Study On Blasting Vibration Control Technology Of Expansion Engineering Of Zhongliangshan Tunnel In Chongqing

With the arrival of twenty-first Century,China’s traffic construction is developing rapidly,and the highway construction is particularly significant,expanding the scale of construction.In some densely populated large and medium-sized cities or the huge traffic flow of the highway,the tunnel transport capacity has become a bottleneck restricting traffic.In the face of more and more serious traffic problems,it has become a research hotspot in the field of tunnel engineering to expand the existing tunnels to meet the needs of transportation.This paper is based on the reconstruction and extension project of Zhongliangshan tunnel in Chongqing,using the method of combining theoretical analysis and numerical simulation,focusing on the new shock absorption measures of tunnel blasting,conventional blasting influence on existing tunnel,cutting position,groove eye and eye position relative damping hole and damping hole cut on the existing tunnel affected by earthquake degree etc.The main contents and results are as follows:(1)In this paper,three measures are put forward,such as changing the position of the cut hole,adding the damping hole and controlling the relative position of the cut hole and the damping hole,trying to control the vibration wave propagation method to control the new tunnel impact on existing tunnel.(2)By field trial explosion test and LS-DYNA numerical simulation,the least squares regression method is used to obtain the Sa Rodolfo J Ki empirical formula:V=216.1723(Q1/3/R)1.5707、V=111.918(Q1/3/R)1.3431There are some differences between the two results,but they have the same change rule.The rock was simplified numerical simulation,without considering the actual situation of the complex topography and geology,and numerical simulation is not considered the face of periphery holes and auxiliary hole on the test results,the numerical simulation result and field test results.(3)In the case of the same distance,the relationship between the particle velocity and the corresponding diffusion angle of the particle:v=-8.6067 sin3β+13.529 sin2 β-6.9827 sinβ+1.2773The constraint condition of the medium particle is closely related to the particle velocity and the magnification factor of the particle on the surface of the structure isλ=1.19.When the vibration wave spread to the existing tunnel,the media suddenly changed into air,which greatly weakened the transmission capacity of the vibration wave.(4)Changing the cut position of the existing tunnel under earthquake has weakened effect.At the same time,to a certain extent,it delay the shock wave energy to tunnel,but it cannot weaken the peak average kinetic energy of lining structure;Adding damping hole of the existing tunnel affected by the earthquake degree is very obvious,and the damping efficiency is more than 0.84.At the same time on the rate of diffusion delay shock wave energy plays a very significant role,which greatly weakened the lining structure by the average kinetic energy peak.(5)The relative position of the cut hole and the damping hole has an influence on the damping effect of the damping hole.When the cut hole is close to the damping hole,the damping effect is the worst,and the damping effect is the best when the cut hole away from the shock hole.