ABSTRACT
This study employed 3D discrete-element analysis to predict the excavation performance of a 7.73 m diameter earth pressure balance (EPB) shield tunnel boring machine (TBM) under various operating conditions. The TBM model included key components such as the cutterhead, disc cutters, chamber, and screw conveyor. A ground model was created using 400,000 spherical particles with properties calibrated to match the project site’s weathered soil. Twelve combinations of cutterhead and screw conveyor rotation speeds were simulated at a constant advance rate. The results show that higher cutterhead speeds led to greater ground disturbance, chamber pressure variation, cutter forces and wear, and muck discharge. The central disc cutters experienced the highest forces while the gauge cutters underwent the most wear. The optimal operating condition of 1.5 rev/min cutterhead and 9.0 rev/min screw rotation balanced chamber pressure and minimized force/torque fluctuations.
