Study on disc cutter chipping of TBM based on field data and particle flow code simulation

Using tunnel boring machines to excavate high-strength intact rock masses is becoming more common. Due to the interactions between disc cutters and rocks, abnormal wear of disc cutters, especially cutter chipping, has become a common phenomenon. Existing research has mainly focused on normal wear of disc cutters without addressing abnormal wear cases. This study used the disc cutter consumption data of a tunnel project in China to investigate the abovementioned problem based on field research. According to the failure patterns and fracture surface characteristics, the cutter chipping patterns were mainly categorized into four types: granule chipping, patch chipping, primary collapse, and secondary collapse. To further simulate the evolution of disc cutter chipping, based on the linear plastic bond model, a new contact model called the modified plastic bond (MPB) model was proposed to solve the metal simulation problem in Particle Flow Code software. To this end, a set of uniaxial tensile and compressive tests were initially conducted to verify the applicability of the MPB model. Then, a series of three-dimensional rock-cutting simulation tests were conducted to reflect the evolutionary processes involved in each type of cutter chipping. The cutter chipping mechanism and morphological characteristics were classified and summarized in detail. The results revealed that the cutting speed and penetration growth led to a rising trend in the probability and intensity of the cutter chipping. The presence of initial defects also induced an adverse effect on the service life of the cutter. The results indicated suitable working conditions for the cutter and suggested ways to control tunneling parameters and avoid frequent cutter chipping cases.