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Based on the similarity theory,taking the horseshoe,city-gate and roond linings as examples,the value and distribution regularities of normal frost heaving pressures (hereinafter as frost heaving pressures) in tunnels excavated in fractured rock mass in cold regions under different constraints and freezing depths were studied by a test model.It was found that the larger the frozen depth,the larger the frost heaving pressure,and the stronger the top constraint,the larger the frost heaving pressure.For the horseshoe lining and city-gate lining,the top constraint has a greater effect on the frost heaving pressures on the arch and the inverted arch.For the round lining,the influences of the top constraint on the frost heaving pressure in all linings are almost the same.The frost heaving pressure is maximum on the city-gate lining and minimal on the round lining.The largest frost heaving pressure all occur near the foot of the inverted arch for the three kinds of lining.Thus,the test data basically coincide with the observed in situ data.