| 基于离心模型试验的库岸滑坡变形特征研究 |
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| 引用本文： | 汤明高,李松林,许 强,龚正峰,祝 权,魏 勇.基于离心模型试验的库岸滑坡变形特征研究[J].岩土力学,2020,41(3):755-764. |
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| 作者姓名： | 汤明高 李松林 许 强 龚正峰 祝 权 魏 勇 |
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| 作者单位： | 成都理工大学 地质灾害防治与地质环境保护国家重点实验室，四川 成都 610059 |
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| 基金项目： | 国家自然科学基金面上项目（No.41977255）；三峡后续工作地质灾害防治研究课题（No.000121 2015C C60 005）；四川省应用基础研究重点项目（No.2019YJ0403） |
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| 摘 要： | 三峡库区蓄水后,大量库岸滑坡发生复活变形,为研究滑坡随库水位升降的变形特征和机制,以库区典型直线形滑面形态滑坡为地质原型,概化设计了大尺度离心模型试验,通过模拟两个水位升降过程,布设高速相机和传感器,获取了滑坡变形演化全过程高清影像、孔压和土压-时间变化曲线,可得以下研究结果:在水位首次下降时,孔压和土压逐渐减小,当下降15 min后滑坡发生整体蠕滑变形,首先是前部产生横向张拉裂缝,中后部则是以竖直位移为主的蠕滑压密变形过程,水位停止下降2 min后变形停止,表明变形对库水位变化具有一定滞后性;当水位再次下降时,前部沿原破裂面再次下滑并失稳,中后部则无变形,变形演化具有典型牵引式特征。在库水首次入渗滑坡时,坡体孔隙水压力对库水位升降具有明显的滞后性,而在下一次水位升降过程中,这种滞后性明显减弱。该类滑坡受水位下降的动水压力效应影响较大,在滑坡变形过程中,中后部滑体变形在竖直方向的蠕滑压密行为使得中后部稳定性有所提高,因此,在后期蓄水过程中不再发生变形,试验现象与实际库岸滑坡吻合。试验揭示了三峡库区该类滑坡在水位升降条件下的变形破坏模式及长期演化趋势,为库区地灾防治提供了参考依据。
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| 关 键 词： | 三峡库区 库岸滑坡 离心模型试验 水位升降 变形演化 |
| 收稿时间： | 2019-01-28 |
| 修稿时间： | 2019-08-02 |
Study of deformation characteristics of reservoir landslide based
on centrifugal model test |
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| TANG Ming-gao,LI Song-lin,XU Qiang,GONG Zheng-feng,ZHU Quan,WEI Yong.Study of deformation characteristics of reservoir landslide based
on centrifugal model test[J].Rock and Soil Mechanics,2020,41(3):755-764. |
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| Authors: | TANG Ming-gao LI Song-lin XU Qiang GONG Zheng-feng ZHU Quan WEI Yong |
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| Institution: | State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, Sichuan 610059, China |
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| Abstract: | Many landslides along the bank have reactivated after the impoundment in the Three Gorges Reservoir Area (TGRA). In order to study the landslide deformation characteristic subjected to fluctuation of reservoir water level, a large-scale centrifuge test model was designed based on typical landslide with rectilinear sliding surface in TGRA. The deformation images, the curves of pore water pressure (PWP) and earth pressure (EP) vs. time were obtained by high-speed cameras and pore water pressure and soil pressure sensors during the modelling of two cycles of reservoir fluctuation. The results could be summarized as follows: in the initial stage of the water level drawdown, the PWP and EP gradually decreased. When the water level fell for 15 minutes, the frontal body pull apart and down, the middle and rear parts of the landslide had a creep movement and compaction process dominated by vertical displacement, and the deformation stopped two minutes after the water level stopped falling. When the reservoir drawdown again, the frontal part slid along the original fracture zone, and no obvious deformation occurred in the middle or rear parts. In addition, when the reservoir water infiltrated into the landslide for the first time, the PWP in the slope lag behind the water level obviously, whereas the lag effect had diminished during the next time. The landslide is greatly affected by the hydrodynamic pressure of reservoir drawdown and its deformation has a retrogressive characteristic. The creep compaction behavior improved the stability of the middle and rear parts of the landslide gradually. Therefore, no deformation occurred during the water storage later, and the experimental phenomena coincide with the deformation characteristics of actual reservoir landslide. It reveals the deformation mode and evolution trend of the landslide in TGRA subjected to reservoir fluctuation, which provides a basis for the geohazard prevention. |
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| Keywords: | Three Gorges Reservoir reservoir landslide centrifugal model test reservoir fluctuation landslide evolution |
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