Disc Cutter’s Rock Breaking Ability and Wear Resistance in Extremely Hard Rock: A Case Study in Qinling Tunnel of Han River to Wei River Water Diversion Project

Contraposing the problem of cutter wear and other issues in TBM boring in erosive and hard strata, this paper analyzes the boring parameters and cutter wear amount in the trial 2 km of TBM section in Qinling Tunnel of Han River to Wei River Water Diversion Project. Then several pieces of advice are proposed and analysis results suggest that the inadequate amount of cutters around No. 43 cutter causes their relatively high wear. Experiments of disc cutter breaking hard rock are conducted, showing that the specific energy of TBM used for breaking rock is relatively low while the efficiency high when the S/p (the ratio of cutter space to penetration) is between 25 and 30. Relevant scaled experiments indicate a critical penetration value beyond which the mass wear rate of disc cutter surges. The experiment also proves that round-blade disc cutter could effectively reduce the wear. The research could provide reference for the cutter-head design and parameter control of TBM in similar geologies.