Influence Of Heat Emission Of The Segments On The Construction Of The Tunnel Cross Passage By Artificial Freezing Method

Ground freezing is widely employed in the construction of cross passage in shield tunnels. With horizontal freezing pipes driven through the segments, cold fluids are supplied to the target ground for its freezing. But segments are usually naked to the air with a higher temperature in the tunnel, and this kind of exposure will induce heat emission that decreases the freezing degree of the ground, brings construction risks, and even leads to the project's failure. To get full understanding of the mechanism of this side effect, a monitoring system detecting the temperature of frozen ground was established in the cross passage construction by freezing method in Shanghai East Fuxing Road tunnel. On basis of temperature field data it provided and the theory of heat transfer, a three dimensional model is presented in this paper to simulate the heat emission of the segments, and its impact on the temperature distribution of the ground can be figured out. This solution is helpful for the similar projects. Then, based on the analysis of the factors concerning to the heat emission of the segments, several methods are presented to reduce the side effects of the heat emission, and analysis of the applicability of these methods is also carried out.