Blasting Structure and Method of Compound Cutting in Medium-deep Hole and Large Section

Abstract

A medium-length hole large cross-section composite cut blasting structure and method. A large-diameter hole (1) perpendicular to a working face is disposed at a position near but lower than a center of a tunneling working face. Several cut holes (2) are disposed around the large-diameter hole (1). The cut holes (2) are distributed in a spiral pattern with a central axis of the large-diameter hole (1) as a center. The lengths of the cut holes (2) increase gradually from the center of the spiral pattern to outside. The cut holes (2) are inclined holes with the inner end inclined toward the central axis of the large-diameter hole (1). Several peripheral holes (4) and several floor holes (5) are disposed along an outer contour of the working face on the tunneling working face for controlling the contour of the working face after the blasting. Two rows of auxiliary holes (3) are disposed between the peripheral holes (4) and the cut holes (2), and one row of auxiliary holes (3) is disposed between the cut holes (2) and the floor holes (5). The cut holes (2), the auxiliary holes (3), the peripheral holes (4) and the floor holes (5) are all provided with water bags, explosives and detonators therein. The configuration of the present invention reduces the vibration velocity of blasting, the charge volume for blasting and the amount of labor, and also causes less damage to surrounding rocks.

Description

technical field [0001] The invention relates to underground engineering blasting technology, in particular to a compound cutting blasting structure and method for medium-deep holes and large sections. Background technique [0002] At present, there are two main types of cuts for tunnels excavated by full-face blasting: vertical cuts and inclined cuts. The disadvantage of vertical cutting is that the spacing of the cutting holes, the quality of the drilling holes and the charge are strict, and it is not easy to master. The number of holes required for cutting and the consumption of explosives are relatively large, and the volume of the cutting is small. It is suitable for blasting excavation. Tunnels with small cross-sections; oblique cutting. Because the cutting eye and the tunnel face are obliquely intersected, the cutting is more reliable, the precision of the drilling is not high, and the operation is relatively simple. Common, and the most widely used in the form of wed...

AI Technical Summary

Problems solved by technology

However, this aspect does not take into account the impact on blasting such as changes in the form of cutting

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