Mechanisms and stability analysis of the Jinjiling landslide in the Three Gorges Reservoir area based on Midas-GTS
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摘要:
金鸡岭滑坡在暴雨后发生明显变形,通过现场勘察、钻探、物探、深部位移监测以及水平位移监测得出初步结论。为进一步查明该滑坡成因机制,通过解译现有勘察监测资料,结合Midas-GTS软件分析不同工况下滑坡的渗流场、位移场、稳定性计算,综合评价其成因机制。结果如下:(1)物探解译得出金鸡岭滑坡为岩土混合、含水滑坡,滑动面位于T2b1泥灰岩和T2b2泥岩分界线;(2)深部位移监测揭示该滑坡为浅表层土体在发生滑移,滑动面与物探解译得出的滑动面位置一致;(3)水平位移监测表明浅表分布的后梆滑坡和潘家岭滑坡变形速率较快,变形强烈;(4)数值模拟结果显示金鸡岭滑坡在现状工况下处于基本稳定状态;在排干地下水工况下处于基本稳定状态;在暴雨工况下处于欠稳定状态,可能产生整体滑移,其上的潘家岭滑坡及后梆滑坡产生土体次级滑移。(5)金鸡岭滑坡的地形地貌、地质构造、地层岩性、为滑坡的形成和发展提供了物源和场地条件,暴雨和人类工程活动作为诱发因素,进一步加剧滑坡变形。该研究成果将为三峡库区类似滑坡的成因机制与稳定性分析提供理论依据,对后期防治措施具有重要指导意义。
Abstract:The Jinjiling landslide was obviously deformed after the rainstorm, and preliminary conclusions were drawn through on-site investigation, drilling, geophysical prospecting, deep displacement monitoring and horizontal displacement monitoring. On this basis, in order to further find out the genesis mechanism of the landslide, this paper interprets the existing survey and monitoring data, combines the Midas-GTS software to analyze the seepage field, displacement field, and stability calculation of the landslide under different working conditions, and comprehensively evaluates its genesis mechanism. The results indicate that (1) geophysical interpretation shows that the Jinjiling landslide is a rock-soil mixed, water-bearing landslide, and the sliding surface is located at the boundary between T2b1 marlstone and T2b2 mudstone. (2) Deep displacement monitoring data reveals that the landslide occurs in a superficial soil mass, and the position of the slip surface is consistent with the location of the slip surface obtained by geophysical exploration. (3) The horizontal displacement monitoring shows that the superficially distributed Houbang landslide and Panjialing landslide have fast deformation rates and stronger deformation. (4) The numerical simulation results show that the Jinjiling landslide is currently in a basically stable state; it is in a basically stable state when the groundwater is drained; it is in a less stable state under heavy rain conditions, which may cause overall slippage, and the Panjialing and Houbang landslides produce secondary soil slippage. (5) The topography, geological structure, stratigraphic lithology of the Jinjiling landslide provide provenance and site conditions for the formation and development of the landslide. Torrential rain and human engineering activities are the inducing factors, which further aggravate the deformation of the landslide. The research results will provide a theoretical basis for the analysis of the genetic mechanism and stability of similar landslides in the Three Gorges Reservoir area, and have important guiding significance for the later control measures.
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Key words:
- Jinjiling landslide /
- Midas-GTS /
- numerical simulation /
- causal mechanisms /
- stability analysis
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表 1 岩土体的物理参数
Table 1. Physical parameters of the rock and soil
岩土介质/参数 崩坡积物 T2b2泥岩 T2b1泥灰岩 天然重度/(kN·m−3) 23.3 25.5 24.9 饱和重度/(kN·m−3) 23.5 25.7 25.1 黏聚力/kPa 16.0 30.2 16.6 内摩擦角/(°) 15 36 38 弹性模量/MPa 26.76 5.46×103 8.18×104 泊松比 0.20 0.35 0.23 渗透系数/(cm·s−1) 3.47×10−4 2.31×10−4 5.0 饱和含水率/% 31 32 18 残余含水率/% 3.1 3.0 1.8 -
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