Study On Dynamic Response And Stability Of Mine Slope With Weak Interlayer Under Earthquake

Earthquake is one of the main causes of slope instability and failure.For limestone mines widely distributed in the southwest of China,because the mine slope contains "weak link" soft interlayer,the slope will show special dynamic response characteristics under the action of earthquake,which further reduces the stability of the slope,so that it is very easy to lead to mine exposed mining slope instability,resulting in major geological disasters.In order to study the dynamic response characteristics and stability of mine slope with weak interlayer under earthquake action,taking the limestone mine slope in Jinding East mining area of Emei Mountain,Sichuan Province as an example,based on engineering geological analysis,theoretical analysis and numerical simulation,the dynamic response characteristics of the slope with weak interlayer under earthquake action were studied,and the instability mode and failure mechanism of the slope were revealed.The stability of the slope is analyzed.The main research conclusions are as follows:(1)Based on the results of literature investigation and engineering field investigation,the regional geological environment characteristics such as natural geographical conditions,formation lithology,formation landform and geological structure of Huangshan Limestone Mine in Emei City,Sichuan Province are expounded,and the characteristics of slope failure and the main factors of slope instability are analyzed.The results of field investigation and analysis show that the rock mass level and joint surface of limestone mine slope are seriously affected by the dissolution action,the dissolution cracks are relatively developed,and the weak interlayer is the main factor controlling the stability of the slope body.The instability mode of the slope rock mass is mainly the landslide along the weak interlayer zone,and the overall form of the landslide is slip-tensile landslide.(2)By numerical simulation,the dynamic response characteristics of slope with weak interlayer under earthquake are studied,the progressive failure process of slope is analyzed,and the failure characteristics and failure modes of limestone mine slope with weak interlayer under earthquake are discussed in combination with the engineering situation of the study area and the field investigation results.By analyzing the dynamic response characteristics and the characteristics of weak interlayer,The main inducement of slope instability is obtained.The results show that earthquake is the external factor to induce the slope instability with weak interlayer,and weak interlayer is the main reason affecting the dynamic response characteristics of slope,and also the internal factor of slope instability.The deformation failure of slope under earthquake is the result of shear failure and tensile failure,and the instability mode is the combination of interlayer sliding and circular sliding.(3)Based on the dynamic strength reduction method,the stability variation trend of the mine slope with weak interlayer limestone is studied under different vertical ground motion,seismic amplitude,step slope Angle and step height.With the increase of vertical ground motion,horizontal seismic wave amplitude,step slope Angle and step height,the slope stability coefficient decreases gradually.The vertical ground motion and horizontal seismic wave amplitude have little influence on slope stability,while the step slope Angle and step height have great influence on slope stability.The internal factor of slope is the key to determine the strength of slope stability.