A Coal Sample Ultrasonic Primary Frequency Detection Device and Method Under the Influence of Three Factors

Abstract

The invention discloses a coal sample ultrasonic dominant frequency detecting device and method under the influence of three factors. A high pressure gas bottle is arranged on the external side of a box; the high pressure gas bottle is communicated with the interior of the box through a pressure increasing / reducing valve; a coal sample placing table is fixed on the bottom of the box, the top, which is corresponding to the coal sample placing table, of the box is provided with a through hole, the through hole is provided with a sealing piston that is matched with the through hole; an ultrasonic wave excitation probe and a ultrasonic wave receiving probe are symmetrically arranged in the box; the ultrasonic wave excitation probe and the ultrasonic wave receiving probe are individually connected to the inner lateral wall of the box through a spring support rod; and an ultrasonic wave detector is electrically connected to the ultrasonic wave excitation probe and the ultrasonic wave receiving probe through a connection wire. The provided device can simulate the actual situation of underground coals so as to obtain the responding characteristics of dominant frequency under the coupled three factors namely crustal stress, gas pressure, and physical mechanical properties of coal, and thus basic technical guide can be provided for preventing outburst of gas and coal.

Description

technical field [0001] The invention relates to a coal sample main frequency detection device and method, in particular to a coal sample ultrasonic main frequency detection device and method under the influence of three factors. Background technique [0002] In recent years, gas accidents in coal mines have dropped significantly year by year, but the number of major gas accidents and the total number of deaths still account for the largest number of accidents and deaths. Gas prevention and control is the top priority of coal mine safety production work; especially The mining depth of my country's coal mines is increasing year by year. At present, there are 47 coal mines in China with a mining depth of more than 1,000 meters, and they are mainly distributed in key coal base areas such as East China. The increase of coal mine mining depth leads to the increase of ground stress, the increase of original gas pressure in coal seams, and the risk of outburst of low-strength structu...

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Problems solved by technology

At present, relevant scholars consider more single factors, such as the response characteristics of the main frequency of ultrasonic waves in coal samples under different stress conditions, the response characteristics of main frequency of ultrasonic waves in coal samples with different physical and mechanical properties, and the lack of main frequency response characteristics under three-factor conditions. The research results have limitations and cannot simulate the actual situation of deep underground coal bodies well; while the main frequency of ultrasonic waves can sensitively reflect the different characteristics of the medium under different conditions (for example, in daily life, the main frequency of sound presented by containers with different scale water volumes large differences), so it is of great significance to study the main frequency of ultrasonic

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