Pressure relief method for high-gas high-ground-stress driving face

Abstract

The invention discloses a pressure relief method for a high-gas and high-ground-stress driving face, belongs to the technical field of coal mining, and relates to a roof fracturing technology. A pressure relief method for a high-gas and high-ground-stress driving face comprises the steps that (1) high-pressure water fracturing is conducted, pressure relief is conducted on surrounding rock of a top plate, obvious cracks are formed, and top plate gas is released in advance; (2) sand is added to the top plate, cracks are expanded, closing is slowed down, and pressure relief is prolonged; (3) drilling while digging, releasing the pressure of the coal seam area, and providing a buffer space for releasing the pressure of the top plate; and (4) monitoring the hydraulic fracturing effect, and eliminating a blank area through empirical data. According to the method, the pressure relief effect is more sufficient and more uniform, and safe and efficient tunneling of the high-gas and high-stress tunneling working face can be guaranteed.

Description

technical field [0001] The invention belongs to the technical field of coal mining, and relates to a roof fracturing technology, in particular to a pressure relief method for a high gas and high ground stress driving face. Background technique [0002] In the process of coal mining, a large area of ​​the hard roof often hangs in the air during the mining process, and it is easy to accumulate a large amount of energy to cause excessive stress concentration, which easily leads to the appearance of strong mine pressure and rock burst. Once it suddenly collapses, it will It will cause a powerful impact airflow and bring serious hidden dangers to underground safety production. The existing roof fracturing technology is widely used in surface wells, that is, the fracturing mode of fracturing the roof of the coal seam rather than the coal seam itself is used to solve the problems that cannot be caused by conventional hydraulic fracturing measures in soft coal. [0003] Due to the ...

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Problems solved by technology

[0003] Due to the rich coal resources in my country and the relatively complex coal seam occurrence conditions, roof CO2 gas-phase fracturing is generally used for pressure relief in high-gas and high-in-situ stress excavation working faces, but there are the following defects: (1) After fracturing, the fractures close quickly and the closure period It is basically 3-4 days, and the control distance is too short; (2) The convergence speed of the two sides of the roadway is too fast, and the pressure relief after fracturing is not sufficient and uneven. (3) The single cost of gas phase fracturing is too high and takes a relatively long time