Application of a Cam–Clay model to overconsolidated clay

Abstract

SUMMARYThe yield locus governing the stress-strain response of a soil may degrade during rebound at high overconsolidation ratios. The cause can be attributed to a breakdown in bonding. A Cam-Clay model is applied to account for the degrading yield locus, and the influence of this degradation is assessed using a theoretical approach for friction pile capacity. Stress changes in the soil continuum due to pile installation and setup are simulated by cylindrical cavity expansion and radial consolidation, and a segment loading model is used to determine the effective stress change in the soil at peak load transfer under undrained conditions. The results indicate that plastic rebound affects peak load transfer to at least the same extent as shear strength.

Transitional Yielding Approach for Soils under General Loading

“…Clearly, within the context of monotonically expanding yield surfaces, the stressstrain behavior of normally consolidated soils alone can be described. In order to remedy this defect and to extend the generality of the constitutive models, several formulations have proposed continuous degradation or contraction of the original yield surface during unloading (1,4,6). Even these models have limited versatility.…”