Development of a temperature and pressure controlled triaxial apparatus and dissociation tests of carbon dioxide hydrate containing soils

Abstract

Methane hydrates are viewed as not only a new energy resource but also a trigger of marine geohazard such as large deformations and landslides of seabed ground. Many researcher have showed that methane hydrate containing sand specimens become stronger than that of without hydrates, however, few study have been performed to investigate the mechanical properties subjected to the hydrate dissociation. The main purpose of our study is to investigate behaviors of the deformation associated with dissociation of the hydrates. In this study, we prepared carbon dioxide hydrate containing specimens and conducted a series of dissociation tests using a heating method under undrained conditions. These experiments require the high pressure and the low temperature conditions to form the carbon dioxide, and we have developed a new triaxial apparatus. The dissociation results indicates that even a small percentage of hydrate saturation produced the large pore gas pressure and the sequential reduction of the effective confining pressure due to the hydrate dissociation, and extensive strain was observed.