Hard roof directional pressurized explosion control method

Abstract

Disclosed is a hard roof directional pressurized explosion control method. Special drilling arrangement, loading structures and hole sealing manners are selected according to self-conditions of a roof, pressurized explosion transferring media is used to fully expel air in cracks, the characteristics of low compressing performance and high dynamite utilization rate of the pressurized explosion transferring media is utilized to perform directional or non-directional control explosion to slotted drilling holes or complete drilling holes, and expansion and pulse of the pressurized explosion transferring media are utilized for secondary loosening and weakening of surround rock of the drilling holes to accelerate development and penetrating of the roof cracks and strengthen presplitting weakening of the hard roof. The method mainly includes parallelly drilling holes and alternately loading dynamites at intervals; cutting grooves of the drilling holes; and explosion safety protection. The method is convenient to implement, simple to operate, low in cost and wide in application range, and can be popularized in loosening and weakening of common roofs or top coal and coal layers.

Description

technical field [0001] The invention relates to the problem of loose pre-cracking and weakening of the roof or top coal and coal seams in coal mine production, in particular to a method for controlling directional blasting under the condition of a hard and thick roof. Background technique [0002] The problem of hard roofs in coal mines has always been an important problem that plagues the safe and efficient production of working faces. Due to the integrity of the roof and the hard lithology, as the working face advances, the hard roof hangs over a large area without collapsing, resulting in the gradual increase of the goaf space and the increasing resistance of the support of the working face. The falling gangue cannot fill the entire goaf space. When the large-scale overhanging roof suddenly collapses, the mine pressure on the working face will be intensified. Protective equipment affects the normal production of the working face and seriously threatens the life safety of...

AI Technical Summary

Problems solved by technology

Due to the integrity of the roof and the hard lithology, as the working face advances, the hard roof hangs over a large area without collapsing, resulting in the gradual increase of the goaf space and the increasing resistance of the support of the working face. The falling gangue cannot fill the entire goaf space. When the large-scale overhanging roof suddenly collapses, the mine pressure on the working face will be intensified. Protective equipment affects the normal production of the working face and seriously threatens the life safety of underground personnel

[0003] At present, there are mainly three types of hard roof control measures: advanced deep hole blasting is carried out with the advancement of the mining face, and the roof of the working face is affected by the impact of blasting and the mining stress of the stope. Compression zone, tension zone and shear zone are formed to realize the treatment and control of the integrity of the coal seam roof, but the blasting control effect on the hard roof, especially the hard thick roof, is not significant, and the drilling is complete under the condition of the hard roof. Good performance, large charge uncoupling space, low energy utilization rate of explosives in boreholes, large amount of dust and harmful gases, relatively concentrated roof damage range, and poor overall control effect on the roof of the working face; Crack weakening technology is to use the drilling water pressure to change the stress state of the coal and rock mass at the edge of the hole, resulting in cracking and crack expansion at the edge of the hole, and then using the crack water pressure to control the expansion of hydraulic cracks and weaken the overall mechanical properties of the coal and rock mass , increase the permeability of the coal and rock mass, make the coal and rock mass fully absorb water and moisten, further soften the coal and rock mass, and change the strength of the coal and rock mass through fracturing and softening, but limited by the existing technology and equipment, the equipment under high pressure water injection conditions The requirements are relatively high and there are certain safety hazards, so the control effect of hydraulic fracturing weakening technology under the condition of hard roof is not significant; There is a large uncoupling space for charges, low energy utilization rate of explosives in boreholes, and poor overall control effect on the roof of the working face

[0004] In short, the implementation of conventional blasting roof control measures for hard roofs always has the characteristics of low explosive energy utilization rate, large amount of dust and harmful gases, uneven roof weakening and damage, serious local damage, and poor overall control effect. The cracking and weakening technology is limited by the conditions of technical equipment, and the existing high-pressure water equipment is difficult to meet the weakening and cracking requirements of the hard roof

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