A Study on the Initiation of Discontinuities in Hypoplastic Granular Materials for Some Simple Motion Fields in Classical Continua

Some theoretical criteria are set forth to study the onset of a strong and/or a weak discontinuity in hypoplastic granular materials under some simple motion fields. The theoretical criteria were based on direct analysis, considering both kinematical and dynamical conditions necessary to be satisfied in order to make a discontinuity of either type possible. We mean by simple motion fields those motion fields that are typically observed in standard laboratory tests, including homogeneous motion fields. A series of comparisons with available experimental data have been made for a simple hypoplastic constitutive equation.