为解决宜兴高铁兴山东隧道含炭质页岩段大变形问题，基于总安全系数法理论体系，以围岩变形和多层结构协同承载控制为目标，建立适用于主动和被动支护体系的支护“强度-变形-时机”一体化设计方法。在强度满足承载要求的前提下，通过调整支护构件本身的变形能力和支护时机，使支护可变形能力大于设计支护力下围岩必需的变形量（防止支护刚度过大），并小于最小支护力下围岩必需的变形量（防止支护刚度过小），从而使整体支护结构按设计意图以最经济的方式“工作”。采用该设计理论，设计“双层初期支护+可缩钢架方案”和“预应力锚索主动支护方案”2种支护体系，提出各分项支护构件的施作时机和安全控制要求，并在现场开展试验。试验结果表明： 1）2种支护方案均有效实现了设计意图，解决了隧道含炭质页岩段大变形问题。2）采用双层初期支护+可缩钢架方案时初期支护安全系数最小值为1.83，隧道最大水平收敛为588 mm，满足设计要求；采用预应力锚索主动支护方案时围岩最大水平收敛为372 mm，锚索最大轴力为310 kN，满足设计要求。
肖明清
,
徐晨
,
谢壁婷
,
邓朝辉
,
王克金
. Research on "Strength-Deformation-Timing" Integrated Design Method for Tunnel Support Based on Total Safety Factor Method(基于总安全系数法的隧道支护“强度-变形-时机”一体化设计方法研究)[J]. 隧道建设, 2024
, 44(12)
: 2480
-2499
.
DOI: 10.3973/j.issn.2096-4498.2024.12.016
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.
