Geomaterials, geostructures and geosystems are subjected to continuous thermal perturbations. In the context of geoenergy exploitations that involve the harvesting or storage of thermal energy from or in the subsurface, these perturbations vary and last from seconds to decades. Complex and coupled phenomena are associated with the previous perturbations, such as heat transfer, mass transfer and deformation. These phenomena critically influence the equilibrium of geomaterials, geostructures and geosystems, controlling the effectiveness of geoenergy exploitations. For this reason, among others, the understanding of the effects of thermal perturbations on the equilibrium of the subsurface is paramount for science and engineering. This lecture presents a fundamental investigation of critical effects caused by thermal perturbations on the equilibrium (e.g., thermo-hydro-mechanical) of geomaterials, geostructures and geosystems. In this context, a focus is given to the effects of thermal perturbations associated with the harvesting of geothermal and waste thermal energy from the subsurface. Changes in the structure and properties of geomaterials caused by thermal perturbations that result from geothermal exploitations are analyzed. Variations in the undisturbed state of geostructures caused by thermal perturbations that derive from an integrated energy transfer role of such structures are expanded. Influences of thermal perturbations due to fluxes of waste thermal energy on the response of the subsurface of cities are investigated. Based on the results of this work, discoveries that can enhance the effectiveness of geoenergy exploitations are proposed, and opportunities related to these applications in meeting human activity needs are highlighted.
Dr. Alessandro Rotta Loria is an Assistant Professor at Northwestern University, USA, where he directs the Mechanics and Energy Laboratory within the Department of Civil and Environmental Engineering. Dr. Rotta Loria received his B.Sc. and M.Sc. degrees in Building Engineering from the Politecnico di Torino, Italy, while his Ph.D. degree in Mechanics from the Swiss Federal Institute of Technology in Lausanne, EPFL, Switzerland. His main research interests are at the interface of Geomechanics, Structural Mechanics and Energy, and are centered on the understanding of the multiphysical behavior of materials and structural systems. Dr. Rotta Loria is the co-author of the book entitled “Analysis and Design of Energy Geostructures” as well as of 20 research articles published in international scientific journals. He is an Editorial Associate of the international journal Geomechanics for Energy and the Environment, as well as the task force leader of the Academia-Industry Partnership for Innovation on Energy Geotechnics for the Technical Committee 308 of the International Society for Soil Mechanics and Geotechnical Engineering. Dr. Rotta Loria is the recipient of the 2019 Zeno Karl Schindler Foundation Award for the excellence of his scientific activities in the field of environmental sustainability. In 2020, he has been recognized the Bright Spark Lecture from the International Society for Soil Mechanics and Geotechnical Engineering.