Spalling permeability increasing method for rapid excavation of underground seam gateway

Abstract

The invention discloses a spalling permeability increasing method for rapid excavation of an underground seam gateway. The method is particularly suitable for advancing pre-pumping of a high-gas low-permeability seam gateway. A first spalling hole is constructed in the head-on geometric center position of the seam gateway, and second spalling holes are formed in the positions over, under, left and right the first spalling hole; third spalling holes are constructed in the positions over and under the second spalling holes horizontal to the first spalling hole, and exhausting and mining holes are constructed in the center points of the connecting lines of the first spalling hole and the third spalling holes; after drilling is finished, quick lime grout is injected into the third spalling holes in a crossing manner, and the spalling holes are control holes of one another; and through spalling pressure generated by the holes, net-shaped cracks are generated between the holes, so that the coal permeability is greatly improved, the gas exhausting and mining efficiency is improved, and the excavation speed of the seam gateway is improved; and the method is simple in technology, convenient to operate, wide in grout source, cheap and low in cost.

Description

technical field [0001] The invention relates to a coal seam fracturing anti-permeability method, in particular to an expansion crack anti-permeability method for rapid excavation of an underground coal seam roadway. Background technique [0002] Most coal seams in my country have the characteristics of high gas, high adsorption, and low air permeability, and with the increase of coal seam mining depth, the problem of low air permeability becomes more prominent, which brings safety hazards to coal seam roadway excavation and seriously affects the excavation speed , leading to tension in coal mining succession. At present, the pressure relief and permeability enhancement measures commonly used in high gassy and low permeability coal seams in my country include hydraulic slotting, hydraulic fracturing, and deep hole pre-splitting blasting. The method of enhanced gas extraction by hydraulic slotting is complex and difficult, the width of the slots is not enough, the resulting cr...

AI Technical Summary

Problems solved by technology

The method of enhanced gas drainage by hydraulic slotting is complex and difficult, the width of the slots is not enough, the resulting cracks are few, and the effect is not ideal; the hydraulic fracturing process is complicated, the equipment is huge and expensive, and the high water injection pressure is easy Destroy the roadway and induce coal and gas outburst accidents; the charging process of deep hole pre-splitting blasting technology is complicated, and phenomena such as "dummy guns" are prone to occur during the blasting process, and the huge energy of the blasting will induce the occurrence of coal and gas outbursts

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