Probabilistic analysis of the disc cutter failure during TBM tunneling in hard rock

Abstract

TBM disc cutters used in a long-distance tunneling particularly in cutting through hard rock would undergo substantial and intense wear. The cutting efficiency may greatly reduce and potentially facing complete suspension if the worn-out cutters were not ascertained in a timely manner. Due to the uncertainty of both geological and technical factors, it is undoubtedly arduous to predict the failure of the disc cutter. In this study, the rock abrasiveness and strength properties of 267 rock specimens, including 9 different rock types were investigated. The uncertainty characteristics of the rock abrasiveness and TBM operational parameters were summarized based on the collected data. The rock abrasiveness, compressive strength, tensile strength, TBM advancing rate and rotation speed of the cutter head were considered as random variables in this study. A probabilistic analysis was performed to investigate the cutter failure and cutters group failure in hard rock excavation. The results show variability in the geological and technical factors withhold an important influence on the cutter failure, in particular on the cutters group failure. It is therefore essential to analyze the performance of the cutter wear in the probabilistic framework to avoid overestimation of the cutters’ lifespan. Lastly, a reliability design chart is proposed for the adoption in the industries to estimate the potential failure of the cutter.