Analysis of spatiotemporal evolution characteristics of thermally-induced stress in pile foundations based on numerical modeling

Purpose To establish a 3D finite element thermo-mechanical coupling model, investigate the spatiotemporal evolution of temperature and thermally-induced stress in pile foundations post-concrete pouring, analyze influences of geometric and material parameters and provide a theoretical basis for engineering design and material selection. Design/methodology/approach A 3D finite element thermo-mechanical coupling model of the pile-surrounding rock system was established using Ckysts1.0 software. The model simulated the spatiotemporal evolution of temperature and thermally-induced stress in pile foundations over 60 days post-concrete pouring. Geometric (diameter and length) and material (elastic modulus and adiabatic temperature rise) parameters were varied to analyze their influences. Data from characteristic points were extracted, processed, and visualized to derive conclusions. Findings Pile concrete experiences temperature rise (peak 68? On day 10) followed by cooling. Stress transitions from compressive (max −5.35 MPa at peak temperature) to tensile (max 1.26 MPa on day 60), with maximum tensile stress at 2/3 pile radius. Larger pile diameter reduces thermal stress, while longer length increases it. Higher elastic modulus (surrounding rock/concrete) and adiabatic temperature rise amplify thermal stress. Originality/value This study innovatively establishes a 3D finite element thermo-mechanical coupling model of the pile-surrounding rock system, targeting the unique thermal stress challenges of slender deep-buried piles. It systematically clarifies thermal stress spatiotemporal evolution and quantifies key geometric/material parameter influences, filling relevant research gaps. The findings offer direct theoretical support for optimizing pile design and material selection, mitigating thermal cracking risks and improving structural safety.