SAR/InSAR Technology Are Applied To Mining Subsidence Survey And Monitoring Research

The large-scale exploitation of mineral resources can not only meet the needs of the national economic construction and bring huge economic benefits for the society, but also cause the occurrence of various geological disasters, leading to the destruction of ecological environment in the mining area,which in turn hinders the of social and economic developments.Full dynamic monitoring of surface deformation in the mining area,obtaining the dynamic evolution of the surface subsidence, slope displacement and mastering its law of development, can provide a scientific basis for safe mining and comprehensive control of environmental damage area.InSAR, which has the advantages of full-weather, full-time, high precision and large coverage, has been widely applied in the monitoring of the mining subsidence and large-scale detection of mining areas and obtained a series of research results. However, some mines have the following features, such as the large-scale subsidence, non-linear deformation in temporal domain and spatial discontinuity and small coverage. Various InSAR techniques based on phases are faced with many problems. The major problem is hard to break through the monitored deformation gradient limitation to accurately obtain the deformations in most area of subsidence center. The Offset-tracking technique is put forward to solve the above limitation, but its monitoring accuracy is restricted and the accuracy in mining subsidence monitoring has not yet been validated from measured data. In addition, the detection of mining subsidence is mainly for the underground mine or it does not been distinguished between underground and open-pit coal mine. The geologic hazards induced by the above two mining methods are not exactly the same.Aiming at these problems, some exploratory researches have been done in the paper. This paper applies multiple information of SAR image and extends the applications of SAR technique in mining. On the one hand, the comprehensive utilization of SAR image intensity and phase information extends the large-scale detection of underground mining to open-pit coal mine. On the other hand, the precision of offset tracking based on intensity has been validated for simulation and measured data in solving the problem of large-scale deformation monitoring in mining;offset tracking based on CR identification is put forward, which makes the observations directly obtained from the SAR technique more accurate, providing more accurate and comprehensive observations for subsequent combination with mining subsidence theory, and extends monitoring methods of SAR technique at the same time, providing reference for the application of SAR technique in other areas. The research results of the paper are as follows:1. The intensity of SAR image is first used in the detection and positioning of open-pit coal mine. The phase, the intensity and the coherent information of SAR image is used to detect and position the mining in ordos coal field of Mongolia border.The basic conclusions can be drawn.(1) It is effective and universal to detect the open-air coal mining area using the SAR intensity change.(2) Coherence coefficient map can be used as supplements for the detection of coal mining area. Its availability can be improved when the influence of atmospheric, registration and baseline is small.(3) The combination of the three techniques can detect and position large-scale coal mining area better.(4) It can scientifically eliminate and classify by analyzing the detected results of various data.2. More rigorous simulation experiments are designed based on the probability integral model of coal mining subsidence and the conclusions are as follows.(1) When the deformation is small, D-InSAR based on phase can obtain the results of high precision, which is superior to the other three methods; but with the increase of deformation magnitude, the monitoring accuracy falls sharply and loses most of the deformation information.(2) The offset tracking based on intensity can break through the deformation gradient limitation on D-InSAR technique and obtain larger deformations,but the overall accuracy is low and the accuracy decreased with the increase of the deformation gradient.(3) The offset tracking based on CR can improve the monitoring accuracy to a certain extent.(4) The RMSE of offset tracking based on CR identification can be up to 3 cm within the mean value of 1 cm which is verified by test and can fully meet the needs of the mining subsidence monitoring.3.SBAS, D-InSAR stacking technique and IPTA-PS which are based on phase information and time-series offset tracking, offset tracking based on CR identification which use SAR intensity information are applied to process seven TerraSAR-X images to obtain the mining subsidence deformation field. Through analysis of the plane, profile and comparison with GPS results, it further shows the disadvantages of InSAR techniques based on phase,the advantages of offset tracking based on the SAR intensity and the high precision based on the offset tracking of the CR identification. The conclusion obtained from real data has an agreement with those of simulation experiments.