Study On The Controlled Blasting In Urban Subway Tunnel

In recent years, large numbers of people into the city, so the city is gradually expanding,the existing transportation can not meet people's travel needs, in order to relieve urban traffic pressure and improve the efficiency of people's life, the construction of urban rail transit has become a hot topic in the development of the city today. Urban rail transit construction in population density, building a relatively concentrated area. Tunnel through the rock blasting method often used part of excavation, blasting vibration effect it is likely to endanger the surrounding buildings(structures) and tunnel own security.Therefore, it is necessary to study the effect of blasting vibration control features for blasting design and construction to provide a scientific basis.In this paper, under construction in Guiyang Rail Transit Line 1 Lot 8 Jiangjunshan station to Yuntan station bored tunnel as the background, through the construction site blasting vibration monitoring, tunneling blasting vibration as the object of study, the following discussion:First, With theoretically in this paper, the rock breaking mechanism of rock, the mechanism of blasting vibration and blasting seismic effect, provides the theory basis for controlled blasting for subsequent research.Second, Using ANSYS/LS_DYNA dynamic finite element program, controlling factors affecting blasting vibration are simulated, according to the simulation results, comparative analysis of different charge structures and blasting method of blasting effects, and finally get control method in shallow tunnel blasting.Third,the field of tunnel blasting construction of the blasting vibration monitoring, and by using the least squares method for regression analysis of experimental data and get Sadaovsk empirical formula k, a value, it is concluded that the section of tunnel excavation blasting seismic wave propagation law; HHT analysis on experimental data, it is concludedthat the spectrum characteristics of blasting seismic wave.Fourth, Jiangjunshan station to Yuntan station tunnel excavation three-dimensional numerical model, using ANSYS / LS_DYNA dynamic finite element analysis program for the numerical simulation of tunnel excavation blasting solid model to study tunneling blasting vibration propagation. By comparing the measured data with the simulation results, the main factors affecting the blasting to guide the determination of blasting parameters. In addition,the tunnel in karst developmental section in numerical simulation, in line with controlled blasting method under karst conditions.