Horizontal single hole blast testing – Part 1: Systematic measurements using TLS surveys

Abstract

Large scale Single Hole Blast (SHB) testing is used to characterize blasting behavior in a cost-effective manner. SHB testing provides the means to assess the effect of blasting specifications (e.g. burden dimension, explosive used, borehole diameter) on rock cratering and blast efficiency. The observed behavior depends significantly on the testing procedure and measurements recorded. Crater characteristics are commonly described by the displaced volume of rock and breakout shape. Analysis of SHB test results relies on reproducible measurements.This paper proposes a method for analysis of horizontal SHB tests using data collected via terrestrial laser scanning (TLS) surveys. The procedural algorithms, point cloud manipulations, and analysis facilitate systematic SHB testing, including the use of a reference axis aligned with the blasthole orientation. The definition of crater extents, absolute burden measurements, methods for crater slicing, and filtering are developed to maintain consistency with the plane strain assumption. Crater partitioning protocols are elaborated to enhanced details of captured data. A detailed workflow of the analysis is provided with examples from compiled field testing. The conventional SHB measurement approach for crater breakout angle is refined to account for superficial surface roughness, and to capture the full crater shape. Data captured for the craters is represented along the blasthole length to capture the plane-strain component of single blasthole cratering. Comprehensive results from full scale field experiments are presented in a companion paper.