Measurement method of protected layer swelling deformation quantity

Abstract

The invention discloses a measurement method of a protected layer swelling deformation quantity. The method comprises the steps of (a) using a drilling machine to drill a hole, (b) using the drilling machine to carry out reaming operation on the drill hole, (c) sending a top plate displacement measuring device to the top of the drill hole, and then sending a bottom plate displacement measuring device to the top end of an expanded hole, (d) fixing a hollow rod to the opening of the drill hole, (e) recording top plate displacement measuring device initial data d1 and bottom plate displacement measuring device initial data d2, (e) after the protection layer working surface is pushed, reading top plate displacement measuring device initial data d3 and bottom plate displacement measuring device initial data d4, (g) substituting the data collected in two times into a formula D=(d4-d2)-(d3-d1) to calculate and obtain the protected layer swelling deformation quantity. According to the method, the displacement measuring devices are arranged at the top plate and the bottom plate of a protected layer, the factors of unstable drill hole and unstable collapse holes are overcome, the swelling deformation of the protected layer can be timely captured, and the measurement is more accurate.

Description

technical field [0001] The invention relates to a method for measuring deformation, in particular to a method for measuring the amount of expansion and deformation of a protected layer, and belongs to the technical field of coal mine anti-gas outburst safety management. Background technique [0002] The "Coal Mine Safety Regulations" clearly stipulates: "When mining coal seam groups in coal and gas outburst mines, the protective layer must be mined first. After mining the protective layer, the protected area in the protected layer shall be excavated as a non-outburst dangerous coal seam. In protected areas, measures must be taken to prevent prominent dangers." Mining protection layer is the most effective regional outburst prevention measure to prevent coal and gas outburst, and it has been widely used in outburst mines with coal seam group mining conditions. Its essence is: after the protective layer is mined, the surrounding rock will expand and deform due to pressure rel...

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Problems solved by technology

[0005] It is not difficult to see that the above-mentioned patents can all measure the expansion and deformation of the protected layer, but in actual operation, due to the fact that drilling penetrates more layers, it is greatly affected by mining, especially the lithology of the roof and floor of the protected layer is relatively soft. The hole is unstable, the hole wall is easy to peel off or even collapses, resulting in large errors in test results, or even errors, which seriously threaten the mining safety of the protected layer

However, when the detection signals based on ultrasonic waves and electromagnetic radiation are observed, the detection signals are subject to more interference, which is more suitable for the detection of areas within the pressure relief range. It is difficult to detect the deformation and expansion of the protected layer, and the accuracy is low, and the overall stability of the system is poor. It consumes a lot of manpower and material resources and the cost is high, so it is not easy to promote on a large scale

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