Shallow close coal seam group exploitation top board first pressing rack support resistance determination method

Abstract

The invention discloses a shallow close coal seam group exploitation top board first pressing rack support resistance determination method. When a lower coal seam working face has first pressing (interlayer rock break off for the first time) through physical simulation, a key layer is broken off for the first time to form an "asymmetric three-hinged arch structure", and a loading layer of the structure is a coal seam goaf collapse roof. An upper coal seam collapse roof structure is activated when the lower coal seam is mined, forming an "asymmetric three-hinged arched girder and arched casing load structure" with the lower coal seam three-hinged arch structure. The parameter of the lower coal seam roof structure block is determined by building a shallow close coal seam group lower coal seam key layer fixed girder mechanics model and correcting a key layer limit collage calculating formula. A rack load calculating model when the close coal seam group lower coal seam exploitation has the first pressing is built. Based on static and dynamic load, a reasonable rack work resistance determination method for the first pressing is disclosed, and a theory basis for the shallow close coal seam group exploitation roof first pressing is provided.

Description

【Technical field】 [0001] The invention belongs to the technical field of coal mining, and relates to a method for determining the support resistance of a supporting support for the initial pressure of a shallow-buried and short-distance coal seam group mining roof. 【Background technique】 [0002] The Jurassic coalfield in northern Shaanxi is a super-large coal resource base in my country. The coal reserves in this area are large, the coal seams are buried shallowly, there are many mineable coal seams, and the mining conditions are relatively simple. However, as the mining scale of each mine in the coalfield increases year by year, the first coal seam in some areas has been mined, and the mining of the second and third main coal seams will begin. According to the production practice over the years, in the process of coal seam group mining, when the lower coal seam is mined, it is easy to appear abnormal pressure frame, coal wall slabs, two road bottom heaving volume increase,...

AI Technical Summary

Problems solved by technology

According to the production practice over the years, in the process of coal seam group mining, when the lower coal seam is mined, it is easy to have abnormal pressure, coal wall slabs, two road bottom heaving volume increase, roof collapse and other severe pressure phenomena, which not only seriously threaten the operators safety, and restrict the safe and efficient production of the mine

[0003] At present, the structural characteristics of the roof and the support load are determined by the roof structure characteristics of the single shallow coal seam mining for the first time in the coal seam mining under the shallow coal seam group, but the calculation process does not take into account the upper coal seam. The action characteristics of uneven load formed by mining, and the breaking law and characteristics of the roof under the action of uneven load are not considered

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