Simultaneous Effects of Joint Spacing and Orientation on TBM Cutting Efficiency in Jointed Rock Masses

Rock mass parameters including weak surfaces are the most important parameters which should be taken into account for an accurate analysis of the rock penetration by disc cutters. To date, many experimental, theoretical, and numerical simulation-based researches have been carried out on the interaction of TBM disc cutter performance and joint spacing and orientation. In this study, the simultaneous effects of joint spacing and orientation on rock indentation and fragmentation process by two TBM disc cutters are investigated by using the discrete element method (DEM). To do this, three intervals of joint spacing together with seven representative values of joint orientation are taken into consideration. Based on the results of geological site investigations, the main lithological units through which the tunnel was driven consist of sandstone, tuff, gypsum, shale, and limestone layers.