| As an important part of China's energy consumption structure,coal resources have made great contributions to the promotion of China's national economic construction.However,the surface subsidence caused by large-scale resource extraction has increased the pressure on the sustainable development of the mining area and ecological environment protection.After the coal is mined,a mined-out area is formed,and the upper surrounding rock is deformed and spread to the surface to form a ground subsidence.Land subsidence damages the environment,severely restricts the sustainable development of the mining area economy,and is not conducive to the development,utilization and protection of the mining area.At the same time,the gradually developed railway and road network makes many lines inevitably pass through the mined-out area,causing the safety of the tunnel and the people's economic properties to be threatened.The impact of the residual settlement of the mined-out area on the tunnel construction cannot be ignored.Therefore,it is very necessary to study the deformation and stability of the new tunnels in the goaf.On the one hand,it can guide the rational mining of underground mineral resources and the control of the ground settlement of the mining area.On the other hand,it can provide environmental protection and production adjustment for the mining area.Early warning and prevention provide scientific basis and have important theoretical significance for studying the law of surface subsidence in mining areas.This paper relies on the National Highway 307 and 207 Line Yangquan City Rerouting and Reconstruction Project,through the combination of D-InSAR technology,orthogonal test design and FLAC3D software,to study the deformation and stability of the new tunnel in the goaf.First,the 8-view single-view complex images of the study area were processed by D-InSAR technology to obtain the ground subsidence monitoring data of the goaf;then on this basis,the FLAC3D numerical simulation software was used to establish a three-dimensional numerical model of the study area,and the orthogonal test The mechanical parameters of overlying rock and soil masses in goaf are inversed;finally,based on the inverted rock and soil mass mechanical parameters,FLAC3D numerical simulation is used to study the effect of goaf on the proposed tunnel.The main research content and results of the paper are as follows:?1?Based on the D-InSAR processing image of the study area,through ArcGIS software for superposition analysis,the surface settlement map and settlement curve of the 15#coal seam 80804 working face in Yangquan No.2 Mine were obtained.According to the settlement data,the maximum monthly settlement speed in the study area from December 13,2016 to March 7,2017 was 37.5 mm/month,the maximum settlement was 105 mm,and the center position of the settlement funnel was determined.?2?Based on ground subsidence monitoring data,combined with orthogonal test design and FLAC3D finite difference software to perform inversion of mechanical parameters of overburden rock and soil mass;collate the test results in Minitab software,and the results of variance analysis show that the elastic mode The quantity has a significant effect on the average ratio of surface settlement rate,and at the same time,the mechanical parameter set of rock and soil mass in the goaf is obtained through response optimization.?3?Based on FLAC3D,the excavation simulation of the proposed tunnel in the goaf is carried out.The simulation results show that the residual deformation of the goaf will have a certain effect on the deformation and stability of the surrounding rock of the tunnel.The vertical displacement of the surrounding rock and the tunnel lining appears as a whole Settlement,it is recommended to control the settlement of the mined-out area by grouting and filling during actual construction,or wait for the settlement of the mined-out area to stabilize after combining with the grouting and filling treatment methods,and then excavate the tunnel. |
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