Small-strain behavior of frozen sand in triaxial compression

Abstract

The stress–strain behavior of frozen Manchester fine sand has been measured in a high-pressure low-temperature triaxial compression testing system developed for this purpose. This system incorporates DC servomotor technology, lubricated end platens, and on-specimen axial strain devices. A parametric study has investigated the effects of changes in strain rate, confining pressure, sand density, and temperature on behavior for very small strains (0.001%) to very large (> 20%) axial strains. This paper presents constitutive behavior for strain levels up to 1%. On-specimen axial strain measurements enabled the identification of a distinct upper yield stress (knee on the stress–strain curve) and a study of the behavior in this region with a degree of precision not previously reported in the literature. The Young's modulus is independent of strain rate and temperature, increases slightly with sand density in a manner consistent with Counto's model for composite materials, and decreases slightly with confining pressure. In contrast, the upper yield stress is independent of sand density, slightly dependent on confining pressure (considered a second order effect), but is strongly dependent on strain rate and temperature in a fashion similar to that for polycrystalline ice. Key words : frozen sand, high-pressure triaxial compression, strain rate, temperature, modulus, yield stress.

Experimental Study on the Mechanical Properties of CH4 and CO2 Hydrate Remodeling Cores in Qilian Mountain

“…Additionally, a significantly continuous hardening tendency up to the end of testing for all of the hydrate-bearing sediments was shown out when the axial strain was more than 16%. Previous work has reported similar stress-strain behaviors for frozen soil and hydrate-bearing sediments [8,[26][27][28]. In addition, the effects of confining pressure on the stress-strain relationship of CH4 hydrate-bearing sediments were consistent with that of CO2 hydrate-bearing sediments.…”

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

“…The initial quasi‐elastic high‐stiffness region extends to an axial strain of ɛ a ≈ 1%, regardless of confining pressure. Ting et al [1983] and Andersen et al [1995] have reported similar stress‐strain behaviors for frozen water‐saturated sand specimens, and Parameswaran et al [1989] and Cameron et al [1990] show this relationship for sand containing THF hydrate. For our hydrate‐bearing specimens, the yield point may correspond to hydrate‐particle debonding or the local breakage of hydrate in the pore space, while the peak strength indicates the global structural collapse of the soil‐hydrate system.…”

Mechanical properties of seasonally frozen and permafrost soils at high strain rate

“…Zhu and Carbee (1984) carried out a uniaxial compression test program on remolded frozen Fairbanks silts under various deformation rates and studied the mechanical properties, including uniaxial compressive strength. Andersen et al (1995) discussed small-strain behavior of frozen sand in triaxial compression tests. More recently, Shelman et al (2014) conducted an experimental investigation to characterize the effects of freezing temperatures on mechanical properties for seismic design of foundations by using remolded soil specimens of five soil types.…”