Effect Of Blasting Vibration On The Stability Of Adjacent Slope In Open-PIT Mining

In order to promote the Production efficiency and economic efficiency, the pen-pit mine enterprises usually uses the large diameter deep-hole bench blasting technology to mining. Meanwhile, with the expansion of the mining scale, the influence of blasting vibration on the slope stability of adjacent bench has seriously threatened to the safety of open-pit mine production. This article takes the open-air bench blasting mining engineering of Baoshan limestone mine in Huizhou as an example, studies the influence of open-pit blasting load on adjacent slope with the use of field monitoring, theoretical calculation and numerical simulation. The main research content and results are as follows:(1) The site monitoring and analysis of blasting vibration. According to the actual situation of the scene, after assigning six station on four steps nearby the working steps, we made three different blasting vibration monitoring tests with different doses. The result showed that the blasting load influenced on the up stage mostly, the influence on the second stage took second place, the influence on lower step was lowest. Then we used regression analysis to fit the calculation formula of vibration velocity and dominant frequency of the slope, in order to induce the bad effect of stability of slope under blasting vibration, we suggested a blasting charge control in 4000~6000kg.(2) Numerical simulation and analysis of the influence of blasting vibration on the stability of adjacent slope. We used the ANSYS/LS-DYNA to make simulation and analysis on the blasting vibration velocity and blasting pressure of the stage nearby working stages. The simulation results showed that the velocity of blasting vibration and the pressure of the explosion were not synchronous with the change of the upper and lower steps. The blasting vibration velocity of the upper bench was higher than that of the lower bench blasting vibration velocity, and the results were in good agreement with the field vibration monitoring test results.The acting time of the stress wave received by the stage was longer than that of the stage, The main energy of the stress wave was dissipated in the upper stage. We made simulation on the blasting with different type explosive and different time, With the decrease of the power of the explosive and the extension of the differential time, the vibration velocity and explosion pressure appeared to decrease, When the difference time was more than 150 ms, because of the weakening of stress wave superposition effect, it would decrease the blasting effect.(3) Study on dynamic stability of bench slope in open pit mine. According to the slope stability of application of strength coefficient reduction method on Baoshan mine, we made the simulation and analysis, the safe factor was 2.30. Then we calculated the damage variables and safety factors of rock slope under blasting load, and the safety factor of slope is 1.79, and the slope is stable.