During shield tunneling process of a metro tunnel in
water-rich sandy layer, rotating
body of the shield central body mechanically malfunctioned, thus a safe
operating environment should be provided for shield chamber opening and
repairing. Herein, a combined vertical excavation face freezing and in-tunnel horizontal freezing method is proposed. Additionally, the
design and strength recalculation of freezing curtain, layout of freezing and
temperature holes, and freezing construction are elaborated. Finally, based on
field tests, the development processes of the temperature field and the frost
heave force in soil chamber are discussed in detail. The results illustrate the
following: (1) Temperature drop trend of each vertical temperature hole is
almost the same during active freezing, whereas the freezing temperature drop
rates in different areas vary obviously. The freezing development rate of
frozen soil in the freezing pipe rows is 2.8 times higher than that outside the
rows due to the influence of superimposed cooling effect. (2) The heat
dissipation of the shield machine reduces the temperature of surrounding soil
body significantly, thus heat preservation measures should be strengthened. (3)
Development rate of horizontal freezing wall is slower than that of vertical
freezing wall due to less horizontal freezing pipes and large space restricted
by the shield structure. (4) The temperature of the measurement point in the
soil chamber is linearly related to depth of hole in soil. The larger the depth
of hole in soil of the measurement point, the smaller the effect of heat
dissipation of the soil chamber panel, and the faster the cooling rate.
PENG Xinkun
,
LIANG Qifan
,
ZHU Bitang
,
ZHOU Yuhang
,
WU Shiliu
. Combined Vertical and Horizontal Freezing
Reinforcement for Excavation Face During Shield Chamber Opening
and Repair in Water-Rich Sandy Layers[J]. Tunnel Construction, 2025
, 45(S1)
: 270
-279
.
DOI: 10.3973/j.issn.2096-4498.2025.S1.027
