非饱和正冻土一维水热耦合模型与试验

Modeling and experimental investigation of one dimension coupled moisture and heat in unsaturated freezing soil

利用Clapeyron方程来描述冻土内温度、冰压力和水压力的关系,根据质量守恒原理和能量守恒原理,建立一维非饱和冻土水热耦合模型。采用数值模拟和室内试验相结合的方法,对建立的水热模型进行检验。研究结果表明:随着冻结时间的增加,冻土的温度变化由剧烈转成平稳,最后沿高度线性分布;冻土段含水量增大,未冻土段含水量减小;在冰透镜体的存在的地方,孔隙比明显增大,含水量明显增大;模拟结果与实测结果较吻合,验证了该模型的正确性。

Clapeyron equation was applied in freezing soil to describe the relationship among temperature, water pressure and ice pressure when ice and water coexist in phase equilibrium. According to the mass and energy conservation principle, a mathematical model of coupled moisture and heat in unsaturated freezing soil was established. The methods of numerical simulation and indoor experiments were applied to verify the correctness of this model. Results show that as freezing time increases, temperature fluctuation tunas from being severe into smooth and the final temperature shows obvious linear distribution by height. Water content increases in frozen soil area, and decreases in unfrozen area. Wherever the ice lens body exists, void ratio tends to increase and water content increases substantially. The simulation results and measured results can match each other well and the effectiveness of this model is fully verified.