The cutterhead of tunnel boring machine is a large-scale metal welding
structure, which is prone to problems such as wear and cracking during
the tunnelling process. For the issue, the fatigue crack propagation
rate model of cutterhead under different reliability was established,
based on the damage tolerance of cutterhead. Its dangerous position of
cutterhead failure was determined by using finite element method.
According to the fatigue load spectrum, the fatigue propagation life of
cutterhead under different reliability was calculated, the main factors
affecting the reliability of cutterhead were analyzed and the
engineering experiment is carried out. The results show that three
dangerous positions of the cutterhead failure are the junction of the
split plane, the maximum deformation of the block and the central cutter
seat. The load stress amplitude and initial crack size are the main
factors affecting the crack propagation life and the reliability of
cutterhead. With the increase of load stress amplitude and initial crack
size of cutterhead, the fatigue crack propagation life of cutterhead
decreases and the reliability is worse. When the initial crack size of
cutterhead is greater than 0.5mm, the fatigue crack propagation life of
cutterhead decreases obviously. The research results provide a
scientific basis for crack detection, life prediction and reliability
evaluation of cutterhead structure.