STUDY ON KEY TECHNIQUES FOR CONSTRUCTION OF METRO CROSSING TRANSFER STATION

The metro transfer stations are increasing with the network formation of Shanghai urban rail traffic. The technical problems,such as the burying depth of stations increasing,excavating adjacent to stations in operation,rebuilding metro station structures,often appear in metro stations construction. Based on the metro crossing transfer station in Dalian Road,Siping Road in Shanghai,the calculation parameters of various soil strata are gained by comparing the monitored and computing data. The key construction cases,including the foundation pit excavation for the new station crossing the existing station,chiseling diaphragm walls of the interchange section of the transfer station,and the structural force-bearing system transition of interchange connection,are simulated by FEM with soil transversely isotropic elastoplastic model and thin-layer element interface model. The different effects on the operation station are compared when symmetrical excavating and asymmetrical excavating in the deep foundation pits beside the existing station are considered. The impact of chiseling on the both side diagram walls in interchange connection of the exiting station is studied;and the regularities of deformation and internal force variation of the transfer station caused by above construction cases are analyzed. The calculation results indicate that symmetrical excavation and symmetrically chiseling diaphragm walls of the interchange section are safer to structures of the transfer station than that of asymmetrical excavation. Finally,some suggestions are given for the using station and around environmental protection.