Research on Key Technologies of Smooth Blasting in NEOM Tunnel Project Adic in Saudi Arabia
To solve the problem of the poor smooth blasting effect of the NEOM tunnel branch project in Saudi Arabia,five influencing factors of smooth blasting effect,such as drilling quality,hole failure radius,load duration,detonation transmission structure and delay interval,were found through field investigation and calculation analysis.Drilling quality is an artificial factor.The delay error between adjacent peripheral holes and the charge structure of buffer holes are the factors that influence the overall smooth blasting effect.The surrounding hole detonation structure and the delay interval between the surrounding hole and the buffer hole are the factors that affect the local smooth blasting effect.Drilling quality can be improved by means of management.The use of a 5 g/m detonating cord to connect the peripheral holes of the vault and a 40 g/m detonating cord to connect the peripheral holes of the side wall can play a joint action mechanism for the stress wave of the peripheral holes and improve the flatness between the peripheral holes.The central and top small-diameter cartridge charge in the buffer hole can reduce the depth of the fracture zone invading the surrounding rock to control the over-excavation.Changing the surrounding hole detonation structure can solve the problem of explosive desensitization failure and reduce local under-excavation.Controlling the delay interval between the peripheral hole and the buffer hole within 200ms can effectively prevent the cartridge in the peripheral hole from being dragged away from the design position to control the local under-excavation.After the implementation of comprehensive improvement measures,the smooth blasting effect has been greatly improved,and the jagged phenomenon of the excavation contour surface has disappeared,which can save the amount of concrete,reduce the time of under-excavation treatment,and accelerate the excavation cycle.
NETL
NSTL
万方数据
维普
