Research On Mine Subsidence Monitoring And Simulation Using InSAR And Mogi\Okada Model

Mining often leads to a series of surface problems,most of which are land subsidence and it seriously affects the safety during mining and the stability of ground infrastructure.Therefore,an accurate and high-density monitoring of land subsidence caused by mining is of great significance in assessing potential geological disasters and analyzing the deformation mechanism of mining.Compared with traditional methods of monitoring deformation,time-series InSAR technology can obtain a large number of monitoring points in mining,which can well reflect the temporal and spatial evolution of mining subsidence.At present,this technology has become the most potential and practically valuable method in monitoring mining subsidence.In addition,using InSAR monitoring results to establish a suitable mining subsidence model,and employing the inversion of model parameters and forward modeling of the mining subsidence,the inversion of key underground mining parameters(mining length,width,depth,dip,strike angle and other working face information)can be realized.It can provide support for scientifically formulating underground mining plans and monitoring of cross-border mining.This article focuses on the time-series InSAR technology combined with geophysical models to monitor mining subsidence and to study the inversion of working face parameters.The least squares technology is used to monitor the mining subsidence in Inner Mongolia to analyse the deformation characteristics and laws;the geophysical model parameters are used to explain the surface deformation caused by longwall mining,and the model parameters are inverted based on the time series InSAR monitoring results.The main work and results of the thesis are as follows:(1)Using LS-InSAR technology to obtain charts of time-series mining subsidenceIn view of the shortcomings of the existing time-series InSAR monitoring of the mining area,this paper uses the least square method to process the 20-scene Sentinel-1A data in the study area from 2016 to 2017 to obtain the velocity of the line-of-sight mining subsidence,and use the MCTSB-InSAR technology to obtain the deformation velocity in the same period.The experimental results show that the use of least squares technology to obtain the mining subsidence has a similar velocity to that of the MCTSB-InSAR technology,and more complete deformation information can be obtained under the condition of ensuring the accuracy of the deformation velocity.These information can provide more accurate references for analyzing the deformation laws of the mining and combining the model to invert the parameters of the mining area..(2)Analyzing the characteristics and laws of mining subsidenceThe characteristics and laws of surface deformation caused by mining in Inner Mongolia during different mining periods are analyzed in detail according to the monitoring results of least squares technology from September 2016 to May 2017 combined with the actual situation of coal mine collapse.(3)Using geophysical model combined with least square technique monitoring results to invert model parametersAiming at the mining subsidence problems,based on the monitoring results of the time-series least squares technology,combined with the Mogi and Okada rectangular dislocation models in the geophysical model,the Bayesian algorithm is used to perform parameter inversion and forward analysis of the mining subsidence.For inversion model parameters are inaccurate,the unconstrained model parameters and the constrained model parameters are inverted respectively in the Mogi model and Okada model.Under the two conditions,the mining subsidence forwarded by solving the optimal parameters has similar deformation gradients and value with the InSAR monitoring results.The model parameters can better correspond to the mining parameters under constrained parameters.Based on the constrained parameter conditions,the time-series InSAR results are used to perform dynamic model parameter inversion.In elliptical mining subsidence,the results obtained through the inverted optimal parameters of the forward Mogi model are of great deviation from the InSAR monitoring results.However,the Okada model can forward the mining subsidence very well,and the change laws of the length parameter of the inversion model is consistent with the laws of mining subsidence.Therefore,the Okada model can be used to explain the underground rectangle subsidence caused by mining at the working face.There are 36 figures,6 tables and 75 references in the paper.