Analysis of constitutive models for peat under deviatoric loading

Abstract

The comprehensive assessment of the deviatoric behaviour in peats is paramount in ensuring the resilience of soil structures. The understanding of this material is riddled with intricacies, given its highly complex fabric, which includes organic matter such as fibers. This thesis evaluates the capabilities of a recent constitutive model (JMC) to adequately describe the response of peat by means of a flexible combination of constitutive ingredients, such as a non-associate flow rule and mixed volumetric and distortional hardening. The JMC model capabilities are tested with respect to laboratory and field data and compared against well-established models such as the NGI-ADP and Soft Soil (SS) model in a 3D FEM environment. The framework of reference is the measured response of the Bloemendalerpolder test, as it involves long-term consolidation, deviatoric behaviour, and soil-structure interaction. The results of this thesis demonstrate, that although the deformation pattern of the measurements is emulated effectively by the JMC and SS models, all the models show an overestimation of the lateral displacement compared to field data. Despite these limitations of the formulations and the modeling environment, the work shows the potential of the JMC model to reproduce reasonably deviatoric peat behaviour.