Research On Application Of InSAR In Deformation Monitoring Of Dachang-Chehe Mining Area

Guangxi is the hometown of non-ferrous metals,rich in mineral resources.The development of minerals is prone to cause a series of problems such as water permeability,goaf subsidence,ground subsidence,etc.,which will have a major impact on the life and property safety of the country and the people.In order to quickly and effectively identify the Dachang-Chehe Deformation Zone in Nandan County and obtain the information about its time series changes,this paper selected 61 scenes of Sentinel-1A ascending data from December 04,2017 to December 18,2019,using Stacking and IPTA-SBAS method respectively to Identify the deformation zone in Dachang-Chehe mining area,and compare and analyze the identification ability,result accuracy and feasibility of the two methods.At the same time,the data set is divided into spring and winter short-term data series and all data series according to seasons,and the pros and cons of these two results are compared.In addition,according to the processing results of the IPTA-SBAS method,two deformation regions are selected to analyze their time series changes.Finally,the PSO-SVR method is used to predict and analyze the time series changes of the goaf center.The main findings are as follows:(1)When using stacking and IPTA-SBAS methods based on Sentinel-1A data to monitor deformations in mining areas,the ability to recognize deformations can be improved by reasonably increasing the number of data sequences;(2)The IPTA-SBAS recognition ability and result accuracy are higher than the Stacking method,but the IPTA-SBAS processing process is relatively complicated,the efficiency is lower than the Stacking method,and it is easily affected by subjective factors.Therefore,in the deformation monitoring of the mining area,two methods should be combined,using Stacking to quickly obtain obvious deformation information,and using IPTA-SBAS to improve the recognition ability and result accuracy.(3)Use the IPTA-SBAS method to obtain the cumulative deformation map of the mining area.Take deformation area a(goaf area)and deformation area h(tin mining area)as examples,and focus on analyzing their temporal and spatial characteristics: deformation areas a and h first form the overall rate deviation The small deformation area then gradually forms an obvious deformation center.As time goes by,the deformation center begins to spread out and finally forms the entire obvious deformation area.The final deformation area of deformation zone a reached about240,300 square meters on December 18,2019,and the relative error between the InSAR interpretation results and the actual measurement results was about 2%.Deformation area h(tin mine)significantly subsided between August 1,2018 and August 25,2018,before August 1,2018 and after August 25,2018,there was no obvious sinking trend in this area.(4)The IPTA-SBAS method was used to extract the time series deformation values of 6sample points in the center of the goaf,and the PSO-SVR time series prediction analysis was carried out.The results show that the PSO-SVR algorithm can quickly and timely provide reliable information for the center of the goaf(the end of mining).Deformation prediction reference.