Gas-solid coupling coal sample wave velocity anisotropism detection device and method

Abstract

The invention discloses a gas-solid coupling coal sample wave velocity anisotropism detection device and method. The device comprises a pressure-bearing cavity, a gas transmission system, a coal sample placing table, a true-triaxial compression system, a transducer set and a sound wave meter, the pressure-bearing cavity is composed of a pressure-bearing container with the upper part being open anda piston top cover, a plurality of axial load rods of the true-triaxial compression system penetrate through the side wall of the pressure-bearing container and the piston top cover to be in contactwith the four side faces and the top face of a test coal sample, and the gas transmission system comprises a vacuum pump, a safety gas cylinder and a high-pressure gas cylinder. The device can simulate the true situation of coal body under deep ground, accordingly the feature of the ultrasonic wave velocity anisotropism of the coal sample with different physical mechanical properties under the joint influences of different gas pressures, different temperatures and different triaxial loading stress, and theoretical support is provided for follow-up coal mine exploration and mining.

Description

technical field [0001] The invention relates to a coal sample wave velocity anisotropy detection device and method, in particular to a coal sample wave velocity anisotropy detection device and method with gas-solid coupling. Background technique [0002] In my country, the safety of the coal industry has always been a major strategic issue related to the national economy, the people's livelihood and national development. In recent years, due to the functional upgrading of the coal industry and the improvement of safety awareness, the incidence of coal mine safety accidents has decreased year by year, but the number of deaths caused by coal mine safety accidents remains high. Therefore, the safe production of coal mines is still the top priority in the coal mining process, especially as the mining depth continues to increase, the ground stress, gas pressure and ground temperature are constantly increasing, which makes low-strength tectonic coal It is more likely to protrude,...

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Problems solved by technology

At present, most of the research on this only considers a single factor, such as the influence of coal samples with different physical and mechanical properties on the ultrasonic wave velocity when one of the three factors of in-situ stress, gas concentration and temperature changes independently.

When considering the influence of ground stress on ultrasonic wave velocity, most scholars only carry out uniaxial loading or pseudo-triaxial loading on coal samples. In fact, underground coal bodies are in a three-dimensional stress state, and the stresses in the three directions are different. , the uniaxial and pseudo-triaxial loading cannot truly reflect the actual state of the stress on the coal body in the deep underground, and the experimental results have limitations. In the case of a change, the pore structure of the coal body will change, which will affect the propagation speed of the ultrasonic wave in the coal body

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