Prediction of Tunnel Blasting Vibration Velocity Considering the Influence of Free Surface

The blast vibration attenuation will change as the tunnel cut hole is blasted to create a new free surface. To guarantee safe construction and optimize design parameters, it crucial understand impact of surface on attenuation. Previous studies have often only qualitatively evaluated effect vibration, failing quantify these impacts In this paper, by analyzing decay law velocity under different surfaces, we quantitatively assessed number faces burden distance peak velocity. Then, introduced free-face parameters enhance current formula for predicting results show that decreases with increasing increases distance; factor cannot be ignored in contributes about 21% more total than scale factor. average tolerance rises from 24.79% Sadovsky 13.32% correction formula, precisely predicts accuracy provides good scientific basis blasting parameters. research were successfully applied Jiujiawan proximity Duyun-Anshun highway Guizhou, effectively guaranteeing safety minimum clear 17.2 m.