Effects of Drainage in Repeated Loading of Clays

An effective stress model for the response of saturated clay soils experiencing cyclic loading is described. Using undrained response as a basis, the influence of periodic drainage during the cyclic loading is illustrated and is quantified within the effective stress model. Behavior is separated for contractive and dilative soils. For contractive soils drainage results in volume decrease and eventual equilibrium under a particular constant level of cyclic loading. As a result of the drainage there is significant strength increase. Dilative soils increase in volume as a result of cyclic loading with drainage and there is a resulting decrease in strength. Stress changes, water content changes, and strength after cyclic loading are predictable using this model.