Effect of Spatial Variability on Disc Cutters Failure During TBM Tunneling in Hard Rock

This study examines the effect of variations of the rock property and TBM parameters on the cutter failure. A new disc cutter wear model is developed by coupling Archard’s model and TBM cutter kinematics. The rock property and the TBM parameters are modelled as anisotropic cross-correlated log-normal random fields. The proposed model with a discretized algorithm allows a quantitative evaluation of the possible cutter failure during the TBM tunneling. The failure of the cutter head system is characterized by a random failure pattern and its failure can be evaluated using a probability method. With this technique, it can be a useful tool in providing an indication for the cutters replacement. Both the cutter and its mechanical system life are determined based on their allowed working distance of the TBM at the targeted safety level. The obtained results indicate that the life of the cutters and its cutter head system decreases with the presence of rock spatial heterogeneity. Finally, the obtained attenuation factors incorporating different randomness levels is practically useful for the evaluation of the cutter life.