Key mechanical properties of hydrate bearing sediment: state of the art and prospects

Natural gas hydrates (NGH), as an exceptionally promising source of clean alternative energy, are widely stored in the seabed. Insufficient understanding of the mechanical behavior of hydrate-bearing sediments (HBS) may increase the risk probability of triggering geological disasters and threatening safe exploitation. The objective of this paper is to make a comprehensive review of the key mechanical characteristics of HBS. Firstly, the preparation technology of HBS samples, including in-situ sampling and indoor synthesis technology was introduced. Then, the compressive characteristics of HBS were systematically concentrated from experimental research, mechanism analysis, numerical simulation and mathematical model. It was followed by the summaries of static mechanical properties, including the current development of test equipment, typical shear behavior of HBS at different conditions, and the major influencing factors. In particular, the research progress of the dynamic mechanical properties of HBS was generalized mainly from two aspects of large or small strain conditions and numerical simulation. Finally, the summary of this review and the shortcomings of the current research, as well as the prospects were made and proposed. This review is expected to deepen the understanding of the mechanical behavior of HBS for subsequent researchers and provide reference for future exploitation.