Study on the vibration effect of open-pit and underground combined mining by piecewise fitting Sadowski formula

Abstract

With the gradual depletion of shallow resources, many metal mines that adopt open-pit mining gradually turn to underground mining. When the open-pit boundary and the underground roadway expand and develop together, a complex open-pit and underground combined mining system is formed. Meanwhile, due to the high strength of ore bodies, metal mines mostly adopt blasting excavation. However, in open-pit mining blasting, the explosive energy will not only achieve the excavation of ore bodies, but also produce blasting vibration effect, affecting the overall stability of the existing structures in the vibration field. Sadowski formula is a common and effective blasting vibration disaster analysis theory, which is widely used in vibration disaster evaluation and vibration impact analysis of metal mines. In this paper, based on the Wulagen zinc mine engineering, blasting vibration monitoring instruments were used to monitor the vibration of open pit slope blasting at locations such as slope surface and underground engineering tunnels, and the in-situ blasting vibration data with different blast core distances were obtained systematically. In the data analysis, considering the difference of propagation law of blasting vibration wave between slope surface and underground rock mass, a new piecewise fitting Sadowski formula vibration disaster evaluation system was proposed. The results show that the attenuation of vibration wave on slope is slower than that in rock mass. The piecewise fitting results accurately represent the vibration effects of different positions in the blasting vibration field, providing data support for blasting parameter optimization, vibration disaster control and even the stability of joint mining, which also proposing a new idea for the study of the interaction between open-pit and underground joint mining of metal mines.