ABSTRACT
The Panama Metro Line 3 is a 24.5km long monorail system and it includes 5km of TBM tunnel excavated using a single large diameter (Ø13.5m) slurry TBM, 308m of cut & cover tunnels, and 264m of mined (NATM/SEM) tunnel. The tunnel is the first ever to be constructed under the Panama Canal and requires one of the largest TBMs in Latin America. The project is designed for high seismic conditions (PGA=0.86g) and exceptionally high hydrostatic pressure (7 bars). This paper will focus on the pre-cast tunnel liner design, including innovative solutions developed to overcome challenging geological conditions, mixed face ground at considerable depths, 70m of Pacific Ocean water pressures, high seismicity with potential faults crossing the alignment and complex internal structures interfaces. This critical infrastructure will allow communities who were separated by the construction of the Canal to reconnect and foster the cultural and economic development of the population that has been for almost a century cut off the Panama City educational and healthcare facilities, while allowing no disruption to the World Economy so much benefited by the Canal.
