Rock burst analysis using DDA numerical simulation

A rock burst can cause a serious disaster. For the mitigation of rock burst-induced disaster, the possibility assessment of a rock burst for an underground excavation is a key undertaking and also a great challenge because rock burst failure involves a dynamic and large deformation process. In this paper, a numerical simulation method of rock burst using discontinuous deformation analysis (DDA) is proposed by showing the advantage of DDA in handling the large deformation of this dynamic process. First, the problem of using the number of the adjacent boundary in the original algorithm of the DDA program was determined and solved, which is critical and important in analyzing artificial mesh models. The DDA model was used for simulating a rock burst process and was verified by a true triaxial test in which the critical stress for rock burst had been clarified. Then, the effects of rock hardness and brittleness on critical stresses were clarified quantitatively. The critical stresses of a rock burst were estimated for rocks with various values of the elastic modulus, Poisson's ratio, cohesion, friction angle, and tension strength. Finally, a strategy is proposed for examining the critical depth of a rock burst for various types of rocks under different tectonic levels. Rocks are classified by the mechanical properties of them, such as elastic modulus, Poisson's ratio, cohesion, friction angle, and tensile strength. The depth condition was converted to initial stress. The tectonic condition was represented by the ratio of horizontal-to-vertical components of the initial stress. Through a large set of simulations, the critical depths of rock bursts in seven types of rocks were estimated for different tectonic levels. The results show that the proposed rock burst analysis using DDA simulation is effective and useful.