Dynamic numerical simulation of cutterhead loads in TBM tunnelling

Cutterhead loads are the key parameters of structure design and construction control for tunnel boring machines (TBMs). They provide a real-time response about the geological conditions and operating parameters. To calculate the thrust and torque on the cutterhead, a three-dimensional finite element model for a cutterhead-rock interaction is developed by considering dynamic effects, material failure and contact with friction. The modified Mohr-Coulomb model combined with a plastic damage law and composite failure criteria, is implemented in a finite element analysis package through a user material subroutine, and is used to describe the mechanical properties of the rock. The proposed method is validated by comparing simulation results with the results from a tunnelling experiment. It is shown that the cutterhead loads approximately obey the normal distribution, both thrust and torque depend largely on the penetration as well as the uniaxial compressive strength (UCS) of rock. The results could provide a reference for loads design and parameters control during TBM construction.