Study on the triggering mechanism of the"group pipe effect"in the freezing process of artificial strata under the action of groundwater
MIAO Siwei
WANG Bin
ZHAO Zong
ZHANG Zihao
LIANG Xiuling
Abstract：In order to investigate the spatial and temporal evolution of the freezing temperature field in different piping methods under the action of groundwater seepage,based on the theory of heat transfer and seepage in porous media,we constructed numerical computational models of seepage in different piping methods,and carried out numerical simulation research on the triggering mechanism of the"group piping effect"during the freezing process of an artificial stratum under the conditions of differ-ent flow velocities.The results show that when the groundwater flow rate is 0 and 5m/d,the freezing time of the double-pipe freezing wall is 93 and 273 h,respectively,and the freezing wall cannot be in-terlocked when the flow rate continues to increase.Under different groundwater flow rate conditions,the downstream expansion area of the freezing curtain for each condition decreases gradually with the increase of flow rate,indicating that the enhancement of convective heat transfer by water flow leads to the slowing down of the expansion rate of the freezing front.When the freezing time reaches 400 h,the expansion distance of the freezing curtain to the downstream of the four pipes under the seepage velocity of 0,5,7,9 m/d is 783 mm,765 mm,745 mm,730 mm,respectively,which is increased by 8.90％,17.32％,19.83％,20.01％,20.17％,26.14％compared with the three-pipe working con-ditions Ⅰ and Ⅱ,respectively,27.11％,29.86％,the analysis of the freezing process found that in-creasing the groundwater flow rate will delay the intersection time,but through the reasonable config-uration of the number of freezing tubes and the layout,it can trigger the"group tube effect"generated by the synergistic action of multiple tubes,which will accelerate the expansion of the freezing front,shorten the intersection time of the freezing wall,and achieve the freezing target more efficiently.This effect will speed up the expansion of the freezing front,shorten the intersection time of the freezing wall,achieve the freezing target more efficiently and improve the safety and stability of the project.
Keywords：freezing of artificial stratagroup pipe effectgroundwater flow ratefreezing temperature fieldtriggering mechanism
Publication Date：2025-02-24
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)