Prediction model for TBM disc cutter wear based on dense core theory

The CCS (constant cross section) type disc cutter wear is an inevitably crucial puzzle that affects the construction efficiency and cost budgeting of hard rock excavation. In this paper, according to the working characteristics of the CCS type disc cutter and the theory of rock squeezing and cutting, the complex stress state of rock-breaking by the cutter is analyzed and the mechanism of disc cutter rock-breaking considering the dense core effect is established. By deducing theoretical analytical expressions of dense core length, the mathematical relationship between cutter wear amount and normal force based on the principle of plastic removal abrasiveness is obtained, then the prediction models for wear rate and the cutting life of a disc cutter are proposed. Based on this context, by analyzing and calculating the measured wear data of the front disc cutter of a total of 757 rings in a section of Metro Line 12 in Shenzhen, China, it is found that the relative difference rate between the predicted value and the measured value is less than 10%, which validates the reliability and accuracy of the prediction model. In addition, by comparing with an existing typical prediction model of the CCS type disc wear, the results show that the calculation results of the prediction model proposed in this paper are more consistent with the field measured values, indicating that the disc cutter wear rate and cutting life can be regarded as reliable indexes to evaluate the cutter wear characteristics, which provides a more reasonable and feasible theoretical basis for the design of tool replacement scheme in TBM engineering.