IMPACT OF BLASTING AT TUNNEL FACE ON AN EXISTING ADJACENT TUNNEL

Experimental and numerical research of the effect of blasting vibrations during tunneling on surrounding structures (rock mass, existing tunnels, buildings, etc.) was widely studied in recent years. However, the effect of blasting vibration from a new tunnel on an existing adjacent tunnel is still unclear. A few researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduced two dimensional and three dimensional numerical with field data investigations on the effect of tunnel face blasting on the surrounding rock mass and on an existing adjacent tunnel along the existing tunnel direction. The Croix-Rousse tunnel project in Lyon (France) was adopted as a case study. The derived results allow predicting the tunnel lining damage areas under the impact of blast loads.