Rapid air leakage detection method for underground goaf

Abstract

The invention relates to a rapid air leakage detection method for an underground goaf. The method comprises the following steps: determining release points and sampling points of air leakage detection of a to-be-detected goaf according to an internal structure and a pressure difference test of the to-be-detected goaf; injecting nitrogen into the to-be-detected goaf at the release point, releasing SF6 gas into the to-be-detected goaf from the release point after monitoring that the flow and the pressure of the nitrogen injection pipe are stable, and recording the release time; when SF6 gas is monitored at each sampling point, collecting a gas sample; detecting the SF6 concentration of each gas sample through a gas chromatograph, and determining the SF6 concentration of the gas sample collected at each sampling point at each sampling time; and according to the shortest air leakage distance between the release point and each sampling point, the release time, the SF6 concentration of each sampling point at each sampling time, the sampling time of SF6 detected by each sampling point for the first time and the sampling time of SF6 detected by each sampling point at the maximum concentration, rapidly obtaining the air leakage condition of the to-be-detected goaf.

Description

technical field [0001] The present application relates to the technical field of coal mines, in particular to a rapid air leakage detection method in underground mined-out areas. Background technique [0002] The broken coal left in the goaf after coal seam mining is extremely prone to spontaneous combustion under the condition of continuous air leakage from the working face and the cracks in the isolated coal pillar. Spontaneous combustion of coal incomplete combustion produces a large amount of CO, C 2 h 6 and other harmful gases, causing the concentration of harmful gases underground to exceed the standard, endangering the life safety of mine workers and affecting the normal production of coal mines. [0003] With the depletion of coal resources in eastern China and industrial transformation, the focus of coal mining in China has gradually shifted to the western region. Due to the small inclination angle of the coal seam and good geological conditions, most of the mine...

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Problems solved by technology

[0005] At present, the method of direct release of tracer gas is generally used in the detection of air leakage in the goaf. In practical applications, due to the slow gas migration in the goaf (usually less than 0.1m / min), the SF 6 The migration of gas inside the goaf is extremely slow, and the length of the air leakage and gas migration path in the large-scale gob is at least thousands of meters. Slow, resulting in the failure to collect gas samples in time, resulting in low accuracy of air leakage detection results in gobs

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