Development of Pre-consolidation Pressure Dependence of Mixed Hardening Multisurface Hyperplasticity Model for Better Prediction of Earthquakes Ground Response Analysis Part I: Model Formulation

Abstract

It was known that soil behavior is dependent upon the history of loading and exhibits hardening behavior when deformed plastically. This paper presents a formulation of mixed hardening multisurface hyperplasticity model with stiffness factors of the kinematic hardening of the yield surfaces proportional to the pre-consolidation pressure to represent the history of loading. Formulation is emphasized for describing the cyclic loading behavior of clay soils. The advantages of this approach are that it can reproduce smooth transitions from elastic to plastic behavior and allows the stress-reversal history to be memorized by the internal variable function. The Modified Cam Clay yield function is selected as a key model to simulate the stress-strain response. The incremental stress–strain response is calculated based on a rate-dependent formulation. Finally, this paper describes the importance of development of the formulated soil model to improve current constitutive models for evaluating the effects of local soil conditions on earthquake ground response analysis. Further results of numerical implementation and simulations and also model verification employing the proposed mathematical model formulation will be reported in a future publication.

Keywords

• hyperplasticity
• mixed hardening
• pre-consolidation pressure
• ground response analysis