Research and application progress of energy underground structures

Energy geostructure refers to a type of structure equipped with heat exchange pipe in the building foundation element and the underground structure, which has the functions of load bearing and heat exchange. It not only effectively saves the valuable and irreversible underground space resources, but also makes full use of the non-carbon based continuous, stable, safe and clean geothermal energy resources, thus having more advantages than the traditional Ground Source Heat Pump (GSHP). Herein, the concept, advantages, research and application progress of energy geostructure at home and abroad were systematically summarized. Moreover, the current situation of four common energy geostructures, namely energy tunnel, energy pile (energy anchor), energy diaphragm wall and energy utility tunnel, were emphatically described. The combined construction of GSHP system and mining areas, such as the coal mine roadway, could not only make comprehensive use of geothermal energy resources, but also effectively solve the problems of high temperature hazard in traditional deep mining excavation, as well as heat preservation & anti-freezing of coal mine roadway in cold areas. Thus, it has the obvious advantages of environmental protection, low carbon, energy saving and high efficiency, and thereby becomes an effective way to achieve the green mine construction and the goals of “carbon peaking and carbon neutrality”, capable of producing significant economic, environmental and social benefits. However, the current research models of energy geostructures have their own applicability and limitation, with the main problems of large deviation between the research results and the actual working conditions, and few researches conducted on energy diaphragm wall and energy utility tunnel. In terms of research on energy geostructures, reference should be made to the actual engineering situations, and the influence of all factors on structural engineering should be considered as far as possible, so as to improve the accuracy and level of the research results. In addition, the feasibility and prospect of using energy geostructures in construction of coal mine roadway were discussed. On the basis of energy geostructures, it is also a good idea to try to build a composite energy utilization system by further integrating the non-carbon based clean energies, including the solar and wind energies. Meanwhile, the suggestions were given for the design of hazard prevention and mitigation of energy geostructures in view of earthquake resistance (reduction), explosion resistance and fire protection, which could provide reference for the research, application and development of energy geostructure and its application in green mine construction.