To explore the mechanical response of tunnel portal in
mechanized construction of cross passage of shield tunnel, a threedimensional
finite element numerical simulation is conducted on tunnel portal structure of
cross passage, i.e., reinforced concrete
segment reinforced by glass fiber + reinforced concrete composite segment,
based on fullscale test, which considers the stress
characteristics of segment during start, presupport,
cutting, tunnel forming, and support dismantling process. Then the test data is
compared with simulation results to validate its accuracy. The calculation
results show the following: (1) The opening area at the main tunnel shows
obvious stress concentration during cross passage breaking. (2) The cutting deforms
after the opening is broken. (3) The maximum bending moment and axial force
appear in the adjacent segments on both sides of the opening. (4) The concrete
damage is mainly distributed in the inner camber of the arch crown and the
outer camber of the arch waist at the opening side. Furthermore, a tunnel
portal structure model of ring beam reinforcement is proposed, whose mechanical
response during tunnel portal breaking of cross passage is compared with the
abovementioned one. The comparison results show that
the axial force and bending moment of the two structures vary little, but the
lining displacement of the ring beam reinforcement structure is much smaller.
The results demonstrate that the longitudinal structural stiffness of the
tunnel can be improved by ring beam, and the differential deformation between
segments can be effectively controlled during segment cutting process.
WANG Ru, ZHAI Wuzhou, NI Haibo, HUANG Hongwei
. Numerical Simulation on Mechanical Response of Tunnel
Portal with Segment Lining in Mechanized Construction of Cross Passage of Shield
Tunnel[J]. Tunnel Construction, 2023
, 43(S1)
: 178
-188
.
DOI: 10.3973/j.issn.2096-4498.2023.S1.021
