Innovative energy based coupled elastoplastic hybrid isotropic and anisotropic damage-healing formulations featuring consideration of the effect due to matric suction (the difference between pore air pressure and water pressure) for geomaterials have been systematically developed and implemented within the continuum damage mechanics framework and the RKPM meshfree codes for earth moving processes and simulations. A class of coupled elastoplastic constitutive damage-healing models, based on a continuum thermodynamic framework, is proposed within the energy-based (initial elastic strain energy and elastoplastic strain energy) formulations. In particular, the governing damage and healing evolutions are coupled and characterized through the effective stress concept in conjunction with the hypothesis of strain equivalence; and plastic flow is introduced by means of an additive split of the stress or/strain tensor for initial elastic strain energy/elastoplastic strain energy -based formulations. In these innovative formulations, two characteristic energy norms of the tensile and compressive strain tensors are introduced for the damage and healing mechanisms, respectively.;By incorporating a micromechanics-motivated brittle (tensile) damage characterization (P+) and a ductile (mixed tension-compression) damage-healing characterization, the proposed hybrid isotropic and anisotropic models and computational algorithms have been implemented to represent different soils (e.g., loose sands vs. cohesive clays). For the initial elastic strain energy based formulations, completely new computational algorithms are systematically developed based on the two-step operator splitting methodology, involving the elastic-damage-healing predictor and the plastic corrector. On the other hand, for elastoplastic energy based formulations, the three-step (elastic predictor, plastic corrector and damage-healing corrector) operator splitting methodology is developed for the corresponding computational algorithms. Several numerical examples of earth excavation, transportation, compaction and pushing are presented to illustrate the salient features and performance of the proposed coupled elastoplastic damage-healing models.;As pointed out by Ju (1990), scalar damage which implies that Poisson's ratio always remains constant is actually a special case of isotropic damage. The most general form of the fourth-order isotropic damage tensor can be composed into two parts featuring the volumetric and deviatoric parts. Innovative initial elastic strain energy based coupled two-parameter elastoplastic damage and healing formulations for geomaterials have been developed and implemented for 2-D earth moving processes. In particular, the governing incremental damage and healing evolutions are coupled in volumetric and deviatoric parts, respectively, and characterized through the effective stress concept in conjunction with the hypothesis of strain equivalence In this innovative formulation, four characteristic energy norms of the tensile volumetric, tensile deviatoric, compressive volumetric and compressive deviatoric strain tensors are introduced for the corresponding volumetric and deviatoric damage and healing mechanisms. Completely new computational algorithms are developed based on the two-step operator splitting methodology. The two-parameter elastic-damage-healing predictor and the plastic corrector are implemented within the continuum damage mechanics framework and the RKPM meshfree codes.;Due to the effect of matric suction on the behavior of partially saturated soils, a class of elastoplastic constitutive hybrid isotropic damage-healing model with the consideration of Bishop's effective stress and modification on soil plasticity model is also proposed within an initial elastic strain energy based formulation and implemented for 2-D earth pushing simulations.
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