THEORETICAL EARTH TEMPERATURE PROFILES FOR DIFFERENT SOILS AND SOIL CONDITIONS

Abstract

The annual temperature variations in earth with depth from the surface offers, by its natural characteristics, a phase lag and reduced variation in the maximum and minimum temperatures. The temperature profiles vary for different soils and soil conditions. Soil temperatures are found to be an explicit function of soil thermal properties, particularly the thermal diffusivity. The earth temperatures stabilize at certain depth, where the annual swings in temperature are negligible and this stabilizing depth varies for different soils. A simple first harmonic approximation method has been used to predict the temperature variations as a function of depth and time for different soils (ordinary light soil, heavy soil, organic soil and sand) and soil conditions (dry, damp and wet). The results are a helpful indicator for deciding external design temperatures for the design of earth sheltered or ground coupled spaces.