Field probe for measuring thermal resistivity of soils

Estimation of thermal resistivity of soils is normally done in the laboratory with the help of a laboratory thermal probe. However, as naturally occurring soils consist of various size fractions, ranging from clay to gravel, this probe cannot be used efficiently for measuring their thermal resistivity. This necessitates fabrication of a field probe that can be used to measure thermal resistivity of a soil either in its remolded state or under in situ conditions. With this in view, efforts were made to develop a field probe that works on the principle of the transient method and is a magnified version of the laboratory probe developed by Rao and Singh in 1999. The results obtained have been validated using the findings of Van Pelt in 1976 and Johansen in 1975 for gravels and crushed rocks.