Experimental method for simulating coal mass fluid-solid thermal-chemical multi-field coupling under thermal-mechanical coupling

Abstract

The invention discloses an experimental method for simulating coal mass fluid-solid thermal-chemical multi-field coupling under thermal-mechanical coupling, which comprises the following steps: preparing a coal sample; loading a test sample, and performing gas adsorption of a coal sample; setting an initial confinement pressure, an initial temperature and an initial axial stress of a molded coal test sample and the loading thresholds for the temperature and the axial stress; injecting oxygen gas, and heating the molded coal test sample; performing first time of data collection; carrying out temperature and stress combined loading; performing second time of data collection; establishing a coal mass seepage-stress-temperature-chemical multi-field coupling model, and studying and revealing coal mass fluid-solid thermal-chemical coupling mechanism under thermal-mechanical coupling in combination with a numerical simulation method. The experimental method disclosed by the invention realizes laboratory simulation of the spontaneous combustion temperature rise rule under coal seam stress loading, can be used for quantitative study of the coal mass stress-strain relationship, coal mass permeability evolution and coal-oxygen reaction rule under thermal-mechanical coupling, and provides basis for predicting coal seam spontaneous combustion sites and time and determining the best time for controlling spontaneous combustion.

Description

technical field [0001] The invention relates to an experimental method for simulating the whole coupling process of underground gas-containing coal bodies prone to spontaneous combustion, and belongs to the technical field of gas control and fire prevention and control in coal mine production. Background technique [0002] my country's coal resource endowment and long-term strong demand have led to coal development shifting to the deep at a rate of 10-25m per year, with an average mining depth of about 700m and 47 pairs of mines exceeding 1000m. With the increase of mining depth, the gas content and pressure of coal seams continue to increase, and the ground temperature increases. A large number of shallow gas mines are upgraded to high gas mines and even coal and gas outburst mines. Coal seams that are not easy to spontaneously combust are transformed into spontaneously combustible or even spontaneously combustible coal seams, resulting in spontaneous combustion of gas and c...

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Problems solved by technology

However, these experimental studies above mainly simulated the effects of different ambient temperatures on coal mechanical properties, permeability, and gas flow field gas extraction, and did not involve the gas-containing coal in the high-temperature and high-in-situ stress environment that actually occurs in the coal seam. Coal-oxygen reaction heat release process, lack of experimental analysis methods for coal spontaneous combustion, gas explosion and other secondary disasters that may be associated with gas drainage in coal and rock fissure fields

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