Numerical Simulation of Rock Fragmentation Process Induced by Two TBM Cutters and Cutter Spacing Optimization

摘要

TBM performance depends on the rock breakage efficiency induced by TBM cutterhead. The rockrnbreakage process is the interaction process between TBM and rock mass, which is affected by thernTBM specifications, such as cutter thrust force, cutter tip width and profile, cutter spacing, revolutionrnper minute, and torque, and rock mass properties mainly including rock material strength, rockrnbrittleness index, joint spacing and orientation. In this study, rock chipping process induced by twornTBM cutters was performed using the discrete element method (DEM). The chipping process isrncomposed of formation of crushed zone, cracks initiation and propagation, side cracks coalescence andrnchip formation. The influence of the difference cutter spacing on the penetration process was alsornsimulated by setting up a series of two dimensional UDEC models. The optimum cutter spacing on thernBukit Timah granite found in Singapore was identified to be about 100 mm provided the critical cutterrnthrust force can be reached.