Evolving NATM for Santiago's Metro

摘要

Caverns of 150m~2 excavated just 7m-9m beneath the city streets, intersected at right angles by caverns of equal size (17m wide x 14m high) form the NATM mined stations for Santiago's new metro extensions in Chile. These impressive spaces, with 60m~2-70m~2 single-tube, double-track running tunnels between, represent some of the most advanced NATM design and excavation underway in the world today. Not only is the method sympathetic to the hectic traffic on Santiago's city streets, the NATM approach is highly cost-effective at a current US$6.5M/km of running tunnel and about US$12.5M/km for station tunnels. For Line 4, currently in design, advanced value engineering is being introduced to reduce costs further, increase productivity and improve durability.