Prediction of post-peak stress-strain behavior for sensitive clays

Abstract

Unlike typical soils, sensitive clays undergo extensive post-peak strength degradation with increasing strain and finally disintegrate into a remolded liquid state. Realization of post-peak stress-strain behavior of sensitive clay up to large strains is vital in assessing large deformation problems such as landslides and mud flows. The conventional experimental approaches are uncertain about accurately determining the post-peak stress curve up to large strains (>100%) owing to rapidly increasing testing problems at increasing strains. This necessitates the exploration of an alternative scientific approach to predict the complete stress-strain curve for sensitive clays, which is addressed in this paper. Post-peak stress-strain curves of sensitive clays for different sites are obtained by converting remolding index vs. strain energy curves. Using site-specific data from eastern Canada sites, a mathematical expression is proposed to predict the complete stress-strain curve. Subsequently, an equation is developed for predicting remolding energy based on the stress-strain curve. Finally, it is observed that the post-peak stress-strain behavior is highly site-specific and can be mathematically expressed with a combination of exponential and linear strain-softening curves. Overall, the knowledge of the complete stress-strain behavior contributes greatly to the prediction of post-failure movements closer to reality.