To explore the support effect and applicability of
system bolt in moderatelyweathered mudstone tunnel, field
comparative tests with and without system anchor are conducted by taking a deepburied largespan tunnel project as an
example. The variation patterns of surrounding rock deformation, surrounding
rock pressure, shotcrete stress, axial force of anchor bolt, and contact
pressure between primary support and secondary lining are analyzed under
different working conditions. Further, the support effect of the system bolt is
examined from the aspects of construction safety and economy. The results show
the following: (1) The system bolt slightly affects the deformation of
surrounding rock and the mechanical properties of lining structure in
moderatelyweathered mudstone formation. (2) The
application of the system bolt prolongs the closing time of the surrounding
rock, thus the deformation of the monitoring section of the surrounding rock
with system bolt is greater than that without system bolt. (3) The maximum
axial force of the bolt monitored on site is only 3.40 kN, which fails to give
full play to its bearing capacity under such formation. (4) The monitoring
results of various indexes show that the support effect of system bolt is
limited, and the removal of system bolt can reduce the secondary disturbance to
surrounding rock, shorten the closing time of surrounding rock, and effectively
control the deformation of surrounding rock. (5) In the case of ensuring the
safety of the tunnel, the economic benefits of removing the system anchor are
also significant.
SUN Xinhai, LI Xianmin, WANG Wei
. Experimental Study of Support Effect of System Bolts
of a DeeplyBuried LargeSpan
Tunnel in ModeratelyWeathered Mudstone[J]. Tunnel Construction, 2023
, 43(S2)
: 151
-161
.
DOI: 10.3973/j.issn.2096-4498.2023.S2.017
