Study on spatiotemporal evolution of surface deformation along Zhengzhou metro corridors and settlement mechanisms at representative stations

Li Chunyi; Wang Zhengxi; Wang Wenjie; Ding Laizhong; Jing Ying; Mai Zhiyao; Li Bin; Zheng Yuesong

doi:10.16186/j.cnki.1673-9787.2023100012

Abstract：Objectives The surface deformation during metro operation and maintenance has become one of the most challenging issues for the current urban construction,planning and management departments,se-verely constraining healthy and sustainable urban development.Monitoring surface deformation along the metro corridors in Zhengzhou and characterizing its subsidence patterns and governing laws are of practical significance for mitigating potential risks during operation and maintenance,and for safeguarding public safety.Methods The main urban area of Zhengzhou is adopted as the study area,with 88 Sentinel-1A as-cending orbit images(February 2016-January 2022)utilized.An MT-InSAR deformation inversion frame-work is employed to retrieve the time-series deformation fields and linear deformation-rate fields,and the spatiotemporal evolution of surface deformation within buffer zones along the metro lines is investigated.The subsidence curves for the representative Shamen station were denoised,using a Bayesian estimation algo-rithm grounded in probabilistic modeling.Measurement noise was removed and the subsidence-rate charac-teristics and sinking mechanism of the station were analyzed.Results The results indicate that the signifi-cant subsidence zones are mainly concentrated in the eastern,northwestern,and southwestern regions of the main urban area.Among them,Huiji District in the northwest(Line 2)and Jinshui District(Lines 1 and 5)in the east exhibit the most pronounced subsidence,with maximum rates of 16 mm/a and 12 mm/a re-spectively The Shamen Station,located at the intersection of Lines 2 and 4,exhibits a subsidence-trough apex whose subsidence rate over the initial,active,and recession phases conforms to a logistic time-function curve.The primary cause for the surface double subsidence funnels above Shamen station within re-stricted mining areas is groundwater drainage during metro operation and maintenance.The twin subsidence funnels at the surface observed above the station are primarily attributed to groundwater drainage during metro operation and maintenance.Conclusions The findings elucidate the mechanisms of surface subsid-ence and provide a theoretical basis and technical reference for the prevention and mitigation of surface de-formation hazards in urban metro corridor zones.