间歇冻结控制人工冻土冻胀的试验研究

Experimental Research on Controlling Frost Heave of Artificial Frozen Soil with Intermission Freezing Method

土体冻胀容易引起地表产生不均匀变形,因此控制冻胀的产生和发展始终是人工冻结技术的重要课题．通过试验比较了人工冻土在连续冻结模式、控制时间的间歇冻结模式和控制深度的间歇冻结模式下,土体冻胀的发展变化规律及冻胀控制与冻结模式之间的关系．结果表明:与连续冻结和控制时间的试验相比,在冻结锋面趋于稳定和温度梯度趋于恒定前,采用控制冻深的间歇冻结模式能够有效地抑制人工冻土冻胀的发展,冻胀量仅为连续冻结模式的19．8％;不同的变温起始时间对冻土冻胀控制的效果不同,在冻结过程刚刚进入拟稳定阶段时,迅速改变冷端温度,将使土样内的温度场不能达到稳定状态,从而推迟起始冻胀的时间,抑制冻胀的产生。

Frost heave often causes non-uniform deformation of surface ground, so, controlling the formation and development of frost heave is always the importance problem. The development laws of frost heave and the relationships between frost heave controlling and freezing models were compared using experiments under（continuous freezing model, intermission freezing by controlling freezing time and controlling frost-depth）, The results show that before the freezing front and the temperature grads tending to stability, the development of frost heave can be effectively restrained by intermission freezing model of controlling frost-depth; and the frost heave amount of intermission freezing model was of 19.8% that of continuous freezing model. The development and controlling of artificial frozen soil frost heave were influenced obviously by different incept time of changing temperature. Changing the cold temperature rapidly will prevent the sample temperature field into stabilization stage at the beginning of quasistable stage of the freezing, which postpone the incept time of frost heave and restrain the occurring of frost heave.