Impact of temperature variations on at-rest earth pressures in unsaturated soils

The purpose of this study is to assess the impacts of temperature variations on at-rest earth pressures in unsaturated soils. Earth-retaining structures and piles are geotechnical structures that directly interact with surrounding soil, and their designs are significantly influenced by the earth pressures acting upon them. While the body of knowledge regarding the evaluation of earth pressures in unsaturated soils is substantial, emerging technologies in the field of energy geotechnics present new challenges that require thorough examination. The introduction of thermal loads into the soil through energy geostructures makes it crucial to expand the existing body of knowledge on earth pressures. To this end, a large-scale experiment was designed and conducted to evaluate the effects of temperature variations on at-rest earth pressures. The experiment was conducted in a large-scale pit with fixed walls, where the unsaturated backfill soil was heated using a system of embedded geothermal pipes connected to a temperature control unit. Following the application of heating, vertical and horizontal pressures were measured using pressure cells. The results indicate that increasing the temperature from 20°C to 60°C can significantly elevate both horizontal and vertical earth pressures, as well as the at-rest earth pressure coefficient.