Numerical Simulation of Excavation Load on Cutterhead in Shield Tunneling Machine

Cutterhead is the most important component of shield tunneling machine.The fundamental problem for the design of cutterhead is the dynamic load distribution on the excavation face during tunneling process.Finite element method(FEM) was used to simulate the interaction between cutterhead and excavation face in tunneling process,in which a 3D cutterhead model was established,and the extended Drucker-Prager elastoplastic model was selected for the soil concerning its material nonlinearity.During the excavating simulation,soil cutting including cutting scrap formation and cutting scrap separation was simulated by using the progressive damage and failure rules,which con-tain element delete function.Based on the above established models the interaction between cutterhead and excavation face was simulated and the cutting load distribution of cutterhead was analyzed.The results show that the cutting load distribution of cutterhead increases apparently in the radial direction at the beginning of the excavation and then the change is smaller.The torque increases significantly to 1 800 kN.m at first and then keeps stable,which is consis-tent with the engineering practice.