Surface Subsidence Measurement And Mechanism Analysis In Coal Mine Area Based On In Sar Technology

Massive coal seam extraction and continuous mine drainage in Fengfeng colliery have caused surface subsidence above mined-out area which is adverse to the urban and suburb construction planning and regional ecological environment protection.Therefore,the study of the large-scale surface subsidence in the mining area cannot only avoid geological and secondary disaster caused by mining activities.but provide valuable technical suggestion for the construction of the subsidence area and future planning of the mining area.In this paper,the advantages and disadvantages of In SAR technique applied to ground subsidence monitoring discussed by means of field monitoring and computer simulation.Using D-In SAR technology and based on 25 pieces of Sentinel 1A data,the surface subsidence field of Fengfeng and Wutongzhuang on July 11,2015 solstice and January 13,2017 in Fengfeng mining area were obtained;The time series analysis was carried out with SBAS-In SAR tenology to obtain surface subsidence of indirect mining influenctial area in Fengfeng urban area,which indicted that underground water environment had dramatically influence of different spatio location of Fengfeng urban area on surface settlement rate.Based on the principle of effective stress,the mathematical model of soil compression in the subsurface and confined water layer is constructed,and the mechanism of surface subsidence in the non-mining disturbed area is revealed.The results are as follows:(1)during the research period,the location of large subsidence is consistent with the spatial distribution location of the mine within the research area.The maximum sinking position is in Xinsan mine,and the maximum sinking amount is 660 mm.The subsidence section of Wutongzhuang mine has a maximum subsidence of 340 mm,and the subsidence basin covers a wide area.(2)The mining of Fengfeng area sampling time series analysis results show that the mining area Fengfeng in the east,west,south,north,the subsidence rate of five space position 6 mm/ month,12 mm/month,14 mm/month,15 mm / month,14 mm/month.In the eastern part of sample is close to Dongwushi reservoir,subsidence rate is less than the other position.so the surface subsidence influenced by the undergroundwater environment.(3)The reduction of water level in the diving layer is in a "parabolic" relationship with the soil compression settlement.The deeper the water level is,the greater the soil compression.There is a linear relationship between soil compression and head drop in confined aquifer.