Influence of cutterhead system structure on load distribution and life of main bearing

Abstract

Service life of main bearing represents the life of tunnel boring machine (TBM) system. It is affected by the raceway load distribution which is related to the stiffness of supporting structure, as the main bearing is not rigid. To improve the service life of main bearing, the influences of key parameters of cutterhead system structure on the uniformity of load distribution are revealed, and the structure is optimized based on that. A finite element method (FEM) model of main structure is constructed to get the accurate load distribution in the main bearing for service life calculation, and the springs with nonlinear stiffness are employed to simulate the relationships between rock and cutters on the basis of Colorado School of Mines (CSM) method. Compared with the original structure, it shows that the uniformity of axial force distribution on thrust raceway increases obviously, and the service life of the main bearing is extended.