Model Test Study of Frost Heaving Pressures in Tunnels Excavated in Fractured Rock Mass in Cold Regions

Base on the similarity theory,taking the horseshoe lining,city-gate lining and round lining for example,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 frozen depths were studied by model test.It is found that the larger the frozen depth is,the larger the frost heaving pressure.The stronger the top constraint is,the larger the frost heaving pressure.For the horseshoe lining and city-gate lining,the top constraint has great effect on the frost heaving pressures on the arch and inverted arch.For the round lining,the influence of the top constraint on the frost heaving pressure in all lining is almost the same.The frost heaving pressure is the maximum on the city-gate lining and the minimum on the round lining.The largest frost heaving pressure all occurs near the foot of an invert arch for the three kinds of lining.The test data basically coincide with the data observed in situ.