为解决大直径盾构在硬岩地层中掘进效率低、刀具消耗大的工程难题，提出中心三刃滚刀掘进方案，并选取3种典型刃型（梯形刃、圆刃、平刃）的406 mm(16英寸)三刃滚刀开展极限工况下的破岩试验。采用TBM掘进模态综合试验平台，通过模拟硬岩掘进工况，测试极限荷载下的刀盘掘进参数、刀具轴承受力、启动转矩、多转速跑合振动特性及岩渣特征等关键参数，分析刀具性能及破岩效果。结果表明： 1）不同贯入度条件下梯形刃滚刀组的刀盘推力和转矩大于圆刃和平刃滚刀组，梯形刃滚刀对破岩能量需求最高。2）三刃滚刀启动转矩单刃端稳定性普遍优于双刃端，部分滚刀双刃端转矩变化超过30%。3）掘进过程中双刃端为主受力区，较单刃端高10%~25%；不同刃型滚刀中，梯形刃受力最大，圆刃受力最小。4）不同滚刀结构稳定性差异显著，振动跑合测试表明，部分滚刀在极限荷载下存在内部损伤，如3#滚刀试验后峰值与峭度指标同步出现异常增长。5）3种刃型的三刃滚刀均能有效破碎硬岩，平刃滚刀破除中心盲区硬岩效果最好。
Large-diameter shield tunneling in hard rock strata has low tunneling efficiency and high cutter consumption. To address these issues, a central triple-disc cutter excavation scheme is proposed, and 16-inch triple-disc cutters with three typical cutter profiles (trapezoidal, round, and flat edges) are selected for rock-breaking tests under extreme working conditions. Using a tunnel boring machine excavation modal comprehensive test platform, hard-rock shield tunneling is simulated to test key parameters, including cutterhead disc cutting parameters, cutter shaft bearing force, starting torque, multispeed running-in vibration characteristics, and rock debris characteristics under extreme loads, thus analyzing cutter performance and rock-breaking effect. The results show the following: (1) Under different penetration conditions, the cutterhead thrust and torque of trapezoidal-edge cutters are greater than those of round-edge and flat-edge cutters, and trapezoidal-edge cutters require the highest rock-breaking energy. (2) Starting torque at the single-edge end is generally more stable than that at the double-edge end, and the torque change at the double-edge end exceeds 30% for some cutters. (3) The double-edge end is the main stress area during excavation, with stresses 10%－25% higher than those at the single-edge end. Among the three cutter profiles, the trapezoidal edge bears the greatest force, whereas the round cutting edge bears the smallest stress. (4) The structural stability of the cutters differs considerably. The vibration running-in test shows that some cutters have initial assembly defects, whereas others have internal damage under extreme loads. (5) Triple-disc cutters with all three cutter profiles effectively break hard rock, and flat-edged cutters produce the lowest central rock ridge.
