A high-pressure water jet spiral cutting groove loosening blasting method

Abstract

The invention provides a method of loose blasting by high-pressure water jet helical cutting. The method includes the steps: 1, drilling; 2, performing high-pressure water jet helical cutting; 3, charging; 4, sealing holes; 5, blasting. The method has the advantages that a crack zone formed by the method compared to traditional loose blasting is wider, coal seam permeability is greatly improved, control holes are fewer, and the cost is reduced; through the application of the water jet helical cutting manner, the defects of traditional mechanical cutting, such as tool jamming and drill locking, are overcome; the size of jet seams is determined by jet parameters, so that the problem that the size of the seams affects blasting effect is solved; helical cutting can be performed in axial and radial directions alternatively, through the application of the helical cutting manner, the range of crack zone is greatly enlarged and compensating space is provided for blasting, cut density can be adjusted, blasting lumpiness is controlled, and energy availability is improved; accordingly, economic benefit is increased on the premise of effectively preventing coal and gas outburst.

Description

technical field [0001] The invention relates to the technical field of loose blasting, in particular to a high-pressure water jet spiral groove loosening blasting method. Background technique [0002] At present, the deep hole loosening blasting technology is one of the technical means to prevent coal and gas outburst during the coal roadway excavation process. This technology is to force the coal seam to produce cracks to release stress and gas by loosening the coal seam by blasting, so as to improve the air permeability and gas permeability of the coal seam. The purpose of prevention and control salient. After the blasting, although the coal body around the blast hole is broken and part of the ground stress is relieved, the coal body far away from the blast hole is compacted because there is no compensation space for blasting cracks and fragmentation, thus blocking the gas migration channel, and in the distance A new stress concentration is formed. Since the working face ...

AI Technical Summary

Problems solved by technology

After the blasting, although the coal body around the blast hole is broken and part of the ground stress is relieved, the coal body far away from the blast hole is compacted because there is no compensation space for blasting cracks and fragmentation, thus blocking the gas migration channel, and in the distance A new stress concentration is formed. Since the working face is the free surface of the blasting, the coal body tends to move towards the working face during the explosion, or the coal body in the sealing section produces a cut-opening at the working face.

In view of the above shortcomings, the control hole (without charge) is introduced as the free surface, and the control hole is drilled near the loose blasting hole to control the blasting direction and compensate the blasting crack space, forming a pressure relief groove, that is, deep hole loosening and pre-splitting controlled blasting technology , and a large number of penetrating cracks are mainly generated in the direction of the connection between the blasting hole and the control hole, so the number of control holes in other directions must be increased to achieve a better loosening effect, which will increase the workload and cost

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