When tunneling in soilsand
interbeded strata, large deformation often occurs. Hence, the causes and
control techniques (such as surrounding rock prereinforcement and arch
replacement) of large deformation of Yangcheng tunnel of HaolebaojiJi′an railway are studied. The site
monitoring results are used to evaluate the control effect of large deformation
section. The research results show the following: (1) The poor properties of
soilsand interbeded surrounding rock and uneven
strength would cause stress concentration and asymmetrical pressure, and
improper countermeasures are adopted, which are the main causes of large
deformation. (2) The pressure of surrounding rock and the stress of grid steel
frame generally show a fluctuation in the early stage and stabilization in the
late stage trend, whereas the shotcrete shows obvious rapid growth, slow
growth, and stabilization trend. The variation range of the pressure of
surrounding rock and the stress of supporting structure is within the safe
state. (3) The material properties of the support structure in large
deformation section are not fully utilized. The maximum compressive stress of
shotcrete is 1 523 kPa, which
is 6.3% of the ultimate strength, and that of grid steel frame is 24 553 kPa,
which is 6.1% of the ultimate strength. (4) After the treatment of the large
deformation section, the pressure of surrounding rock varies in the range of 0
~ 85 kPa, the shotcrete stress varies in the range of -2 400 ~ 420 kPa, and the
steel frame stress varies in the range of -33 000 ~ 1 600 kPa, indicating that
the tunnel structure is in a stable state with large safety reserve. The
monitoring results show that the control techniques of large deformation
proposed is feasible in controlling the large deformation of tunnel in soilsand interbedded strata.
WANG Zhijie, CAI Libin, QIU Zhihong, RUI Xiaohao, MA Zhaofei, CHENG Hongsheng, ZHANG Zengzhao, XU Haiyan
. Large Deformation Control Techniques of SoilSand
Interbedded Tunnel： a Case Study of Yangcheng Tunnel
of HaolebaojiJi′an Railway[J]. Tunnel Construction, 2021
, 41(S2)
: 469
-478
.
DOI: 10.3973/j.issn.2096-4498.2021.S2.060
