A Novel Continuous-Discontinuous Multi-Field Numerical Model for Rock Blasting

Abstract

During blasting, rock failure is caused by blasting wave and explosive gas pressure, as a multi-field coupled process. Most numerical models focus on the effect of blasting wave where the gas pressure is commonly accounted for by empirical relations, ignoring the penetration and permeation of gas flow in cracks. This can underestimate the failure region. In this work, a novel multi-field model is developed in the framework of a continuous-discontinuous element method (CDEM), which is a coupled finite-discrete method with explicit integration strategy. The deformation and cracking of rock mass and the distribution of gas pressure are captured. The proposed method is verified by comparing the results to other results provided in published literature. Especially, by simulating the cases with blocked and unblocked blasting hole, we found that: (i) The fracture degree of the case with blocked blasting hole was 30% higher than that of the unblocked blasting hole. (ii) The radial main cracks in the fracture area are mainly caused by the explosive gas, and the tiny and dense cracks near the hole are induced by the explosion stress wave. (iii) The explosion crushing zone is mainly formed by the action of explosion stress wave, while the crack zone is formed by the combined action of the explosion stress wave and explosive gas. The proposed method provides a useful tool to properly simulate a rock blasting process.

Damage evolution law of multi-hole blasting igneous rock and quantitative evaluation model of damage degree based on fractal theory and clustering algorithm

“…Raina et al 5 introduced the blasting damage index to quantitatively describe the response mechanism of blasting damage degree of rock mass to structural plane spacing, dip angle, blasting hole depth, spacing, charge concentration and other factors. Li et al 6 adopted CDEM method to explore the influence of joint strength, stiffness and spacing on stress wave propagation and blasting effect. Miranda et al 7 analyzed the effect of rough or smooth joint characteristics on acoustic wave propagation through acoustic wave test experiments.…”