American Society of Civil Engineers

Low-Stress Dilation Test

by Bobby O. Hardin, F.ASCE, (Prof. of Civ. Engrg., Univ. of Kentucky, Lexington, KY 40503)

Journal of Geotechnical Engineering, Vol. 115, No. 6, June 1989, pp. 769-787, (doi:

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Document type: Journal Paper
Abstract: A new test to measure the low-stress dilation behavior of cohesionless soils subjected to plane strain has been developed. Very large strains (30–35%) have been applied to sand specimens while approximately maintaining the parallelopiped shape of the specimen. A small version of the apparatus designed to test sands is described. However, it should be relatively easy to construct larger devices with the potential for testing rockfill-like materials. A model approximating the effect of initial density on dilation behavior is presented that suggests a method for defining and measuring index void ratios that are intrinsically related to dilation behavior. The ultimate constant volumetric strain void ratio for low-stress plane strain was found to vary with the initial void ratio of the specimen. The effect of fabric anisotropy on dilation behavior has been studied and modeled. A dilation test on sand-cement shows that contact cohesion increases the rate of dilation of a loose sand to the rate expected for an uncemented dense sand.

ASCE Subject Headings:
Equipment and machinery
Plane strain