关键词: 深海能源土, 本构模型, 水合物饱和度

Abstract: Methane hydrate (MH) is usually formed in marine deposit under specific temperature and pressure conditions. MH can enhance the shear strength of its bearing sediments due to bonding effect. Based on the framework of damage mechanics, the structured sand constitutive model is employed to simulate the mechanical behavior of methane hydrate bearing sediments. By simulating the consolidated drained triaxial compression tests, a quantitative relationship between the initial yield parameter and the methane hydrate saturation is developed according to the stress-strain relationship. The primary damage law is modified to develop an elasto-plastic constitutive model for methane hydrate bearing sediments. Furthermore, another set of triaxial tests and isotropic compression test on methane hydrate bearing sediments are simulated by the established model. Results show that this elasto-plastic constitutive model can effectively describe the relationship between the mechanical behavior of methane hydrate bearing sediments and the methane hydrate saturation. When methane hydrate saturation increases, the peak shear stress and the secant modulus increase in the triaxial tests, and the yielding stress under isotropic path increases along isotropic compression path.

Key words: methane hydrate bearing sediments, constitutive model, saturation of hydrate