水位升降和降雨联合作用的岸坡流固耦合及失稳机理分析:以贵州平塘六硐南岸滑坡为例  

Fluid-solid Coupling and Instability Mechanism Analysis of Bank Slope under the Combined Effect of Water Level Fluctuation and Rainfall:Taking the South Bank Landslide of Liudong in Pingtang County of Guizhou Province as an Example

作　　者：刘晶 左双英[2] LIU Jing;ZUO Shuang-ying(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China;Key Laboratory of Karst Environment and Geohazard,Ministry of Land and Resources,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学资源与环境工程学院,贵阳550025 [2]贵州大学喀斯特地质资源与环境教育部重点实验室,贵阳550025

出　　处：《科学技术与工程》2024年第12期4876-4886,共11页Science Technology and Engineering

基　　金：国家自然科学基金(42167025);贵州省科学技术基金重点项目([2020]1Z052)。

摘　　要：为探讨涉水滑坡受水位升降及降雨作用变形机制及稳定性影响,以贵州平塘六硐南岸滑坡为研究对象,通过野外调查及现场监测,分析滑坡灾害产生的地质背景和变形特征。基于非饱和渗流理论和极限平衡分析,运用有限元软件Geo-studio,计算滑坡在673~685 m水位波动和降雨作用不同工况组合下的稳定系数,得到渗流场、应力场和位移场的变化规律,探明滑坡变形迹象及破坏机制。结果表明:该滑坡累计位移曲线呈现“阶跃状”特征,变形与河流水位变化、强降雨在时间上存在对应关系;雨强增大会降低滑坡稳定性,雨停滞后一定时间稳定性恢复;水位上升和下降,分别会使坡体稳定性增加和降低,且升降速率越大,稳定性变化程度越明显;水位下降和降雨联合作用为最不利工况,正是因为2020年7—9月坡体历经2次最不利工况,导致滑坡复活并且变形加剧。研究成果可为山区河岸滑坡防灾减灾提供一定参考。In order to explore the influence of water level fluctuation and rainfall on the deformation mechanism and stability of wading landslide,taking the South Bank Landslide of Liudong in Pingtang County of Guizhou Province as the research object,the geological background and deformation characteristics of landslide disasters were analyzed through field investigation and on-site monitoring.Based on unsaturated seepage theory and limit equilibrium analysis,the stability coefficients of landslides under different combinations of water level fluctuations and rainfall at 673~685 m were calculated by using the finite element software Geo-studio,the change rule of seepage field,stress field and displacement field was obtained,and the signs of landslide deformation and damage mechanism were detected.The results show that the cumulative displacement curve of the landslide shows the characteristic of“step shape”,and the deformation corresponds to the change of river level and heavy rainfall in time.The increase of rain intensity will reduce the stability of the landslide,and the stability will be restored after the rain stops for a certain period of time.The rise and fall of water level will increase and decrease the stability of the slope respectively,and the greater the rate of lift,the more pronounced the degree of change in stability.The combine effect of falling water level and rainfall is the most unfavorable conditions,precisely because the slope experienced two most unfavorable conditions from July to September 2020,resulting in the resurrection of the landslide and increased deformation.The research results can provide some reference for landslide prevention and mitigation in mountainous river banks.

关 键 词：滑坡 有限元数值模拟 水位升降及降雨 流固耦合 

分 类 号：P642.22[天文地球—工程地质学]