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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, B04106, doi:10.1029/2006JB004484, 2007

Mechanical properties of sand, silt, and clay containing tetrahydrofuran hydrate

T. S. Yun

School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA


J. C. Santamarina

School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA


C. Ruppel

School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA


Abstract

The mechanical behavior of hydrate-bearing sediments subjected to large strains has relevance for the stability of the seafloor and submarine slopes, drilling and coring operations, and the analysis of certain small-strain properties of these sediments (for example, seismic velocities). This study reports on the results of comprehensive axial compression triaxial tests conducted at up to 1 MPa confining pressure on sand, crushed silt, precipitated silt, and clay specimens with closely controlled concentrations of synthetic hydrate. The results show that the stress-strain behavior of hydrate-bearing sediments is a complex function of particle size, confining pressure, and hydrate concentration. The mechanical properties of hydrate-bearing sediments at low hydrate concentration (probably < 40% of pore space) appear to be determined by stress-dependent soil stiffness and strength. At high hydrate concentrations (>50% of pore space), the behavior becomes more independent of stress because the hydrates control both stiffness and strength and possibly the dilative tendency of sediments by effectively increasing interparticle coordination, cementing particles together, and filling the pore space. The cementation contribution to the shear strength of hydrate-bearing sediments decreases with increasing specific surface of soil minerals. The lower the effective confining stress, the greater the impact of hydrate formation on normalized strength.

Received 4 May 2006; accepted 27 December 2006; published 17 April 2007.

Keywords: Gas hydrate; sediment strength; elasticity; mechanical behavior; stiffness.

Index Terms: 3004 Marine Geology and Geophysics: Gas and hydrate systems; 5104 Physical Properties of Rocks: Fracture and flow; 3909 Mineral Physics: Elasticity and anelasticity; 1865 Hydrology: Soils (0486); 5422 Planetary Sciences: Solid Surface Planets: Ices.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 1042914 bytes)

Citation: Yun, T. S., J. C. Santamarina, and C. Ruppel (2007), Mechanical properties of sand, silt, and clay containing tetrahydrofuran hydrate, J. Geophys. Res., 112, B04106, doi:10.1029/2006JB004484.