| Relying on the regional project of National Natural Science Foundation of China(51464015),taking the blasting technology of mine roadway as the research object,this paper optimizes the smooth blasting technology adapted to the actual conditions of Makeng Iron Mine by means of field investigation,empirical method,theoretical calculation method,numerical simulation and field test,so as to achieve the goal of high efficiency,safety,economy and relatively simplified construction management of mine roadway excavation.It also provides a reference for the follow-up drilling and blasting construction in mines.The main research contents and conclusions are as follows:(1)Through field investigation,the basic geological conditions of rock in roadway and the general situation of traditional blasting technology are obtained.The physical and mechanical parameters of rock are obtained through rock mechanics laboratory test,which provides parameter basis for the proposal and optimization of smooth blasting.(2)Combining with the existing traditional blasting method and smooth blasting technology principle,the relevant parameters of peripheral eye are designed by empirical method and theoretical calculation method,and three kinds of cutting methods are simulated by numerical analysis method,and the cutting scheme is selected.In order to get a bigger footage,the depth of blasting hole is deepened.The excavation method of roadway is changed from step-by-step excavation to full-face one-time shaping.The charge structure and initiation mode are determined,and the complete smooth blasting scheme for roadway excavation is given.According to the field smooth blasting test,the proposed smooth blasting scheme is optimized,and good blasting effect is achieved.In terms of basic material consumption,smooth blasting method has obvious advantages over traditional blasting method,which can save a lot of costs for mines.(3)In the process of Sadovs baseline fitting,it is found that the k values of traditional blasting method and smooth blasting method are not very different,but the attenuation coefficient a value of the former is significantly smaller than that of the latter,which indicates that smooth blasting method has faster attenuation rate of blasting seismic wave than the traditional blasting method and can effectively reduce blasting vibration.(4)The original vibration signals of the traditional blasting method and the smooth blasting method are mainly distributed within 2 seconds,but the peak particle vibration velocities of the two blasting methods are quite different,mainly because of the difference of charge quantity and tunnel lithology between the two blasting methods.According to Fourier spectrum and power spectrum,the frequency band of vibration signal of traditional blasting method is mainly below 200 HZ,and the peak value appears in the frequency band of 0-50HZ,while that of smooth blasting method is mainly below 300 HZ,and the peak value appears between 200-250 HZ.The energy of traditional blasting vibration signal and surface blasting vibration signal are concentrated in the frequency range of 0~2s and 0~500HZ.The cumulative energy peak of the former reaches 11×10~4J,and mainly lies in the frequency range of 0~50HZ,while the cumulative energy peak of the latter is about 780J,and mainly distributes in the frequency range of 50~150HZ.Therefore,smooth blasting method can effectively control the blasting vibration effect. |
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