Accession Number : ADA193021

Title :   Rate Effects in Shear for Cares-Dry Soil.

Descriptive Note : Final rept.,

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS STRUCTURES LAB

Personal Author(s) : Carroll, William F

PDF Url : ADA193021

Report Date : Feb 1988

Pagination or Media Count : 62

Abstract : Thirty-six individual specimens of CARES-Dry soil were tested in the fast triaxial shear device (FTRXD) at three confining pressures and at six test velocities. The slowest were static, unconsolidated, undrained triaxial tests. The fastest (9.0 ips) were the fastest that could be obtained while maintaining constant deformation velocity. The FTRXD performed well. Load and displacement as a function of time were measured accurately. Constant velocities were achieved. Procedures developed to prepare specimens, mount them in the FTRXD, and assemble and operate the FTRXD were reasonably efficient. The new upper load cell was accurate, durable, and easy to use. During this test series, discrepancies between the upper and lower load cells were essentially eliminated. Neither the dynamics of the FTRXD nor specimen inertia influenced the test results noticeably, despite the fact that some specimens were brought to failure in 2 to 3 msec. In the fastest tests, a small lag in the response of the lower load cell occurred, the time it took for a disturbance at the top of the specimen to propagate to the bottom. Thus using faster test velocities or longer test specimens will require that specimen inertia be taken into account. The FTRXD permits assessing rate effects of soils subjected to triaxial shear throughout meaningful ranges of principal stress difference and nominal axial strain. During deformation, the CARES-Dry soil appeared to pass through three behavior modes: initial grain structure response, grain structure collapse, and plastic shear failure.

Descriptors :   *SOIL MECHANICS, *EXPLOSION EFFECTS, *SHEAR STRESSES, *CRATERING, COLLAPSE, DEFORMATION, DELAY, DISPLACEMENT, FAILURE(MECHANICS), GRAIN STRUCTURES(METALLURGY), INERTIA, LOAD CELLS, PLASTIC PROPERTIES, PRESSURE, RATES, SHEAR PROPERTIES, SOILS, STRUCTURAL RESPONSE, NUCLEAR EXPLOSION SIMULATION, DRY MATERIALS, MOISTURE CONTENT

Subject Categories : Soil Mechanics
      Explosions

Distribution Statement : APPROVED FOR PUBLIC RELEASE