Study On The Blocking Mechanism And Protection In The Propagation Of The Blasting Air Shock Wave In The Tunnel

Compared with open space,the air shock wave generated by tunnel blasting has the propagation characteristics of restricted space.Due to the spatial limitation of the longitudinal direction of the tunnel and the excavation face,the propagation of the air shock wave in the tunnel will cause very complex refraction and reflection.longer and more damaging and damaging.In order to ensure the safety of construction personnel,construction equipment and equipment at the tunnel blasting site,it is very necessary to conduct research on the blocking mechanism and protection during the propagation of air shock waves in tunnel blasting.This paper uses theoretical analysis,field test and numerical simulation to carry out research on the blocking effect,action mechanism and protection safety of air shock waves generated by tunnel blasting.Blasting air shock wave safety protection technical measures.The specific research conclusions are as follows:1.Theoretical analysis of blasting air shock wave propagation was carried out.Based on the empirical formula of overpressure value of blasting air shock wave in underground engineering such as tunnels and tunnels,the size of overpressure generated by blasting air shock wave when propagating in free field and tunnel restricted space was selected through analysis.Using the dimensional analysis and theΠ theorem,the corresponding function expressions are deduced.At the same time,a relatively applicable prediction model of blasting air shock wave overpressure is initially formulated based on the engineering field test conditions.2.Aiming at the on-site working conditions of the engineering test,the blasting air shock wave test plan with and without baffles has been systematically formulated,and the blasting air shock wave test and air shock wave waveform under the above two working conditions are also carried out.3.The analysis of the blasting air shock wave waveform under the condition of blocking shows that the blocking effect of the baffle is mainly reflected in the reduction of the overpressure peak of the shock wave.With the increase of the baffle area,the blasting air shock wave peak weakens more;As the distance between the baffle and the measuring point increases,the reduction effect of the blasting air shock wave peak is weakened,and the two together affect the blasting air shock wave overpressure.4.On the basis of the comparative analysis of the test data with and without baffles and the relevant empirical formulas,the relevant parameters of the empirical formula for the overpressure value of blasting air shock waves under the condition of no baffles are corrected.The blasting air shock wave prediction model of blasting air shock wave,combined with the measured data under the condition of the baffle,the dimensional analysis and the Π theorem are used to deduce the blasting air shock wave blocking attenuation prediction model under the condition of the baffle,and the rationality of the prediction model is verified and analyzed.5.According to the corresponding working conditions of tunnel blasting,the numerical analysis model of air shock wave propagation in tunnel blasting with and without baffles is established,and the propagation process and propagation characteristics of air shock wave in tunnel blasting are simulated and analyzed.Combined with theory and field test analysis,The research on the blocking mechanism of the baffle was carried out,and the applicability of the prediction model of the air shock wave in tunnel blasting with and without the baffle was further analyzed and discussed.