Creep Behavior of CO₂ Hydrate-Bearing Sand and Its Simulations by an Elasto-Viscoplastic Constitutive Model

Abstract

Recently, a possibility of a new technique of CO₂ storage in the ground, namely, CO₂ storage as hydrate, has been under discussion. In the present study, the mechanical behavior of CO₂ hydrate bearing sediments was investigated to provide the fundamental mechanical properties of CO₂ hydrate sediments. Especially, time dependent behavior was focused on and a series of undrained triaxial tests were conducted using high pressure and low temperature triaxial apparatus. From the results, it is found that hydrate-bearing sand specimen exhibits acceleration creep under undrained condition while sand specimen does not. In addition, an elasto-viscoplastic model considering the effect of hydrate saturation is adopted to reproduce the test results.