Triaxial multiple coal and gas outburst test method

Abstract

The invention discloses a triaxial multiple coal and gas outburst test method. The method comprises the following steps of: 1) installing a telescopic steel sleeve provided with a raw coal test specimen between a confining pressure cavity upper cover and a lower bearing plate; 2) placing various sensors in the telescopic steel sleeve; 3) arranging a sealing aluminium sheet I on a sealing taper sleeve; 4) installing a primary pressure chamber and a secondary pressure chamber at the top of a main pressure chamber; 5) monitoring variations of stresses, temperatures and gas pressures of the raw coal test specimen before and after tests; 6) pressurizing the test specimen in the main pressure chamber; 7) evacuating air inside a rubber sleeve of the main pressure chamber; 8) filling gases into the raw coal test specimen in the main pressure chamber and the secondary pressure chamber; 9) carrying out a primary outburst test; and 10) carrying out a secondary outburst test. By adopting the test method, raw coal in different sizes can be adopted to carry out coal and gas outburst tests in the triaxial stress state to study the coal and gas outburst occurrence principles more comprehensively and scientifically.

Description

technical field [0001] The invention relates to a coal and gas outburst test method, in particular to a triaxial coal and gas multiple outburst test method. Background technique [0002] Coal and gas outburst is an extremely complex dynamic phenomenon in coal mines, which seriously threatens the safe production of coal mines and affects the production capacity of coal mines. Delayed outburst of coal and gas often occurs in the excavation face, especially in the process of unearthing coal in Shimen. After the first outburst, the sharply inclined coal seams also experienced secondary or even three outbursts. According to incomplete statistics, the number of postponed outbursts in the country accounts for a few percent of the total number of outbursts. Although the proportion is not large, such outbursts are often beyond people's expectations because of "delay". , there is no certain rule, it can be as short as a few minutes, as long as more than ten hours, or even a few days...

AI Technical Summary

Problems solved by technology

According to incomplete statistics, the number of postponed outbursts in the country accounts for a few percent of the total number of outbursts. Although the proportion is not large, such outbursts are often beyond people's expectations because of "delay". , there is no certain rule, it can be as short as a few minutes, as long as more than ten hours, or even a few days; the second outburst often occurs during the cleaning process after the first outburst; Or it is cleaning up after the last outburst, and the personnel cannot retreat in time, which will cause great harm to the miners, cause heavy casualties and property losses, and seriously threaten the safe production of the mine.

The mechanism and form of coal and gas outburst are complex. With the increase of coal mining depth and the increasingly complex mining conditions, the occurrence of coal and gas outburst is also more difficult to predict. At present, scholars at home and abroad have studied the mechanism of coal and gas outburst Research has yielded some results, but most of them are hypotheses from field statistics and laboratory studies

These hypotheses can only explain a certain part of the phenomenon of coal and gas outburst, but cannot constitute a complete quantitative principle system

It is very difficult to predict coal and gas outburst using existing hypotheses, and the accuracy is not high, which brings huge hidden dangers to mine safety production

[0003] At present, the equipment for coal and gas outburst tests mainly has the following problems: (1) Most of the test pieces used are briquettes. Although briquettes are similar to raw coal to a certain extent, there are still large differences between the two. There are certain limitations in the research on the mechanism of coal and gas outburst; (2) Some briquettes are large in size, and the test preparation period is long; (3) The installation of the device is relatively complicated; (4) The device can only generate once Prominent, cannot truly reflect the phenomenon of coal and gas outburst underground; (5) The opening speed of the outburst is slow, which affects the time of coal and gas outburst to a certain extent, and cannot be close to the situation on site

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