双层滑带滑坡土环剪试验与稳定性分析

Ring Shear Test and Stability Analysis of Landslide Soil in a Double-layer Slip Zone Landslide

以云南省文山至麻栗坡高速公路K39段复合型双层滑带滑坡为例,采用室内环剪试验探明该滑坡深层、浅层滑带各自的残余强度,分析不同含水率、法向应力和剪切速率对滑带土残余强度的影响;采用FLAC3D软件进行数值模拟,基于滑坡应力-应变历史对滑坡稳定性进行评价。结果表明:滑带土在低含水率情况下力学强度较高,饱和状态抗剪强度参数表现出明显的衰减趋势;在地下水位保持高位时,深层滑带更易发生渐进式蠕动滑移。模拟结果显示:滑坡的深层滑带应力集中现象较为显著,浅层滑坡危险性较小,滑坡在暴雨工况下整体稳定性明显降低,存在一定风险,可通过设置排水洞等降水措施进行治理。

Taking K39 section of Wenshan—Malipo Expressway in Yunnan Province as an example,the indoor ring shear test was used to explore the respective residual strengths of the deep and shallow slip zones of this landslide,and to analyze the effects of different water contents,normal stresses and shear rates on the residual strengths of the slip zone soils;numerical simulation was carried out using FLAC3D software to evaluate the stability of the landslide based on the stess-strain history.The results show that the mechanical strength of the slip belt soil is higher at low water content,and the saturated state shear strength parameter exhibits an obvious attenuation trend.When the water table is kept at a high water level,the deep slide zone is more prone to progressive creep slip.The simulation results show that the stress concentration phenomenon in the deep slide zone of the landslide is more significant,and the danger of the shallow landslide is smaller,and the overall stability of the landslide is obviously reduced under heavy rainfall conditions,and there is a certain risk,which can be managed through the installation of drainage holes and other water reduction measures.