Abstract:The basic structure and working principle of Tunnel Boring Machine (TBM) cutter-head breakout driver system were introduced. The influences of the key parameters of the hydro-viscous speed clutch, an important device of TBM cutter-head driver on the breakout process, were expounded. Through simulation, the relationship between the breakout torque and speed, torque and oil film thickness of hydro-viscous speed clutch, oil film thickness and control pressure during the breakout process were analyzed. The results indicate that the TBM breakout driving device can improve the output torque of the cutter-head greatly. The oil film thickness of the hydro-viscous speed clutch can be adjusted by control the displacement of the cylinder. Therefore, the range of output torque of the cutter-head driver system can be regulated accordingly. Additionally, the damage caused by the direct contact of the friction plates of the hydro viscous speed clutch can be avoided effectively.