Numerical Simulation Research on Multi-field Coupling of Underground Energy Pile

Abstract The bearing capacity of the pile foundation determines the safety and stability of the upper structure. However, during the thermal cycling of the energy pile, the stress of the pile will be changed due to temperature changes., which will affect the bearing capacity of the energy pile foundation. In order to analyze the mechanical properties of the energy pile under multi-field coupling, the finite element software COMSOL Multiphysics is used to establish the thermal-mechanical coupling analysis model of the energy pile. We apply thermal load on the pile body and vertical load on the top of the pile. The results show that: Under the multi-field coupling of temperature and mechanical load, the energy pile body expands when heated, and the displacement of the pile top decreases; this will cause uneven settlement between the energy pile foundation laying the heat exchange tube and other pile foundations, which will lead to the tilt and damage of the superstructure; the stress of the pile during the heating of the energy pile will increase.