Abstract:

The disc cutters wear rapidly and the abnormal wear is serious when shield tunneling in hardsoft mixed strata. Based on the onsite monitoring wear data of disc cutters of shield tunneling in the water conveyance tunnel of Tuancheng lake No.9 water plant of SouthtoNorth Water Diversion Project in Beijing, the evaluation index of unit rock breaking volume wear rate is introduced to conduct regression analysis on the number of cutter change and abnormal wear in mixed strata such as fault fracture zone and fullsection hard rock. Furthermore, the cutter wear and failure laws in different strata are compared and analyzed based on the abnormal wear modes. The results reveal that the cutter wear state is greatly affected by average wear rate. The main failure modes of disc cutter in fault fracture zone are eccentric wear and cutter ring failure. The eccentric wear is affected by average wear rate, while the cutter ring failure is mainly due to abnormal impact caused by uneven lithology. The main failure modes of disc cutter in fullsection hard rock are eccentric wear, cutter ring failure, and insert loss. The insert loss is also affected by average wear rate. Additionally, corresponding cutter wear reduction measures are proposed according to the research results.

Key words: shield, disc cutter wear, fault fracture zone, fullsection hard rock, average wear rate, regression analysis, wear reduction measure