Effects of sand contents on mechanical characteristics of methane hydrate-bearing sediments in the permafrost

As a new resource, NGH (Natural gas hydrate) has aroused wide concern around the world, and it is instructive to use mechanics experimental technique to research the strength and deformation characteristics of hydrates and their sediments. In this research, firstly the triaxial compression tests had been conducted under various conditions, and the influence of sand contents on the mechanical characteristics of sediments containing methane hydrates was researched. The results showed that the stress-strain type was affected by quartz sand content, and the failure strength increased as sand content rose. The confining pressure, temperature and strain rate also had a remarkable influence on the failure strength of samples. Moreover, according to Mohr-Coulomb failure criterion, the mathematical relationships between the inner friction angle, the cohesion force and the sand content were also set up, and it was found that the inner friction angle was greatly changed by the sand content of the sediment matrices.