Study On The Surface Subsidence Law Of Multi-surface Deep Mining In Multi-surface Deep Mining Combined With Full-field Line Survey And Numerical Simulation

Coal mining will bring a series of environmental geological problems,among which surface subsidence is one of the serious disasters caused by mining.Therefore,it is of practical significance to study the law of surface subsidence caused by underground mining for safe mining and reducing the damage caused by mining.At present,the mining of coal resources has gradually extended to the deep,and the deep mining subsidence law has important practical significance.As the geological environment of deep mining becomes more complicated,the monitoring methods and techniques of surface movement and deformation need to be more intelligent and precise,and the law of surface subsidence needs to be further studied.In this paper,the specific coal mine is taken as the research object.Firstly,the traditional field observation is carried out on the surface of the mining area,and combined with INSAR and UAV-LiDAR technology,the surface movement and deformation data of the study area are obtained,and the surface subsidence law of the study area is obtained.According to the data of mining area 3^-15,ABAQUS numerical simulation software was used to design a model to simulate the condition of surface subsidence under under different mining sequence conditions of multiple working faces,and the following conclusions were drawn:(1)Combined with InSAR,UAV-LiDAR and traditional line survey method to monitor the surface subsidence caused by mining of the 3-1501 working face of a mine,a complete and accurate surface subsidence basin can be obtained by combining the three technologies.By December 4,a subsidence basin appeared on the surface,and the center of the subsidence basin was about 600m away from the incision,forming an elliptic boundary basin with the maximum subsidence point as the center,800m in strike direction and 300m in dip direction.It spread outwardly from the center of the basin,and the amount of subsidence gradually decreased.(2)ABAQUS software is used to conduct numerical simulation of surface movement of a mine's 3-1501 working face.With the advance of mining face,the scope of goaf increases.When the influence of goaf on the surface increases to a certain extent,the surface subsidence and deformation occur.The maximum subsidence point on the surface is the central position above the goaf,and the subsidence curve is symmetric about the maximum subsidence point in the central goaf,and the maximum subsidence value on the surface increases with the advance of the working face.Under different propulsive lengths,the more far away from the central part of goaf,the less obvious surface settlement.The accuracy and feasibility of numerical simulation can be verified by comparing the simulated results with the measured results of surface subsidence.(3)The influence of mining sequence of different working faces on surface subsidence characteristics is analyzed,and numerical simulation of sequential mining,interval mining of one working face,interval mining of two working faces,interval mining of three working faces and relative mining is established by USING ABAQUS.Different mining sequence in mining area 3-15 results in different surface subsidence.Relative to mining sequence,the surface settlement value is the least,reaching368.28cm.Under the influence of mining on adjacent working face,the surface subsidence and deformation law are special.The surface subsidence and horizontal displacement in the center of goaf are asymmetrically distributed.The subsidence basin with surface subsidence value over 300cm formed by sequential mining is the largest,which is 3000m in strike direction and 2000m in dip direction.Through comparative analysis,it is found that the surface subsidence caused by mining with three intervals is less than that of mining with other sequences.By combining different monitoring technologies to study the mining subsidence law,the research on the surface subsidence law is more detailed and accurate,which provides certain help for the monitoring and prediction of mining subsidence,and has important reference value for the safety mining of the selected mining area and similar mining areas.