Abstract: In order to explore the law of gas outburst in soft coal seam, similar materials, which were different each other in composition, were prepared on the basis of orthogonal experiments. In the similar materials, sodium humate solution was used as a cementing agent and pulverized coal as aggregate. The effects of mass fraction of sodium humate in the solution, moisture content and other parameters on the mechanical, adsorption and other properties of similar materials were studied by means of range analysis and data fitting. The results show that the mass fraction of sodium humate in the solution plays a major role in controlling the mechanical properties of similar materials, that both the molding moisture and the mass fraction of sodium humate in the solution have a significant impact on the gas adsorption and desorption characteristics of similar material, the cumulative desorption volume, and the gas adsorption volume increases with the increase in the mass fraction of sodium humate in the solution, that the cumulative desorption volume decreases with the increase of moisture content, and the gas adsorption volume increases with the gas pressure increasing, that the permeability of similar materials changes with the increase of mass fraction of sodium humate in the solution as a negative exponential function.

Key words: soft coal, solid-gas coupling, similar material, orthogonal method, adsorption properties, gas outburst