Tunnel Boring (Shield) Machine
Tunnel Boring Machine (TBM) is used to excavate tunnels with a circular cross section through a variety of soil and rock strata. It uses drilling and blasting (D&B) methods in rock and conventional “hand mining” in soil. TBMs have the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in heavily urbanized areas.