Thermal Conductivity of Soils from the Analysis of Boring Logs

Recent interest in greener geothermal heating and cooling systems as well as developments in the quality assurance of cast-in-place concrete foundations has heightened the need for properly assessing thermal properties of soils. Therein, the ability of a soil to diffuse or absorb heat is dependent on the surrounding conditions (e.g. mineralogy, saturation, density, and insitu temperature). Prior to this work, the primary thermal properties (conductivity and heat capacity) had no correlation to commonly used soil exploration methods and therefore formed the focus of this thesis. Algorithms were developed in a spreadsheet platform that correlated input boring log information to thermal properties using known relationships between density, saturation, and thermal properties as well as more commonly used strength parameters from boring logs. Limited lab tests were conducted to become better acquainted with ASTM standards with the goal of proposing equipment for future development. Finally, sample thermal integrity profiles from cast-in-place foundations were used to demonstrate the usefulness of the developed algorithms. These examples highlighted both the strengths and weaknesses of present boring log data quality leaving room for and/or necessitating engineering judgment