锦屏一级水电站左岸边坡变形监测及机制分析

何如许 裴向军 刘明 文旭 徐岗

摘 要：针对锦屏一级水电站左岸边坡的持续变形现象，以左岸边坡的地质结构为基础，通过表面变形监测与深部变形监测相结合的综合监测手段，对其变形机制进行分析。研究结果表明，其整体的变形机制可概括为“上部持续倾倒—深部张裂—表部锁固体松弛—下部与坝体协调”。开口线以上自然边坡倾倒变形体的持续变形主要受砂岩、板岩软硬互层以及浅表部卸荷作用控制，还受下部坡体变形调整向上累积效应的影响。左岸边坡深部变形主要是受坡体深部裂缝区的持续拉张变形及断层f42-9和煌斑岩脉X所体现的非滑移式拉裂松弛变形影响，而且强支护的群锚效应明显强化、深化了对变形的作用。开口线以下人工开挖支护边坡的持续变形原因是锚墙锁固的部分坡体浅表部出现整体性侧向松弛卸荷变形。标准蓄水位附近的坡体受库水浮托力的影响较大，而抗力体边坡在蓄水之后则受到坝肩推力的影响而产生压密和抬升的周期性变化特征。

关键词：边坡;监测分析;变形机制;锦屏一级水电站

中图分类号：TV642.4 文献标志码：A

doi：10.3969/j.issn.1000-1379.2021.10.025

引用格式：何如许，裴向军，刘明，等. 锦屏一级水电站左岸边坡变形监测及机制分析[J].人民黄河，2021，43（10）：128-133，138.

Abstract： In view of the continuous deformation of the left bank slope of Jinping I Hydropower Station， the deformation mechanism of the left bank slope was analyzed by means of comprehensive monitoring combined with surface deformation monitoring and deep deformation monitoring. The results show that the overall deformation mechanism can be summarized as “continuous toppling of the upper part-deep tension fracture-surface locking solid relaxation-coordination between the lower part and the dam body”. The continuous deformation of toppling deformation body of natural slope above the opening line is mainly controlled by the unloading action of sandstone， slate soft-hard interbeds and shallow surface， and is also affected by the upward accumulation effect of deformation adjustment of lower slope. The deep deformation of the left bank slope is mainly due to the continuous tension deformation in the deep crack area of the slope and the non-slip tension and relaxation deformation embodied in f42-9 and lamprophyre dike X. Moreover， the group anchor effect of the strong support obviously strengthens and deepens this effect. The continuous deformation of the slope supported by manual excavation below the opening line is mainly due to the integral lateral relaxation and unloading deformation of the shallow part of the slope secured by the anchor wall. The slope near 1880m is greatly influenced by the buoyancy of reservoir water， while the slope of resisting body is affected by the thrust of abutment after impoundment， resulting in the characteristics of compaction and uplift. The monitoring results and deformation mechanism of this project can be used for reference in other hydropower projects in the future.

Key words： slope; monitoring and analysis; deformation mechanism; Jinping-Ⅰ Hydropower Station

我國西南山区拥有丰富的水电资源，近年来随着清洁能源需求的不断增加，金沙江、澜沧江、雅砻江等流域的水电工程开始大规模地投入建设和运营。西南山区极为复杂的地质条件、颇为频繁的地震活动，加上水电工程边坡所特有的大规模、强开挖的特点，给水电工程的施工及运行带来了极为艰巨的挑战。……