洞坪水库大沟湾滑坡体变形机制

项伟; 江洎洧; 唐辉明; 崔德山; 黄玲

洞坪水库大沟湾滑坡体变形机制

中国地质大学工程学院，湖北武汉 430074

基金项目:

中国地质调查局“鄂西恩施地区滑坡形成机制与危险性评估”项目 1212010640604

详细信息

作者简介:
项伟（1953-），男，教授，博士生导师，长期从事大型水利水电工程地质、软弱夹层、岩土性质、地质灾害防治、遥感监测和环境地质工程的教学与科研工作．E-mail：xiangwei@cug.edu.cn

中图分类号: P641
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出版历程
- 收稿日期: 2008-12-25
- 刊出日期: 2009-09-25

Deformation Mechanism of Dagouwan Landslide in Dongping Reservoir

Faculty of Engineering, China University of Geosciences, Wuhan 430074, China

摘要

摘要: 大沟湾滑坡是瞿家湾滑坡群中相对高差最大的滑坡体, 洞坪水库蓄水后滑坡体产生了较大变形且变形机制表现出一定的特殊性.野外调查研究表明: 蓄水前该滑坡体稳定性良好; 蓄水至452m后, 滑坡后缘堆积体与基岩交界处产生贯通滑坡两侧冲沟的连续裂缝, 剪出口位于整个滑体中部580m高程附近, 由于下部坡体的抗滑作用而使整个坡体仍处于稳定状态; 蓄水至488m后, 从整个滑体前缘到570m高程附近又形成另一滑坡体, 与先前上部滑坡呈梯级分布, 分析得出大沟湾滑坡为上部牵引-下部推移的复合式滑坡, 两个滑坡共同作用导致整个滑体发生明显变形.分析并利用FLAC3D模拟再现整个变形过程, 对滑坡体变形破坏机制做出了很好解释.
- 洞坪水库 /
- 大沟湾滑坡 /
- 有限差分法 /
- 变形机制 /
- 复合滑坡
Abstract: Based on engineering survey and experiments, slide mass structure and the mechanical parameters of Dagouwan landslide were obtained.FLAC3D was employed to analyze the stability and the deformation mechanism of Dagouwan landslide at different working conditions and water levels.The results of analysis show that: when the water level rose to 452 m, there showed a continuous crack at the back of the landslide from one side of gully to another, and the shear outlet of the landslide was located in the thick deposits of the slope at 580 m, but the whole slope still showed stability; when the water level rose to 488 m, another independent landslide formed from the toe of the landslide to 570 m.Interactions between two landslides caused the failure of the whole slope.The phenomenon had been confirmed during the two field explorations.The failure reasons of the landslide can be concluded as the loose structure of the landslide, high frequency of showers and the fluctuation of the water level in the reservoir, which finally led to the form of this complex retrogressive-progressive landslide.
- Dongping reservoir /
- Dagouwan landslide /
- FDM method /
- deformation mechanism /
- complex landslide

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图 1 大沟湾滑坡平面地质图

Fig. 1. Schematic geological map of Dagouwan landslide

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图 2 大沟湾滑坡体主滑面地质剖面图

Fig. 2. Geological section of Dagouwan landslide

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图 3 大沟湾滑坡单元剖分

Fig. 3. Numerical simulation meshes of Dawongou landsliole

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图 4 滑坡中部贯通的拉裂缝

Fig. 4. Consecutive tension cracks at the central of the landslide

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图 5 不同库水位暴雨工况滑坡体体积应变速率等值线

Fig. 5. Contour of volumetric strain rate in different water levels

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图 6 滑坡后缘拉张裂缝

Fig. 6. Tension-extension cracks at the back of the landslide

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图 7 滑坡整体失稳过程(数字代表变形次序)

Fig. 7. Invalidation progress of the landslide

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表 1 大沟湾滑坡物理力学参数

Table 1. Mechanical parameters of Dagouwan landslide

表 2 不同水位、工况下的滑坡稳定系数

Table 2. Factor of safety in different situations

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