Numerical simulation of rock mass blasting vibration using particle flow code and particle expansion loading algorithm

Abstract

In the numerical analysis of rock mass blasting using the particle expansion loading algorithm in the PFC method, the size of the blasting funnel is usually consistent with the experiment, but the blasting seismic wave produced is quite different from the reality. By reasonably determining the micro-parameters that affect the simulation effect of blasting vibration, the particle expansion loading algorithm can better simulate the actual situation of the blasting effect of the rock mass. The studied rock's density, uniaxial compressive strength, and elastic modulus are 2500 kg/m3, 80.1 MPa, and 65 GPa, respectively. Firstly, based on the theory of the PFC method and the law of energy conservation, the attenuation process of the seismic waves was controlled by the critical damping ratio and contact stiffness of the model. Then, the rock blasting numerical simulation is carried out using the particle expansion loading algorithm. The critical damping ratio mainly affects particle vibration's kinetic energy attenuation rate. At the same time, the contact stiffness can control both the peak velocity and the duration of blasting vibration. Finally, the field blasting experiment verifies the rationality of the quantitative relationship between the critical damping ratio and contact stiffness and the specific parameters of blasting seismic waves in the simulation of rock blasting vibration. It is verified that the particle expansion loading algorithm in the PFC method can not only simulate the blasting funnel forming well but also simulate the blasting vibration effect in the outlying area, which provides a more reliable numerical simulation method for the simulation of rock blasting.