The authors investigate the
interface temperature field during the freezing method used for the connecting
channel of a super-large diameter shield tunnel.
They also examine how the length of the non-circulating
section of the freezing pipe affects the thickness of the frozen wall at the
interface between the soil and segments. The research focuses on the freezing
construction of the connecting channel for the super-large
diameter shield tunnel on the East Sixth Ring Road of Beijing, employing both
field measurements and numerical simulations to analyze both the temperature
field and the thickness of the freezing wall at the soil-pipe segment interface. The results reveal the following: (1) The
length of the non-circulating section in front of the
freezing pipe significantly affects the freezing effect at the interface. As
this length increases, the thickness of the freezing wall at the interface
decreases. Under the working conditions of the Beijing East Sixth Ring Road, a
non-circulating section length of 450 mm with a
freezing pipe span of 1 m results in the inability to achieve a closed freezing
wall within 56 d. (2) The thickness of the freezing wall at the interface and
the maximum permissible length of the non-circulating
section are greatly enhanced through the superposition freezing of a single-row of tube. Notably, a circular single-ring
freezing configuration with an equivalent span yields similar results to that
of single-row of tube freezing. (3) The thickness of
the frozen wall at the interface significantly increases when the frozen
interface is curved, compared to when the segment is flat. For a non-circulating segment length of 300 mm, the upper wall thickness
increases by 15%, whereas the lower wall and sidewall each increase by 35%.
This indicates that segment curvature is beneficial for freezing at the
interface. (4) The interface between the frozen wall and tunnel segment
represents a weak point in the frozen wall structure. During the freezing
construction process, efforts should be made to minimize the length of the non-circulating section, and careful attention should be given to
temperature fluctuations at the interface. Active thermal insulation measures
should be implemented during freezing and excavation to prevent groundwater
from penetrating the frozen wall, thereby avoiding potential water and sand
gushing incidents due to defreezing at the interface during construction.
LI Ming
,
WANG Lei
,
CUI Hao
,
CHEN Honglei
,
SUN Changsong
,
YANG Zhe
.
Interface Temperature Field of Freezing Method Construction for a Super-Large Diameter Shield Tunnel Connecting Channel: A Case Study of Beijing East Sixth Ring Renovation
Project
[J]. Tunnel Construction, 2025
, 45(2)
: 352
-360
.
DOI: 10.3973/j.issn.2096-4498.2025.02.011
