Exploiting protective layer is one of the most effective measures for control of coal and gas outburst; and the key problem is to locate the protection scope exactly. Aimed at the problem of locating the protection scope for the exploiting of steeply clined upper-protective layer

based on the theory of gas leak flow and the coupling effect between deformation of coal & rock and gas seepage

the methane gas seepage field equation and coal & rock deformation field equation are established; and then the mathematical models of gas leak flow coupled solid and gas of steeply clined upper-protective layer are also established. Taking a coal mine in Nantong mining area for engineering example

by using multi-physical field coupling system for numerical calculation of the model

the law of gas pressure distribution in protected layer is gained after protective layer was mined. Furthermore

the pressure-relief scope of protective layer mining is also obtained. It is shown that the protection scopes of numerical simulation are basically closed to the results of practical test. Therefore

this study results can provide theoretical guidance for locating protection scope and are of great significance for practical matters.