Model test study on vibration blasting of large cross-section tunnel with small clearance in horizontal stratified surrounding rock

Abstract During the construction process of excavation blasting in small clearance tunnel, the blasting vibration inevitably disturbs and damages the interlaid rock and influences the stability. A large-scale three-dimensional tunnel excavation simulation test system is designed and developed. The system includes the monitoring system and the test bench which is composed of steel members, reaction frame and hydraulic loading device. Based on the system and portable electric spark source, the dynamic response disciplinarian of the interlaid rock of large cross-section tunnel with small clearance during excavation is studied. The results indicate that the blasting process during the backward tunnel excavation has a greater influence on the stability of the interlaid rock, yet the surrounding rock at the skewback of the tunnel had a low sensitivity to excavation blasting vibration and is affected by the blasting process for a long time. The research methods and results will guide similar engineering.