Abstract: In ground freezing construction, the spacing of freezing tubes is always larger than the freezing front radius of a single pipe and the influence range of the freezing tubes is limited. To improve the calculation accuracy of freezing temperature field, a formula for the superimposed steadystate temperature field for doubletube freezing is derived based on the superimposition principle of potential function. And it is periodized to obtain a singlerow equidistant multitube steadystate temperature field, which is verified by numerical simulation according to the formation parameters of the engineering project. The results of the study indicate the following: (1) The formula for calculating the doubletube steadystate temperature field, considering the finiteness of the superimposed range of influence of the adjacent frozen tubes, can accurately predict the temperature distribution during freezing. (2) In the temperature superimposition zone of the doubletube, the midpoint of the freezingpipe connection line is the lowest temperature point on the midperpendicular line, and as the spacing of the freezing tubes decreases, the temperature at this point decreases, while the thickness of the frozen wall does not change across the midperpendicular line. (3) As the thickness of the frozen wall increases, the doubletube steadystate temperature field approaches the enhanced singletube steadystate temperature field.

Key words: shield tunnel, artificial freezing method, multitube freezing temperature field, freezing tube, potential function superimposition principle, red sandstone stratum