Hard rock tunnel presplitting smooth surface combined blasting structure and method for reducing blasting vibration

Abstract

The invention discloses a hard rock tunnel pre-splitting smooth surface combined blasting structure and method for reducing blasting vibration, and relates to the field of tunnel blasting, the hard rock tunnel pre-splitting smooth surface combined blasting structure comprises haunch pre-splitting holes, and the haunch pre-splitting holes are formed in a haunch contour line of a tunnel to be blasted; the first-level underholing hole, the second-level underholing hole, the auxiliary-level underholing hole and the lower end caving hole are symmetrically formed in the lower middle portion of a to-be-blasted tunnel from inside to outside, the top caving hole is formed in the upper end of the to-be-blasted tunnel in an arc shape, the arch crown hole is formed in the contour line of a tunnel arch crown, and the bottom two-circle holes are symmetrically formed in the two sides of the lower middle portion of the to-be-blasted tunnel in an arc shape. The bottom plate hole is formed in the bottom edge of the tunnel to be blasted. The method has the advantages that a partial pre-splitting blasting method is adopted, the haunch pre-splitting holes are formed in the contour line of the haunch of the tunnel to be blasted for pre-splitting blasting, the pre-cracks are formed in the haunch of the tunnel, then section-by-section delayed blasting of the shot holes in the main blasting area is conducted, and blasting vibration caused by the shot holes in the main blasting area can be reduced through the pre-cracks.

Description

technical field [0001] The invention relates to the field of blasting and excavation of hard rock tunnels, in particular to a structure and method for pre-splitting smooth surface combined blasting of hard rock tunnels that reduce blasting vibration. Background technique [0002] Tunnels have become an indispensable part of mining engineering, traffic engineering, water conservancy and hydropower engineering. The drill and blast method is a commonly used method for tunnel excavation at home and abroad. In addition to the drill and blast method, there are also mechanical excavation and shield machine excavation. However, in the excavation of hard rock tunnels, it is difficult to use mechanical excavation and other methods, and the construction efficiency is low, while the drill and blast method has strong adaptability to geological conditions and low excavation costs, and is especially suitable for the construction of hard rock tunnels. [0003] Tunnel blasting will inevitab...

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Problems solved by technology

[0004] In order to solve the above technical problems, a hard rock tunnel pre-splitting and smooth surface combined blasting structure and method are provided to reduce the blasting vibration. Excessive rock damage can easily cause tunnel instability; increased tunnel structural damage will increase operating costs in the later period; blasting in hard rock tunnels in high-stress sections may induce rockburst disasters; blasting vibration will affect surrounding buildings and affect stability. Especially in the blasting of hard rock tunnels, more explosives will be used, resulting in greater blasting vibration. Therefore, it is very necessary to adopt appropriate vibration reduction measures during the blasting and excavation of hard rock tunnels. Pre-splitting blasting As one of the commonly used controlled blasting technologies in rock engineering and mining engineering, it has obvious vibration reduction effect, which reduces the area of ​​the area affected by blasting vibration in the surrounding rock and reduces the vibration intensity of the surrounding rock in the area. However, in hard rock tunnels In the full pre-splitting blasting, the cracks in the peripheral eye cannot penetrate, resulting in the problem of pre-cracks

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