The application of resin
bolts to weak and broken surrounding rocks in tunnels faces numerous
challenges, such as difficult operations, poor anchorability, and a lack of
long-term reliable monitoring means. To
address these issues, a novel technical scheme of prestressed hollow anchor
bolts with built-in resin is applied to a weak and
broken rock tunnel in southwest China to validate its feasibility. Prestressed
hollow force-measuring anchor bolts are utilized for
tunnel monitoring, while a bolt supporting scheme is optimized based on the
monitoring data of surrounding rock deformation and bolt stress. Finally, the
proposed optimization scheme is verified by combining numerical simulation
results. Research results indicate the following: (1) The prestressed hollow
anchor bolts with built-in resin realize the mechanical
and rapid construction of broken and soft rock tunnels. The operation time
(including drilling) of these bolts in collapsed sections ranges at 6－10 min, and the construction efficiency of bolts is improved by
>33%. (2) The prestressed hollow force-measuring
anchor bolts with built-in resin can effectively
monitor their mechanical state, and the wavelength value shows a good linear
relationship with the anchor bolt pulling force. (3) Field measurements
indicate asymmetric tunnel deformation with a maximum displacement of 305 mm
and a peak axial force of 149 kN in anchor bolts, both of which are observed on
the right side of the tunnel crown. Therefore, the original bolt supporting
scheme needs to be reinforced and optimized on the right side. (4) Numerical
simulation shows that the maximum axial force and maximum deformation of the
surrounding rocks of the optimized solution are reduced to 204 mm and 126 kN,
respectively, indicating that the developed bolts can significantly enhance the
effectiveness of controlling surrounding rock deformation.
XU Haotian
,
MA Weibin
,
ZHANG Jinlong
,
AN Zheli
,
ZOU Wenhao
,
WANG Xu
. State Perception and Scheme
Optimization of Tunnel Support Using Prestressed Hollow Anchor Bolts With Built-in Resin[J]. Tunnel Construction, 2024
, 44(12)
: 2415
-2423
.
DOI: 10.3973/j.issn.2096-4498.2024.12.011
