Modified Computational Approach to Thermal Resistivity and Thermal Conductivity to Enhance Result Repeatability and Accuracy

Thermal resistivity or conductivity is a measure of the ability of soil material to conduct or dissipate heat from the source to the environment. Different soil types are characterized with their diverse thermal resistivity and conductivity values, which also indicate its ability to dissipate heat generated by a pipeline or electrical cable. The ranges of thermal resistivity values are so close that, slight change in temperature with the conventional method of computational could cause the result to differ appreciably, which could lead to wrong interpretation. Hence, this research work is aimed at developing a new computational approach that will improve thermal resistivity result accuracy and repeatability. The method employed in data acquisition involves measuring temperature changes due to heat source as a function of time. The new computational approach results revealed wide differences that exist between range of thermal resistivities determined through stepwise technique, of which if any of these individual value is adopted as the actual thermal resistivity result, as it is always the case in conventional approach, it could lead to erroneous result. The result also exposed the fact that the thermal resistivity and conductivity results determined with modified computational approach showed a high level of consistency and accuracy that was conveniently tied to the soil lithological composition at that depth. The conventional method of computation registered a high level of disparity and inconsistency in values, that could not be tied to any lithological composition, or effectively be used to for soil classification, for safety purpose. The first two digits in thermal resistivity values, by which thermal resistivity is mainly reported, showed a high level of uniformity at both survey points, which are clear indication of high repeatability in the thermal resistivity results. The statistical analysis carried out on the thermal resistivity results determined with modified computational approach had the least standard deviation from the mean compared to the conventional techniques. It is a clearly evident that the modified computational approach is a better and effective technique for obtaining more accurate and reliable thermal resistivity results with high level of repeatability.