Research On The Blasting Shock Absorption Technology In Large Span And Shallow-buried Tunnel Under-traversing The Unhistorical Buildings

Blasting Technology is not just used for mining industry, but also widely used intunnels, subways, highways, dams and other civil engineering projects. With thevigorous development of China’s railway transport services, more and more shallowtunnel projects born in big city. In consideration of both process technology andeconomic technology, blasting is the most suitable method for metro tunnelexcavation in hard rock region. But blasting vibration effect do a lot of damage to thesafety of ground building. How to reduce the blasting vibration as well as how toproperly handle the conflict has become one of the key issues in tunnel blasting.This paper puts blasting excavation of Qingdao metro tunnel under-traversing thehistorical buildings between Railway Station and People’s Hall as project background.There are many German unhistorical buildings that almost one hundred years betweentwo stations.Most of these unhistorical buildings fell into disrepair, and seismic level is low, sothe blasting vibration control requirements are more stringent. Through thecombination of theoretical analysis and field test, then according to the monitoringdata analysis, constantly modify blasting parameters, establish reasonable and safetyblasting plan, ensure the safety of unhistorical buildings when the subway tunnelsbeneath them. Based on a lot of blasting vibration monitoring and test data, itresearches wave attenuation rules and integrated shock damping effect measures ofblasting seismic, mainly research aspects as following:(1) Assessed these unhistorical buildings，then formulate safety standards ofblasting vibration velocity that applicable to the construction environment in Qingdao,according to the blasting vibration control at home and abroad;(2) Do the blasting vibration test, and monitoring the ground vibration velocityall the time. Regression analysis of monitoring data, calculated Sadov’s VibrationFormula modulus K、α of rock formations of the tunnel and the blasting vibrationpropagation rule in rock;(3) By doing field tests to determine a reasonable damping method, and seriouslydo real-time monitoring of ground vibration velocity, ensure the safety of unhistoricalbuildings when tunnel across the them;(4) This article employs the explicit dynamic finite element softwareANSYS/LS-DYNA to simulated the practical construction process of cut blasting，and do the time history analysis of blasting vibration velocity and evaluate the safety ofblasting scheme.