Investigation of Thermal Loading Effects on Behavior of Energy Piles Subjected to Lateral Loading

The operation of the ground source heat pumps (GSHPs) coupled with energy piles subjects the foundation and the surrounding soil to temperature changes and cycles, which affect the thermo-mechanical behavior of energy piles. The majority of the research presented in the literature focuses on the effects of temperature change on axial serviceability and resistance of energy piles. However, studies evaluating the effects of temperature change and cycles on the behavior of energy piles subjected to lateral loading are scarce. The behavior of soils surrounding energy piles is affected by temperature changes and cycles, soil volumetric change, thermally induced pore water pressure, and thermally induced water flow. Hence, it is anticipated that the thermo-mechanical soil-structure interaction of laterally loaded energy piles is affected by similar factors. This paper aims to assess the behavior of laterally loaded model energy piles subjected to thermal loading. An instrumented aluminum energy pile with diameter of 51 mm and an embedded length of 0.41 m installed in saturated moderately overconsolidated clayey soil was utilized in this study. The pile was instrumented with strain gauges and temperature sensors, and the surrounding soil was instrumented with temperature and pore water pressure sensors. The mechanical and thermal responses of a heating and a baseline (no temperature change) test are analyzed and compared in the current study. The experimental results indicate that the operation of the GSHPs connected to energy piles affects the soil strength and the soil-pile interaction behavior when the pile is subjected to lateral loading.