非饱和土热导率预估模型研究

Prediction model for thermal conductivity of unsaturated soil

非饱和土的导热系数是进行岩土工程中有关热现象分析的最基本参数之一。以土体结构三相体系的分布特征为基础,通过把热量在土中的传播方式类比为水在土中的渗流,概化出热量在土体内部传导的并联组合模型。推导出了非饱和土导热系数的数学模型,并对模型参数进行了分析。对于某类具体的土,孔隙率对其导热系数的影响非常剧烈,而饱和度的影响相对不显著。最后,对比分析了导热系数预估模型计算值与KD2导热系数测试仪所测得的数据,其误差范围最大值小于10%,结果表明预估模型能有效预测土体的热导率系数。

The thermal conductivity of unsaturated soil,one of the key parameters,is very important for analyzing the thermal phenomenon in geotechnical engineering.Based on the distribution features of three-phase system in soil,through analogy the heat propagation in the earth is regarded as the seepage in soil.A parallel combination model for heat conduction in the soil is generalized.A mathematical model for thermal conductivity of the unsaturated soil is derived,and the model parameters are analyzed.To some specific soil,the porosity has dramatical influence on the thermal conductivity,but the influence of saturation is not significant.Finally,by comparing the predicted value of thermal conductivity to the data measured by KD2 instrument,the maximum error range is less than 10%.The results show that the proposed model can be employed to predict the thermal conductivity of the soil.