00731162

Component

https://doi.org/10.3141/1548-08

http://scholar.google.com...dler&publication_year=1996

The hydrometer method is the standard method of grain size analysis used in geotechnical engineering. Although the hydrometer method provides accurate grain size distributions and is relatively easy to conduct, it takes a minimum of 2 days to complete and is subject to operator error. In studies where small-magnitude changes or more rapid results are required, an alternative method to hydrometer testing is to use an automated particle size analysis instrument employing X-ray absorption. This technique passes a finely collated X-ray beam through a suspension of settling particle in a fluid. Because the intensity of the X-ray is directly related to the percentage mass of soil in a suspension, Stokes' law can be used to calculate the grain size distribution of a soil assuming an equivalent particle diameter for the soil grains. X-ray absorption has been found to produce accurate grain size distributions in the 75 micrometer to 1 micrometer size range when sample preparation adheres to AASHTO T88-90 specifications and suspension concentrations are approximately 2% by volume. Testing for particles sizes down to 1 micrometer takes approximately 20 min per sample. Technical concerns remaining involve obtaining representative samples of the soil in the 75 micrometer to 1 micrometer size range suspension for testing. One method being evaluated is injection flow analysis, which is an inexpensive method of obtaining representative samples used with a variety of inorganic, industrial, and environmental materials in which direct sampling of fluid is required.

This paper appears in Transportation Research Record No. 1548, Small-Magnitude Measurements in Geotechnical Engineering.

English

p. 51-59

1996

Transportation Research Record

0309059178

Figures (7) ; Photos (1) ; References (10)

Accuracy; Grain size (Geology); Sampling; Sieve analysis; Soils; X rays

Geotechnology; Highways; I42: Soil Mechanics

TRIS, TRB

Feb 3 1997 12:00AM

• ANALYSIS OF METHODS USED IN TIME DOMAIN REFLECTOMETRY RESPONSE
• BEHAVIOR OF SHAFT-SAND INTERFACE FROM LOCAL MEASUREMENTS
• CHARACTERIZATION OF GRANULAR SYSTEMS BY DIGITAL SIGNAL PROCESSING OF LOW STRAIN WAVE RESPONSE
• CYCLIC SIMPLE SHEAR APPARATUS FOR LOW-STRAIN SOIL TESTS
• DEVELOPMENT OF CYCLIC TRIAXIAL APPARATUS WITH BROAD FREQUENCY AND STRAIN RANGES
• DISPLACEMENT DURING PROGRESSIVE FAILURE ESTIMATED FROM MICROSEISMIC ACTIVITY
• INSTRUMENTATION FOR LATERALLY LOADED MODEL PILES
• LOW STRAIN DYNAMIC SHEAR MODULUS OF CEMENTED SAND FROM CONE PENETRATION TEST RESULTS
• MEASUREMENT OF SOIL RESILIENT PROPERTIES USING NONCONTACTING PROXIMITY SENSORS
• MICRODEFORMATIONS IN SANDS BY DIGITAL IMAGE PROCESSING AND ANALYSIS
• RADIAL STRAIN MEASUREMENTS IN RESONANT COLUMN AND TORSIONAL SHEAR TESTS
• SMALL- AND HIGH-STRAIN MEASUREMENTS OF IN SITU SOIL PROPERTIES USING THE SEISMIC CONE PENETROMETER