Vibration Reduction Control Blasting Technology Research Of The Xian NV Yan Tunnel Underneath Pass Oil And Gas Pipeline

The exit section of Xian-nvyan tunnel near four buried oil and gas pipeline, and underneath pass the gas transmission pipeline. In the process of tunnel excavation blasting construction, the blasting seismic effect will be damage or even destruction to near the pipelines, especially the above gas pipeline. So the excavation blasting technology research of tunnel underneath pass pipeline has great significance for site construction. At the same time, further enrich the theory of blasting vibration reduction design.Based on the above project as the background, through the in-situ blasting test measured the surface above the pipeline vibration strength, the analysis found that it does not accord with the formula of Steve sadove. On the basis of the influence factors of blasting vibration and the research of the tunneling blasting technology, proposing the technology solutions of cuthole with deck charge, and numerical modeling with finite element software for the cuthole with continuous charge and deck charge. The show that the cuthole with deck charge than continuous charge has obvious effects of vibration reduction, the peak particle velocity of the horizontal direction X reduce about 44%, that of the vertical direction Y reduce about 44.3%, that of the tunnel axis Z reduce about 32.9%. The two blasting waveform of deck charge will superposition in the communication process, the peak particle velocity backwards, the changes of attenuation as a wave form. In addition, in the case of cuthole with deck charge, the vibration of pipeline and soil has very big difference in place where the pipeline contact with the soil, the speed and frequency of pipeline are all bigger than soil, the peak particle velocity of pipeline top is 1.21 times that of soil, the peak particle velocity of middle part is 1.41 times, the peak particle velocity of bottom is 1.39 times; the Von-Mises stress appears on the top of the pipeline at the same time, and the distribution laws of Von-Mises stress at different time are not the same.Combined with the construction site conditions, on the basis of the results of numerical simulation, designing the blasting scheme on cuthole with deck charge of top bar of the Xian-nvyan tunnel. The result of the field test indicate the peak particle velocity of the surface above the pipeline is 0.907cm/s, in the range of allowed safety standards, at the same the scheme has economic benefit of engineering.Taking the Xian-nvyan tunnel as engineering background, study the blasting vibration about cuthole with different parameters of deck charge. The condition of the same dose, the charge of outer segments less than the that of inner segments is more advantageous to reduce blasting vibration; the peak particle velocity of the zone far from the explosion source get the influence of the charge of inner segments.