the effects of base-only-restrained and both-ends-restrained conditions on the ultimate bearing capacity of energy piles using physical modeling

Today, ground-source heat pumps (gshp) are one of the most efficient solutions to reduce energy consumption. utilizing energy piles as a kind of energy geostructure can enhance the cost-effectiveness of projects incorporating gshp systems. in this study, the ultimate bearing capacity of an energy pile was compared in the two general base-only-restrained and both-ends-restrained conditions. for each of these two conditions, the relative densities of 48% and 85% and the temperature changes of δt= 17 °c and δt= 30 °c were regarded as variables. during the test, the soil and pile temperatures, the pile head, the pile tip displacements, and the thermomechanical strains in a pile were recorded. these parameters are used for calculating the temperature profile, thermal stresses of the pile, side shear stresses, and the ultimate bearing capacity of the pile. the results showed that the increase in relative density and temperature led to an increase in thermal stress and ultimate bearing capacity. the minimum ubc increase was obtained for the base-only-restrained condition with a relative density of 48% and δt= 17 °c, which was about 10%, while the maximum increase of 21% was obtained for the both-ends-restrained condition with a relative density of 85% and δt= 30 °c.