Fracture Analysis of Disc Cutter of Pipe Jacking Machine

The disc cutter of a pipe jacking machine fractured in the process of construction, which seriously affected the construction efficiency and increased the construction cost. Statistical analysis was conducted on the fractured and partially-worn disc cutters, it was found that their fracture positions and patterns were similar, which is of great significance for the quality improvement of disc cutters. Macroscopic observation, composition testing, hardness testing and metallographic structure analysis were carried out on the fractured disc cutter. The results show that because of the poor sealing of the disc cutter, sand and mud entered the inside of the disc cutter in the construction process, causing the failure of internal bearings. As a result, the disc cutter could not rotate by itself, leading to partial wear. The rollers squeezed each other, causing outward thrust, which resulted in the fracture of the bearing outer ring and the cutter ring, eventually causing the fracture of the disc cutter. It is suggested that the sealing of the disc cutters should be improved to prevent the external foreign matter that may affect the bearing operation from entering the bearing and effectively avoid the early failure of the cutters.