Evaluation of blasting parameters for hydraulic tunnels based on multiple monitoring information

Abstract

AbstractBlasting excavation is frequently used in myriads of hydraulic tunnels in Southwest China. To evaluate the effects of blasting parameters on the stability of tunnels and reveal reasonable blasting parameters, a field test on blasting parameters is carried out in typical sections of a diversion tunnel at a large hydropower project in Southwest China. Two different charging methods are designed. The multiple monitoring techniques, i.e. blasting vibration test (point), wave velocity test (line), three-dimensional laser scanning (plane), and microseismic monitoring (volume), combined with corresponding criteria are adopted to evaluate the effects of two different blasting parameters on construction safety. Multiple monitoring results well reflect the disturbance of blasting excavation on rock mass. In addition, the effects on rock damage and deformation of two different blasting parameters have some differences. The blasting parameters with less charge in the cut and breaking holes and more charge in the perimeter hole contribute to reducing rock mass damage and deformation. Therefore, the more reasonable blasting scheme is revealed. Present study will provide a new thought for the evaluation and optimization of blasting parameters in hydraulic tunnels.

Keywords

• Blasting parameter evaluation
• multiple monitoring
• Xulong hydropower station
• diversion tunnel
• rock mass damage