Effects of fines on triaxial shear behavior of methane hydrate bearing sands

Abstract

Recently there has been much research into Methane Hydrate (referred to as MH hereafter) as a developable material in the deep seabed in Nankai Trough. In this study, specimens were prepared to simulate the sediments in Nankai Trough, and a series of triaxial tests were performed on samples with varying density and fines content Fc of 0%, 8.9% and 25%. MH was produced with almost 30 and 50% MH saturation in the specimens. The apparatus can simulate the deep sea-bed environment. From the results of only the host sands, it was found that as the fines content increased, stiffness decreased and the volumetric strain increased. In the case of MH bearing sand however, an increase in fines content tended to lead to an increase in stiffness and maximum axial deviator stress, with positive dilative behavior occurring during shearing.