Application of a Thermodynamic Framework–Based Constitutive Model for Hydrate-Bearing Sediment Considering Grain Breakage and Stress History

Abstract

The physical cementation and grain breakage effects play a vital role in influencing the mechanical properties of hydrate-bearing sediment. In this study, a thermodynamic model for hydrate-bearing sediment considering stress history, grain breakage, and drainage condition is developed based on granular thermodynamic and critical state theory. The concept of breakage ratio is defined and incorporated into the critical state line to capture the grain breakage effect under a large range of confining pressures. To describe the structural effects induced by cementation and stress history, a new cementation degradation term and the structure factor of stress history are incorporating into the elastic potential function. By employing a rigorous parameter calibration approach, the theoretical model is applied and verified under various stress histories, hydrate saturations, and confining pressures, and a comparison is drawn between with/without considering grain breakage effect. The theoretical model, accounting for the grain breakage effect, demonstrates superior prediction accuracy and can reflect the inhibitory effect of hydrate saturation on grain breakage under high stress, as well as the strength and deformation characteristics under diverse drainage conditions and stress histories.