An experimental study of the bank slope instability mechanism of dual structure reservoir
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摘要: 水位升降条件下库岸边坡变形失稳问题是水库建设中必须考虑的重要安全性问题。二元结构是库岸岩土体的一种特有结构，其变形破坏失稳有特殊的力学机制及规律。为揭示库岸边坡处于不同坡角及不同土岩界面倾角条件下的失稳机制，尤其是水位变化条件下库岸岩土体浸润线的分布及演化特征，文章通过构建水位升降条件下的二元结构库岸边坡物理实验模型，借助监测及摄影的技术手段观测边坡土体内浸润线及岩土体变形破坏特征，揭示二元结构库岸边坡的变形失稳机制。研究结果表明：二元结构库岸边坡在水位升降条件下整体坡角的改变会引发不同的变形破坏模式：55°边坡以垮塌失稳为主，35°边坡稳定性较好，45°边坡易发生由坡脚破坏牵引的局部失稳；土岩界面倾角对边坡稳定性也产生较大影响，较大的倾角易于引发坡体沿土岩界面发生滑动失稳。本研究结果可为揭示二元结构库岸边坡失稳致灾机制及有效防治提供借鉴。Abstract: The deformation and instability of bank slope under the condition of water level rise and fall is very important for the safety of reservoir construction. The dual structure is a special structure of rock and soil mass on the bank of reservoir. Its deformation and failure characteristics have its special mechanical mechanism and law. In order to reveal the instability mechanism of bank slope under the condition of different slope angles and different soil rock interface angles, especially the condition of water level change, the distribution and evolution characteristics of the saturation line of the rock and soil mass in the lower reservoir bank are studied in this paper by constructing the physical experiment model of the dual structure reservoir bank slope under the condition of water level rise and fall, and by means of monitoring and photography the characteristics of the saturation line, and the deformation and failure of the rock and soil mass in the slope are observed. The deformation and instability mechanism of the dual structure reservoir bank slope are revealed. The research results show that under the condition of the dual structure reservoir bank slope during the water level rise and fall, the change in the overall slope angle will lead to different deformation and failure modes：the 55° slope is dominated by collapse and instability, the 35°slope has good stability, and the 45° slope forms local instability pulled by slope toe failure. The slope stability will be greatly affected by the inclination of soil rock interface, which is easy to cause sliding instability of slope along the soil rock interface. The results also show that the mechanism and effective prevention and control of the landslide can be used for reference.
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Key words:
- dual structure /
- slope /
- model test /
- saturation line /
- mechanism of instability
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