A new constitutive model for blast damage

Abstract A simple new constitutive model for blast damage is presented to model rock damage resulting from impulsive loading from stress waves. In the model it is assumed that brittle failure of rock during blasting is controlled by extensional strain. The latter is used to distinguish brittle failure from plastic yield. The model covers the majority of rock failure modes observed in laboratory studies. Damage accumulation and loading rate-dependence are also included. The model has been implemented in a transient, dynamic finite element code by a user defined subroutine. In order to study blast induced damage and verify the blast damage model, experiments were conducted at the Queen's University (Kingston, Ontario) blast test site. Two single hole blast experiments were carried out using two different commercial explosives: an emulsion and a slurry. Blast damage was measured using seismic tomography, surface observations and borehole camera studies. The model was calibrated by reproducing the observed crater shape. Other model derived quantities (such as particle acceleration and degraded Young's modulus) were compared with field measurements and found to give realistic values. Prediction for a different explosive was also conducted and trends agree well with field observation.