Model of rock blasting-induced damage considering integrity of rock mass and its application

The influences of the integrity of rock mass on blasting effects are not taken into account by the current models for rock blasting-induced damage. Based on the blasting-induced damage model proposed by R. Yang et al., an elastic-plastic constitutive model for blasting-induced damage and the corresponding criterion for determining the blasting influence zone of the surrounding rock, both of which consider the initial damage of rock, are suggested by connecting the initial damage with the initial values of integrity index and acoustic wave velocity of rock mass. This model can be used to consider the influence of the initial integrity of rock mass on the blasting damage effects by changing its initial integrity index. The constitutive model is introduced into software LS-DYNA for blasting simulation in line with practical engineering. The blasting-induced damage nephogram and the blasting influence zone are obtained. The blasting influence zones obtained respectively by the suggested model, the field tests and the conventional model-TCK are compared. In the end, for the maximum influence radius of blasting and the maximum influence depth of blasting, the relations between them with the initial integrity index of rock mass are analyzed. The results show that, for the maximum influence radius and the maximum influence depth, their values decrease with the decrement of the initial integrity index of rock mass while the change of the former is more remarkable than that of the latter. The proposed model considering the initial integrity of rock mass is rational. The results obtained by the suggested numerical model agree well with those from the field tests. The proposed model can provide references for theoretical research and engineering practice, in both of which the influences of integrity of rock mass on blasting excavation should be considered.