Visual liquid nitrogen freeze-thaw coal crack propagation dynamic monitoring system

Abstract

The invention relates to a frozen-thawed coal body laboratory device, in particular to a visual liquid nitrogen frozen-thawed coal body crack propagation dynamic monitoring system. The visual dynamic monitoring system comprises a liquid nitrogen injection system and a liquid nitrogen freezing and thawing system, and is characterized by further comprising an optical speckle monitoring system and an inverted metallographic microscope monitoring system. Visual observation of coal sample crack propagation in a liquid nitrogen freezing and thawing experiment is realized; acquiring crack propagation image data in the whole freezing and thawing process; through the experimental device, the change of microscopic cracks of a coal sample under the action of liquid nitrogen can be monitored in real time, and the law and effect of damage, deformation and fracture of a coal body are dynamically analyzed when the coal sample is fractured by the liquid nitrogen; and combining the morphology, displacement and strain of the coal sample to obtain the relationship among the liquid nitrogen freeze-thaw characteristic parameters, the mechanical parameters and the fracture deformation.

Description

technical field [0001] The invention relates to a laboratory device for freezing and thawing coal bodies, in particular to a dynamic monitoring system for crack extension of liquid nitrogen freezing and thawing coal bodies. Background technique [0002] my country's energy consumption structure has been dominated by coal for a long time. As of 2020, coal resources still account for 56.80% of my country's primary energy consumption structure, which is an important pillar for the sustained and stable development of my country's national economy. In recent years, coal mining technology and technology have been continuously improved, and my country's coal mining has gradually transitioned from shallow mining to deep mining. With the increase of mining depth, the gas content and gas emission in coal seams increase sharply, and mine gas disasters become an important factor restricting the safe and efficient mining of coal mines. According to statistics, my country's high-gas mine...

AI Technical Summary

Problems solved by technology

Most laboratory experiments can only observe the changes of coal samples before and after liquid nitrogen freezing and thawing, and cannot effectively monitor the expansion of micro-cracks on the coal surface and the characteristics of coal deformation and failure during the whole process of liquid nitrogen freezing and thawing.

At present, the equipment involved in the detection of the whole process of liquid nitrogen focuses on the internal structure changes of the coal body, and there are few experimental researches and related equipment on the visualization of the crack propagation and deformation characteristics of the coal body in the whole process of liquid nitrogen freezing and thawing.

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