Study On Influence Of The Surface Buildings Caused By Blasting Construction Of Subway Station

With the modern development of the city, the subway construction is the key link to improve the urban traffic system in many cities of our country. Most mountain city subway tunnels need to be exeavated by drilling and blasting due to the restriction of engineering geologiea lconditions, and the vibration effects produced by blasting will endanger the safety of buildings close to tunnel. At the same time, the mechanism, propagation characteristics and attenuation law of blasting seismic wave, and the dynamic response of buildings, also including other issues has caused more and more attention in academia and engineering. Therefore, it has became an urgent challenge for blasting workers to solve, that how to forecast the blasting vibration effects and control it so as to ensure the safety of building.In this paper, based on the safety monitoring of sha zheng jie station tunnel exeavation blasting in Chongqing Rail Transit Link project, obtains the attenuation law of blasting seismic wave by regression analysis of blasting vibration monitoring data, combine with a numerical simulation of the finite element software MIDAS-GTS to study the law of dynamic response of buildings under the action of blasting vibration. The main researches and findings are as follows:(1) Through regression analysis on the monitoring data by the least square method to determine the parameter value k and α, then obtained blasting seismic wave attenuation empirical formula of peak velocity in this area. And analyzed the main frequency of blasting seismic waves, summarized the variation law of main frequency along the blasting distance.(2) Based on three-dimensional entity model established by finite element software MIDAS-GTS, the law of dynamic response of frame structure and masonry structure on the earth’s surface under the action of blasting vibration is studied through numerical simulation, then summarized the dynamic response of the two kinds of structures under blasting vibration along the height, and analyzed the effects of blasting distance and cavity to dynamic response of the two kinds of structures.(3) Considering the characteristics of blasting and surrounding environment of sha zheng jie station, proposed a variety of damping measures, such as: shock absorbing cutting blasting, select the appropriate explosive, pre-splitting blasting, millisecond microsecond delay blasting, hydraulic blasting technology, reasonable choice of drilling and blasting parameters, formulate rational detonating sequence, determine the appropriate excavation cycle footage, choose good blasting equipment, etc.