SEDL / STP / STP623-EB / STP26993S

Identification of Dispersive Clays in the Texas Gulf Coast Area

Marshall, AF
Senior project manager and geotechnical engineer, McClelland Engineers, Inc., Houston, Tex.

Workman, JP
Senior project manager and geotechnical engineer, McClelland Engineers, Inc., Houston, Tex.

Pages: 13    Published: Jan 1977

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Abstract

Laboratory testing was done to determine the dispersive characteristics of typical clay soils from two sites near Houston, Texas. The tests included (a) the crumb test, (b) the Soil Conservation Service Laboratory Dispersion Test, (c) chemical analysis of pore water, and (d) the pinhole test. The soils tested consisted of inorganic clay of low to medium plasticity (CL) and inorganic clay of high plasticity (CH) with plastic limits varying from 12 to 32, liquid limits varying from 26 to 99, and activity ratios of 0.7 to 1.3. With a few exceptions, each of the four types of tests showed good reproducibility. The pinhole test results were not affected by variations in compaction moisture content, from three points dry to three points wet of the plastic limit. The four types of tests were found to be in excellent agreement for nondispersive clays. Of the tests judged as dispersive on the basis of sodium content or percent dispersion from the SCS test or both, surprisingly few were dispersive in the pinhole test.