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目前国际上对于高温下土壤的完整热导率数据极其缺乏,通过KD2 Pro测试了粉砂质黏壤土和细砂在较宽广温度(5℃～88℃)和含水率范围内的热导率。测试结果表明,由于水蒸气的凝结和蒸发产生的潜热传输效应,在88℃下热导率最高可达5℃时的3～4倍,热导率随含水率的变化存在明显的临界含水率(依赖于颗粒组成)。对基于de Vries假设的de V-1和Campbell理论模型的验证和对比表明,参考文献中的一些参数及其获取方法的适用性需要改进,修正后的模型基本能较好地预测不同温度下热导率的变化(RMSE<30%),且温度越接近40℃误差越小,粉砂质黏壤土在高温下(58℃～88℃)的θAWC～θPWP区间建议乘以传质增强因子ζ(ζ=2.5)。模型均较为复杂,有待于在此基础上进一步建立易用的经验性模型。
At present, there is an extremely lack of complete thermal conductivity data for soils under high temperature. The thermal conductivity of silty clay and sand over a wide range of temperature (5 ° C to 88 ° C) and moisture content is tested by KD2 Pro. The test results show that due to the latent heat transfer effect caused by water vapor condensation and evaporation, the thermal conductivity at 88 ℃ is up to 3 ~ 4 times higher than that at 5 ℃. The thermal conductivity with the change of water content has obvious critical moisture content (Depending on the particle composition). The verification and comparison of the de V-1 and Campbell theoretical models based on the de Vries hypothesis show that some parameters in the reference and their applicability need to be improved. The revised model can basically predict the heat loss under different temperatures (RMSE <30%). The closer the temperature is to 40 ° C, the smaller the error is. In the θAWC ~ θPWP interval of silty clay loam at high temperature (58 ℃ ~ 88 ℃), it is suggested to multiply the mass transfer enhancement factor ζ ζ = 2.5). Models are more complex, subject to further build on this basis easy to use empirical model.