ABSTRACT
The seismic response analysis of a subway structural system constructed using two shield tunnels connected by a crosspassage including a shield tunnel-vertical shaft intersection is analysed herein with the objective to identify visually the vulnerable locations of a subway structural system during a strong earthquake. Such identification is based on the evaluation of shear strains and stresses due to the torsional effects induced by the rotational motion of the vertical shaft at the tunnel-vertical shaft intersection. The zones of great variation of shear strains and stresses in the compression and tension zones represent the zones of potential cracks which mean unsafe structural zones. Three models are used herein for the nonlinear finite element analysis to represent the coupling between the structural components of the subway system. The results presented herein show that the structural unsafe zones in a subway structural system are located in the vicinity of intersections.
