Research On Blasting Vibration Law Of Adjacent Subsea Tunnel Based On Mining Method

In the adjacent submarine tunnels constructed by the mining method,there are few studies on the propagation of blasting vibration under the seabed,and it is impossible to determine the impact of the new tunnel blasting vibration on the existing tunnel structure or adjacent buildings.Therefore,studying the attenuation law of blasting vibration propagation under the seabed and the vibration response law of existing tunnels are of guiding significance for ensuring the safety of buildings around the explosion source and reducing construction risks.In this paper,the submarine tunnel of Jiaozhou Bay under the seabed conditions and the submarine tunnel of Qingdao Metro Line 1 are taken as the engineering background.Firstly,the vibration vibration waveform,frequency and velocity are attenuated with the blasting heart distance.Regression,the prediction formula of blasting vibration velocity under this condition is obtained,and the existing tunnel structure is evaluated safely.Then ANSYS/LS-DYNA software is used to establish the corresponding numerical model based on actual engineering,and the existing tunnel is blasted.The vibration response under the action is verified and supplemented.Finally,the single-variable principle is used to establish the tunnel axial direction under different tunnel spacing,rock conditions and seawater depth by establishing numerical models with different spacing Rs,rock conditions and seawater depth H.And the vibration response law in the lateral direction.The main conclusions are as follows:(1)The propagation of blasting vibration under the seabed has the characteristics of large value and fast attenuation,so attention should be paid to vibration monitoring under this condition;when the safety allowable vibration velocity[V]=0.5cm·s-1 and the tunnel spacing R=250m The maximum single-stage explosive charge allowed for the new tunnel is 29.92kg,while the maximum single-stage dose in the construction site is 39.6kg,exceeding the site control requirements.(2)In the existing tunnel,the impact of the blasting vibration near the side arch wall of the face is the largest,and the maximum vibration velocity is 0.62cm·s-1,which exceeds the engineering site[V]=0.5cm·s-1.Control standard;on the corresponding face,the three-way vibration velocity and its attenuation rate are generally represented by radial vibration velocity>tangential vibration velocity>vertical vibration velocity,indicating the horizontal vibration of the existing tunnel space caused by the new tunnel blasting.The speed has a significant reduction effect and the reduction of the vertical vibration speed is small.(3)In the axial and lateral directions of the existing tunnel,the vibration velocity increases with the increase of seawater depth,but the variation of the vibration velocity in different directions with seawater depth is different.As the depth of the seawater increases,the vibration velocity in the horizontal direction first decreases and then increases,and the vertical vibration velocity appears to increase strictly.In the vibration velocity in all directions,the depth of seawater has the greatest influence on the vertical vibration velocity.(4)In the axial direction of the existing tunnel,the influence of seawater depth on the decay rate of blasting vibration is not obvious,and the attenuation rate under sea and land is not much different.In the lateral direction of the existing tunnel,the attenuation rate of the horizontal vibration velocity does not change much with the depth of the seawater,and the attenuation rate of the vertical vibration velocity decreases with the increase of the seawater depth.