| Abstrakt: |
The main objective is to clarify the rock-fragmentation mechanism of a conical-shaped Tunnel Boring Machine (TBM) cutterhead that has rarely been investigated before. The main method is a numerical simulation which is verified by laboratory rock-fragmentation tests. The research process is as follows: Firstly, the numerical model is designed based on cutting mode analysis; Then, the rock sample is synthesized using a Grain-based Discrete Element Method (GDEM) that is verified via scaled rock-fragmentation tests; Finally, a series of numerical simulations are conducted to study the influence of cutterhead cone angle, cutter spacing, and cutter installation angle on the rockfragmentation performance. The main findings are as follows: First, the rock fragmentation mechanism of conical-shaped TBM cutterhead is free-face-assisted rock breaking; Second, the rockfragmentation efficiency can be improved by appropriately increasing the conical angle, reducing the cutter spacing, and increasing the cutter installation angle; Third, for the studied granite, the optimal conical angle is 25°, the tilt cutter spacing is suggested to be no more than 70 mm, and the cutter tilt angle is suggested to be no more than 3°. This study reveals the rock fragmentation mechanism of conical-shaped TBM cutterhead and provides suggestions for cutterhead design. [ABSTRACT FROM AUTHOR] |
