Triaxial Testing of Frozen Sand: Equipment and Example Results

Abstract

This paper describes a high-pressure, low-temperature triaxial testing system that has been specifically designed and built at the Massachusettes Institute of Technology in order to study the physical mechanisms controlling the strength-deformation behavior of frozen sands. The computer controlled system is capable of performing high-stress monotonic triaxial compression tests on specimens measuring D=3.6cm×H=7.6cm and incorporates advanced technology for temperature, strain rate, and loading control. One of the most important and unique features of the system is the technology used for the measurement of small axial strains that makes use of two miniature submersible linear variable differential transformers mounted on a pair of yokes that clamp to the specimen. A description of the specimen preparation equipment and triaxial testing techniques is presented to aid in developing standardized testing approaches, which are currently lacking in the literature. Representative test results on frozen Manchester fine sand are presented to demonstrate the capability of this system to accurately characterize the entire stress-strain and volumetric strain behavior in triaxial compression. Results are provided to illustrate the influence of relative density, confining pressure, strain rate, and temperature.