The authors investigate the rock-breaking
efficiency of the disc cutter in tunnel boring machines and the damage modes of
the crushed rock slices under different surrounding rock pressures. Based on
the principles of servo and linear parallel bonding theory, the discrete
element software PFC2D is employed to establish a two-dimensional
simulation model of the rock-breaking process,
calibrated with parameters specific to granite. Six surrounding rock pressure
conditions of 1, 5, 10, 15, 20, and 30 MPa are set and the cutter penetrating
the rock by 5 mm is simulated. The propagation of microcracks in the rock, the
specific energy consumption of the cutter during the breaking process, the
evolution of tensile shear cracks, and the failure modes of the broken rock
pieces are analyzed. The results reveal the following: (1) As surrounding rock
pressure increases, the internal rock cracks transition from along-crystalline to through-crystalline cracks,
with the proportion of shear cracks rising from 9.4% to 21.3% at 1 and 30 MPa,
respectively. (2) At a surrounding rock pressure of 10 MPa, the cracks within
the two disc cutters become interconnected, leading to the generation of larger
rock fragments compared to the other five pressure conditions. Consequently,
the specific energy consumption is reduced, indicating a more effective rock-breaking performance. (3) Following a 5 mm penetration of the disc
cutter into the rock, the radial propagation of cracks is constrained as the
surrounding rock pressure increases.
ZHOU Peng
,
SHANG Jianxu
,
ZHANG Tianyu
,
XU Jiacan
,
WANG Zinan
,
HE Enguang
. Rock-Breaking Mechanism and Specific
Energy of Disc Cutters in Tunnel Boring Machines Under
Different Surrounding Rock Pressures[J]. Tunnel Construction, 2025
, 45(5)
: 887
-894
.
DOI: 10.3973/j.issn.2096-4498.2025.05.003
