Abstract The unloading of deep rock mass means energy redistribution. In the processes of energy release, dissipation and transfer,the volumetric deformation experiences elastic resilience and volumetric dilatation,and the shear deformation may experience pre-peak(elastic and internal frictional hardening stages) and post-peak (softening and residual failure stages) stages. In order to describe these characteristics,a new dynamic constitutive model to describe the whole deformation process is presented. The characteristics of this model can be summarized as follows:(1) Juamann derivative is employed to compute large deformations. (2) The elastic resilience and volumetric dilation with time are considered to establish the volumetric deformation constitutive relationship. (3) The enforcing process of strength and three coaxial conical surfaces(yield surface,peak strength surface and residual strength surface) are used to describe this evolution process. (4) According to physical mesomechanics,the lag time of fracturing which can present the contribution of different structural levels is employed to establish the rheological equation for hardening stages. (5) According to crack propagation theory,fracturing time to present the propagation and evolution of macrocracks is employed to establish the equation of strength evolution. Finally,deformation constitutive equation is given using theory of plastic flow. Secondary development of the model is operated in ABAQUS platform. With case studies of deformation and failure patterns of rocks excavation in deep tunnel,the prospective of this model to describe the mechanical behaviors of deep rock mass and its engineering applications are shown.
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Received: 05 November 2012
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