Construction device and method for fracturing and softening hard and difficultly-collapsing top plate in underground coal mine

Abstract

The invention discloses a construction device and method for fracturing and softening a hard and difficultly-collapsing top plate in an underground coal mine. The construction method comprises the steps of S1, obtaining a hard and difficultly-collapsing top plate by using the combination of geological data and the key stratum theory, that is, determining a fracturing target stratum; S2, drilling aplurality of fracturing holes at intervals in the hard and difficultly-collapsing top plate, wherein the depth of the fracturing hole is matched with the position of the fracturing target stratum; S3, delivering high-pressure water into the fracturing holes through a fracturing device for hydraulic fracturing, wherein the fracture structure of the hard and difficultly-collapsing top plate is destroyed under the action of the high-pressure water so as to form cracks; S4, injecting quartz sand into the fracturing holes through the fracturing device; S5, injecting an acid liquor into the fracturing holes through the fracturing device; and S6, repeating the steps S3-S5 for each fracturing hole. The hard and difficultly-collapsing structure of the coal seam is destroyed through hydraulic fracturing and acid fracturing, the integrity and the rock mass strength are reduced, and the possible harms imposed on the normal mining of the working face, the personnel and the equipment by the hard and difficultly-collapsing top plate in the mining process are weakened or even avoided.

Description

technical field [0001] The invention relates to the technical field of mine pressure control on hard and difficult roofs in underground mines, in particular to a construction device and method for fracturing and softening hard and difficult roofs in coal mines. Background technique [0002] The hard and difficult-to-break roof rock mass in coal mines has a large layer thickness and strong integrity, and the structural weak planes and joints and fissures are not developed, which makes it difficult to caving after coal mining. Once it falls, it will be accompanied by obvious dynamic phenomena, such as strong impact load, large-area pressure on the roof, hurricane, coal and gas outburst, etc., resulting in damage to supporting equipment and even vicious accidents that endanger personal safety. The control methods of hard and difficult roof in coal mine are mainly coal pillar support method, goaf filling method, pre-splitting blasting forced caving method, pressure water injec...

AI Technical Summary

Problems solved by technology

Although the above-mentioned technologies have achieved some results in the control of hard and difficult roofs, they still have the following deficiencies: (1) The coal pillar support method and the goaf filling method both utilize the integrity of the hard and difficult roof; (2) the support The disadvantage of the method is that the coal loss is large, but it still has the risk of large-scale pressure, and it is basically not used now; (3) the cost of the gob filling method is too high and is rarely used; (4) the forced blasting caving technology and deep hole Pre-splitting blasting technology has certain safety hazards for high-gas mines; (5) The water injection weakening roof method has a limited range of weakening of the hard and difficult roof, and it is difficult to form artificial cracks in a large area; (6) Although the hydraulic fracturing method makes the hard and difficult roof Cracks are formed when the rock layer of the roof breaks, which weakens the integrity of the hard and difficult roof, but the effect of weakening the strength of the rock mass is not obvious

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