Gongbei tunnel of Zhuhai Link Road of HongkongZhuhaiMacao Bridge is proposed to be constructed by freezingsealing pipe roof method. In the paper, the effect of limiting tubes is studied by means of prototype experiment so as to obtain the rational parameters for the freezingsealing pipe roof scheme. Conclusions drawn are as follows: 1) When the frozen soil wall above the pipe filled with concrete is growing at a relatively high rate, the method of circulating warm brine in the limiting tubes can be used to control the overgrowth of the frozen body. Considering the brine temperature in the brinetube for limiting the overgrowth of the frozen body, the temperature of 8 ℃ is more effective than the temperature of 2 ℃. 2) When the frozen soil between the pipe filled with concrete and that without concrete filled and the frozen soil above the pipe filled with concrete need further freezing, the brine temperature of 2 ℃ can be adopted, the frozen soil wall is still growing, however at a lower speed. The result of the prototype experiment proves the effect of the limiting tubes.