Mechanical properties of gas hydrate-bearing sediments: Research progress, challenges and perspectives

We provide a comprehensive overview and summarizes the recent advances in the mechanical properties of hydrate-bearing sediments (HBS) from three aspects: experimental investigation, numerical simulation, and constitutive model. Mechanical properties and microscopic mechanisms under the influence of multiple factors are expounded in depth. The results show that hydrate saturation and confining pressure are the most significant factors affecting the mechanical behavior of HBS, and the effects of various factors are different and coupled. The essence of macroscopic mechanical properties is the evolution of microscopic particle relationships. Numerical simulation is an important means to study cross-scale mechanical behavior. The constitutive model is typified by the elastoplastic model based on critical state theory. Further, the challenges facing current research are discussed, and the solutions and development directions are clarified. In the future, the focus should be on the crossscale unification of micro (atomic and crystal scales), meso (particle scale) to macro (sample and reservoir scales), also including the study of non-homogeneous fracture-filling hydrate. Meanwhile, there is an urgent need to establish unified industry standards and a global database to accelerate academic exchanges and sharing of achievements.