Numerical analysis of energy piles under different boundary conditions and thermal loading cycles

¹ Assistant Professor, Civil Engineering Department, Sharif University of Technology, Tehran, Iran
² Graduate Student, Civil Engineering Department, Sharif University of Technology, Tehran, Iran
³ Associate Professor, Department of Structural Engineering, University of California San Diego, La Jolla, USA
⁴ Ph.D., Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado Boulder, Boulder, USA

^a Corresponding author: khosravi@sharif.edu

Abstract

The thermo- mechanical behavior of energy piles has been studied extensively in recent years. In the present study, a numerical model was adapted to study the effect of various parameters (e.g. heating/cooling temperature, head loading condition and soil stiffness) on the thermo-mechanical behavior of an energy pile installed in unsaturated sandstone. The results from the simulations were compared with measurements from a thermal response test on a prototype energy pile installed beneath a 1-story building at the US Air Force Academy (USAFA) in Colorado Springs, CO. A good agreement was achieved between the results obtained from the prototype and the numerical models. A parametric evaluation were also carried out which indicated the significance of the stiffness of the unsaturated sandstone and pile’s head loading condition on stress-strain response of the energy pile during heating/cooling cycles.