Benchmarking tunnelling production rates: Challenging case histories of mechanized and conventional tunnelling in different geological conditions

Starting from the early stages of the project, the correct estimate of the tunnelling production rate, is necessary to meet the Client's requirements and make the working time reliable for the Contractor. This paper aims to provide a benchmarking tunnelling production rates on the basis of several challenging case histories for both mechanised and conventional tunnelling. A number of variables, including ground conditions, tunnelling method, length, diameter, tunnel layouts, maintenance requirements will be critically analysed in order to compare the theoretical and real average advancing rate. The case histories include mainly the major Alpine railway base tunnels built or under construction excavated with Hard-Rock Gripper TBM, Single and Double Shield TBMs and conventional tunnelling with full-face or partial excavations.