Study on Thermophysical Properties in Shallow Ground

－Influence of Factors on Effective Thermal Diffusivities－

Abstract

The effective thermal diffusivities of shallow ground to a depth of 10 m was investigated by a heating method from 2015 to 2018. The measurement point was the College of Engineering, Nihon University in Koriyama city, Fukushima prefecture. The effective thermal diffusivities were from 0.42 mm²/s to 2.72 mm²/s. Precipitation and ground temperature were considered as factors affecting thermal diffusivities. The daily mean precipitation ranges from 1.9 mm to 3.3 mm, and the ground temperature ranges from 4.6 ℃ to 23.9 ℃. The regression analysis shows the effective thermal diffusivities deeper then depth 5 m depend on the aforementioned factors, and the correlation coefficient between the effective thermal diffusivities at each depth and precipitation was 0.63, while in the case of ground temperature it was 0.38. As a result, the effective thermal diffusivities deeper then depth 5 m are found to be influenced by precipitation.