Identification of a general poro-viscoelastic model of one-dimensional consolidating soft soil

A poro-viscoelastic model is useful for modeling a consolidating soft soil with intrinsic time-dependent effects. This paper presents a methodology for identifying (calibrating) the values of the parameters that go into a general linear poro-viscoelastic soil model. As part of the identification methodology, which is based around the familiar oedometer test, a semi-analytic solution of consolidation in an oedometer test has been developed. The methodology then involves using the levenburg-marquadt nonlinear regression technique to regress the model parameters by fitting the theoretical semi-analytic solutions to the measured oedometer test data. Although the methodology can be applied to any general poro-viscoelastic model, the paper uses the 3-element, 4-elelment and modified 4-element mechanical poro-viscoelastic models, all of which can potentially model the creeping soft soil, as examples to illustrate the identification methodology. The modified 4-element model has been found to give the best results.