Monitoring And Analysis Of Secondary Deformation Of Closed Mine In Western Xuzhou Based On InSAR

Under the continuous development of coal resources and the coal de-capacity policy implemented by the state in recent years,mines that do not meet the requirements of safe production and resource exhaustion will be closed or will be closed soon,resulting in a large number of closed or abandoned mines.After the mine is closed,the groundwater level rises,which induces the compaction of the voids in the rock mass and the closure of the cavities,which causes the secondary movement and deformation of the overlying rock and the surface,landslides,fault activation and other geological disasters.The secondary movement and deformation of the surface is caused by the closure of the mine.Monitoring,obtaining time and space surface deformation data of closed mines,and studying its laws and prevention methods have important theoretical and practical value.At present,traditional measurement methods for surface deformation monitoring are time-consuming,laborious and inefficient.DIn SAR technology can make up for some of the shortcomings of traditional measurement,but limited by factors such as time-space baseline decoherence and atmospheric delay,the monitoring accuracy is limited.The timing In SAR technology based on the development of DIn SAR technology can overcome the influence of unfavorable factors such as time-space decoherence and atmospheric delay.Because the phase change caused by the secondary surface deformation of the closed mine is small,it is difficult to separate from the noise phase mixing,resulting in the loss of part of the secondary surface deformation phase of the interferogram in the denoising process.Therefore,while improving the denoising ability,keeping as much as possible the information of the secondary surface deformation has become the key to the monitoring of the secondary surface deformation of the closed mine.Based on the research and improvement of the interferogram filtering method,this paper uses the time-series In SAR technology to monitor and analyze the secondary surface deformation of the closed mine in the west of Xuzhou.The main research work and results are as follows:(1)In order to enhance the filtering effect and improve the quality of the interferogram,based on the Goldstein filter,a Laplacian pyramid-based Multiscale Iterative Goldstein(MI-Goldstein)filter method is proposed,which uses the Laplacian The pyramid constructs a multi-scale description of the interferogram,separates the high-frequency and low-frequency information of the interferogram,and uses targeted filtering methods respectively.Finally,the filtered multi-scale image is reconstructed to obtain the filtered interferogram.Combining simulation and real interferogram experiments prove the effectiveness and reliability of MI-Goldstein filtering method.(2)The improved MI-Goldstein filtering method is applied to Sta MPS technology and TCP-In SAR technology.Based on 38 Sentinel-1A data of closed mines in western Xuzhou,the secondary surface deformations of closed mines in western Xuzhou are obtained,combined with surface leveling.The measured data,horizontally compared the accuracy of the existing time-series In SAR technology and the time-series In SAR technology integrated with the MI-Goldstein filter method,and the vertical comparison of the reliability of the different time-series In SAR technology to monitor the surface secondary deformations of closed mines in western Xuzhou.The comparative analysis shows that: Compared with the Sta MPS technology,the TCP-In SAR technology based on MI-Goldstein filtering obtains higher accuracy of secondary deformation on the surface of the closed mine.(3)Based on the deformation data obtained by TCP-In SAR technology integrated with MI-Goldstein filtering method and the geological and mining data of closed mines in western Xuzhou,the mechanism and laws of surface subsidence of closed mines in western Xuzhou are analyzed.The analysis results show that: the maximum cumulative settlement is linearly negatively correlated with the average mining depth of the working face,and linearly positively correlated with the mining thickness of the working face;Point time series cumulative settlement value analysis obtains the stepwise regression equation of rise and settlement,and the conclusions are drawn that the mechanism of surface deformation is related to the height of the groundwater level;the analysis results of settlement in the central part of Pangzhuang mine show that the secondary surface deformation appears faster first The characteristic of slowness,meanwhile,the change of the sedimentation rate gradually slows down with time.The research results provide basic data for the assessment,prevention and control of subsidence disasters from closed mines in western Xuzhou.The paper has 46 figures,14 tables and 104 references.