A Wear Rule and Cutter Life Prediction Model of a 20-in. TBM Cutter for Granite: A Case Study of a Water Conveyance Tunnel in China

Disc cutter wear is one of the comprehensive results of the rock–machine interaction in tunnel boring machine (TBM) tunneling. The replacement of the disc cutter is a time-consuming and costly activity that can significantly reduce the TBM utilization (U) and advance rate (AR), and has a major effect on the total time and cost of TBM tunneling projects. Therefore, the importance of predicting the cutter life accurately can never be overemphasized. Most cutter wear prediction models are only suitable for 17-in. or smaller disc cutters. However, use of large-diameter disc cutters has been an irresistible trend for large-section hard rock TBMs. This study attempts to reveal the genuine wear rule of a 20-in. disc cutter and develop a new empirical model for predicting the cutter life in granite based on field data collected from a water conveyance tunnel constructed by the TBM tunneling method in China. The field data including the actual cutter wear and the geological parameters along the studied tunnel were compiled in a special database that was subjected to statistical analysis to reveal the genuine wear rule of a 20-in. disc cutter and develop the reasonable correlations between some common intact rock parameters and the disc cutter life. These equations were developed based on data from massive to very massive granite with a UCS range of 40–100 MPa, which can be applied for the assessment of the cutter life of a 20-in. disc cutter in similar hard rock projects with similar rock strengths and rock abrasivities.