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THE FORMATION OF LABORATORY ANALOGUES OF NATURAL HYDRATE-BEARING FINE-GRAINED SOIL
Session: Laboratory Testing I / Essais en laboratoire I
William Smith, University of Calgary (Canada)
Jocelyn Grozic, University of Calgary (Canada)
Jeffrey Priest, University of Calgary (Canada)
Gas hydrates form in deep-water marine sediments, and have been suggested as being a geohazard when temperature or pressure changes result in hydrate dissociation, with fine-grained hydrate-bearing sediments posing the greatest potential risk. Recent drilling expeditions with improved sampling techniques have revealed that within fine-grained soils, hydrates form complex, sub-vertical veins. These veins are hypothesized to lead to an increase in the strength and stiffness of the hydrate-bearing soil. However, current understanding of the strength and deformation behaviour of hydrate-bearing sediments is limited to laboratory studies in which hydrate is formed within the pore space of sediments. This paper presents a detailed procedure in which vertical, cylindrical synthetic hydrate veins are formed within a consolidated laboratory-mixed fine-grained soil, and are then isotropically reconsolidated within a triaxial cell. Results indicate that hydrate veins remain intact throughout this process.
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