为解决复杂多变地层条件下单一模式或双模式掘进机适应性不足的问题，依托广州地铁7号线萝岗站—水西站区间三模式掘进机施工案例，开展三模式掘进机选型及模式转换技术研究。该区间包含软土、富水砂层、硬岩等复杂多变的地质，通过对区间地质特征、掘进风险、模式适应性等方面的综合分析，结合三模式掘进机工程应用效果的反馈和进一步探究，确定三模式掘进机选型及模式转换方案。结果表明: 1）长距离、高强度硬岩地层适合采用敞开式硬岩模式，沉降要求高的富水砂层适合采用泥水平衡模式，带孤石的软土地层适合采用土压平衡模式； 2）集3种模式于一体的三模式掘进机能有效解决地铁盾构区间穿越多种复杂地层（软土地层、沉降控制要求高的地层以及硬岩地层）时的盾构选型和地层适应性问题，实现掘进机多模式一体、一键切换、一机多用； 3）掘进模式转换流程、工艺的工程应用，形成了掘进模式快速、安全转换技术； 4）硬岩掘进的双排渣方案能有效解决一般硬岩条件下的高效排渣（硬岩掘进螺旋输送机出渣模式）和硬岩富水条件下的防喷涌（硬岩掘进泥水出渣模式）问题。

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.