Abstract DEM (Distinct Element Method) models have found numerous applications in a number of engineering disciplines, such as material handling and transport, chemical, industrial, civil, mining and mineral processing. The thesis describes developments using PFC3D (Particle Flow Code in 3D) for simulating rock fragmentation by commercial explosives. Emphasis is on the realistic simulation of explosive detonation in the blasthole as well as the flow of explosive gas from the blasthole, through the fracture network and venting to the atmosphere. Detonation can be initialized at any point along discretized blastholes and proceed up or down the hole according to the Velocity of Detonation of the explosive. Each of the explosive properties (pressure, density, extent of reaction, energy and their time derivatives) is computed according to the conservation equations and the explosive equation of state at any point along the hole. At initiation, the product calculation begins at the sonic locus with input of the detonation product provided by the non-ideal detonation code Vixen-n. The Taylor wave is then computed as a function of the blasthole expansion, which depends on the rock mass response to loading. The explosive gas is treated as a non-steady, compressible fluid and can flow through an arbitrary and evolving fracture network developed in the rock mass as a function of explosive loading. The fracture network (and flow paths) is defined by the coalescence of discrete macro-cracks. The gas has the effect of draining the blasthole and loading the fracture surface by its pressure and drag forces. Fracture intersection with free-surfaces is monitored and venting to the atmosphere is allowed. Validation of the fluid flow scheme is performed by comparing numeric results to analytic solutions for flow in shock tubes. The complete model is demonstrated by simulating stress only models, gas flow models and complete models of field-scale blasts.
| Identifer | oai:union.ndltd.org:ADTP/254095 |
| Creators | Marc Robert Ruest |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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