PI: Muhannad Suleiman
University: Lehigh University
The goal of this project is to understand the effects of temperature changes and cycles on the soil-structure interaction (SSI) of laterally loaded energy piles installed in clayey soils. The use of thermal foundations (energy piles) has been growing to achieve the requirements of sustainable codes in different countries. Energy piles have an important advantage due to their dual capability of supporting structural loads and exchanging heat with the ground for heating and cooling of buildings and snow melting of bridges. During operation, the ground source heat pump (GSHP) connected to energy piles operates in cycles where it functions for a period of time (running time) then stops for another period of time (stoppage time). This intermittent operation subjects the piles and surrounding soil to temperature changes and cycles. If the soil temperature during stoppage time does not return to the original ground temperature, the soil will experience a cumulative increase of temperature with number of cycles. When installed in clays, this leads to accumulation of pore water pressure and reduction of soil shear strength and stiffness within the zone that affects the SSI of energy piles.

There have been several funded studies in the U.S. and abroad on energy piles, focusing on understanding their SSI behavior when subjected to vertical (or axial) loading. However, the behavior of laterally loaded energy piles has not been investigated. Accordingly, the goal of this research is to conduct a preliminary investigation on the behavior of energy piles subjected to lateral loading. This research will focus on performing preliminary small-scale lateral load tests on energy piles subjected to temperature changes.