Method for fracturing retained filled wall of adjacent coal face

Abstract

Disclosed is a method for fracturing a retained filled wall of an adjacent coal face. The method is applicable to continuous pressure relief mining of deep coal seam groups. The method comprises the steps that the arrangement mode and parameters of drilled holes and the explosive load are designed according to the size, the construction mode and the earlier-stage breakage state of the filled wall; one to three rows of downwards-inclined reused drilled holes for construction of the filled wall are retained by a leading coal face for the adjacent coal face in a roadway; one to two columns of drilled holes which are formed in the rear portion of the interior of an end hydraulic support are filled with slurry and explosives and are sealed; and the drilled holes which are formed in the rear portion of the interior of the end hydraulic support and filled with the explosives enter the position behind the coal face along with propulsion of the coal face, fracturing of the filled wall is enhanced through microcracks generated by the earlier-stage mine pressure of the filled wall, and finally the retained filled wall is fractured through the combination between the microcracks and the lagged mining-induced stress influence. According to the invention, the filled wall retained by the adjacent coal face in goaf can be fractured, and therefore the influence of the filled wall on stress concentration in an upper adjacent coal seam and a lower adjacent coal seam is effectively eliminated, the purpose of continuous pressure relief is achieved, and the potential safety hazard of adjacent coal seam mining is eliminated.

Description

technical field [0001] The invention relates to a method for cracking the left filling wall of an adjacent coal mining face, and is especially suitable for continuous pressure relief mining of deep coal seam groups. Background technique [0002] Gobside retaining is to build a wall with a certain bearing capacity along the edge of the goaf, and retain the mining roadway of the adjacent coal mining face for use as the mining face of the coal mining face. It is one of the key technologies for continuous pressure relief mining of deep coal seam groups, and it is used to solve safety problems such as rock burst, coal and gas outburst, high gas, and high ground pressure. [0003] At present, it is more and more common to use cement-based materials to construct gob-side retaining walls, especially in deep mining areas. The cement-based walls are quick-setting and early-strength, supplemented by reinforcement methods such as shear anchors and three-dimensional reinforcement ribs, ...

AI Technical Summary

Problems solved by technology

Although the cement-based wall has micro-cracks induced by the two mining operations, it still continues to increase resistance and cannot self-destruct the bearing capacity. A concentrated stress zone is formed in the upper and lower adjacent coal seams, which cannot achieve the purpose of continuous pressure relief. is a potential safety hazard for adjacent coal seam mining

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