Rock Mass Quality for Open Tunnel Boring Machines

Several parameters that influence the performance of a TBM are incorporated in the Q-system to obtain Q TBM including rock mass quality for an open tunnel boring machine. In addition to the six parameters of Q, there are five more parameters to get Q TBM . Using Q TBM the performance of TBM in a particular type of rock mass may be estimated. The approach for estimating the advance and penetration rate of TBM is highlighted. There are several examples to predict the actual rate of tunneling in rock masses.