Research on surrounding rock abrasivity and its influence factors in TBM tunnelling inclined shaft project

The rock abrasivity index of Cerchar Abrasivity Index (CAI) is an important indicator affecting TBM cutter wear. This paper aims to study the relationship between rock abrasivity and its influencing factors. Based on the inclined shaft tunnelling project in Bulianta coal mine, fourteen groups of rock specimens were selected to perform CAI test and relevant mechanical experiments. Also, the analyses of linear regression and multiple regression are conducted to discuss and predict CAI correlated with its influencing factors. The results indicate that rock specimens are medium abrasive and each mechanical parameter has significant effect on rock abrasivity. Uniaxial compressive strength (UCS) has a strong linear relationship with CAI when single factor is considered, while mineral weighted hardness value (WHV) and UCS impose most influence on CAI and account for 93.6 percent of the factors influencing rock abrasivity. If other factors remain unchanged, the CAI value increases by 0.01 (or 0.438) unit when UCS (or WHV) increases by one unit. Accurate measure of CAI can provide cutter wear prediction issue with certain guidance and reference.