The use of fast Fourier transform techniques in blasting analysis

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:398365

Rholl, S A; Stagg, M S ^[1]

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1. Bureau of Mines, Minneapolis, MN (United States). Twin Cities Research Center

The US Bureau of Mines has developed computer software which uses fast Fourier transform (FFT) techniques to evaluate blasting data. The software is useful because it allows blasters to evaluate (1) the frequency content of ground vibration time history data; (2) the effects of initiator scatter on the frequency spectra of ground vibrations; and (3) the fragmentation distribution of rock muckpiles from photographs. A one-dimensional version of the software was used in the first two cases. Monte Carlo techniques were used to simulate the scatter of initiators. The results are shown in computer generated three-dimensional color contour plots. To determine the fragment size distribution using photographic and digital image processing techniques a two-dimensional FFT routine was written. The FFT of the digitized muckpile images are filtered to remove lower spatial frequencies. The higher spatial frequencies, which are associated with rock particle edges, are subsequently enhanced. The inverse two-dimensional FFT was used to reconstruct the digital image. Photographic images taken of rock muckpiles resulting from full scale blasts at a limestone quarry were digitized and evaluated using the new FFT techniques. The fragment size distributions determined from the photographs agree with the distributions determined by partial screening.

• OSTI ID: 398365
• Report Number(s): CONF-9502142--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
COMMINUTION
COMPUTER CALCULATIONS
EXPLOSIVE FRACTURING
FOURIER ANALYSIS
GROUND MOTION
ONE-DIMENSIONAL CALCULATIONS
PARTICLE SIZE
RESERVOIR ROCK
TWO-DIMENSIONAL CALCULATIONS