一种考虑显热和潜热双重效应的冻土比热计算方法

Specific heat of frozen soil considering sensible and latent heat of pore water

对土在冻结过程中孔隙水的相态演变过程进行了分析,并在研究显热、潜热物理本质的基础上,将冻土进一步划分为冻结土和冻实土。根据潜热的物理意义指出,随土温从一般地温逐渐降低至较大负温,土的比热应该分段计算,即分为融土阶段、冻结阶段和冻实阶段。在融土阶段,孔隙水始终为液态;在冻结阶段,存在可以进一步冻结为冰的液态水;在冻实阶段,不再存在进一步可能冻结为冰的液态水。因此,冻结土的进一步降温将同时伴有显热释放和潜热释放。而在冻实土中,进一步的降温只伴有显热释放。在此基础上,基于混合物比热容的加权叠加法则,研究了冻土的比热构成,给出了涵盖潜热的冻土比热计算方法。

The phase change evolution of pore water was analyzed in the freezing process. Based on the mechanism of sensible heat and latent heat, the frozen soil was divided into freezing soil and stable frozen soil. According to the physical meaning of latent heat, the specific heat of soil should be stepwisely calculated, namely melting stage, freezing state and frozen state as the temperature gradually drops from a general temperature to a larger negative temperature. In the melting stage, the pore water is always in the liquid phase. In the freezing stage, existing liquid water can be frozen into ice. In the frozen state, there exists no liquid water can be frozen into ice. Thus, the cooling of freezing soil would be accompanied by releasing of sensible heat and latent heat. In frozen soil, the further cooling was accompanied by releasing of sensible heat. Then, based on the weighted superposition of specific heat capacity of mixture, the specific heat of the frozen soil is investigated. A method is developed for calculating the specific heat capacity of frozen soil with consideration of latent heat.