A method of utilizing cone penetration tests (CPTs) is presented which gives continuous profiles of both the in situ thermal conductivity and volumetric heat capacity, along with the in situ temperature, for the upper tens of meters of the ground. Correlations from standard CPT results (cone resistance, sleeve friction and pore pressure) are utilized for both thermal conductivity and volumetric heat capacity for saturated soil. These, in conjunction with point-wise thermal conductivity and in situ temperature results using a Thermal CPT (T-CPT), allow accurate continuous profiles to be derived. The CPT-based method is shown via a field investigation supported by laboratory tests to give accurate and robust results.

The Thermal Cone Penetration Test (T-CPT) records temperature dissipation during an interruption of the Cone Penetration Test (CPT) to determine the thermal properties of the ground, taking advantage of heat generated in the cone penetrometer during normal operation. This paper compares two interpretation models for thermal conductivity. It is found that the thermal conductivity can
be accurately determined. Care must be taken of the initial heat distribution and sensor location within the temperature cone to achieve accurate results. Furthermore, laboratory test data are presented that show that the full-displacement push of a penetrometer into sandy strata has limited influence on thermal conductivity values.