Study On The Technology Of Reducing Blasting Vibration Of Millisecond Blasting In JDC Open-pit Mine Nearby The Tunnel

Dong chuan river diversion tunnel is under JDC open-pit mine, whose wall rock joint and fault structure are well developed, and it is badly stable, so the diversion tunnel's safety is greatly influenced by blasting vibration in the mine area. Therefore, blasting vibration reduction becomes an urgent problem in the mine. Millisecond blasting is one of the main methods to control harm of blasting vibration, so how to choose the reasonable millisecond delay time is the key technology to improve the effect of blasting vibration reduction.Based on analysis the geological structure of Dong chuan river diversion tunnel, by consulting researches home and abroad on vibration reduction of millisecond blasting, in the paper, the dynamic response relationship under the blasting load is studied by numerical simulation. Besides, it is deeply discussed on decreasing vibration of different millisecond delay time using the method of numerical simulation, energy analysis in frequency bands of blasting seismic wave and field test, the main achievements are as follows:(1) Using dynamic measuring system, measure the velocity and any other data of the diversion tunnel's lining under the blasting vibration. Arrange and analyze the data abtained, and find the law of the velocity and dynamic deformation of the tunnel in different situation, then do the safty assessment.(2) Using LS-DYNA, and based on the bench blasting parameters of JDC open-pit mine, establish a finite element model of millisecond blasting of double-hole whose millisecond delay times are Oms,25ms,42ms and65ms respectively. Compared the peak particle velocity of each points in the situation of same hole pattern parameters, blast center distance, and different delay time, it can be known that peak particle velocity in each points of42ms delay time are smaller overall, which illustrates that effect of vibration reduction in42ms delay time is the best.(3) Based on viewpoints of the energy analysis in frequency bands of blasting seismic wave, get the total energy of particles when it has the same hole pattern parameter, blast center distance and different millisecond delay intervals. Then attenuation rate in each delay time is known, comparing which could proof the best delay time is42ms. (4) According the field test, comparatively analyze the peak particle velocity of the double-hole millisecond blasting and simultaneous blasting in the situation of the same blast center distance and hole pattern parameters, moreover prove the correction of vibration reduction rate of millisecond blasting.The practice shows that the achievement of the paper provide a reference for blasting design in mine on the reasonable millisecond delay time and the effect of reducing blasting vibration. Additionally it has a guiding significance for controlling blasting vibration nearby the tunnel, in order to supply reference for the same mine.