| Using drill and blast construction of urban rail transit tunnel, you need to advance to grasp the effects of vibration caused by blasting excavation of the surface, in order to take appropriate measures to control the scope and extent of the blast to protect the surface and structure safety. This paper analyzes the scene to declare Cape Mapo-speed method of shallow tunnel three workers blasting vibration monitoring data points, MIDAS-GTS numerical simulation software to study the use of surface drilling and vibration control measures blast method. The following conclusions:(1) Peak velocity of ground particle is exponential decreased with the increase of ratio distance, and the maximum value of peak velocity appears in vertical direction with high probability.(2) Using the principles of statistics, the thesis concludes attenuation formulas of peak velocity on 3 different construction sites. By using these formulas, people can modify the parameter of blasting to reduce blasting vibration effect.(3) The main vibration frequency of ground particle is in range of 20～70Hz,but no strict link between main vibration frequency and ratio distance is found.(4) Through the comparative analysis between numerical simulation results and field measured data, the feasibility of numerical simulation method is interpreted in tunnel blasting vibration effect study. Using numerical simulation, carried out in different blasting distance and different depths, such as ground vibration response of a variety of conditions under Ⅲ, Ⅳ, Ⅴ grade rock.(5) Through theoretical analysis and study of the Shallow tunnel of blasting vibration control of sensitive areas and field measurement, made by increasing the number of single-stage controlled blasting initiation dose, increase the interval to reduce the difference between the segment and vibration reduction boring footage and other measures to reduce the tunnel excavation blasting impact on the surface. |
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