Research On Deformation Of Accumulated Landslide Under The Influence Of Mining Based On Seepage-stress Coupling

Mining landslides are a type of landslides,which occur very frequently in my country.Accumulated-layer landslides account for a large proportion of landslide disasters.Their formation is mostly related to rainfall,groundwater movement,and earthquakes.In order to analyze the hazard mechanism of the accumulation layer landslide caused by underground mining,this paper analyzes the influencing factors and formation mechanism of the accumulation layer landslide induced by underground mining and rainfall factors through data collection and investigation of the accumulation layer landslide in the study area.Combined with the measured deformation data of the accumulation layer in the study area,the MIDAS/GTS finite element numerical simulation software was used to construct the underground mining model of staged mining,and the underground mining simulation without considering the seepage conditions,seepage-stress coupling conditions,and rainfall conditions,respectively,The disaster mechanism of the accumulation layer landslide under the joint action of underground mining,seepage and rainfall factors is studied.the result shows:(1)The formation of accumulated layer landslides in the study area is the result of many factors,which can be divided into natural factors and man-made factors.The natural factors mainly include slope geometry,rock and soil physical and mechanical properties,slope geological structure,hydrogeological conditions Human factors are mainly human engineering activities,including mining influence and building load,of which mining influence has the greatest impact on the entire slope stress field.(2)3~#coal mining has little effect on the deformation of the accumulation layer.After the mining started in 2018,the total displacement increased rapidly,of which the horizontal displacement was the smallest and the vertical displacement was the largest.The displacement exhibits the characteristics of small settlement on both sides of the middle,which is consistent with the displacement characteristics of the deformed crack under investigation.After 3~#coal mining,the original compressive stress on the accumulation layer is reduced.After the 15~#coal mining started in 2016,the slope of the accumulation layer showed a transition characteristic from compressive stress to tensile stress.After mining in 2018,the accumulation layer The deformation is increased,the lower accumulation body is pulled by the bedrock,and the upper accumulation body is affected by mining to produce thrust to the lower part,which appears to be compressed,but the thrust is greatly affected by the terrain and is weakened on the platform,so the first level A tension crack developed at the junction of the platform and the secondary platform.The lower part of the slope from the primary platform to the secondary platform swelled and deformed,but it was not completely unstable.(3)In the case of seepage-stress coupling,the changes of surface stress and displacement of the accumulation layer are greater than the conclusion of ignoring the seepage field,but the change trend is the same.Dynamic factors,according to the deformation characteristics of surface cracks measured on site,the seepage-stress coupling is closer to reality.(4)After the rainfall infiltration,since the foot of the slope is the development location of three springs,the amount of water flowing into the accumulation layer after the rain includes the recharge from the surface and interior of the mountain behind,and the temporary position of the slope foot first In the saturated state,the accumulated water will infiltrate along the interface between the accumulation layer and the bedrock,which will have a great adverse effect on the overall stability of the accumulation layer.(5)According to the displacement characteristics of the accumulation layer,the slope deformation area is divided into three areas:collapse area,bending-subsidence area and tensile deformation area.In the rain-induced phase,in these three phases,groundwater and rainfall are key factors that cannot be ignored.(6)At present,the commonly used mining methods for surface deformation control include filling mining,partial mining,coordinated mining,and grouting from layers,which can prevent the formation of accumulated layer landslides in mined-out areas.After the deformation in the area tends to be stable,the research area can adopt measures such as drainage engineering,retaining engineering,and soil reinforcement.