Numerical investigation on the tunneling efficiency of TBM considering the argillization effect based on the energy evolution

When tunnel boring machines (TBMs) excavate in mudstone, argillization of the rock reduces tunneling efficiency. To investigate the influence of argillization on TBM performance and determine the optimal operational parameters, numerical investigation was conducted based on the energy evolution by Particle Flow Code 3D (PFC3D). Argillization was simulated by adhesive rolling resistance Linear model. The effects of argillization on forces acting on the disc cutter, crack evolution, and energy consumption were analyzed. Furthermore, the influence of operational modes, tip angles, and tip widths on energy consumption, the mass of slurry adhered to the cutters, and tunneling efficiency were investigated. Results indicate that argillization decreases the normal force while increasing the rolling and lateral forces. Besides, argillization significantly increases mechanical work, thereby reducing tunneling efficiency of the TBM. When excavating in the mudstone, load control mode, coupled with a cutter tip angle of 40° and a tip width of 15 mm, can effectively mitigate argillization risks and improve efficiency. This study provides valuable references for the operation of the TBM in mudstone, thereby expanding the machine's range of application.