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Aiming at the problems of easy spalling and roof fall in the soft coal seam under the influence of strong deep mining, the 31020 working face of Pingdingshan No.12 coal mine is used as the engineering background, combined with nuclear magnetic resonance, etc. Various technical methods have carried out research on the water absorption characteristics, composition, micro-structure, and fracture morphology of coal at different immersion time. The experimental results show that the coal sample in this mining area belongs to coking coal under the bituminous coal category. The main inorganic substances are kaolinite and calcite.

As coal mining gradually extends deeper, coal seams in China generally show high stress, high gas pressure and low permeability, bringing more difficulty to coal mining. Therefore, in order to strengthen gas extraction, it is necessary to carry out reservoir reconstruction after deep coal seams reached. In this paper, the distribution and evolution laws of fracture zone overlaying strata of J15 seam in Pingdingshan No. 10 coal mine after excavation were studied by combining similar simulation and numerical simulation, meanwhile, the gas transport law within fracture zone was numerically simulated. The results show that the fracture zone reaches a maximum of 350 mm in the vertical direction and is 75 mm away from W9,10 coal seams in vertical distance. Since W9,10 coal seams are in an area greatly affected by the bending zone of J15 coal seam under the influence of mining, the mining of J15 coal seam will exert a strong permeability enhancement effect on W9,10 coal seams. The J15 coal seam can act as a long-distance protective layer of W9,10 coal seams to eliminate the outburst danger of the long-distance coal seams in bending zone with coal and gas outburst danger, thereby achiev?ing safe, productive and efficient integrated mining of coal and gas resources. The gas flux of mining-induced fractures in the trapezoidal stage of mining-induced fracture field is far greater than that in the overlaying stratum matrix. The horizontal separation fractures and vertical broken fractures within the mining-induced fracture field act as passages for gas-flow. Compared with gas transport in the overlaying stratum matrix, the horizontal separation fractures and vertical broken fractures within the mining-induced fracture field play a role in guiding gas-flow. The research results can provide theoretical support for the arrangement of high-level gas extraction boreholes in roof fracture zones.

In this paper, we consider the 1-D heat transfer equation with radiative loss. The variational iterative Sumudu type integral transform is used to obtain the analytical solution for the heat transfer problems. The presented method is efficient and accurate.