Ground and Air Vibrations Caused by Surface Blasting. Volume 3. Computer Simulation Predictor of Ground Vibrations Induced by Blasting

摘要

A computer program was written to simulate ground vibrations induced by multiple-hole surface blasts. The program is an inexpensive and relatively easy to use tool for predicting the principal blast vibration characteristics that determine damage and annoyance potential: peak particle velocity, frequency content, and pulse duration. The program generates a complete ground motion history by superposing, at any surface position, the vibrations induced by each individual explosives charge. It requires specification of and allows accounting for the blast geometry, initiation sequence (including random delays), position with respect to blast, pulse characteristics induced by each charge, and propagation laws. A methodology is outlined to determine the necessary variables either on the basis of site investigations (velocity, attenuation, pulse), or by backcalculation from measured blast vibration records. The latter procedure was applied to blasts from two coal strip mines. It was determined that the main difficulties are backcalculating individual pulses, propagation (especially dispersion) parameters, and delays. It was shown that a normal distribution of delays influences the results and the response of a single degree of freedom structure significantly.