Abstract

Geothermal energy has emerged as a promising energy source in recent years for heating and cooling system of buildings using its foundations (e.g. piles, diaphragm walls). This presentation mainly focuses on energy piles, which serve not only as load bearing structures but also as energy exchangers. Although such piles are gaining popularity in recent years, their engineering behaviour under thermo-mechanical loads is still not clear and very few studies are available to-date. The main objective of this research it to investigate the behaviour of such piles by performing full-scale mechanical load test coupled with thermal loading (temperature cycles). Piles and the surrounding ground were instrumented to monitor strain and temperature. The applied load and movement at the pile head were also recorded. The impacts of heating /cooling cycles on the response of the test piles are described. In particular, forces mobilised in the piles shaft, resistance mobilised at the pile-soil interface have been inferred from the test response and discussed with respect to allowable concrete stresses and geotechnical factor of safety.

Key Words: Energy Piles, geothermal energy, thermo-mechanical load, shaft resistance