111 / 2016-12-05 10:15:10

STUDY ON BLASTING VIBRATION RESPONSE ANALYSIS AND CONTROL OF SMALL SPACING AND GRADUAL OVERLAP TUNNEL

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The vibration response of the shoulder, side wall and arch foot of adjacent tunnels under the blasting vibration of Huahuiyuan - Dalongshan small spacing and gradual overlap tunnel is analyzed by numerical simulation. The results show that the effect of stress wave on the stability of the existing tunnels plays a dominant role in blasting excavation of small clear-distance overlapped tunnels, and the impact load of surrounding rocks of the large-span tunnels is 3.564 MPa. The upper tunnel blasting has great influence on the shoulder and side wall of the lower tunnel. The impact of the lower tunnel blasting on the shoulder, the side wall and the arch foot of the upper tunnel is very big, and should focus on monitoring the most imprinted side wall. The influence of the redistribution caused by blasting on the existing tunnels is great, especially when the spacing is less than 1D. This effect can not be neglected. The static blasting control, the single-shot initiation dose control and the noise control are put forward based on the research rule, which are fully utilized in the later construction and have achieved remarkable results. The research results have reference value for similar projects.