Analysis of dynamic THM response in multilayered marine sediments considering nonlocal effects and imperfect thermal contact conditions

Imperfect thermal contact phenomena may occur when fluid or air in voids impedes heat transfer across soil interfaces, thus causing thermal resistance. To explore the coupled impacts of this resistance and non-local dynamics in layered marine sediments, this paper establishes a non-local thermo-hydro-mechanical (THM) model incorporating three imperfect thermal contact models to simulate the heat flux concentration at layer interfaces. Analytical expressions for multi-field variables are derived and verified against prior findings. The influence of non-local parameters, thermal resistance coefficients and interfacial contact coefficients on the dynamic response is further explored. The results show that: non-local effects are negligible at low frequency but significantly attenuate peak pore water pressure and stress at 100 and 500 Hz due to spatial energy dispersion. Furthermore, enhanced thermal contact resistance triggers thermoelastic wave reflection. When RT reaches 1010, it effectively obstructs heat transfer, shifting the response from thermally driven expansion to an inertia-dominated mechanical state; Increasing the partition contact coefficient ηT enhances energy dissipation through high-frequency wave scattering. Comparative analysis reveals that neglecting the effects of thermal resistance and non-local parameters may lead to inaccuracies in predicting dynamic behavior of marine sediments under extreme THM environments.