Examination of Soil Thermal Resistivity Distribution Pattern, Within a Gridded Zone.

Abstract

The essence of carrying out thermal resistivity survey is to measure the capacity of the ground to conduct or dissipate heat. However, most often, soil thermal resistivity are determined at a point or along straight line, where an electrical cable or a pipeline is to be laid; information regarding the thermal resistivity distribution of the adjoining soil materials and their effect are not often put into consideration. Hence, this research work is aim at examining the nature of soil thermal resistivity distribution pattern, within a specified location. The obtained results has shown that the rang of thermal resistivity at the survey area is between 0.075798824 ^oCm/W to 0.455356332 ^oCm/W. The generated 2D model was able to depict a very low thermal resistivity at the center of the model that stretched North South, that is flanked by region of high thermal resistivity in the west and relatively low thermal resistivity to the East, also stretching North South. The model result gave a clear indication that any heat generated by a pipeline or electrical cable placed within the center of the model will be more effectively dissipated toward the Eastern region with low thermal resistivity than the Western region with high thermal resistivity that will naturally resist the flow of  heat. The result has shown that this effect has to be put into cognizance during thermal resistivity measurement, because the effect could be catastrophic if the thermal resistivity of the adjoining soil, next to a thin layer of low thermal resistivity soil surrounding a pipeline or electrical cable goes beyond the optimum safety limit of 0.9 ^oCm/W. The one dimensional thermal resistivity graph extracted from the model along the straight line where the pipeline or electrical cable is to be laid only registered relatively low thermal resistivity values. It could not delineate the high thermal resistivity adjacent to the lowest thermal resistivity it measured. It was therefore concluded that 2D thermal resistivity measurement that will take into consideration the thermal resistivity distribution of the adjoining soil is a more effective tool for thermal resistivity measurement, than a one dimensional thermal resistivity measurement carried out on a single line or at a point.