土体电阻率与导热系数的相关性实验研究

Experimental Study on Correlation between Soil Resistivity and Thermal Conductivity

将南京下蜀土与中砂以不同比例混合,配制了四种土样,利用室内四极法分别测试了每种土样在不同含水率条件下的电阻率,发现随含水率和黏土颗粒含量的增加,土体电阻率减小;同时,采用DRE导热系数测试仪测试了每个试样的导热系数,发现随含水率和砂含量的增高,导热系数增大。已有研究表明,土的电阻率与导热系数均与土体饱和度及孔隙率等物理性质有关。通过将土的电阻率与导热系数进行拟合,发现两者符合指数关系,并建立了表征电阻率与导热系数相关性的数学模型。该文研究结果为利用现场实测的电阻率指标间接求取土体的导热系数提供了依据。

Four different types of soil were made by mixing Nanjing Xiashu soil and fine sand in different proportions.The resistivity of soil with different water content was measured by four electrodes method.It was found that the resistivity of soil decreased with the increase of water content and clay content.Meanwhile,the thermal conductivity of soil samples was tested by DRE thermal conductivity apparatus,and it was found that the thermal conductivity increased with the increase of water content and sand content.It has been verified that the soil resistivity and thermal conductivity are related to the physical properties of soil,such as saturation and porosity,etc.By fitting the resistivity and thermal conductivity of the soil,a good exponential relationship was found.A mathematical model was established to characterize the correlation between resistivity and thermal conductivity.This study provides the basis for the indirect determination of the thermal conductivity of the soil by using the measured in-itu resistivity index.