SEDL / STP / STP623-EB / STP26975S

Some Engineering Problems with Dispersive Clays

Sherard, JL
Consulting engineer, Devonshire

Dunnigan, LP
Head, Soil Mechanics Laboratory, Soil Conservation Service, Lincoln, Nebr.

Decker, RS
Senior soil engineer, Hoskins-Western-Sonderegger, Lincoln, Nebr.

Pages: 10    Published: Jan 1977

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Abstract

Laboratory tests show that filters containing some fine sand sizes (such as ASTM Specification for Concrete Aggregates (C 33-74a) concrete sand) will generally control piping and seal leaks through dispersive clay. The authors believe that it is reasonable practice to build major embankment dams with cores of dispersive clay with appropriate design details. Existing dams of dispersive clay which have given no trouble are not usually considered unsatisfactory structures. Piping of dispersive clay in dam foundations is believed generally unlikely below the depth where the clay is continuously saturated in nature. Some observations are given on the geologic origin, surface topography, and appearance (color) of deposits of dispersive soil. Damage to canals is described.