Study On Vibration Characteristics And Laws Of Blasting Excavation Of Mountain Tunnel

During the blasting excavation of the tunnel nearby,the blasting vibration will not only have a greater impact on the nearby slope,but also cause a certain degree of damage to the surface structures(buildings)and nearby residents.In this paper,the LS-DYNA numerical simulation method is used to establish a proportional numerical model.First,the blasting vibration characteristics and laws of the mountain tunnel are studied from the three aspects of blasting parameters,slope rock mass characteristics and slope-tunnel geometric conditions,and then derived A formula for predicting the maximum vibration velocity of the slope was developed,and a platform for predicting the maximum vibration velocity of the slope was developed.Finally,the reliability of the platform was verified in conjunction with the Bulunkou-Gonger Hydropower Project.The main research results are as follows:(1)With the increase of the time interval between the differentials,the maximum peak vibration velocity of the slope and the safety degree of the slope decrease exponentially,and the plastic zone of the rock mass decreases in the form of power series.Relative to the far zone of the explosion source,the effect of the differential initiation interval on the peak vibration velocity is greater in the near zone of the explosion source.The maximum peak vibration velocity of the slope slope increases linearly with the increase of the total charge,the maximum charge and the tunneling footage.The slope safety decreases exponentially with the increase of the total charge.(2)Changes in the thickness and number of weak interlayers have almost no effect on the vibration velocity of the particle on the side of the weak intercalation,mainly damping the vibration velocity of the particle on the opposite side.The peak value of the maximum vibration velocity on the slope decreases linearly with the increase of the thickness of the weak interlayer,and decreases linearly with the increase of the number of weak interlayers.Both the thickness attenuation rate and the number attenuation rate increase linearly with the increase of the thickness of the weak interlayer.The maximum peak vibration velocity of the slope decreases with the increase of the slope angle in the form of power series,and the safety of the slope increases with the increase of the slope angle.(3)When the tunnel elevation is constant,the peak peak vibration velocity of the slope decreases with the increase of the horizontal blasting distance of the tunnel,and the peak point elevation of the slope increases with its increase,and the slope safety increases with its increase.When the horizontal distance from the center of the tunnel to the slope is constant and the elevation of the tunnel is increased,the peak value of the maximum vibration velocity of the slope has basically no effect,and the peak point increases as it increases.When the elevation of the tunnel center is constant,the peak value of the maximum vibration speed of the slope,the distance from the position of the maximum vibration speed of the slope to the foot of the slope,and the safety of the slope change linearly with the increase of the elevation.When the slope angle increases,the peak value of the maximum vibration velocity of the slope becomes smaller and smaller,and the height of the peak point increases first and then decreases.It reaches the maximum when the slope angle is 50°,and the slope safety increases Increase linearly.(4)Based on the research results of the maximum peak vibration velocity of the slope varying with the differential initiation interval time,on the basis of the Sadoff s empirical formula,the peak vibration peak prediction formula for the blasting slope of the mountain tunnel is derived,and the mountain is developed The platform for predicting the vibration velocity of the blasting slope of the tunnel and applying it to the Bulunkou-Gongeer Hydropower Station project showed that the prediction error did not exceed 10%,which verified the reliability of the platform.The prediction error of this platform is small,it has high accuracy,and the running speed is fast,which can provide reference and technical support for the rapid design of the blasting of the mountain tunnel.