OasisLMS

Underground Metros became the major source of transportation in metropolitan cities due to various advantages such as less fuel consumption, reduced environmental pollution and reduction in traffic congestion. The underground metros are generally constructed by Cut & Cover method, Shield or Tunnel Boring Machine (TBM) method and New Austrian Tunneling Method (NATM) method. Shield or TBM method is most widely used in urban metro transportation because its impact on the environment and surrounding structures are quite minimum compared to other methods. The TBM shield method of construction involves construction of vertical shaft at the start (TBM Launch) and end of the tunnel (TBM Retrieval) followed by soil excavation, TBM lowering, TBM advancement through cutter head, soil loss or tunnel contraction at the tunnel face and along the shield, primary grouting at the tail void, installation of tunnel lining and secondary grouting. The tunnel lining to be designed considering various critical sections such as change in overburden, variation in ground water table, surcharge loads and its eccentricity, uneven ground surfaces and presence of adjacent tunnel at present or in future. In this paper, a case study of an underground metro tunnel construction is considered. The various stages of TBM Tunnel construction is simulated in Plaxis 2D. Various critical sections are analyzed in Plaxis 2D and the most critical section is identified for the design of Tunnel Lining.

Sowmiyaa V S, L&T Construction, Heavy Civil Infrastructure IC; Suresh Chikati, L&T Construction, Heavy Civil Infrastructure IC; Doraswamy Raju, L&T Construction, Heavy Civil Infrastructure IC

International Conference Proceedings