Geomechanical behavior of jointed rock mass versus delay interval in seismic load zone of large-scale blasts

Experimental tests show that velocities of seismic vibrations from quarry blasts generally lower as delay intervals between large-scale blasts are increased. At the same time, a seismically safe delay interval is governed by geological conditions, which vary appreciably within an open pit mine field, and by geotechnical conditions of mining. This study was aimed to obtain theoretical formulas of vibration velocities, compressive stresses and relative strains in rock mass as functions of the delay interval based on the mechanism of seismic waves induced by short-delayed blasting in jointed rock mass. These formulas were to be justified. After review of reference sources, the mechanism of blast-induced seismic waves in jointed rock mass was developed. According to this mechanism, high-velocity collisions of fractured and intact blocks under the action of pressure from detonation products generate elastic waves. The theoretical research allowed formulas for the delay interval dependence of the vibration velocities, compressive stresses and strain rates in rock mass in the seismic impact zone of blasting. The comparison of the mathematical and numerical analysis results with the actual practice data validates the formulas of vibration velocities as function of blast-to-blast delay intervals. These formulas make a framework for the development of regulations for blasting at minimized seismic impact on guarded objects in different geological and geotechnical conditions.

Tyupin V. N., Khaustov V. V. Geomechanical behavior of jointed rock mass versus delay interval in seismic load zone of large-scale blasts. MIAB. Mining Inf. Anal. Bull. 2021;(2):45-54. [In Russ]. DOI: 10.25018/0236-1493-2021-2-0-45-54.

The study was supported by the Ministry of Science and Higher Education of the Russian Federation, Grant No. 075-03-2020-474/1 от 05.03.2020.

V.N. Tyupin¹, Dr. Sci. (Eng.), Professor, e-mail: tyupinvn@mail.ru,
V.V. Khaustov¹, Dr. Sci. (Geol. Mineral.),
¹ Belgorod State National Research University, 308015, Belgorod, Russia.

V.N. Tyupin, e-mail: tyupinvn@mail.ru.

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