If you would like to continue learning about thermal analysis, we recommend the resources below.

Do bad rho values lead to power failures? | Even in a well-designed underground cable system, the soil may account for half or more of the total thermal resistance. A safe, professional installation requires actual measurement and evaluation of thermal rho.

Thermal properties: Why the transient line heat source method outperforms other techniques | There’s no way to measure the properties of moist, porous materials with the steady state method (guarded hot plate). The transient line heat source method, however, is able to measure the thermal properties of moist, porous materials, and it can even measure thermal conductivity and thermal resistivity in fluids.

Thermal properties of stony soils: How to get the right answer in a soil/rock mix | Get the right thermal conductivity or thermal resistivity value for your soil profile. Find out how to combine rock and soil measurements.