甘肃临夏盆地韩集北山滑坡群致灾特征与稳定性评价

    Disaster characteristics and stability evaluation of the Hanjin Beishan landslide group in Linxia Basin, Gansu Province

    • 摘要: 2018年8月24日,甘肃省临夏县韩集镇北山出现明显裂缝、局部下滑并形成滑坡群,紧邻坡脚和坡体上的房屋、基础设施遭到破坏。滑坡群在降雨、地震等影响下存在继续滑动的可能,对集镇和省道交通安全具有潜在威胁,因此开展滑坡群稳定性评价十分迫切。采用野外调查、极限平衡分析和有限元数值模拟方法,对北山滑坡群的各次级滑坡稳定性进行了系统评价,认为连续降雨或强降雨是造成北山出现大面积变形和形成多个次级滑坡的主要诱发因素,滑坡区地形、坡体结构和不合理的人类工程活动为滑坡的形成创造了条件。应用GeoStudio软件对滑坡群不同块体进行定量稳定性评价,结果表明:在自重工况下,滑坡群稳定性较好;在降雨工况下,除H10滑坡外,其余次级滑坡均可能进一步失稳破坏;若区内受到超越其地震基本烈度的地震作用,滑坡群稳定系数将迅速降低,各次级滑坡均可能出现快速失稳现象。根据滑坡群不同次级滑坡的变形特点和成灾模式,建议有针对性地采取坡脚挡土墙、削坡减载、锚杆框架、截排水渠、吊沟及排水抗滑设计等综合治理措施。为保证滑坡影响范围内的居民、建筑及交通安全,应加强滑坡群风险管控,在滑坡治理前需加强监测预警,动态掌握滑体的稳定状态。

       

      Abstract: On August 24, 2018, obvious cracks appeared in Beishan mountain, Hanji Town, Linxia County, Gansu Province, part of the mountain slide in different direction and landslide group formed.It is very urgent to carry out stability evaluation of the landslide groups.Field geological survey, limit equilibrium analysis and finite element numerical simulation were used to systematically evaluate the stability of each secondary landslide in Beishan landslide group.The results show that: ①Continuous rainfall or heavy rainfall was the main inducing factor that caused such a large area of deformation and the formation of multiple secondary landslides.The topography of the landslide area, the structure of the slope body and the unreasonable human engineering activities creat conditions for the formation of landslide.②According to the quantitative stability evaluation of different blocks of the landslide group, under the self-weight condition, the landslide group is in a better stable state.Under the rainfall condition, except for the H10 landslide, the rest of the secondary landslides will be further destabilized.If the area is subjected to an earthquake that exceeds its basic seismic intensity, the stability coefficient of the landslide group will decrease rapidly.All secondary landslides will experience rapid instability.③According to the deformation characteristics and disaster patterns of different secondary landslides in the landslide group, it is recommended to take targeted management measures such as retaining walls at the slope foot, slope cutting and load reduction, anchor frames, intercepting and draining channels, hanging ditches drainage anti-skid design.In order to ensure the safety of residents, buildings and traffic within the affected area of landslides, it is recommended to further strengthen the risk management and control of landslide groups, strengthen monitoring and early warning before landslide treatment, and dynamically grasp the stability of landslide groups.

       

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