| In recent years,the scale of Chinese mined-out area has been continuously expanded with the development and utilization of mineral resources.Along with the expansion of goaf,goaf induced a series of serious geological disasters.Therefor it had very important significance to monitor the deformation of mining area in a full coverage and long-term way.Nowadays,InSAR technology has been widely applied in monitoring the surface deformation because of its advantages in all time,all weather and wide coverage.In this study,the 54 high-resolution Sentinel-1A data covered by Dayangquan mine area were monitored by MT-InSAR technology to get the time-series cumulative subsidence map and linear average subsidence rate map.Meanwhile,the influence of coal mining on vegetation was analyzed by the change of NDVI and the inversion of soil moisture content change trend in experimental mine area.The major research contents of this article were as following:(1)The 54 Sentinel-1A image data and MT-In SAR technology was used to get the temporal subsidence accumulation map and subsidence rate map of Dayangquan mine area.The feasibility of monitoring the terrain changes in experimental mine area was verified by MTInSAR technology combining with leveling.(2)The differential interferogram,temporal subsidence accumulation map and subsidence rate map which was obtained by MT-InSAR technology were analyzed combined with the mining conditions and the geological conditions of the mining area.It was concluded that some surface deformation might happen in the process of coal mining.The old subsidence area would have a certain impact on the new subsidence area and the cumulative effect area between the two goafs would be the most serious.The impact of coal mining on the surface above the rock layer was less than the surface above the loess.(3)Based on Sentinel-1A image data and Landsat-8 image data,the total radar backscatter coefficient,incident angle information and leaf area index LAI of the vegetation covered surface were extracted and the water content trend of the soil in the mining area were calculated by the water cloud model.Combined with the subsidence funnel obtained by MT-InSAR technology and the analysis of the soil moisture content,the results showed that coal mining had a certain impact on the change of soil water content and the soil water content in the center of the settlement funnel was lower than that in the edge of the settlement funnel.(4)Based on the actual soil water content data,the NDVI changes extracted from landsat-8 image data were used to measure the impact of mining on vegetation and the loss on the image.The soil water content values of different dominant species of surface vegetation in the same region,the same dominant species of surface vegetation in the same region and different regions were compared and analyzed.It was proved that the soil moisture content was the main factor affecting the vegetation growth in this area.(5)Comparing the change trend of NDVI value at the center of the settlement funnel with the change trend of soil water content,the change trend of the two values was approximately the same;comparing the change trend of the two values with the mining of the working face respectively,it was found that the mining of the working face was the main reason for the change.It was proved that the surface subsidence caused by coal mining will lead to the decrease of groundwater level,reduce the water content of surface soil and have a certain impact on the growth of vegetation. |
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