To learn the deformation and pressure variations of
surrounding rock in the widened sections of super-large
tunnel, the Caijianweishan #2 tunnel in Xiamen is studied as a typical example.
In different widened sections of the tunnel, various deformation control
measures, like optimizing construction method, increasing step sequence, and
closing the loop as early as possible are taken, and on-site monitoring and comparative analysis for deformation,
surrounding rock pressure, and supporting axial force are carried out. The
results show that: (1) In tunnels with super-large
cross-section, the total amount and duration of
surrounding rock deformation increase with span, but its deformation rate does
not change with construction method. (2) The peripheral convergence of
surrounding rock near the vault is larger than that at the arch waist, and the
total amount difference of their convergence increases with the excavation
span, thus the deformation of surrounding rock at the vault should be focused
on in construction. (3) As deviatoric pressure is produced at the vault in the
middle of two tunnels, more attention should be paid to the stress monitoring
of the middle rock side. (4) The analysis results verify that the construction
method optimization is effective to control deformation in this super-large section tunnel.
HUANG Jianguo, YU Jin, LI Xiaogang, LIN Congbo
.
Analysis for Surrounding Rock Deformation and Pressure
Monitoring in Different Widened Sections of Super-Large
Cross-Section Tunnel
[J]. Tunnel Construction, 2021
, 41(S2)
: 115
-122
.
DOI: 10.3973/j.issn.2096-4498.2021.S2.014
