Analytical investigations on thermomechanical behavior of energy pile groups resting on stiff soil strata

Abstract

Abstract Energy piles are increasingly being exploited worldwide because of their dual role of exchanging heat with the ground and providing structural support for buildings. Despite the existing studies, simplified but reasonable methods for estimating the vertical displacement of end-bearing energy pile groups subjected to thermal loads are lacking. To address this challenge, an analytical approach was proposed to analyze the thermomechanical behavior of energy pile groups bearing stiff soil strata. To consider the reduction in soil displacement caused by the presence of a bearing layer, an approximate method where the energy piles comprising solid and mirror-image elements was introduced. The proposed approach was implemented using a self-developed program and validated against the results of existing numerical studies. The results indicated that the thermally induced displacement interaction between the predominant end-bearing piles was more pronounced than that between the floating piles. The displacement interaction decreases with decreasing shaft and base soil stiffness, increasing pile spacing, and decreasing pile slenderness ratio. In addition, a simplified method for estimating the displacement of energy pile groups resting on stiff soil strata was established by superimposing the interaction factor.