Shear Localization in Granular Bodies with Micro-Polar Hypoplasticity

Abstract

This book presents numerical simulations of shear localization in granular materials using a hypoplastic constitutive model enhanced by a characteristic length of the micro-structure in the form of a mean grain diameter. Due to the presence of the characteristic length, the boundary value problems are well-posed, the numerical results are mesh-independent (load-displacement diagrams, spacing and thickness of shear zones), and a deterministic size effect related to the ratio between a mean grain diameter and specimen size is captured.

A comprehensive exposition of the hypoplastic constitutive equation and its extension within the framework of the micro-polar continuum are provided. Problems simulated include: plane strain compression, monotonic and cyclic shearing of an infinite long layer, direct and simple shearing, direct shearing along structure wall, sandpile, strip foundation and earth pressure. Some challenging problems are discussed, e.g. wall boundary conditions, non-coaxiality and stress-dilatancy rule, and textural anisotropy. Moreover, deterministic and statistical size effects are investigated.