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为了研究温度梯度、冻结速率、土样高度和竖向压力对冻胀的综合影响,在不同试验条件下对饱和粉土进行了一系列一维土柱冻胀试验,试验中测量土样温度、竖向压力、冻胀量和补水量。试验结果表明:在温度场处于准稳态时,冻胀速率与温度梯度成正比例增长关系,冻胀速率随着竖向压力增大而线性减小;定义比冻结速率为冻结速率与土样高度之比,当温度场处于瞬态时,冻胀速率随比冻结速率成幂函数增长,增长率随着比冻结速率增大而减小。提出了综合考虑温度梯度、冻结速率、竖向压力和土样高度的冻胀计算公式,在此基础上推导了考虑水分迁移的冻土热扩散方程,提出了模拟冻胀和温度变化的数值模拟方法,通过一个数值算例计算了冻结过程中的温度和冻胀量变化,并与实测结果对比验证了该方法的可靠性。
In order to study the combined effects of temperature gradient, freezing rate, soil height and vertical pressure on frost heave, a series of one-dimensional soil column frost heave tests were carried out under different experimental conditions. The soil temperature, Vertical pressure, frost heave volume and recharge volume. The experimental results show that when the temperature field is in a quasi-steady state, the frost heaving rate and the temperature gradient are directly proportional to each other, and the frost heaving rate decreases linearly with the vertical pressure increasing. Defining the specific freezing rate as the relationship between the freezing rate and the soil sample height When the temperature field is transient, the frost heaving rate increases exponentially with the freezing rate, and the growth rate decreases with the increase of the freezing rate. The calculation formula of frost heave considering the temperature gradient, the freezing rate, the vertical pressure and the height of soil sample is put forward. Based on this, the thermal diffusion equation of frozen soil considering water migration is deduced, and numerical simulation of frost heave and temperature variation is proposed Method, a numerical example is used to calculate the change of temperature and frost heaving volume during the freezing process. The reliability of the method is verified by comparison with the measured results.