Variations in rock support capacity due to local variations in bond strength and shotcrete thickness

• Highlighting the correlation between load capacity and shotcrete thickness. Modelling of local variations in thickness bond strength. Verification material models for interface failure rock. Local weak zones do not have a significant impact on capacity. Fibre reinforced (sprayed concrete) is often used to support tunnels hard The should be designed carry from loose block, which assumed transferred surrounding rock mass over narrow band. It commonly accepted that width this band constant, independent In paper, numerical simulations are show strongly correlated mean around perimeter block. Furthermore, it also shown strong linear exists strength Based this, lower bound function estimate structural lining suggested. No was found minimum or maximum This indicates that, under certain conditions, areas with low can exist block without having any effect