Research On The Coupling Relationship Between Surface Deformation Disaster And Mining In Dahongshan Iron Mine Based On InSAR

High-intensity and large-scale mining in metal mining areas will cause damage to the surface structure and potential safety hazards,posing a serious threat to the lives and property safety of people around the mining area.Therefore,it is very important to grasp the overall situation of metal mine risk disasters,determine its mining spatial distribution,clarify its development dynamics,and obtain the coupling relationship between mining and surface deformation disasters.Therefore,based on the time-series InSAR technology,the surface deformation of metal mining areas is monitored,and then the coupling relationship between surface deformation and mining is carried out in-depth research.Firstly,data is selected based on terrain factor analysis and radar visibility analysis,and time-series InSAR technology is used to extract the information of surface deformation caused by mining.Mask the area affected by geometric distortion in the InSAR monitoring results to obtain the deformation information of the effective deformation area.The accuracy of the data is evaluated,the InSAR data is compared with the level data,and the deformation characteristics of the monitoring results are compared with the deformation disaster situation to verify and analyze the data to ensure the reliability of the data.Secondly,it analyzes in detail the temporal and spatial deformation trend of the settlement funnel and the surface mining subsidence law of the mining area.Based on the probability integral method model,the ground subsidence and slip mechanism are analyzed in depth,and the deformation is divided based on the deformation characteristics of the rock.Finally,mainly mining factors,the coupling relationship between surface deformation and mining factors is deeply studied and analyzed,supplemented by natural factors,the influence of geological factors and rainfall factors on deformation is analyzed.The research content and conclusions are as follows:(1)Using time series InSAR technology,using ALOS PALSAR de-orbit data from2006 to 2009 and Sentinel-1A elevating orbit data from 2014 to 2019,the information of surface deformation caused by mining in the mining area is extracted.Mask the area affected by geometric distortion in the InSAR results to obtain the deformation information of the effective deformation area.A total of 14 deformation areas were monitored,including 3 potential landslide areas and 11 surface subsidence areas.(2)The results of SBAS-InSAR monitoring are completely consistent with the time node of mining work advancement,which reflects the extremely high reliability of SBAS-InSAR technology in monitoring ground deformation caused by mining.Analyzed the reason why the mining did not quickly trigger the surface subsidence,and revealed that the surface subsidence is mainly controlled by the high-intensity mining and the unloading of the surrounding rock in the mined-out area.During the mining process,the space of the rock mass is overlaid and the time and space mining occurs.Sequence,mining depth and mining method of sublevel caving without sill are the main factors that cause surface subsidence.(3)From the analysis of the time series curve of surface deformation and the relationship between mining,it can be seen that the time sequence of surface subsidence,recession,and secondary subsidence caused by mining indicates that the traction and drag of adjacent mining areas will cause mining.The surface subsidence of the empty area has been repeatedly activated,and the second subsidence period will be entered into on average 2 to 3 months after mining.(4)By analyzing the correlation between surface subsidence and mining factors,it can be seen that during mining,the cyclic peak value of subsidence velocity is proportional to the mining thickness.After mining stops,the cyclic period of subsidence velocity is proportional to the mining depth.It is inversely proportional to the advancing speed of the working face and the mining thickness.However,it should be noted that the actual mining conditions and geological factors in different study areas are different,and there will be certain differences in correlation.(5)Combining the surface deformation map obtained by InSAR technology and the mining geological profile map,it is found that the roof and surrounding rocks of the mining area are poorly stable,and the collapse of the rock mass causes the surface to undergo subsidence and deformation,and the mining and unloading of the mining area The combined action of load will cause stretch-slip deformation in adjacent mining areas.The vertical caving area is formed by the rock mass above the goaf gradually falling to the surface.However,due to the complex geological conditions and the influence of the mining sequence,the scope of the caving area is not completely consistent with the scope of the goaf.(6)Demonstration of the influence of rainfall on surface deformation,which is mainly reflected in the peak rainfall and accumulated rainfall.During the monitoring period from 2006 to 2009,when the monthly rainfall exceeds 100 mm after the rainy season,the cumulative rainfall is an important factor that promotes the aggravation of subsidence and slip deformation.During the monitoring period from 2014 to 2019,the precipitation rate will increase in the short term after the peak of rainfall,and there will be periodic small fluctuations in the deformation during the stable period,but the precipitation trend has not been aggravated in the long term,indicating that rainfall does not constitute the surface.The leading factor in the development trend of settlement.