Abstract:  To investigate the influence of tearing cutter arrangement modes on the wear of tearing cutters during earth pressure balance shield tunneling in cobble strata, a case study is conducted on shield tunneling projects of the Ping′anliJishuitan and NiujieJinrongjie sections of Beijing metro line 19.  Using mathematical regression analysis, the wear coefficients of tearing cutters under two arrangement modes: large height difference and distance and small height difference and distance, are investigated and compared. The findings are as follows. (1) Under identical geological conditions, excavation parameters, and soil improvement techniques, the wear is significantly higher with the small height difference and spacing arrangement mode compared to the large height difference and spacing arrangement mode. Furthermore, the wear coefficients for high tearing cutters, low tearing cutters, and scrape cutters are 1.5, 3.2, and 2 times greater, respectively, under the small height difference and spacing arrangement mode. (2) The high and low tearing cutters, when placed with a large height difference and spacing, effectively contribute to layering and loosening, thus reducing tearing cutter wear. (3) Scrape wear coefficients under the large height difference and spacing arrangement modes are 42.7% and 36.1% lower compared to the small height difference and spacing arrangement modes, respectively.

Key words: metro, cobble stratum, earth pressure balance shield, tearing cutter, cutter height difference, cutter spacing, wear coefficient