The complex geological
conditions of rich gas and dynamic water in the Qiantang river considerably
affect the evolution and distribution characteristics of the temperature field
during the freezing process of the connecting gallery. A case study is conducted
on the in-situ monitoring of a freezing
project at the connecting gallery of the Hangzhou metro line 6 in the Qiantang
river. The process of formation temperature variation at different positions
during the freezing process is investigated, and the temperature variation
characteristics of the freezing pipe after freezing are analyzed to determine
the influence of gas and groundwater flow on the freezing-temperature field of the connecting gallery. The main results are
summarized as follows. (1) Under bilateral hole distribution, the average speed
of frozen soil inward development is 1.47 times that of outward development.
When the freezing is stopped for 6 h, the temperature in the outer and inner
tubes increase by 5 ℃ and 10 ℃,
respectively. (2) The presence of bubbles hinders the cold transfer process of
the freezing tube to the surrounding soil, thereby significantly affecting the
freezing effect. The formation temperature at which bubbles exist during the
freezing process is 8–18.4 ℃ higher than that at end position of freezing tube. (3) Groundwater flow also
affects the distribution of cooling capacity in the formation. After a frozen
period of 57 d, the temperature difference between the upper and downstream
positions in the freezing tube reaches 8 ℃. When the freezing is stopped for 6 h, the temperature in the
freezing tube at the corresponding position increased by 5 ℃ and 2 ℃, respectively. The results show
that the bilateral divergently-arranged freezing tubes
in tunnel can effectively mitigate the influence of gas and dynamic water on
the formation of the freezing of the connecting gallery. Additionally, the
bubbles in the formation and the flow of groundwater affect the distribution characteristics
of the freezing-temperature field.
SUN Feng
. In-situ Freezing-Temperature Field Monitoring
of a Metro Connecting Gallery With a Double-Sided Hole Arrangement in Qiantang River[J]. Tunnel Construction, 2024
, 44(6)
: 1214
-1222
.
DOI: 10.3973/j.issn.2096-4498.2024.06.008
