Simulation study of rock-breaking performance of TBM cone-shape cutterhead under different tunneling parameters in spiral tunnel

Compared with plane cutterhead, the cone-shape cutterhead has better rock-breaking performance with a free surface during the rock-breaking process. Tunneling parameters of cone-shaped cutterhead have great influence on the rock-breaking efficiency and cutterhead thrust. A full-scale excavation model of cone-shape cutterhead was constructed using LS-DYNA to characterize the rock-breaking process accurately and efficiently. The effects of penetration depth and rotation speed on the damage, cutterhead thrust, and rock-breaking efficiency in each area were investigated. The results show that the penetration depth is more sensitive to the field penetration index and thrust fluctuation index than the rotation speed. When the penetration depth and rotation speed is 4 mm/r and 4.5 r/min, respectively, the cone-shape cutterhead performs best with high rock-breaking efficiency and smallest fluctuation of cutterhead thrust under specific geological conditions. It provides suggestions for the selection of tunneling parameters during cone-shape cutterhead construction.