Experimental and Numerical Study of the Thermo-Mechanical Behaviour of Energy Piles for Belgian Practice

The use of energy piles remains a topic of discussion in Belgian practice. The main concern is the lack of knowledge and documented experience with regard to the energy performance. Another issue is the potential impact of temperature changes and temperature cycles on the pile response (bearing capacity, settlements), in particular for piles with a relative small diameter. To address this challenge, an extensive full-scale test campaign on several types of energy piles has been set up. The energy piles are instrumented over their entire length with Fibre Bragg Grating (FBG) optical sensors and thermocouples. The tests aim at thermally characterizing the piles, as well as determining the combined thermo-mechanical behaviour. This paper presents an overview of the first, preliminary results of the test campaign and assesses the potential of a fully coupled analysis with the Finite Element Method (FEM) in Plaxis 2D software, showing a good agreement with the measurements.