Study On The Stability And Interplay For Shallow-buried Tunnel Under-traversing The High-rise Buildings

This paper is based on high-rise buildings along the top of the tunnel of QingdaoMetro Project Phase I Line M3, which is from Qingdao Railway Station to Daxue Roadand cut through Shandong Entry-Exit Quarantine Bureau. In this paper, buildings,tunnels and soil are considered as an organic whole according to the geologicalinformation and collected building data. Based on dual control indicators of strengthand deformation, the safety and stability of the tunnel and buildings is discussed byABAQUS combine with strength reduction and field tests. Furthermore, core issuessuch as the surface subsidence, cavern convergence, rock stability assessment methods,and structural displacement control standards are also discussed in the paper. Here arethe main works of this paper：(1) The effects of yield criterion on the safety factor of strength reduction arediscussed. Draw a conclusion that the modified M-C criterion has universalapplicability to shear yield and the tensile yield of rock mass.(2) Based on the established finite element model and the integration analysis andnumerical simulation of surrounding rock pressure, basal pressure and supportresistance, the effect of tunnel excavation on surface subsidence and deformation ofcaverns is analyzed. By adopting safety factor, the stability of tunnel surrounding rockand initial lining is evaluated. Different surrounding rock safety factor based ondifferent down-traversing schemes and lining qualities are given. Meanwhile thestability is analyzed according to finite element strength reduction method. Therationality of tunnel lining support parameters are evaluated by lining safety factorcalculated by finite element numerical simulation.(3) The subway neighbor building displacement control indicator is defined. Thatis the sum of occurred building deformation and deformation after excavation which hasto be no greater than the permissible values according to the building codes. Researchshows that the sum of the deformation of superstructure and lower base meet thestandard of the displacement control, and the structural innerforces also meet thespecification requirements.(4) Based on the on-site construction data, the relation of working face stabilityand surface subsidence is discussed and the supporting structure deformation situation, the impact of excavation on the building and surface subsidence are analyzed. Thus, thestability of tunnel itself and buildings can be determined.