Physical Mechanisms Controlling the Strength-Deformation Behavior of Frozen Sand: I

• Main Authors: Andersen, Glen R., Germaine, John T., Ladd, Charles C., Swan, Chris W.
• Other Authors: MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CIVIL ENGINEERING
• Format: Text
• Language: English
• Published: 1992
• Subjects: Soil Mechanics; Snow; Ice and Permafrost; *SAND; *ICE MECHANICS; *FROZEN SOILS; *SOIL TESTS; TEST AND EVALUATION; COMPRESSION; STRESS STRAIN RELATIONS; DENSITY; MEASUREMENT; TEMPERATURE; VOLUME; LOW TEMPERATURE; YIELD STRENGTH; BEHAVIOR; PRESSURE; ICE; SOILS; STRAIN RATE; STRENGTH(MECHANICS); SENSITIVITY; STRAIN(MECHANICS); FINES; SHEAR STRENGTH; HARDENING; MODELS; MATERIALS; COMPOSITE MATERIALS; DEFORMATION; MODULUS OF ELASTICITY; HIGH PRESSURE; COLD REGIONS; COMPRESSION TESTS; COMPRESSIVE STRENGTH; AXIAL LOADS; TRIAXIAL COMPRESSION; TRIAXIAL STRESSES; MANCHESTER FINE SAND; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA253903; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA253903

A high-pressure low-temperature triaxial compression testing system with on specimen axial strain measurements and lubricated end plattens was developed in order to measure the stress-strain-volume change behavior of frozen Manchester Fine Sand (MFS) from very small (0.01%) to very large (25%) axial strains. The main testing program was conducted at a temperature of T=-9.5 deg C and varied the relative density from 20 to 100%, the confining pressure from 0.1 to 10 MPa, and the strain rate from 0.000003/sec (slow) to 0.0004/sec (fast). These data show a constant Young's modulus that can be explained in terms of a composite materials model; provide the first detailed evaluation of the upper yield stress, which is essentially independent of sand density and confining pressure, and has a rate sensitivity similar to that of granular ice; and show that the peak strength generally increases linearly with sand density, increases nonlinearly with confinement, and has a rate sensitivity much less than granular ice. Initial tests at different temperatures indicate a larger temperature sensitivity than predicted for granular ice. A similar triaxial system was used to measure the stress-strain behavior of unfrozen MFS as a function of relative density and confining pressure. These data are used to evaluate Ladanyi's dilatancy-hardening model developed to predict the strength of frozen sand.