Abstract: Tunnel boring machines with single or dualmodes often face challenges adapting to complex geological conditions. Therefore, the modeselection and conversion technology for threemode tunnel boring machines using the Luogang stationShuixi station section of the Guangzhou metro line 7 as a case study. This project section encompasses soft soil, waterrich sand, and hard rock strata. The tunnel boring machine′s geological characteristics, tunneling risk, and mode adaptability are comprehensively examined, providing guidance for modeselection and conversion technology for threemode tunnel boring machines. The results demonstrate the following: (1) The open and hard rock mode is suitable for long hard rock formations with high strength,  the slurry balance mode is effective in waterrich sandy strata with high settlement requirement, and the earth pressure balance mode is effective in soft soil layer with boulders. (2) The threemode tunnel boring machine exhibits adaptability to various geological strata, facilitating functional integration and ease of operation. (3) The modeconversion capability of the tunnel boring machine is rapid, enabling fast construction. The screw and slurry mucking modes efficiently handle mucking operations and prevent slurry gushing under hard rock and waterrich challenging conditions, respectively.

Key words:  , threemode tunnel boring machine, selection of tunnel boring machine, mode conversion process, mode conversion technology