Journal Published Online: 05 January 2017
Volume 40, Issue 2

Protocol for Cohesionless Sample Preparation for Physical Experimentation

CODEN: GTJODJ

Abstract

Energy application during cohesionless soil sample preparation significantly influences behavior, strength characteristics, and repeatability, resulting in high degrees of epistemic uncertainty within laboratory testing and analyses. Relative density and void ratios have been used to compare materials and specimens in an attempt to address this uncertainty. However, the maximum void ratio of the material is often determined by wet or air pluviation, while the minimum void ratio is determined by vibratory compaction, yet actual sample preparation may use another method. Each method yields different soil fabric and behaviors unrelated to soil mechanics. The lack of standardized protocols for cohesionless sample preparation can result in numerous confrontational analyses, which are more likely an artifact of sample preparation techniques rather than intrinsic behavior. To accurately compare two materials, consideration must be made to the method by which the sample is made, and the normalization method use to account for variability in physical properties between the sample materials. The aim of this paper was to present (a) a standardized method for cohesionless sample preparation that will yield highly repeatable sample reconstitution; and (b) a means to normalize cohesionless materials, for multiple material comparisons, using first order controllable characteristics in laboratory testing. The protocol presented herein controls the three principle components of sample reconstitution: mass/type of material, quantity of water, and quantity/means of applied energy. All other properties are products of sample preparation. By controlling these components, high sample tolerances of increased repeatability can be readily achieved. To validate both, the sample repeatability and the normalization procedures a total of 203 laboratory tests were performed on two cohesionless sands: 25 compaction tests, 40 sensitivity tests, 45 triaxial, 32 simple shear, 30 hollow core, and 31 ring shear tests. The stress-strain and volumetric behaviors illustrate that sample repeatability and normalization are possible with this protocol.

Author Information

Taylor, O.-D.
Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS, US
Berry, W.
Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS, US
Winters, K.
Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS, US
Rowland, W.
Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS, US
Antwine, M.
Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS, US
Cunningham, A.
Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS, US
Pages: 18
Price: $25.00
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Stock #: GTJ20150220
ISSN: 0149-6115
DOI: 10.1520/GTJ20150220