Estimation of disc cutter life in consideration of secondary fragmentation through TBM tunneling

Tsusaka, Kimikazu; Koizumi, Yu*; Tanimoto, Chikaosa*; Kameyama, Katsuhiro*; Miyajima, Yasuyuki*

In TBM tunneling, secondary fragmentation is considered as a phenomenon that rock pieces between a cutter head and face are fragmented through the excavation process. The fragmentation should cause damage and excessive wear to the disc cutters which pass through the dome-shaped part where scrapers scoop up muck. Based on the cutter replacement records in four TBM applications through sedimentary and granitic rocks, the authors investigated the difference in the rolling distance per unit disc diameter loss between the inner cutters and the outer ones. As a result, it was clarified that the cutter life at the outer part were shorter than that at the inner part by more than 20% by the secondary fragmentation.