The Research On The Attenuation Rule Of Blasting Vibration In Open Pit Bench

Blasting vibration is one of the problem that affect the security of environment in open-air blasting,and the environment safety is taken more and more attention in recent years that forcing mining enterprises to solve the problem by improving technology. The blasting vibration energy not only causes unnecessary waste of the explosives,but also affects the stability of the slope or constructs,which is not favorably to the development of mining enterprises.For the blasting itself,there is transient,mutagenicity,complexity of the structure that makes the analysis of the blasting vibration more difficult.So the paper will use the blasting virbration monitoring as the primary mean and analyze blasting vibration of Dagushan from multiple factors,which expect to reduce blasting vibration effect at the same time and improve utilization of explosives energy.In the paper,the main context will begin with the quality of rock fragmentation in the process of Dagushan iron mine and research and analysis for the bad quality of typical three kinds of rock in the blasting.The reference is based on previous studies,which set forth the seismic of process from generation to propagation and propose measures to reduce the effects of vibration.Through carrying on the investigation and study on the blasting filed and taking the typical rocks,then drilling the core of rock,making the static experiment and the dynamic experiment of the Split Hopkinson pressure bar in the laboratory,which confirm that the characteristics of three kinds of rock mechanical properties in blasting fragmentation.Monitoring the vibration of three kinds of area based on vibration monitoring programs and obtain the data of vibration at the same monitoring point.Then analyzing the blasting vibration attenuation from the perspective of velocity and energy,and giving three types of rock vibration attenuation formula by regression analysis.Blasting vibration signal processing techniques is combined with HHT method which obtain IMF components,three-dimensional instantaneous energy spectrum and analyze the change of energy in different rocks.Some of the major conclusions are:(1) Blasting virbration attenuation law is directly related to the nature of the species,the different types of rocks have the different attenuation gradient.The peck velocity of vertical is greater than the other two directions and the attenuation is relatively large.Instantaneous energy attenuation have the same trend with speed.The quantity and velocity of explosive have the effect on the distribution of vibration energy.(2) Using the analytical method of HHT get the IMF, three-dimensional energy spectrum,instantaneous energy spectrum of three types of rock in the different position,which reveals the different response to seismic wave and the different propagation.(3) Monitoring the seismic velocity of three kinds of rocks at 30 m and contrasting the vibration level by the normalization process,showed that:The energy efficiency is different,the lowest is magnetite,the highest is migmatite and granite.