| 三峡库区顺层灰岩岸坡劣化?溃屈灾变机制研究 |
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| 引用本文： | 闫国强,殷跃平,黄波林,胡雷.三峡库区顺层灰岩岸坡劣化?溃屈灾变机制研究[J].岩土力学,2022,43(9):2568-2580. |
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| 作者姓名： | 闫国强 殷跃平 黄波林 胡雷 |
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| 作者单位： | 1. 中国地质大学（武汉）工程学院，湖北 武汉 430074；2. 中国地质环境监测院，北京 100081；
3. 三峡大学 防灾减灾湖北省重点试验室，湖北 宜昌 443002 |
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| 基金项目： | 国家自然科学基金项目（No.42077234）；国家重点研发计划项目（No.2018YFC1504803） |
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| 摘 要： | 三峡库区巫峡段发现多处顺层岸坡滑移?弯曲变形迹象，库水循环涨落加剧了岸坡前缘劣化损伤与失稳破坏。以巫峡段青石 6号坡为例构建室内概化模型，开展顺层灰岩岸坡在消落带岩体劣化下的灾变机制研究。研究结果表明：蓄水前岸坡整体长期处于稳定状态。随着劣化进行，蓄水后岸坡变形加剧直至溃屈破坏，岩体劣化缩短了劣化?溃屈失稳进程。运动学分析显示，溃屈破坏时同一岩层达到速度峰值近似。岩层“弯折点”后部运动特征较为一致，前部较为离散。溃屈破坏点是岸坡能量释放的转折点和顶点；随劣化演变位移、应力逐渐递增，呈现提前破坏征兆，溃屈破坏前后应力产生“集中?释放”。整体来看，应力变化提前于位移，表明应力监测更有效。应力监测的核心在于关键区段的确定，对于劣化?溃屈型岸坡来讲，前缘“挠曲段”处应力陡增可作为岸坡临界失稳的重要表征；“劣化?溃屈”演化进程中后缘推挤始终存在，它是岸坡灾变的前提。但岸坡失稳的主导因素却是消落带岩体持续不断的劣化。青石 6 号坡当前处于向强烈弯曲隆起演化进程中，由于消落带岩体持续劣化，可能由稳定/基本稳定逐渐演变为欠稳定状态。
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| 关 键 词： | 物理模型试验 岩体劣化 顺层灰岩岸坡 劣化?溃屈 三峡库区巫峡段 |
| 收稿时间： | 2021-11-30 |
| 修稿时间： | 2022-05-11 |
Deterioration-buckling failure mechanism of consequent bedding limestone bank slope in Three Gorges Reservoir area |
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| YAN Guo-qiang,YIN Yue-ping,HUANG Bo-lin,HU Lei.Deterioration-buckling failure mechanism of consequent bedding limestone bank slope in Three Gorges Reservoir area[J].Rock and Soil Mechanics,2022,43(9):2568-2580. |
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| Authors: | YAN Guo-qiang YIN Yue-ping HUANG Bo-lin HU Lei |
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| Institution: | 1. Faculty of Engineering, China University of Geosciences, Wuhan, Hubei 430074, China; 2. China Institute of Geological Environment Monitoring, Beijing 100081, China; 3. Hubei Key Laboratory of Disaster Prevention and Mitigation, China Three Gorges University, Yichang, Hubei 443002, China |
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| Abstract: | In the Wuxia section of the Three Gorges Reservoir area, it is found that there are many deformation signs of sliding-bending along the bedding bank slope, and the cyclic fluctuation of reservoir water worsens the deterioration and instability of the bank leading edge. Taking Qingshi #6 slope in the Wuxia section as an example, an indoor generalized model is constructed to study the catastrophe mechanism of bedding limestone bank slope under the deterioration of rock mass in hydro-fluctuation belt. The research shows that: the bank slope is in a stable state as a whole for a long time before impoundment. After impoundment, with the deterioration aggravation of rock mass, the bank slope deformation intensifies until buckling failure. The deterioration of rock mass shortens the instability process of ‘deterioration-buckling’. Kinematic analysis shows that the peak velocity of the same rock stratum is similar during buckling failure. The movement characteristics of the rear part of the ‘buckling point’ of rock mass are relatively consistent, but the front part is relatively discrete. The buckling failure is the turning point and apex of bank slope energy release. Both displacement and stress show signs of premature failure after gradually increasing with deterioration evolution. The stress produces ‘concentration-release’ around the buckling failure. On the whole, the stress variation is earlier than the displacement variation, indicating that the stress monitoring is more effective. The core of stress monitoring is to determine the ‘key section’. For the ‘deterioration-buckling’ bank slope, the sharp increase of stress at the ‘deflection section’ of the front edge can be an important characterization of the critical instability of the bank slope. The trailing edge pushing always exists in the evolution process of ‘deterioration buckling’, which is the premise of bank slope catastrophe failure. However, the dominant factor of bank slope instability is the continuous deterioration of the rock mass in the hydro-fluctuation belt. The Qingshi #6 slope is currently in the process of evolution toward ‘strong bending uplift’, it may gradually evolve from a stable/basically stable state to an understable state, due to the continuous deterioration of the rock mass in the hydro-fluctuation belt. |
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| Keywords: | physical model test rock mass deterioration consequent bedding limestone bank slope deterioration-buckling Wuxia section of the Three Gorges Reservoir |
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