Purpose This study aims to analyze the thermo-mechanical-diffusive response of a cylindrical tunnel subjected to thermal and concentration shocks. Design/methodology/approach A fractional-order dual-phase-lag (FDPL) thermoelastic diffusion model with strain relaxation is developed. The governing equations for temperature, concentration, chemical potential, displacement and stress are formulated in a cylindrical coordinate system. Laplace transform techniques combined with numerical inversion are employed to obtain time-dependent solutions. Findings The results indicate that the fractional order parameter controls the attenuation of temperature and concentration fields, with lower values causing slower decay and smoother stress and displacement responses. Thermal relaxation time reduces temperature gradients and weakens thermo-mechanical coupling, while strain relaxation predominantly influences stress and deformation fields. Thermal loading magnitude strongly affects the amplitude of all physical responses. Research limitations/implications The present analysis is limited to a homogeneous cylindrical tunnel embedded in single-phase soil under idealized thermal and concentration shocks. Future work may consider nonlinear material behavior, geological heterogeneity and experimental validation. Originality/value This work develops a coupled thermo-mechanical-diffusive formulation for a cylindrical tunnel under thermal and concentration shocks based on FDPL thermoelasticity with strain relaxation, providing insights into transient heat-mass transfer and stress evolution in tunnels under extreme thermal environments.
Peng et al. (Mon,) studied this question.