Gas drainage drill hole structure formed in coal layer and method for fabricating same

Abstract

The invention provides a gas drainage drill hole structure formed in a coal layer and a method for fabricating same. The gas drainage drill hole structure comprises a gas drainage drill hole (2) and multiple auxiliary holes (3) arranged around the gas drainage drill hole; and the auxiliary holes are filled with expanding agents. According to the gas drainage drill hole structure and the method for fabricating same, coal wall cracks in two coal wall pressure relief bands on a roadway can be effectively blocked to block a channel for air in the roadway to flow to the gas drainage drill hole so as to reduce the air leakage quantity of the gas drainage drill hole and greatly improve the gas drainage efficiency. In addition, the gas drainage drill hole structure is capable of improving the stability of the coal walls and reducing the accidents of injuring the people by coal wall cavings, and has important meaning in field construction safety.

Description

technical field [0001] The invention relates to the technical field of gas drainage borehole sealing in high-gas mines or coal and gas outburst mines, and in particular relates to a gas drainage borehole structure formed in a coal seam and a manufacturing method thereof. Background technique [0002] Gas drainage is the root cause of comprehensive management of mine gas in high gas mines and coal and gas outburst mines. There are many methods of gas drainage, which can be divided into coal seam drainage, adjacent layer drainage, and goaf drainage according to space; According to the time, it can be divided into pre-mining extraction, extraction while digging, extraction while mining, and gob drainage; according to the extraction process, it can be divided into roadway drainage method, drilling drainage method, combined drainage method of roadway and drilling According to whether it is affected by pressure relief, it can be divided into non-pressure relief pumping, pressure r...

AI Technical Summary

Problems solved by technology

At the same time, in the area after the concentrated stress peak, the coal seam as a whole turns into a plastic state, and the limit plastic zone around the borehole expands sharply, and a large number of cracks are connected with the gas drainage borehole and coal roadway. Under such circumstances, even if cement mortar or polyurethane is used to seal the gas drainage borehole itself tightly, it cannot prevent the air in the roadway from entering the gas drainage borehole from the cracks in the coal walls of the two sides of the roadway, resulting in gas drainage boreholes. serious air leak

Moreover, with the widespread promotion and application of directional long drilling in my country, during the construction process of directional long drilling, due to the high pressure water (generally reaching about 30-40MPa) will discharge the coal powder from the drilling hole to the roadway. The broken medium in the pressure relief zone of the coal wall has a certain scouring effect, which seriously affects the stability of the coal wall, and there is a danger of fragmentation, which also poses a serious threat to the personal safety of the construction workers on site

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