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MULTIPLE TUNNELS IN SOIL WITH SHOTCRETE LININGS ON TREN URBANO, SAN JUAN, PUERTO RICO (2004)
Tunnelling was part of the new Tren Urbano transit system in San Juan, Puerto Rico. Four tunnels in soil were designed and constructed with shotcrete linings using the sequential excavation method (SEM), which uses some aspects of the New Austrian Tunneling Method (NATM). Tunnel lining convergence measurements revealed the lining displacements due to excavation of adjacent or overlying tunnel construction to be within acceptable limits. Design and construction of the tunnels as sequentially excavated with shotcrete support (SEM) was unprecedented in Puerto Rico and not in widespread practice in the continental United States.
Fifth International Conference on Case Histories in Geotechnical engineering, 2004
Parsons Brinckerhoff, USA