Study on the Floating Law of Metro Segments in Water-Rich Sandy Silt and Silty Clay Strata
- Release time:2024-08-09
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Affiliation of Author(s):
土木工程学院
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Journal:
KSCE Journal of Civil Engineering
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Key Words:
Silty clay
Subway engineering
Mortise and tenon segments
Floating law
Numerical simulation
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Abstract:
During the construction of subway shields, the problem of floating segments is particularly
prominent in silty clay strata. The resulting segment problems, such as cross-platform, cracks,
damage and leakage, cause great harm to the tunnel. Through field test, combined with
mathematical theory and numerical simulation analysis, this paper studies the floating law of
segments in water rich sandy silt and muddy clay layer, which provides a basis for analysing
the control measures of segment floating, which can improve the safety of the project and
save the project cost. The typical section of shield tunnel of Hangzhou Metro Line 7 is selected
as the test section, and the segment floating law is deeply analysed through field test. By
combining numerical simulation and theoretical research, the mechanism underlying the
effects of the grouting slurry properties, the main physical parameters of the soil and the
distance of the segment from the shield tail on segment floating is discussed. The results show
that shield segments floating in muddy clay strata can be divided into three typical stages:
rapid change, buffering and stability. In the first stage, segment up-floating develops rapidly,
accounting for 70 − 90% of the total up-floating within 15 hours after leaving the shield tail. In
the second stage, buffer up-floating develops slowly, and the average up-floating amount
accounts for 7.59% of the total amount of up-floating. In the third stage, segment up-floating
gradually stops with the condensation and hardening of the slurry. The results show that there
is a negative correlation between the slurry condensation rate and the number of floating
segments, a negative correlation between the segment distance from the shield tail and the
number of floating segments, and a positive correlation between the elastic modulus of the
soil and the number of floating segments. The multifactor calculation model is proven to have
good adaptability in silty soft soil layers.
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First Author:
meiyuan
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Indexed by:
Journal paper
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ISSN No.:
1226-7988
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Translation or Not:
no
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Date of Publication:
2022-04-01
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