College of Construction Engineering��Jilin University��Changchun 130012��China

The authors presented a new measuring method of the soil thermal conductivity��the probe method�� which is designed and made based on the theory of line heat source�� This method is used to measure thermal conductivity of coarse sand��fine sand and silty clay in different water contents�� The results that measured by the probe method are well consistent with those of QTM- D 2 �� The soil thermal conductivity increases in different levels with the increase of the water content�� Compared the soil thermal conductivity measured by the probe method in laboratory with in- situ experiment��it shows that the measuring gap gradually increases with the in- crease of the depth�� The reason is that the in- situ measuring thermal conductivity can reflect the actual situation of the soil mass��