A Phased Array Approach to Rock Blasting

Abstract

A series of laboratory-scale simultaneous two-hole shots was performed in a rock simulant (mortar) to record the shock wave interference patterns produced in the material. The purpose of the project as a whole was to evaluate the usefulness of phased array techniques of blast design, using new high-precision delay technology. Despite high-speed photography, however, we were unable to detect the passage of the shock waves through the samples to determine how well they matched the expected interaction geometry. The follow-up mine-scale tests were therefore not conducted. Nevertheless, pattern analysis of the vectors that would be formed by positive interference of the shockwaves from multiple charges in an ideal continuous, homogeneous, isotropic medium indicate the potential for powerful control of blast design, given precise characterization of the target rock mass.

Investigation of the Failure Response of Masonry Walls Subjected to Blast Loading Using Nonlinear Finite Element Analysis

“…The unilateral contact law, provided in Equations ( 1)-( 3) for a single degree of freedom system, is assigned in the interfaces between masonry blocks. Equation ( 1) is the nonpenetration relation, Equation (2) states that only compressive stresses (t n ) can be developed in the interfaces, and Equation ( 3) is the complementarity relation, stating that either contact takes place (u − g = 0, where u is a single degree of freedom and g is an initial gap) or separation in the interface occurs (t n = 0).…”

“…Blasting is used to fragment the rock overlying the coal seams in most mines. When the explosives are detonated, most of the energy is consumed in rock fragmentation [2]. According to [3], energy not used to break rock radiates out from the blast site in the form of ground vibrations and air blasts.…”