To rationally select
construction methods and support parameters in the design and construction
process of super-large span highway tunnels, a
case study is conducted on a double-hole eight-lane super-large span highway tunnel of the
Shenzhen-Shantou western expressway extension project
in Guangdong province, China. The investigation, engineering analogies, and
simulation calculations are employed to examine the construction method,
supporting parameters, "one-hole nine-line" large-scale mechanized tooling configuration,
and related optimization design of super-large span
highway tunnel. Furthermore, the design scheme is validated through monitoring
and measuring. The results reveal the following: (1) The design methods for two- and three-lane tunnels in the current
specifications are still basically applicable to four-lane
tunnels. (2) The centerdiaphragm(CD) method is
suitable for deep and strongly-weathered strata with a
thickness in the arch no less than 1 times the excavation width of the tunnel;
whereas the three-bench method is suitable for deep and
moderately-weathered strata with a thickness in the
arch no less than 1 times the excavation width of the tunnel. (3) The
mechanized construction method can be applied in Grade Ⅳ surrounding rock after implementing advance
middle pipe roof, glass fiber anchor, expanded shell prestressed anchor, and
C30 early high-strength shotcrete. (4) Under the
premise of advance pre-reinforcement and support
optimization mentioned above, the mechanized construction method is applicable
when the distance between the invert and the tunnel face is optimized to 106 m
(CD method) or 118 m (three-bench method), and the
distance between the secondary lining and the tunnel face is optimized to 160 m
(CD method) or 190 m (threebench method).
LIANG Ganbo, YANG Baofeng, ZHU Xin
. Design and Practice of
Super-Large Span Tunnel for Shenzhen-Shantou Western Expressway Extension
Project[J]. Tunnel Construction, 2024
, 44(S1)
: 301
-310
.
DOI: 10.3973/j.issn.2096-4498.2024.S1.033
