Numerical Modelling of Structural Response Characteristics of Energy Piles under Long-term coupled Thermo-Mechanical Loads

Abstract

The structural response and bearing capacity of energy piles under heating and cooling conditions are investigated using COMSOL finite element software, and the reasonableness of the numerical simulation results is confirmed using experimental data from TPT tests in Tianjin Binhai Lake; the performance of energy piles under long-term load in winter and summer is also investigated using steady-state simulation. The results show that the cooling pile has a greater influence on the pile’s axial load and axial strain, and that the settlement under thermal coupling is less than that of the pile in normal condition; in the steady-state simulation of the friction pile in long-term operation, the overall axial load under thermal condition is increasing compared to the pile subjected to structural load only, and that the settlement under thermal coupling is less than that of the pile in normal condition; the axial load on the upper portion of the pile is partially growing, while the axial load on the bottom part of the pile is greater than the force under structural stress alone, and the energy pile’s lateral frictional resistance is increasing. In the case of cooling, the lateral frictional resistance of the pile body shows a pattern of decreasing in the top portion and increasing in the lower part.