Application Of Blasting Technology In Towns Under Shallow Tunnel

With the rapid development of economy,shallow tunnel engineering and urban subway engineering,as the important infrastructure of transportation engineering,have gradually become an important part of Engineering construction.Drilling and blasting method is the main construction method of underground space excavation.The seismic wave vibration effect produced by the blasting process is the main factor affecting the engineering efficiency and endangering the surface structures.How to control blasting vibration damage and correctly handle the contradiction between blasting vibration control and construction efficiency is the key problem of tunnel blasting construction.Based on the engineering background of Korla Tunnel of Geku Railway passing through Korla Economic and Technological Development Zone,aiming at the construction requirements such as dense houses on the ground,complex and diverse structures,low aseismic grade of houses and strict blasting control standards,the digital detonator shock-absorbing blasting technology was formed through the comparative test of digital detonator and ordinary detonator blasting,and large-scale digital detonator was used.Blasting excavation ensures safe and rapid passage of the tunnel through Kurla Economic and Technological Development Zone.On the basis of earlier blasting tests and development section blasting engineering,the applicability of blasting vibration reduction technology and digital detonator is studied.Based on the statistical and regression analysis of the measured data of blasting vibration,the relationship between the vertical,horizontal and radial seismic velocities of Korla tunnel and the distance between the particle and the source of vibration and the amount of explosives is obtained by using the least square method,which can roughly reflect the impact of seismic waves on the ground buildings during blasting.The spectrum and energy analysis of blasting vibration waveform shows that the energy of blasting vibration frequency band increases with the increase of the maximum explosive quantity,and the vibration frequency band will develop toward the low frequency direction.The peak energy of blasting vibration signal increases obviously.In the process of seismic wave propagation,the vibration intensity decreases,the frequency band becomes wider,and the proportion of medium and low frequency signal increases.On the basis of good blasting effect,the blasting excavation construction of digital detonator effectively improves the construction efficiency of the project,ensures the particle vibration speed of the surface structure,avoids the large-scale removal cost caused by blasting,reduces the risk of environmental pollution to a certain extent,and has higher social,economic and environmental benefits.