为探索盾构直接切削ϕ25 mm主筋的钢筋混凝土桩基可行性,解决盾构切削桩基出现的刀盘卡死、刀具损坏及效率低等难题，依托TBM模态掘进试验平台模拟开展滚刀和撕裂刀切削桩基试验，通过对钢筋断裂形态、受力特性、切削参数、刀具损坏及刀盘振动特性综合分析，主要结论如下： 1）滚刀切削钢筋主要破坏形式为碾压破坏，钢筋有效断筋占比为90.6%，撕裂刀切削钢筋主要破坏形式为剪切破坏，钢筋有效断筋占比为85.4%； 2）全盘撕裂刀和全盘滚刀切削钢筋相比，撕裂刀切削参数波动较大，切削过程不平稳，振动冲击较大，且因承受较大侧向冲击力，撕裂刀合金崩裂崩脱损坏形式较多； 3）滚刀切削钢筋耐冲击效果优于撕裂刀，撕裂刀切削钢筋正向切割效果优于滚刀，可采用组合刀具布置充分发挥各自切削优势； 4）钢筋切削推进速度不宜过快，切削过程需重点关注转矩波动，建议撕裂刀切削桩基推进速度不大于3 mm/min，滚刀切削桩基推进速度不大于5 mm/min。试验成果成功应用于深圳地铁切桩工程，试验与实践共同表明盾构直接切削ϕ25 mm主筋的大直径钢筋混凝土桩基是可行的。

When shield cuts the pile foundation directly, the cutterhead is jammed and the cutters are damaged often. As a result, it is urgent to explore the feasibility of directly cutting of reinforced concrete pile foundation with ϕ25 mm main reinforced bar by shield to improve the construction efficiency. The test on pile foundation cut by disc cutter and tearing cutter is carried out on TBM modal tunneling test platform, and the fracture morphology of reinforced bar, force characteristics, cutting parameters, cutter damage and cutterhead vibration characteristics are comprehensively analyzed. The analytical results show that: (1) The main failure mode of reinforced bar cut by disc cutter is rolling failure, and the effective reinforced bar breaking ratio is 90.6%; and that by tearing cutter is shear failure, and the effective reinforced bar breaking ratio is 85.4%. (2) Compared with full disc cutter, cutting parameters of the full tearing cutter fluctuate greatly, the cutting process is unstable, and the vibration impact is large; moreover, due to the large lateral impact force, the collapse form of tearing cutter alloy varies. (3) The impact resistance effect of the disc cutter is better than that of tearing cutter, and the forward cutting effect of the tearing cutter is better than that of the disc cutter, which indicates that the combination of disc cutter and tearing cutter can be adopted. (4) The advancing speed of reinforced bar cutting should not be too fast (less than 3 mm/min for tearing cutter and less than 5 mm/min for disc cutter), and the torque fluctuation should be paid more attention to during the cutting process. The test results have been successfully applied to Shenzhen Metro pile cutting project, and the test and practice results show that it is feasible to directly cut the large diameter reinforced concrete pile foundation with ϕ25 mm main reinforced bar.