The artificial ground
freezing has disadvantages such as long reinforcement time and insufficient
reinforcement effect. Therefore, a novel technology of multi-refrigerant combined refrigeration is proposed. Meanwhile, a case
study is conducted on a shield cutterhead replacement project in the Pearl
River Delta water resources allocation, and a combined freezing scheme of
liquid nitrogen + brine doublerefrigerant is
presented. Moreover, the feasibility of the multi-refrigerant
combined freezing technology is analyzed from four aspects: geological
conditions, program design, numerical calculation verification, and application
effect. Some conclusions are drawn as follows: (1) The liquid nitrogen freezes
quickly with poor uniformity after reinforcement, and the brine freezing
freezes slowly with good uniformity, thus the combined freezing of liquid
nitrogen and brine can provide conditions for shield chamber opening in high-risk strata. (2) The liquid nitrogen freezing lowers the working
environment temperature of tunnel face. In this case, the temperature of the
tunnel face is lower than －40 ℃,
and the ambient temperature is approximately －13 ℃, thus low-temperature protection measures
should be applied. (3) To ensure construction efficiency, the slurry in shield
chamber should be cleaned after freezing wall intersection to prevent mud
frozen.
DONG Tao, LIAO Xianbin
. Application of Multi-Refrigerant Combined Freezing Technology in Shield Rescue[J]. Tunnel Construction, 2024
, 44(S1)
: 381
-386
.
DOI: 10.3973/j.issn.2096-4498.2024.S1.041
