FEM Analysis and Simplified Approach for a Single Energy Pile Subjected to Thermomechanical Loads

The distribution of temperature in sand soils was measured through laboratory tests, and the temperature influence on friction resistances at the concrete-soil interface was analyzed. Based on the results of laboratory tests, the finite element model was established using the sequential thermal coupling method. The influences of temperature on the bearing characteristics of energy pile were analyzed. The analysis results show that the cyclic temperature will cause additional displacement along pile depth. It is pointed out that if applied vertical loads at energy pile head exceed the value from which nonlinear settlements would be initiated, irrecoverable additional settlement will occur at pile head. Based on the analysis results, a simplified approach was proposed to estimate the zero point of additional displacement along pile shaft and the additional axial pile force. The comparison between the calculated results obtained by the proposed method and that of ABAQUS on single energy pile was given to verify the accuracy of the proposed method. It is shown that reasonable predictions can be obtained without expensive and time-consuming analyses by the proposed method in this paper.