The temperature of freezing refrigerant is a key
factor affecting the frost heaving force of upper structure undercrossed by
tunnel. Hence, in order to quantitatively study the effect of increasing
refrigerant temperature on reducing the frost heave of soil, the tunnel of
Shanghai Metro Line No. 18 crossing underneath the station of Line No.
10 is taken as an example, and the temperature field
and stress field of soil under the freezing temperatures of -18 ℃ and -28 ℃ are studied by laboratory
experiments and similar simulation experiments. The sample test is a closed oneway freezing test, and the results show that the peak of frost heave
pressure generated by the freezing of -18 ℃ refrigerant
is 52.9% smaller than that of -28 ℃ refrigerant, and
the rising rate of frost heave pressure is 20.1% lower. The similar simulation
experiments are based on a similar law to calculate parameters such as station
size, frozen pipeline diameter and the refrigerant flow, and it is concluded
that the frost heave peak of -18 ℃ refrigerant is 20%
lower than that of -28 ℃ refrigerant, and the raising
rate of the frost heave pressure is 58% lower. The results of two groups of
experiment show that the model of -18 ℃ refrigerant
freezing can reduce the increasing rate and peak value of frost heave pressure
effectively, and the frost heave pressure generated under lateral restraint
conditions is larger than that generated in the similar simulation model test.
The experimental results can provide a technical reference and data supporting
for frost heaving sensitive and major risk projects.
WANG Lei
,
LI Fangzheng
,
FANG Liangwen
,
DING Hang
,
FU Cai
. Experimental Study on Influence of Frost Heaving of
Undercrossed Tunnel by Freezing Method with -18 ℃ Refrigerant on Upper Structure[J]. Tunnel Construction, 2020
, 40(9)
: 1307
-1313
.
DOI: 10.3973/j.issn.2096-4498.2020.09.009
