55°）与产状为230°～290°∠35°～55°的另一组结构面构成滑坡的滑动控制面。基岩内发育的大量的软弱片理结构面，大气强降水，滑坡上部相对平缓的地貌及人类工程对地表植被环境的破坏，滑坡体下部喷护层的存在等因素的综合影响，导致了坡体的失稳滑动。

A landslide occurred near the discharge water tower of Jinpen reservoir in Xi＇an. It was a residual body of the downstream boundary segment of old landslide 1^# on the tight bank of the Jinpen reservoir. A short - term strong precipitation induced deformation of the slope and its sliding motion. The landslide was drawn with bedding -plane slip. At different plane sections, extents of the deformation and breakdown were different. The motion is similar to the plane rotation of a slope. The landslide was controlled by four group structure planes. The softening schistosity surface has the dipping direction from 150° to 170° and the dip angle from 35° to 55°. The second structure interface has the dipping direction from 230° to 290° and dip angle from 35° to 55°. They formed the control surfaces of sliding motion. The causes of the landslide are the softening schistosity surface, the strong precipitation, the gentle inclined and defective ground cover, and the gunite coveting layer at the bottom of the slope.