Multi-scale non-local approach for geomaterials

A thermodynamically consistent multi-scale, rate dependent, non local approach is developed in this work for geo-materials in conjunction with the anisotropic modified Cam Clay model. The gradient for the micro-structure is incorporated through the micro level gradient of the back-stress and volumetric strain while the gradient for macrostructure is incorporated through the macro level gradient of back-stress and volumetric plastic strain. Gradient results in the regularization of the local behavior. Visco-plasticity is also incorporated for an additional regularization of the local behavior. Therefore, the effects of two separate regularizations are naturally separated. The plastic spin is incorporated to separate the effect of micro-structural rotation from the gradient effect. The flow characteristics of the soil is also incorporated in order to separate the viscosity effect from the flow effect. Through this multi scale non local approach, a more realistic simulation of large strain problems such as shear band formation can be achieved. (C) 2002 Elsevier Science Ltd. All rights reserved.