Modeling and Implementation of the Isotache Concept for Long-Term Consolidation Behavior: Fid-Bau Portal

Modeling and Implementation of the Isotache Concept for Long-Term Consolidation Behavior

Leroueil, Serge

AbstractA practical use of the isotache concept in creep settlement prediction is newly introduced in this study. The isotache concept introduces a unique relationship between the strain and the consolidation pressure corresponding to the strain rate in association with viscosity. The authors have proposed a method to simply introduce the isotache concept, which uses a compression curve normalized by preconsolidation pressure [ε–log(σ′/σp′)] and a strain rate dependency relationship between the preconsolidation pressure (σp′) and strain rate (ε˙=dε/dt). The strain rate dependency relationship is modeled as an equation based on power law. According to the authors’ method, the slope of the strain rate dependency relationship (log⁡σp′–logε˙), which coincides with Cαe/Cc, can be calculated as a function of strain rate, showing that Cαe/Cc is not constant but decreases with decreasing strain rate. In engineering practice, consolidation settlement is generally estimated based on the compression curve obtained from the 24-h incremental loading oedometer test, which corresponds to a strain rate of about 1×10−7 s−1. Using the compression index Cc at the consolidation pressure and initial void ratio e0, creep settlement can be easily calculated as a function of Cc/(1+e0) and in situ strain rate (several orders of magnitude smaller than 1×10−7 s−1).