Systematic Performance Evaluation of Shield TBM Cutters for Excavating Multiple Soft Rock

Abstract

Cutter performance evaluation is important for shield TBM during the design and refurbishment stage. To face the challenges of choosing the proper cutters for tunneling in complex condition, according to the concept of parameter profile analysis, a systematic evaluation method was proposed. In this novel method, by comparing with their expected best value and the corresponding unacceptable limit, all of the selected performance parameters can be synthesized to assess the proximity of the overall merit of each cutter with respect to all the performances considered under all possible geological conditions. Performance indexes including cutting efficiency, structural strength, wear life, and dynamic response were individually analyzed based on linear cutting tests, finite element analyses, and theoretical calculations. Finally, a case study was carried out to demonstrate how the method is applied to find the optimal cutter among a small-scale disc cutter and two scrapers used for cutting multiple soft rock. In this case, three types of concrete specimens with distinct mechanical properties were carefully prepared to substitute for soft rock. The evaluation results show that the method has an intrinsic applicability in helping to make a reasonable trade-off between cost and cutting performance during the cutter selection process.