Numerical investigation of the development of the excavation damaged zone around a deep polymetallic ore mine

Abstract : This paper deals with the development of a non-linear constitutive model of a rock mass and its application to predict the extension of the excavation damaged zone (EDZ) around openings. A comparison of the model results with the simulations of triaxial compression tests shows a good agreement between predictions and theoretical values of peak and residual strengths as well as a good reproduction of the transition between brittle failure and ductile response. The relevance of the proposed model to evaluate the potential failure around stopes of the Garpenberg mine was examined. The comparison of the results proved satisfactory and highlighted the interest of considering a more realistic mechanical behavior of hard rock masses in rock engineering compared with the elastic perfectly plastic models generally used in numerical modeling of underground deep mines. Finally, a 3D simulation of the complete mine geometry was carried out in order to model the first phases of stope mining operations. The predicted stresses were compared with the continuous measurements of induced in situ stresses recorded by stress cells at different points around the stope. The predictions of the proposed constitutive model provided a much better agreement with stress measurements than those obtained with elastic perfectly plastic models.