Analysis Of Surface Deformation In A Region Of LuNan High-Speed Railway Caused By Coal Mining

With the rapid development of China's economy,people are increasingly pursuing the speed of transportation,and high-speed rail is born.However,the planning and infrastructure of high-speed railway lines often need to cross rivers,mountains and coal mine goafs.Therefore,it is of great theoretical and practical significance to study the prediction methods and ground subsidence law of coal mining near the high-speed railway.In this paper,the ground deformation caused by coal mining is taken as the research background.According to the geological environment of the mining area,a method for predicting the surface settlement of coal mining is constructed.On the basis of theoretical analysis,on-site measurement and numerical simulation,the law of coal mining surface movement is studied.Combined with the hydrogeological data of the mining area,the impact of groundwater decline caused by coal mining on the surface subsidence is predicted.The main work and results are as follows:According to the geological situation in the study area,the positional relationship between the Lunan high-speed railway and the coal mining faces,the monitoring method of the observation route and ground subsidence was established and the observation accuracy was analyzed.Based on the measured data of surface movement and deformation in a mine of Shandong,the wavelet threshold denoising theory is used to denoise the measured data of surface movement.According to the wavelet denoising evaluation criteria,select the appropriate threshold function,control threshold adjustment method,wavelet basis function and signal n-layer decomposition to get the best results.According to the denoised data,use MSDFVS software to realize the data visualization,generate surface subsidence curve and horizontal movement curve,and then use SODP software to invert the surface movement parameters in the measurement area,and use the probability integral method to predict surface movement and deformation after mining in working area.Taking the coal mine geological mining conditions as the research background,the FLAC3D software was used to simulate the surface deformation caused by the actual mining of the 3303,3307 and 3311 working faces,and the reasons for the errors between the numerically simulated surface subsidence and the measured data were analyzed.Then the 3307 working face was mined,and the surface deformation caused by the different distance between the stop line of the single working face and the high-speed rail was analyzed.Then proceed to mine 3307,3303 faces and 3303,3307,3311 faces respectively.The surface deformation caused by the simultaneous mining of 2 working faces and 3 working faces was analyzed.At the same time,the impact of mining at different working faces on the high-speed rail monitoring line was obtained.Considering the drop in groundwater level caused by coal mining,relying on the hydrogeological data of coal mines,the surface subsidence caused by the drop in groundwater level caused by coal mining was simulated using Visual Modflow software,and the contour of ground subsidence caused by the drop of groundwater level from January 2015 to December 2019 were obtained.According to the downward trend of water level,the surface subsidence from 2020 to 2025 is predicted,and analyze the impact of the surface subsidence caused by the groundwater level decline caused by coal mining in the next 5 years.Based on FLAC3D's numerical simulation results of mining impact and the ground subsidence data caused by groundwater from January 2015 to December 2019,compared with the measured data,it is found that the surface subsidence is caused by the double effects of coal mining and groundwater dredging.