Method for forecasting of surface facilities vibrations reasoned by impulse action of air shock waves

One of the safety concerns in blasting is the adverse effect of air shocks on surface facilities. The dynamic impact of air shocks is conventionally predicted using empirical laws of excessive air pressure and software systems of engineering analysis. This article considers the improved accuracy prediction procedure of dynamic impact of air shocks through experimental determination of a set of free vibrational modes of a guarded facility. The procedure uses the differential equations of dying oscillations under the action of disturbing force. The general solution for vibration velocity is found as a linear superposition of vibrational modes. After loss of effect of the disturbing force, the solution for the vibrational mode is approximated by the equation of dying oscillation. The procedure was trialed in the study of the effect exerted by air shocks from ammunition disposal by blasting on a dwelling house. The curves of air shocks and the house roof particle velocity were plotted using records of seismic station Blastmate III. Modeling of radial particle velocity is carried out for modes 1–9. Parameters of the building vibrations were determined from the best agreement between the modeling and experimental curves of particle velocity. The measuring errors of amplitude and frequency of vibrational modes are determined. The identified free dying oscillations of the building allow predicting maximum value of peak particle velocity. It is found that in the single-mode presentation of particle velocity, the value of the subsidence ratio is twice as large as the same parameter in the multi-mode presentation. As the peak pressure of air shocks increases, the low-frequency components dominate the set of vibrational modes. Under small peak excess pressure of air shocks, the frequencies of vibrational modes of the building mostly obey the normal distribution law.

Kholodilov A. N., Vinogradov Yu. I. Method for forecasting of surface facilities vibrations reasoned by impulse action of air shock waves. MIAB. Mining Inf. Anal. Bull. 2021;(2):55-63. [In Russ]. DOI: 10.25018/02361493-2021-2-0-55-63.

A.N. Kholodilov, Cand. Sci. (Phys. Mathem.), Assistant Professor, e-mail: kholodilov@mail.ru, Saint-Petersburg State University of Aerospace Instrumentation, 190000, Saint-Petersburg, Russia,
Yu.I. Vinogradov, Cand. Sci. (Eng.), Assistant Professor, Saint-Petersburg Mining University, 199106, Saint-Petersburg, Russia.

A.N. Kholodilov, e-mail: kholodilov@mail.ru

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