Thermomechanics for Geological, Civil Engineering and Geodynamic Applications: Rate-Dependent Critical State Line Models

Antoine B. Jacquey, & Klaus Regenauer-Lieb

Published August 23, 2021, SCEC Contribution #11709

Equilibrium thermodynamics has been of fundamental importance to many branches of engineering including cyclical mechanical applications. However, in geomechanics and geological applications it has not yet reached a consensus in the community. Reason for the failure of establishing thermodynamic laws as a ground principle is the far from equilibrium nature of geomechanical problems which prevent the local equilibrium assumption. Problems including rate-dependence and poromechanical complexity, where deformation often occurs in a highly localized manner, were therefore thought to be not amenable to a thermodynamic approach. Here we show that the theory of thermomechanics, originally proposed for quasi-static hyperplastic deformation problems can be extended to include rate-dependent critical state-line models for porous rocks. The development therefore makes thermodynamic-consistent modeling available for civil engineering, geological and even geodynamic problems. In this two-part contribution, we present extensions of the thermomechanics theory to account for the poromechanics of path- and rate-dependent critical state line models and we cover the relevance of this thermodynamic-consistent model for civil engineering, geological and geodynamic applications. In this first part, we review the concepts behind the thermomechanics theory and present a thermodynamic extension of generic critical state line models for visco-plasticity and damage mechanics and analyze the model prediction for strain localization.

Citation
Jacquey, A. B., & Regenauer-Lieb, K. (2021). Thermomechanics for Geological, Civil Engineering and Geodynamic Applications: Rate-Dependent Critical State Line Models. Rock Mechanics and Rock Engineering,. doi: 10.1007/s00603-021-02397-z.