Incorporação de modelos elasto-plásticos ao método dos pontos materiais para simulação de problemas geomecânicos

Abstract

The study of soil and rock is an essential step to develop more economical and efficient structures in Civil Engineering. More specifically, geomechanical problems, i.e., problems involving the investigation of geomaterials (soil and rock), are addressed in Geomechanics, a subdiscipline within the geosciences that deals with Geology concepts associated with its mechanical behavior. Due to the high complexity involved in the analysis of geomechanical problems, as soil and rock properties present great variability, one tends to apply computational modelling and numerical methods to predict the behavior of structures, geomaterials and the interaction between them. Furthermore, as most of the geomechanical problems comprise large deformations, choosing a numerical method capable of simulating such behavior is crucial, such as the Material Point Method. The MPM is a numerical method created to solve problems concerning large deformations and history-dependent stress-strain relations, required features to simulate geomechanical problems from different fields, for instance, analysis of the formation of folds and faults (Structural Geology), wellbore stability (oil and gas industry) and slope stability (Civil Engineering). In addition, the relation between stresses and strains, named constitutive models, defines the mechanical behavior of materials during the simulations. Thus, one needs to choose an appropriate constitutive model as the mechanical response of the simulations in MPM is directly related to the established constitutive relations. This work presents the numerical implementation of elasto-plastic constitutive models, in which the behavior is initially linear elastic, with reversible deformations, and after a certain level of stress the material presents plastic behavior, where permanent deformations take place (aspects of a geomaterial). After the implementation of the models, this work presents the analysis of the results from simulations of Structural Geology applications. Initial Structural Geology concepts about the formation of folds related to contractional regimes (target of chosen applications) are presented, in which give support to the discussion of results. Moreover, comparisons of the effect of material properties, and the choice of constitutive model, on fold geometry are made, for each application.