Research On Gas Seepage Characteristics And The Construction Of Gas And Solid_ Coupling Model

Disaster prevention and control of coal and gas outburst is the major challenges of the coal mine production faced, gas seepage in the coal body is an important indication of judge to the degree of difficulty of coal and gas outburst. The flow of gas in the coal seam was affected by a number of factors, which is a complex solid - gas coupling process. In this paper, the gas-filled coal as research object,coal gas containing pores, fracture structure,seepage characteristics are studied by Micromeritics ASAP 2020 physical adsorption-type instrument, VEGAⅡtype built-spectrum scanning electron microscopy, and Self-developed triaxial permeameter and so on. Through In-depth analysis of the theory, establish the gas and solid coupling model. Some progress has been made through these as follows:1) Summarize the genesis, pores and cracks causes, classification , and micro-structural characteristics of outburst coal; and use fractal dimension of the theory of the case to deal with SEM images of coal by means of scanning electron microscope; comparative analysis of the outburst coal's and not outburst coal's the internal pore structure.2) Analyze in-depth the seepage characteristics of the sensitive factors the impact of the gas-filled coal. It is proved by experiments and numerical simulation that: the gas seepage velocity of outburst coal samples increase with the increase of gas pressure under fixed axial and confining pressures, and the relationship between gas seepage velocity of outburst coal samples and gas pressure can be described as quadratic polynomial function; the phenomenon that the increase of gas pressure result in the permeability of outburst coal showing a first decreases and then increases known as the Klinkenberg effect; the permeability of outburst coal was "V" shape change with the increase of gas pressure; with the increase in gas pressure, Klinkenberg coefficient b and the absolute permeability Kg can be described as power function relationship; the gas pressure p and the permeability K can be described as quadratic polynomial function.3) With 3 different types of adsorbed gases were studied for their adsorption properties of coal flow impact of the law. It is proved that: N2 permeability higher than the permeability of CH4, CH4 permeability greater than CO2; gas adsorption was stronger, the Klinkenberg effect was more obvious, the permeability of coal was worse.4) Selected two outstanding dangerous gases CH4 and CO2, carried out experiment of the coal all the stress - strain with two kinds of gas cases, its complete stress - strain process was divided into five phases, and comparative analysis of the two kinds of gas in the coal complete stress - strain during the change of flow rate.5) From the physical parameters of the basic definition, Presented porosityφ, permeability than the surfaceΣand K by using advanced mathematics, rock mechanics, elasticity, seepage mechanics and other physical parameters of the knowledge, and the establishment of mathematical models based on fractal theory of the stress field coupling seepage field equations and nonlinear coupled equations.