Vibration control of blasting excavation of large cross-section highway tunnel over metro line

The blasting excavation of the new tunnel may cause damage to the adjacent tunnel. Taking the Hongshi road tunnel in Chongqing as a research object, the paper analyzed the influence of the maximum charge on the vibration speed of the existing tunnel by comparing the influence of adjacent tunnel blasting team on the existing tunnel simulated by ANSYS/LS-DYNA with the actual monitoring results. The results show that when adopting the “three steps + invert” four steps excavation, the maximum charge quantity of each excavation step is 56.8 kg, 40.2 kg, 37.1 kg, and 21.6 kg, and the combined vibration velocity of the control measuring points is less than 1.5 cm/s. All meet the design requirements. The vibration velocity of the blasting side of the existing subway tunnel is mainly in the horizontal direction and relatively small in the vertical direction. With the increase of distance from the blasting point, the maximum vibration velocity is the charge quantity of large sections and can be increased gradually.