| The drilling and blasting construction method is the most commonly used method in mountain tunnel excavation, the blasting excavation made the excavation efficiency increase greatly, but the blasting vibration has the disadvantage of the tunnel structure and the surrounding structure, which restricts the blasting efficiency. So it is very important to study the influence of blasting vibration on the initial support structure and control standards. This paper combines the Chongqing Jiangbei District Station Road Tunnel Engineering Blasting Experiment Monitoring Project, then study on the safety vibration velocity of concrete and bolt initial supporting structure under the influence of blasting vibration.①The measured vibration data from the tunnel face 5m~21m side wall shotcreting were analyzed, and then the attenuation law of the vibration velocity of the shotcreting along the side walls is obtained. And calculated the velocity from the tunnel face 1m~5m shotcreting vibration standard and compared with the safe velocity.②The finite element software MIDAS-GTS is used to establish a numerical model for the blasting vibration problem, the series of maximum vibration velocity is extracted respectively, which belongs to the tunnel shotcreting of tunnel vault, the tunnel waist and the side wall. The vibration velocity attenuation law of the three is obtained and compared with the measured.③The vibration speed data of each node is summarized and analyzed by FEM, the excavation area of the Station Road Tunnel is more than 2/3 and the tunneling blasting is the first step, getting the ratio of the vibration velocity of the three speed of the shotcreting in the vault, the arch and the side wall, for the engineering projects of monitoring the vibration speed of the side wall injection concrete, the upper bench blasting of the step method is similar to the excavation, which can be referenced while calculating the vibration velocity of the shotcreting of the tunnel vault or tunnel arch. |
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