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Modeling and Analysis of Temperature Field of Tunnel Concrete Structure with Cold Plates
(1 Headquarters of Guangzhou Metro Group ConstructionEnterprise, Guangzhou 510330; 2 School of Mechanics and Civil Engineering,China University of Mining and Technology, Xuzhou 221116 )
Abstract It is common to lay a cold plate on the concrete structure to improve freezing effect during tunnel con? struction by freezing method. Taking a water blocking project by freezing method on Guangzhou-Foshan line of Guangzhou metro for example, a numerical calculation model of temperature field regarding the cold plate applied on the tunnel structure was established with Ansys software based on existing theoretic researches, and the factors affecting freezing temperature field were analyzed. The results show that the distribution curves of temperatures on main face and interface of frozen wall varying with depth are of the logarithmic curve form, the temperature difference on the main face is large at the first freezing stage and it becomes small with the time of freezing; the temperature distribution curve on the interface between segment and soil mass near the cold source is of the parabolic form and it gradually transits to a flat curve in the distance; the temperature on the interface is obviously lower than that on main freezing face after ten days of freezing in the case of small interval of cold plates due to superposition of double cold plates, and the freezing effect of the interface is better than that of the main face. The cooling rate significantly slows down and the increase of freezing scope is small after 40 days of freezing; there is an optimal interval for cold plates in the case of keeping all parameters unchanged, which makes the frozen wall thickness on the interface being maximum.
Abstract：
It is common to lay a cold plate on the concrete structure to improve freezing effect during tunnel con? struction by freezing method. Taking a water blocking project by freezing method on Guangzhou-Foshan line of Guangzhou metro for example, a numerical calculation model of temperature field regarding the cold plate applied on the tunnel structure was established with Ansys software based on existing theoretic researches, and the factors affecting freezing temperature field were analyzed. The results show that the distribution curves of temperatures on main face and interface of frozen wall varying with depth are of the logarithmic curve form, the temperature difference on the main face is large at the first freezing stage and it becomes small with the time of freezing; the temperature distribution curve on the interface between segment and soil mass near the cold source is of the parabolic form and it gradually transits to a flat curve in the distance; the temperature on the interface is obviously lower than that on main freezing face after ten days of freezing in the case of small interval of cold plates due to superposition of double cold plates, and the freezing effect of the interface is better than that of the main face. The cooling rate significantly slows down and the increase of freezing scope is small after 40 days of freezing; there is an optimal interval for cold plates in the case of keeping all parameters unchanged, which makes the frozen wall thickness on the interface being maximum.
QIU Peiyun1 SHI Rongjian2
.Modeling and Analysis of Temperature Field of Tunnel Concrete Structure with Cold Plates[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(4): 143-148
2019, Vol. 56 