InSAR Monitoring Study On Substation Field Safety And Stability On The Surface Of Coal Mine Goaf

With the demand for land in the urban economic development of coal mine resources,engineering construction on the surface of the goaf has become an inevitable trend.The resulting electricity demand must be accompanied by the construction of substations.However,there is no precedent for the safe construction and operation of substations in the underlying goaf.Therefore,it is an urgent problem to evaluate and monitor the stability of the site reliably and efficiently.As a new technology for surface deformation monitoring developed in recent years,InSAR can overcome the problems of discontinuous monitoring,long period,low efficiency,and small coverage of conventional deformation monitoring methods.And it can realize all-weather,realtime,efficient,and large-scale monitoring of the study area.Aiming at the safety and stability of the proposed substation site in an underlying goaf in Pingdingshan City,Henan Province,the safety and stability monitoring research was carried out by applying InSAR technology.Through theoretical research and data operation analysis,DInSAR was used to study the spatial distribution characteristics of surface subsidence,SBASInSAR and PS-InSAR were used to study the temporal subsidence law of the land surface.In addition,based on monitoring results and industry standards,the security and stability of the proposed substation site in the goaf are evaluated comprehensively.The following research work has been mainly completed:(1)Through the D-InSAR operation,the settlement spatial distribution characteristics of the substation site in the goaf were obtained.The quantitative analysis results show that the cumulative subsidence and the maximum subsidence increment within the proposed substation site above the goaf were-19.3mm and 6.3mm respectively,and the surface settlement of the proposed site tends to be flat.(2)Based on the SBAS-InSAR and PS-InSAR operations,the time series subsidence law of the surface substation site in the goaf could be obtained.By calculation and analysis,the temporal deformation and temporal deformation rate information of monitoring points within the proposed substation site in the goaf could be obtained.The maximum subsidence values of the time series were-12.42 mm and-13.05 mm respectively,and the maximum subsidence rates of the time series were-4.98mm/a and-5.02mm/a respectively.In the past three years,the subsidence rate was completely within-2.60mm/a,and the subsidence rate was decreasing year by year.(3)According to the subsidence value and subsidence rate,the safety and stability evaluation of the substation site in the underlying goaf shall be carried out.The three methods of D-InSAR,SBAS-InSAR and PS-InSAR to monitor the maximum subsidence of the proposed substation site were-19.30,-12.42 and-13.05 mm,all of which were less than 150 mm.The maximum subsidence velocities of the three methods were-0.012,-0.014 and-0.014 mm/d,respectively,which were all less than-1mm/d.And the maximum inclinations are 0.057,0.091 and 0.070,which were all less than 0.2mm/m,respectively.According to the substation equipment foundation deformation control standard and the ground movement deformation discrimination standard,it could be seen that the proposed substation site was in a stable state.To ensure the safety and stability of the substation during operation and use,the certain anti-subsidence safety technical measures for the foundation of buildings(structures)could be adopted as safety reserves.The paper has 48 pictures,21 tables,and 89 references.