To ensure the construction progress and quality of
open-cut tunnels while preventing temperature-induced
cracks in the lining structure after mold removal, a case study is conducted on
a reserved high-speed railway project at Xianyang
Airport in Xi′an, China. The simulation involves the
tunnel lining structure with the largest cross-sectional
size, employing finite element simulation and field tests. The analysis
considers the locations and variation patterns of temperature cracks and
maximum principal stress in the open-cut tunnel lining
structure. The comprehensive assessment considers the time variability of the
construction environment and the lining concrete. The simulation results are
then compared with the concrete strengths at different ages, indicating that
temperature cracks in the tunnel lining structure do not occur within 48 h
after concrete casting. A calculation formula for the mold removal time of
tunnel lining structures of different sizes is developed based on the
simulation results. Subsequently, timevarying
reliability theory is introduced to validate the rationality of mold removal
time. The load effect and statistical characteristics of the most unfavorable
section of the lining structure are determined through a combination of uniform
design and response surface methods. These parameters are then incorporated
into the limit state equation, and the reliability of the most unfavorable
section of the lining structure 48 h after mold removal is calculated using the
MATLAB program. The calculation employs the firstorder
secondorder moment method. The resulting reliability
value is 6.61, surpassing the standard specified in the guidelines. This
outcome demonstrates the feasibility of the proposed mold removal time.
HU Changming
,
WANG Yahui
,
TIAN Penggang
,
ZHANG Lisha
,
YANG Kunda
. Mold Removal Time and Reliability of Open-Cut
Tunnel Lining[J]. Tunnel Construction, 2023
, 43(11)
: 1821
-1830
.
DOI: 10.3973/j.issn.2096-4498.2023.11.002
