茨菇滑坡滑带土扰动样强度参数取值分析及滑坡稳定性评价
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摘要
位于近坝库区的茨菇滑坡,在水库正常蓄水后有近1/3坡体浸没于水位面以下,蓄水前后的滑坡稳定性对工程影响很大。滑坡区地质环境条件复杂,滑坡成因机制为弯曲折断-滑移的地质力学模式。本文进行了对滑坡区扰动样滑带土在不同含水率条件下的剪切强度试验,试验结果表明,粘聚力与含水量相关性好,而摩擦系数则变化不大。结合极限平衡及有限元数值计算,对茨菇滑坡在蓄水前后天然、暴雨及地震工况条件下的稳定性进行分析。结果表明蓄水前滑坡处于稳定状态,水库蓄水以后,天然工况及暴雨工况下滑坡仍然处于稳定状态,地震工况下,滑坡的稳定性系数在1.0以下,滑坡可能失稳破坏。
The Cigu landslide is located near a reservoir region.Its stability would be largely influenced after water is stored in the reservoir because the water level will be at 1/3 of the landslide slope height.Geological conditions of the landslide are complex and the progressive mechanism is toppling or slip.This paper examines the slide zone clay shear strength with different moisture contents.The test results show that the cohesion has a good correlation with the moisture content but the friction does not have a good correlation.The landslide stability before and after the storage of reservoir water is analyzed with limit equilibrium method combined with FEA under conditions of natural heavy-rain and earthquake.The numerical analysis shows that the landslide would be stable after water storage under native and rainstorm conditions,but unstable under earthquake.The factor of safety is less than 1,which indicates the landslide instable.
The Cigu landslide is located near a reservoir region.Its stability would be largely influenced after water is stored in the reservoir because the water level will be at 1/3 of the landslide slope height.Geological conditions of the landslide are complex and the progressive mechanism is toppling or slip.This paper examines the slide zone clay shear strength with different moisture contents.The test results show that the cohesion has a good correlation with the moisture content but the friction does not have a good correlation.The landslide stability before and after the storage of reservoir water is analyzed with limit equilibrium method combined with FEA under conditions of natural heavy-rain and earthquake.The numerical analysis shows that the landslide would be stable after water storage under native and rainstorm conditions,but unstable under earthquake.The factor of safety is less than 1,which indicates the landslide instable.
引文
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[2]张倬元,王士天,王兰生编著.工程地质分析原理[M].北京:地质出版社,1994.Zhang Zhuoyuan,Wang Shitian,Wang Langshen.Principle of en-gineering geology analysis.Beijing:Geological Publishing House,1994.
[3]Application of the finite element method to slope stability.Roc-science Inc.Toronto,2001～2004.
[4]黄润秋.20世纪以来中国的大型滑坡及其发生机制[J].岩石力学与工程学报,2007,26(3):434～454.Huang Runqiu.Large-scale landslides and their sliding mecha-nisms in China since the20thcentury.Chinese Journal of Rock Mechanics and Engineering,2007,26(3):434～454.
[5]聂德新,符文熹,任光明,张咸恭.天然围压下软弱层带的工程特性及当前研究中存在的问题分析[J].工程地质学报,1999,7(4):298～302.Nie Dexin,Fu Wenxi,Ren Guangming,Zhang Xiangong.Analy-sis of engineering proerties of weak layerzone under natural confi-ning pressure and the existing problems in present studies.Journal of Engineering Geology,1999,7(4):298～302.
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