A laboratory testing program for predicting undrained excess pore pressures beneath embankments constructed on sensitive clays is reported. A study of the pore pressure response, based on Henkel's equation applied to triaxial and plane strain tests performed on marine clay from South Gloucester, Ontario, provides a basis for comparing behaviour under conditions of axisymmetry and plane strain. Comparison shows that (1) pore pressure is smaller in plane strain than in axisymmetric conditions; (2) a below-elastic response prevails at the prepeak stage of the stress-strain curve; and (3) there is an elastic response at the peak. Finite element and modified elastic methods are developed for estimating undrained excess pore-water pressures from laboratory test results. The estimated values are used to evaluate the effect of consolidation under the center of an embankment during construction. The procedure is illustrated with case records.
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