Tunnel Boring Machine an overview ScienceDirect Topics
Aug 18, 2010 Bhawani Singh, R.K. Goel, in Engineering Rock Mass Classification, 2011. Introduction. Tunnel boring machines (TBMs) have extreme rates of tunneling of 15 km/year and 15 m/year and sometimes even less. The expectation of fast tunneling places great responsibility on those evaluating geology and hydrogeology along a planned tunnel route.