Blast-Induced Dynamic Response and Vibration Control of an Existing Water Diversion Tunnel During Adjacent Tunnel Excavation

Blasting excavation of adjacent tunnels can induce significant vibrations in existing underground structures under complex spatial constraints. This study investigates the dynamic response and vibration control of an existing water diversion tunnel subjected to blasting-induced disturbances from an adjacent tunnel. Field monitoring, three-dimensional numerical simulation, and blasting parameter optimization were integrated to reveal the vibration characteristics and control mechanisms. The propagation characteristics of blasting vibrations were first analyzed based on field measurements. A three-dimensional dynamic model was then established using MIDAS GTS NX and validated against the monitoring results. The vibration velocity, displacement response, and stress evolution of the existing tunnel lining were systematically investigated. Results indicate that vertical vibration dominates the dynamic response, while stress evolution reflects the propagation, energy transfer, and dissipation processes of blasting stress waves. Furthermore, entropy weight–gray relational analysis identified six key factors influencing blasting vibration. Based on these factors, blasting parameters were optimized by reducing energy concentration. Field verification demonstrated reductions of 11.05%, 10.69%, and 21.54% in vibration velocities along the X, Y, and Z directions, respectively. This study provides insights into vibration response mechanisms and effective control strategies for similar underground engineering projects.