Tunnel construction often
encounters severe deformation and frequent collapse of primary support. Thus, a
case study is conducted on the Chazhenliangzi tunnel of the G0615 Jiuzhi-Maerkang expressway. A series of technologies, such as micro-bench excavation, increasing the reserved deformation, double-layer steel frame support, strengthening locking feet, mechanized
construction to quickly seal the ring, and strengthening construction
management, are adopted to effectively control the large deformation of the
surrounding rocks. The research results indicate the following: (1) By
strengthening the support parameters in a targeted manner, the primary support
deformation can be controlled, effective excavation can be achieved, and the
primary support intrusion rate can be reduced from 29% to 0. (2) By reducing
the length of the benches, adopting micro-bench, and a
single process, the primary support closure time is reduced from 40－50 days to 15－20 days. (3) Due to limited
space, some mechanical devices are introduced in a timely manner, and a gantry
trolley is used to effectively reduce the erection time and accelerate the
construction progress. The minimum monthly excavation footage of a single face
is increased from 6 to 36 m.
JIN Yafeng, ZHOU Jiebin, ZHOU Weijin
. Mechanism Analysis and
Control Technology of Large Deformation in Extremely-Fractured Soft Rock Tunnels in Western Sichuan, China: A Case Study of Chazhenliangzi Tunnel[J]. Tunnel Construction, 2024
, 44(S1)
: 344
-354
.
DOI: 10.3973/j.issn.2096-4498.2024.S1.038
