This paper presents a kinematic approach for blast modeling with examples of a few blast models that were developed previously. A kinematic approach was adopted in these blasting models, which were applied successfully in field applications. A kinematic approach to blast modeling refers to using kinematic quantities such as the velocity, strain, or displacement as controlling parameters to model blasting phenomena, rather than using the stress- and material-constitutive relations.
The kinematic quantities are easier to measure in the field than stresses. The formulation of kinematic models using the kinematic quantities does not need to involve the rock stiffness or constitutive relations. It is well known that the constitutive relations for rock mass is very hard to obtain even for a simple linear problem and is even more difficult to define nonlinear relations in blasting. This is due to the complexity and inhomogeneity of rock mass properties. If the model is built based on first principles of physics, many parameters of the rock properties and explosive properties must be involved, which are hard or impossible to quantify. This creates a major impediment when trying to simulate the total process of blasting based upon first principles of physics.
The 3D kinematic model for muckpile formation was developed and applied as a useful tool to open pit blasts. The multiple blasthole fragmentation (MBF) model developed during recent years has been applied successfully to many mine sites around the globe. These models are typical examples of blast modeling using the kinematic approach, which avoids the difficulties of using rock constitutive relations and enables the models to catch major trends of blasting mechanisms and explicitly simulate full blast design parameters and complex geometries. Blast modeling using the kinematic approach results in easy model calibration and validation against field measurements and effective applications to practical problems. Using kinematic models of the muckpile formation and the MBF, this paper demonstrates the merits of a kinematic approach for blast modeling.
In addition, the paper briefly illustrates that the kinematic approach can also be applied to other geotechnical applications. If rock failure or damage criterion are established using kinematic quantities as controlling parameters, some geomechanics problems may be solved in a manner simpler than the current use of stress as a controlling parameter.