The Xingshandong tunnel of
Yichang-Xingshan high-speed railway passes through carboniferous shale ground, where large
deformation may occur. "Strength-deformation-timing" integrated design method is used for the design of the
support of the large deformation section of Xingshandong tunnel. "Strength-deformation-timing" integrated design
method for tunnel support is established on basis of the total safety factor
method. The design method, suitable for the active and passive support
patterns, achieves the coordinated load-undertaking of
the multiple support layers subject to the deformation of the surrounding rock.
Under the premise that the strength of the tunnel support meets the load-undertaking requirements and by adjusting the deformation capability
and the installing time of the support components, the deformation capability
of the tunnel support is greater than the necessary deformation of the
surrounding rock under the designed supporting force (to prevent too-high support rigidity), and is less than the necessary deformation
of the surrounding rock under the minimum supporting force (to prevent too-low support rigidity). Thus, the overall support structure
"works" is in the most costeffective way
according to the design intention. Two support patterns, i.e., support pattern
consisting of double layers of primary support and yielding steel arches and
active support pattern with prestressed anchor cables, are designed for the
large deformation section of Xingshandong tunnel, and the installing time and safety
control requirements of each support component are provided. The two support
patterns are used in the trial sections of Xingshandong tunnel. The monitoring
result shows that the supporting parameters of these two support patterns
effectively realize the design intention and solve the problem of the large
deformation in the carboniferous shale section of the tunnel. In the case of
the support pattern consisting of double layers of primary support and yielding
steel arches, the minimum safety factor of the primary support is 1.83 and the
maximum horizontal convergence of the tunnel is 588 mm, which meets the design
requirements; in the case of the active support pattern with prestressed anchor
cables, the maximum horizontal convergence is 372 mm and the maximum axial
force of the anchor cables is 310 kN, which meets the design requirements.
XIAO Mingqing
,
XU Chen
,
XIE Biting
,
DENG Zhaohui
,
WANG Kejin
. Research on "Strength-Deformation-Timing" Integrated Design Method for Tunnel Support Based on Total Safety Factor Method[J]. Tunnel Construction, 2024
, 44(12)
: 2480
-2499
.
DOI: 10.3973/j.issn.2096-4498.2024.12.016
