The Study Of Vibration Isolation Mechanism And Effect Of Damping Hole In Blasting Seismic

In blasting engineering, more and more people take it into consideration to effectively control or reduce the blasting vibration damage to protected areas. Taking the Changsha Metro-North Station Excavation Blasting as engineering background, through theoretical analysis,numerical simulation and field monitoring data of these three aspects, the influence of damping hole on the isolation of blasting seismic wave theory, the effect of vibration isolation and damping hole etc are studied in this Paper.(1) The principle of isolation damping hole theoretically are analyzed in this Paper. Damping hole vibration isolation effect is a complicated problem between the attenuation of stress wave propagation in the medium and stress wave response of buildings.From the bottom of the damping hole, the blasting stress wave is divided into the upper Part of the bottom of the stress wave and stress wave.Stress wave produces reflection, transmission and the phenomenon of winding in the damping hole, damping hole can Part of the propagation of stress wave, accelerate the attenuation of stress wave energy and reduce the damage of protection zone.(2) This Paper, by Midas/GTS software simulation, obtains a result that damping hole has certain effect of vibration isolation.Using the formula of Excel software to fit the vibration isolation effect of damping holes with different Parameters combination, this Paper reached the following conclusions:Increasing the damping hole diameter and row number, and reducing the effective vibration isolation distance between holes, the vibration isolation effect of damping holes become worse with the increase of damping hole and main blast hole spacing.(3) With the use of Changsha Metro North station monitoring data of blasting, and based on the least square principle, regression analysis was carried out using of monitoring data of blasting, the following conclusions can be obtained from the analysis: Vibration velocity of region with damping holes is less than that without damping holes, and the damping ratio is between 10%~20%;The damping ratio decreases with the increase of the distance from the blasting center, damping effect is better in the area near blasting hole.Finally, comparing the Midas/GTS numerical simulation data and field monitoring data in this Paper, two kinds of results obtained are roughly consistent, which shows that numerical simulation of blasting vibration,which analyze damping vibration isolation effect factors on the influence law of practical.