The immersed tunnel segments of EastWest
Axis Project in Xiangyang are prefabricated by integral fullsection down pouring method, which is characterized by high
strength, large crosssection and large volume, and the
segment crack is difficult to control. In order to verify the feasibility and
reliability of concrete mixing proportion, construction technology and crack
control measures, the finite element software Midas FEA is used to conduct
numerical simulation and calculation on hydration heat temperature stress of
immersed tunnel joints under design conditions, and the internal temperature
and stress variation of concrete during the casting of immersed tunnel segment
are analyzed. The numerical simulation results show that the anticracking safety factor at the joint is low. Therefore, the
chamfering position of the sidewall with the highest theoretical cracking risk
and that of the middle separation wall with the highest construction difficulty
are selected for model test. In the model test, the construction process of
reinforced bars and embedded parts is simulated, the reliability of raw
materials, mixing proportion, concrete construction performance, etc. are
comprehensively checked, and an intelligent temperature monitoring system is
set up. Through the partial block test, the structural types and installation
procedures of reinforced bars and embedded parts are rationally optimized, so
as to validate the concrete performance and optimize the construction mixing
proportion. Meanwhile, the raw material temperature control standards are
proposed to analyze the monitoring data for model testing.
WANG Cong
,
PENG Hao
.
Experimental Study on Prefabricated Partial Block of
Immersed Tunnel of Xiangyang
East-West Axis Project
[J]. Tunnel Construction, 2020
, 40(10)
: 1433
-1440
.
DOI: 10.3973/j.issn.2096-4498.2020.10.006
