Please use this identifier to cite or link to this item: https://hdl.handle.net/11681/20814
Title: The influence of end restraint and method of consolidation on the drained triaxial compressive strength of crushed Napa basalt
Authors: United States. Assistant Secretary of the Army (R & D)
Al-Hussaini, Mosaid M.
Keywords: Napa basalt
Shear strength
Soil mechanics
Soil properties
Soil testing
Soil tests
Soil consolidation
Publisher: U.S. Army Engineer Waterways Experiment Station.
Engineer Research and Development Center (U.S.)
Description: Miscellaneous Paper
Summary: Tests were carried out on crushed Napa basalt in triaxial compression apparatus to examine the influence of boundary restraint and the method of consolidation (i.e., isotropic or Kš—ˆ consolidation) on the observed stress-strain, volume change, strength, and crushing of the grains. To accomplish this objective, new enlarged low-friction end platens for the triaxial compression apparatus and a special specimen former were designed and constructed. The Kš—ˆ consolidation phase of the test was conducted by using a special lateral strain sensor instrumented with strain gages and placed around the specimen. The lateral strain sensor is sensitive enough to detect any tendency for radial deformation during consolidation. Three test series were conducted in this study. In the first series, the specimens were consolidated isotropically, and regular rough end platens were used. Specimens of the second series were also consolidated isotropically, but enlarged low-friction end platens were employed. In the third test series the specimens were consolidated under Kš—ˆ conditions, and the enlarged low-friction end platens were used. The specimens of each series were prepared at two initial relative densities (70 and 100 percent) and sheared under drained conditions at consolidation pressures of 60, 125, 300, and 500 psi. The results show that, for the material tested, the effect of low end restraint is to increase the uniformity of radial strain on the boundaries and to increase the axial strain at failure, but it has no significant effect on either the strength or the volume change during shear. The results also indicate that specimens consolidated under Kš—ˆ show a slightly higher angle of internal friction and more crushing of the grains, but a lower initial tangent modulus than specimens consolidated isotropically. It is evident that more reliable information concerning strains, volume change, and stresses can be obtained by employing enlarged low-friction end platens than by using the regular rough end platens.
Rights: Approved for public release; distribution is unlimited.
URI: http://hdl.handle.net/11681/20814
Appears in Collections:Miscellaneous Paper

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