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blocks that are in one of two states: “block – in the rock mass”, “block – separated from the
rock mass” [9].
The size of the simulation area is set based on possible dispersion of rock fragments separated from the rock mass. Elementary blocks which are not separated from the rock mass,
have a shape of a cube of the same size (Figure 2). Elementary blocks which are separated
from the rock mass, keep the mass and material composition but moving and increase the
volume due to loosening. To accelerate the calculations we give these blocks a spherical shape.
4 MODELLING OF THE BREAK LINE SURFACE IN THE CASE OF SHORTDELAY EXPLOSION OF BOREHOLE CHARGES
Blasting of a group of boreholes is modelled in accordance with their initiation scheme.
When modelling the blast of each subsequent borehole, changes in the free surface geometry
made by the blast of previously blown boreholes are taken into account.
The break line surface is formed as follows:
1. For a boundary block that simulates the rock mass surface, the sum vector of radial
stresses from spherical charges exploded by one delay is calculated.
2. If the module of the stress vector exceeds the ultimate value of the break line stress, all
blocks along the vector line from the boundary block to the charge axis are considered
Figure 2. Initial block model of the rock mass.
Figure 3. Wireframe model of an open pit sector, changed by the break line surface after the blast.
blocks that are in one of two states: “block – in the rock mass”, “block – separated from the
rock mass” [9].
The size of the simulation area is set based on possible dispersion of rock fragments separated from the rock mass. Elementary blocks which are not separated from the rock mass,
have a shape of a cube of the same size (Figure 2). Elementary blocks which are separated
from the rock mass, keep the mass and material composition but moving and increase the
volume due to loosening. To accelerate the calculations we give these blocks a spherical shape.
4 MODELLING OF THE BREAK LINE SURFACE IN THE CASE OF SHORTDELAY EXPLOSION OF BOREHOLE CHARGES
Blasting of a group of boreholes is modelled in accordance with their initiation scheme.
When modelling the blast of each subsequent borehole, changes in the free surface geometry
made by the blast of previously blown boreholes are taken into account.
The break line surface is formed as follows:
1. For a boundary block that simulates the rock mass surface, the sum vector of radial
stresses from spherical charges exploded by one delay is calculated.
2. If the module of the stress vector exceeds the ultimate value of the break line stress, all
blocks along the vector line from the boundary block to the charge axis are considered
Figure 2. Initial block model of the rock mass.
Figure 3. Wireframe model of an open pit sector, changed by the break line surface after the blast.