Strength behavior of methane hydrate bearing sand in undrained triaxial testing

Gas hydrates represent a potential future energy source as well as a considerable geohazard. In order to assess both the benefits and risks that gas hydrate bearing sediments pose, fundamental information about their physical properties is required. In this study, the undrained shear strength of methane hydrate bearing sand was investigated. The experimental program required modifications to an existing triaxial apparatus and accurate determination of the hydrate saturation lead to the use of two methods for comparison of the saturation calculations. Strength results indicated that the presence of gas hydrate will increase the sediment's undrained shear strength and corresponding stiffness. The relative contribution of cohesion and friction angle was observed to be a function of the hydrate saturation, for this particular hydrate formation methodology.

► A system was developed to maintain constant gas pressure during hydrate formation. ► Estimated hydrate contents, based on two different methods, are comparable. ► The presence of hydrate increases shear strength and stiffness of sand samples.