Influences of thermo-mechanical properties of clay on mechanical responses of energy piles

Under the action of temperature variation induced by energy piles, the mechanical properties of soils surrounding the piles will be changed, thereby affecting their deformation, the stress of the pile-soil interface and the bearing capacity of the pile foundation. The ACMEG-T constitutive model for the thermal properties of soils is developed in ABAQUS commercial software. The accuracy of the program is verified by simulating the triaxial test results by using the UMAT subroutine. Based on the numerical simulation, the influence of thermo-mechanical properties of soils on the displacement of pile head, the stress of the pile-soil interface and the axial force of the energy piles in clay are studied. The results show that the change of soil temperature can lead to irretrievable settlement of soils, and further lead to negative skin friction on the pile shaft. The additional settlement and irreversible change of axial force of the energy piles can be induced by the negative skin friction. With the increase of the over-consolidation ratio of clay, the effects of thermo-mechanical properties of soils on the mechanical response of the energy piles decrease.