三峡库区水位变化对树坪滑坡变形影响机制研究
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摘要
三峡水库蓄水后,众多涉水型滑坡均有变形迹象,尤其在库水位下降过程中,多数滑坡变形加剧。树坪滑坡属巨型古堆积体滑坡,距三峡大坝坝址约47 km,数年监测结果显示树坪滑坡在库水位下降过程中有强烈变形,若失稳将造成重大损失。为此,现场采集了树坪滑坡近几年监测数据,结合地质调查及勘探资料对其变形机制进行分析,结果表明:树坪滑坡地下水位与库水位涨落保持一致,库水位相对滞后,库水位下降时产生不利于滑坡体稳定性的动水压力,此时GPS数据表现出滑坡发生较强烈的变形,具有典型的动水压力型滑坡特征;自动位移计监测结果表明:树坪滑坡在库水位蓄水至175 m水位后主要发生整体变形,由下部变形牵引上部滑动,具有牵引式滑坡的变形特征。
After impoundment of the Three Gorges reservoir,numerous landslides relevant to water have the signs of deformation. Deformation of most landslides rapidly increases,especially in the process of decline of reservoir water level. Shuping landslide,about 47 km from the dam site of Three Gorges,belongs to a kind of giant ancient accumulation body. Monitoring results for several years showed that Shuping landslide strongly deformed when reservoir water level dropped,significant losses will occur if the landslide loses stability. In light of the problem,we collected monitoring data of Shuping landslide in recent years and analyzed its deformation mechanism in association with geological survey and exploration data. The results show that: 1) the fluctuation of underground water level of Shuping landslide is consistent with that of reservoir water level,but the variation of reservoir water level is relatively lagged; 2) hydrodynamic pressure occurs in the condition of decline of reservoir water level,which is unfavorable to landslide stability,at the same time,GPS data indicate intense deformation of the landslide with typical features of hydrodynamic pressure-type landslide; 3) monitoring results measured by auto-recording displacement meter show that overall deformation is the main kind of deformations for Shuping landslide after impoundment with water level of 175 m,and it has deformation features of tractive landslide whose deformation in the bottom leads to slip in the top.
After impoundment of the Three Gorges reservoir,numerous landslides relevant to water have the signs of deformation. Deformation of most landslides rapidly increases,especially in the process of decline of reservoir water level. Shuping landslide,about 47 km from the dam site of Three Gorges,belongs to a kind of giant ancient accumulation body. Monitoring results for several years showed that Shuping landslide strongly deformed when reservoir water level dropped,significant losses will occur if the landslide loses stability. In light of the problem,we collected monitoring data of Shuping landslide in recent years and analyzed its deformation mechanism in association with geological survey and exploration data. The results show that: 1) the fluctuation of underground water level of Shuping landslide is consistent with that of reservoir water level,but the variation of reservoir water level is relatively lagged; 2) hydrodynamic pressure occurs in the condition of decline of reservoir water level,which is unfavorable to landslide stability,at the same time,GPS data indicate intense deformation of the landslide with typical features of hydrodynamic pressure-type landslide; 3) monitoring results measured by auto-recording displacement meter show that overall deformation is the main kind of deformations for Shuping landslide after impoundment with water level of 175 m,and it has deformation features of tractive landslide whose deformation in the bottom leads to slip in the top.
引文
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[7]肖诗荣,胡志宇,卢树盛,等.三峡库区水库复活型滑坡分类[J].长江科学院院报,2013,30(11):39-44.(XIAO Shi-rong,HU Zhi-yu,LU Shu-sheng,et al.Classification of Reservoir-Triggered Landslides in Three Gorges Reservoir Area[J].Journal of Yangtze River Scientific Research Institute,2013,30(11):39-44.(in Chinese))
[8]易武,尚敏,黄海峰,等.秭归树坪滑坡地质模型研究报告[R].宜昌:三峡库区地质灾害教育部重点实验室,2010.(YI Wu,SHANG Min,HUANG Hai-feng,et al.Research Report of Geological Model of Shuping Landslide in Zigui County[R].Yichang:Key Laboratory of Geological Hazards on Three Gorges Reservoir Area under Ministry of Education,2010.(in Chinese))
[9]王力,王世梅,向玲.库水下降联合降雨作用下树坪滑坡流固耦合分析[J].长江科学院院报,2014,31(6):25-31.(WANG Li,WANG Shi-mei,XIANG Ling.Interaction of Coupling Seepage and Stress of Shuping Landslide under the Condition of Reservoir Water Decline and Rainfall[J].Journal of Yangtze River Scientific Research Institute,2014,31(6):25-31.(in Chinese))
[10]王力.库水联合降雨作用下三峡库区树坪滑坡复活机理研究及预测评价[D].宜昌:三峡大学,2014.(WANG Li.Research of Revived Mechanism and Prediction of Shuping Landslide under Water Level Variation and Rainfall in Three Gorges Reservoir Area[D].Yichang:China Three Gorges University,2014.(in Chinese))
[2]王世梅,郑宏,童富果,等.水库蓄水后三峡库区重大水库复活型滑坡空间预测评价研究[R].宜昌:三峡大学,2013.(WANG Shi-mei,ZHENG Hong,TONG Fu-guo,et al.Spatial Prediction and Evaluation Study on Major Reservoir Revived Landslides after the Impoundment of Three Gorges Reservoir Area[R].Yichang:China Three Gorges University,2013.(in Chinese))
[3]WANG F W,ZHANG Y M.Deformation Features of Shuping Landslide Caused by Water Level Changes in Three Gorges Reservoir Area,China[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(3):1 371-1 386.
[4]汪发武,彭轩明.三峡库区千将坪滑坡的高速远程滑动机理与库水位变动条件下树坪滑坡的变形模式[C]∥第八届全国工程地质大会论文集.北京:工程地质学报编辑部,2008:536-541.(WANG Fa-wu,PENG Xuan-ming.Rapid and Long-travel Mechanism of Qianjiangping Landslide and Deformation Model of Shuping Landslide in Three Gorges Reservoir Area[C]∥Proceedings of the 8th China Engineering Geology Congress.Beijing:Editorial Office Journal of Engineering Geology,2008:536-541.(in Chinese))
[5]WANG G,ZHANG Y M,WANG F W.Displacement Monitoring on Shuping Landslide in the Three Gorges Dam Reservoir Area,China from August 2004 to July2007[C]∥CHEN Z Y,ZHANG J M,HO K,et al.Proceedings of the 10th International Symposium on Landslides and Engineered Slopes(Vol.2),Xi'an,China,June 30-July 4,2008:1321-1327.
[6]李小凡,MULLER J P.基于Terra SAR-X强度图像相关法测量三峡树坪滑坡时空形变[J].岩石学报,2011,27(12):3844-3850.(LI Xiao-fan,MULLER J P.Measuring Displacement Field from Terra SAR-X Amplitude Images by Subpixel Correlation:(An Application to the Landslide in Shuping,Three Gorges Area[J].Acta Petrologica Sinica,2011,27(12):3844-3850.(in Chinese))
[7]肖诗荣,胡志宇,卢树盛,等.三峡库区水库复活型滑坡分类[J].长江科学院院报,2013,30(11):39-44.(XIAO Shi-rong,HU Zhi-yu,LU Shu-sheng,et al.Classification of Reservoir-Triggered Landslides in Three Gorges Reservoir Area[J].Journal of Yangtze River Scientific Research Institute,2013,30(11):39-44.(in Chinese))
[8]易武,尚敏,黄海峰,等.秭归树坪滑坡地质模型研究报告[R].宜昌:三峡库区地质灾害教育部重点实验室,2010.(YI Wu,SHANG Min,HUANG Hai-feng,et al.Research Report of Geological Model of Shuping Landslide in Zigui County[R].Yichang:Key Laboratory of Geological Hazards on Three Gorges Reservoir Area under Ministry of Education,2010.(in Chinese))
[9]王力,王世梅,向玲.库水下降联合降雨作用下树坪滑坡流固耦合分析[J].长江科学院院报,2014,31(6):25-31.(WANG Li,WANG Shi-mei,XIANG Ling.Interaction of Coupling Seepage and Stress of Shuping Landslide under the Condition of Reservoir Water Decline and Rainfall[J].Journal of Yangtze River Scientific Research Institute,2014,31(6):25-31.(in Chinese))
[10]王力.库水联合降雨作用下三峡库区树坪滑坡复活机理研究及预测评价[D].宜昌:三峡大学,2014.(WANG Li.Research of Revived Mechanism and Prediction of Shuping Landslide under Water Level Variation and Rainfall in Three Gorges Reservoir Area[D].Yichang:China Three Gorges University,2014.(in Chinese))