建设区顺层岩质滑坡地质力学演化模型:以万州铁峰乡麦地坪滑坡为例  

Geomechanical evolution model of bedding rock landslides in construction areas:A case study of the Maidiping landslide in Tiefeng Town,Wanzhou

作　　者：王禹 冯霄 杜娟[2] 刘洋 李东 柴波[1] Wang Yu;Feng Xiao;Du Juan;Liu Yang;Li Dong;Chai Bo(School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan 430074,China;Badong National Observation and Research Station of Geohazards,China University of Geosciences(Wuhan),Wuhan 430074,China;Zhejiang Geological Big Data Application Center Limited Company,Hangzhou 310000,China;Chongqing Wanzhou District Geological Environment Monitoring Station,Chongqing 404100,China)

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074 [2]中国地质大学(武汉)湖北巴东地质灾害国家野外科学观测研究站,武汉430074 [3]浙江地质大数据应用中心有限公司,杭州310000 [4]重庆市万州区地质环境监测站,重庆404100

出　　处：《地质科技通报》2023年第5期43-51,共9页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42172318)。

摘　　要：工程建设是诱发滑坡的主要原因和风险承灾对象,其中坡脚的开挖对斜坡的稳定性产生了较大的影响。在万州区内的顺层斜坡区,泥岩、页岩等软弱夹层在自然条件与工程活动共同作用下渐进破坏,导致滑坡大范围发生,造成无法挽回的经济损失,因此需要对滑坡的破坏过程进行分析与讨论。根据调查万州铁峰乡典型顺层岩质滑坡,建立了降雨与工程活动作用下滑坡演化过程的地质力学模型。通过环剪实验获得软弱泥化层的力学参数,应用FLAC3D模拟了滑坡在人工开挖和降雨条件下滑动面的剪切变形,与刚体极限平衡法相结合分析了滑坡稳定性的变化趋势,并结合野外调查结果进行了对比验证。计算结果表明,软弱夹层经历了自然缓慢软化和人工开挖快速软化2个阶段,受剪切位移控制,属于应变软化模型,强度随剪切位移增大而不断衰减,在达到某一临界位移时强度快速衰减,进而转化为滑动面,降低了斜坡稳定性。研究区内的麦地坪滑坡大变形出现在坡脚开挖后的降雨期,与实验分析结果相符。实验和模拟结果与野外调查相匹配,验证了建设区顺层岩质滑坡地质力学模型的合理性,研究结果对于顺向坡的建设活动和防灾减灾具有指导意义。[Objective]Engineering construction is the main cause and risk-bearing object for landslides,where excavation at the foot of a slope has a great impact on the stability of a slope.In the cascading slope areas,the progressive damage of soft inclusions such as mudstone shale under the combined effect of natural conditions and engineering activities has led to the occurrence of landslides on a large scale,which cause irreparable economic losses.Therefore,the destruction process of landslides needs to be analysed and discussed.[Methods]A geomechanical model of the landslide evolution process under the action of rainfall and engineering activities was established based on the investigation of a typical bedding rock landslide in Tiefeng Town,Wanzhou.The mechanical parameters of the soft muddied layer were obtained by ring shear experiments.FLAC3D was applied to simulate the shear deformation of the landslide under the conditions of manual excavation and rainfall,which was combined with the rigid body limit equilibrium method to analyse the trend of landslide stability and compare with the field survey results.[Results]The results show that the weak interlayer goes through two stages of natural slow softening and artificial excavation rapid softening and belongs to the strain softening model.The strength decreases continuously with the increasing shear displacement,and the strength decreases rapidly when a critical displacement is reached.The large deformation of Maidiping landslide occurs during the rainfall period after the excavation of the foot of the slope,which is consistent with the experimental results.[Conclusion]The experimental and simulated results agree with the results of field investigation,which verify the present geomechanical model of the cis-layered rock landslide.The results are of guidance for construction activities and disaster prevention and mitigation of cis-slopes.

关 键 词：顺层岩质滑坡 软弱夹层 地质力学模型 环剪实验 麦地坪滑坡 

分 类 号：P642.22[天文地球—工程地质学]