A wall-mounted surrounding rock section blasting excavation method for tunnels in karst areas

Abstract

The invention discloses a wall-hanging surrounding rock section blasting excavation method for tunnels in karst areas. The wall-hanging surrounding rock section blasting excavation method is characterized in that shot holes comprise arc-shaped auxiliary holes uniformly distributed in surrounding rock and peripheral holes on the counter line; the first row of auxiliary holes are formed from the bottom of the wall-hanging surrounding rock; from the first row of auxiliary holes, three rows of equally-spaced auxiliary holes are formed in the direction of the counter line from the inside out; vibration reduction holes are formed between the auxiliary holes; the peripheral holes are formed in the area of the counter line, distributed in an equally-spaced manner, and high-density in edge and regular in middle; decoupling charging is performed on the auxiliary holes and the peripheral holes, and the auxiliary holes and the peripheral holes are charged with different charging coefficients respectively; the auxiliary holes and the peripheral holes are connected through a parallel net, and a detonating tube blasting system is utilized to control millisecond detonating; and the blasting sequence is that the auxiliary holes are blasted from the inside out and the peripheral holes are blasted from the middle to two sides. The wall-hanging surrounding rock section blasting excavation method effectively controls the blasting effect, maximally reduces outline overexcavation and karst cavity perturbation, and meanwhile, guarantees the construction quality and the economical benefits on the basis of traditional blasting.

Description

technical field [0001] The invention relates to a tunnel excavation method, in particular to a wall-mounted surrounding rock section blasting excavation method for a tunnel in a karst section. Background technique [0002] Usually, the excavation of highway tunnel projects will adopt the drilling and blasting method for construction. Although the blasting construction technology can bring certain benefits to the project in terms of cost and construction period, it is difficult to control the intensity of traditional blasting and will affect the surrounding rock. A large degree of disturbance is generated, so it cannot be applied to tunnel engineering with some special geological conditions. [0003] At present, with the expansion of my country's high-grade highways to the southwest, tunnel engineering will inevitably encounter karst areas. In rare super-large karst areas, due to the extremely complex geological conditions of the karst area through which the tunnel passes, i...

AI Technical Summary

Problems solved by technology

In rare super-large karst areas, due to the extremely complex geological conditions of the karst area through which the tunnel passes, great care must be taken when excavating the karst section of the tunnel. Conventional blasting may cause large-scale cave collapse and tunnel contour overexcavation , how to effectively control the blasting effect on the basis of traditional blasting, minimize contour overbreak and karst cavity disturbance, and at the same time ensure construction quality and economic benefits has become a new challenge for karst tunnel blasting construction

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