Field test study on vibration reduction effect of blasting barrier hole during excavation of foundation pit

In order to reduce the dynamic disturbance of adjacent structures caused by blasting construction of foundation pit by using blasting, field test to study the vibration reduction law of the blasting barrier holes was conducted relying on the blasting construction project of foundation pit of No. 1 comprehensive well of Shenzhen Metro Line 16. Based on monitoring of the ground vibration under different blasting barrier hole parameters, influence of blasting barrier hole on peak velocity and dominant frequency of particle vibration on the ground and the influence of parameters of blasting barrier hole on its vibration barrier effect were analyzed. It is found that when the diameter of the blasting barrier hole increases, the vibration isolation rate of vibration barrier hole (VIR) in horizontal radial and horizontal tangential directions increase first and then decrease, the VIR in vertical direction increases and the VIR based on resultant velocity increases. Furthermore the VIR decreases first and then tends to be stable with increase of the row spacing of the damping vibration barrier holes. In addition, when the proportion of water filling in the blasting barrier hole increases, the VIR in horizontal radial direction decreases, the VIR in horizontal tangential and vertical directions increase first and then decrease, and the VIR based on resultant velocity increases first and then decreases.