Investigations and Analysis of Cross-Passage between Subway Twin Tunnels: Case Study Shiraz Subway Twin Tunnels

One of the most important roles of cross-passages between subway twin tunnels is passing the passengers from one tunnel to another in case of emergency. The number of galleries between twin tunnels is a function of distance between stations, total length of tunnels, number of passengers per hour in each direction (PPHPD), and specific condition of safety in each subway line. Subway tunnels are bored by TBM in loose and unstable soil below ground water level, and final tunnel linings are installed as the tunnel advances. In cases where excavating the cross-passages when final linings are installed, some problems like settlement of ground level, seepage of underground water into the tunnel, and water proofing the cross-passage gallery after excavation will be arisen. In this paper, number of necessary cross-passages, the distance between cross-passages, and also parameters affecting on methods of excavating of the cross-passages for Shiraz subway twin tunnels are taken into account.