Mechanical Properties of Natural Gas Hydrate Bearing Sediments Retrieved from Eastern Nankai Trough

摘要

MH21 research consortium of Japan conducted off-shore drillings to survey gas hydrate in Tokai-oki and Kumano-nada areas of Eastern Nankai Trough in early 2004 and recovered drill cores of gas hydrate bearing sediment successfully. Marine gas hydrate was confirmed mainly in sandy drill cores retrieved from mud and sand alternation strata. Tri-axial compression test on those core samples has been conducted to ascertain mechanical properties of natural hydrate bearing sediments for the first time. The results from the tests show that with increase in pore saturation of gas hydrate, shear strength and elastic modulus tend to arise, whereas no significant tendency was found in Poisson's ratio in relation to hydrate saturation.