潇水电站斜向层状边坡的变形机制分析

Deformation mechanism analysis of a slant bedded slope nearby Xiaoshui Power Plant

潇水电站变形边坡为斜向层状岩质边坡,根据前期勘察成果及开挖反馈,发现该边坡岩体上部为碎裂岩体,结构松散,下部为基岩,较完整,碎裂岩体沿软弱夹层呈视向滑动,且保持着原岩构造。基于该边坡的结构面统计和分析,确定该边坡存在一组优势节理面JL1,该组节理面与层面的交棱线产状与视向擦痕线产状非常接近。结合岩体变形特征及结构面分析,对该边坡变形机制有几点认识:该边坡变形破坏受优势节理面与软弱夹层所控制,边坡变形并非简单地顺层滑动,而是以软弱夹层面为主界面,以优势节理面与岩桥构成的组合边界为另一界面,整个边坡变形呈类似楔形形状的变形破坏;边坡的变形破坏是内外营力共同作用的结果,其变形破坏仍处于"拉裂—蠕滑"阶段。

The deformed rock slope nearby Xiaoshui Power Plant is a slant bedded slope. According to the investigation and excavation finding,the upper slope is cataclastic rock mass with fractured structures,and the lower is intact. The slope slides along the weak intercalation. Based on the statistics and analysis of the discontinuities,it is confirmed that there is a set of dominant joints JL1. The occurrence of intersection between dominant joint plane and the weak bedding plane is very close to the occurrence of the apparent dip slide. Combined with characteristics of the slope deformation and joints,it is found that the slope deformation is governed by the dominant joint and the weak layer; the deformation is not a simply slide along the weak layer,but slide along wedge-shaped planes formed by the weak layer and the dominate joints; the deformation is the consequent of the internal and excernal agencies; the deformation of slope is still in the tension-creep stage.