Methods for preventing floor heave in coal mine roadways based on floor blasting pressure relief

Abstract

This invention relates to the field of coal mine roadway deformation control, specifically a method for preventing floor heave in coal mine roadways based on floor blasting pressure relief. The method includes: S1: determining the side support pressure curves of the coal seam and the side support pressure curves of the coal pillar or roadway backfill in the mining roadway; introducing Rankine earth pressure theory to analyze the stress characteristics of the mining roadway floor, determining the range of the coal seam side slip body and the range of the coal pillar or roadway backfill side slip body; S2: determining the blasting pressure relief strata in the floor; S3: determining the blasting pressure relief range; S4: blasting the determined blasting pressure relief range using blasting pressure relief boreholes. This invention selects the blasting pressure relief zone in the thick, hard coal seam floor, close to the slip body, allowing for floor heave prevention based on the minimum blasting pressure relief zone during construction; simultaneously, after determining the slip body using Rankine earth pressure theory, this invention determines a reasonable blasting pressure relief zone range based on the slip body and the support pressure.

Description

Technical Field

[0001] This invention relates to the field of coal mine roadway deformation control, specifically a method for preventing floor heave in coal mine roadways based on floor blasting pressure relief. Background Technology

[0002] Coal mine roadways, especially those on both sides of the working face, face the risk of floor heave during or after the working face is excavated. This can affect normal mine production and threaten the safety of personnel and equipment. Most existing prevention methods are passive, involving cleaning away the heave portion when it occurs. This method requires multiple cleanings, impacting production and is relatively dangerous. Another method involves excavating trenches in the roadway floor to relieve pressure, but the excavation volume is difficult to determine, and excavation also affects production. Therefore, this paper proposes a floor heave prevention method that allows for a single pressure relief operation without affecting roadway use. This method is of great significance for improving mine production safety and ensuring normal mine operation. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a method for preventing floor heave in coal mine roadways based on floor blasting pressure relief, specifically including the following steps:

[0004] S1: Determine the coal seam side support pressure curve and the coal pillar or roadway backfill side support pressure curve of the mining roadway; introduce Rankine earth pressure theory to analyze the stress characteristics of the mining roadway floor, and determine the range of coal seam side slip and the range of coal pillar or roadway backfill side slip.

[0005] S2: Identify the blasting and decompression rock strata in the bottom plate

[0006] S21: First, identify the thick, hard base strata in the base plate;

[0007] S22: Secondly, select the thick and hard bottom rock layer that is closest to and does not intersect with the side slip body of the coal seam and the side slip body of the coal pillar or the roadway filling body as the blasting decompression rock layer;

[0008] S3: Determine the blasting pressure relief range

[0009] S31: Calculate the area S1 of the coal seam lateral slip body and the area S2 of the coal pillar or roadway filling body lateral slip body;

[0010] S32: Determine the energy E1 that can be released by the deformation of the bottom heave of the side slip body of the coal seam per unit area; determine the energy E2 that can be released by the deformation of the bottom heave of the side slip body of the coal pillar or roadway filling body per unit area; determine the capacity E that can be absorbed by the compression deformation of the blasting decompression zone per unit area.

[0011] S33: Determine the area of ​​the blasting pressure relief zone S = (E1 × S1 + E2 × S2) / E;

[0012] S34: Determine the boundary of the blasting pressure relief zone on the coal seam side, wherein the boundary of the coal seam side should reach or exceed the peak position of the coal seam side support pressure curve; determine the boundary of the blasting pressure relief zone on the coal pillar or roadway filling body side, wherein the boundary of the coal pillar or roadway filling body side should reach or exceed the peak position of the coal pillar or roadway filling body side support pressure curve; then determine the left and right widths of the blasting pressure relief zone, and the height of the blasting pressure relief zone can be calculated based on the area S of the blasting pressure relief zone;

[0013] S35: Determine the top boundary of the blasting pressure relief zone. The top boundary is the top boundary of the blasting pressure relief rock layer. The bottom boundary of the blasting pressure relief zone can be determined based on the height of the blasting pressure relief zone.

[0014] S4: Use blasting decompression drilling to blast the determined blasting decompression range.

[0015] Preferably, in step S21, the thick and hard base rock layer is determined based on the critical layer theory, or a rock layer with a large thickness and hard lithology is selected based on experience.

[0016] Preferably, step S4 further includes S41: constructing pressure relief boreholes from the mining roadway to the blasting pressure relief zone, loading explosives into the pressure relief borehole portion within the blasting pressure relief zone, sealing the pressure relief borehole portion between the blasting pressure relief zone and the sliding body, and then carrying out blasting.

[0017] Preferably, step S4 further includes S42: grouting to reinforce the pressure relief borehole section in the side slip body of the coal seam, coal pillar, or roadway filling body.

[0018] The beneficial effects of this invention are as follows: The method for preventing floor heave in coal mine roadways based on floor blasting pressure relief in this invention selects the blasting pressure relief zone in the thick, hard coal seam floor, close to the slip body, allowing for floor heave prevention based on the minimum blasting pressure relief zone required for construction. Furthermore, by introducing Rankine earth pressure theory to determine the slip body, this invention determines a reasonable blasting pressure relief zone range based on the slip body and the supporting pressure. The pressure relief borehole serves a dual purpose: it can be used to construct the blasting pressure relief zone and to reinforce areas prone to floor heave in mining roadways. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a front (tendant) cross-sectional view of the coal mine roadway floor heave prevention method based on floor blasting pressure relief according to the present invention;

[0021] Figure 2 This is a side view (direction) cross section of the coal mine roadway floor heave prevention method based on floor blasting pressure relief according to the present invention;

[0022] Figure 3 This is a front (tendant) cross-sectional view of the drilling construction of the coal mine roadway floor heave prevention method based on floor blasting pressure relief according to the present invention;

[0023] In the diagram, 1-basic roof, 2-immediate roof, 3-coal seam, 41-first floor stratum, 42-second floor stratum, 5-thick and hard floor stratum (blasting pressure relief stratum); 6-mining roadway; 7-coal pillar or roadway filling body, 8-goaf, 9-coal seam side support pressure curve, 10-coal pillar or roadway filling body side support pressure curve, 11-coal seam side slip body, 12-coal pillar or roadway filling body side slip body, 13-blasting pressure relief zone, 14-pressure relief borehole. Detailed Implementation

[0024] To illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to the accompanying drawings.

[0025] like Figure 1-3 As shown, the working conditions involved in the embodiment of the present invention are as follows: above the coal seam 3 are the immediate roof 2 and the basic roof 3 in sequence, and below the coal seam 3 are the first floor stratum 41, the second floor stratum 42, and the thick and hard floor stratum 5 in sequence; a mining roadway 6 (goaf excavation) needs to be excavated along the goaf 7 in the coal seam. At this time, the left side of the mining roadway 6 is the side of the coal seam to be mined, and the right side is the coal pillar 7; or the mining roadway 6 is the roadway left during the mining of the previous working face. At this time, the left side of the mining roadway 6 is the side of the coal seam to be mined, and the right side is the roadway filling body 7 (goaf retention); since the coal seam 6 is buried at a large depth, floor heave is prone to occur. In this regard, the present invention proposes a method for preventing and controlling floor heave in coal mine roadways based on floor blasting pressure relief, including the following steps:

[0026] S1: Determine the coal seam side support pressure curve 9 and the coal pillar or roadway filling body side support pressure curve 10 of the mining roadway 6; introduce Rankine earth pressure theory to analyze the stress characteristics of the mining roadway floor, and determine the range of the coal seam side slip body 11 and the range of the coal pillar or roadway filling body side slip body 12; for specific determination methods, please refer to the master's thesis "Research on the Mechanism and Control Technology of Thick Coal Seam Roadway Heave Along the Goaf in Gucheng Mine", China University of Mining and Technology, author Zheng Yu, Section 3.1.

[0027] S2: Identify the blasting and decompression rock strata in the bottom plate

[0028] S21: First, determine the thick and hard base rock layer 5 in the base plate. The thick and hard base rock layer 5 can be determined based on the key layer theory, or it can be selected based on experience, with a larger thickness and harder lithology.

[0029] S22: Next, select the thick and hard bottom rock layer 5 that is closest to and does not intersect with the coal seam side slip body 11 and the coal pillar or roadway filling body side slip body 12 as the blasting pressure relief rock layer;

[0030] S3: Determine the blasting pressure relief range

[0031] S31: Calculate the area S1 of the coal seam lateral slip body 11 and the area S2 of the coal pillar or roadway filling body lateral slip body 12;

[0032] S32: Determine the energy E1 that can be released by the bottom heave deformation of the coal seam side slip body 11 per unit area; determine the energy E2 that can be released by the bottom heave deformation of the coal pillar or roadway filling body side slip body 12 per unit area; determine the capacity E that can be absorbed by the compression deformation of the blasting decompression zone 13 per unit area.

[0033] S33: Determine the area of ​​the blasting decompression zone 13, S = (E1 × S1 + E2 × S2) / E;

[0034] S34: Determine the boundary of the blasting pressure relief zone 13 on the coal seam side. The boundary of the coal seam side should reach or extend to the left beyond the peak position of the coal seam side support pressure curve 9. Determine the boundary of the blasting pressure relief zone 13 on the coal pillar or roadway filling body side. The boundary of the coal pillar or roadway filling body side should reach or extend to the right beyond the peak position of the coal pillar or roadway filling body side support pressure curve 10. Then determine the left and right widths of the blasting pressure relief zone 13. The height of the blasting pressure relief zone 13 can be calculated based on the area S of the blasting pressure relief zone 13.

[0035] S35: Determine the top boundary of the blasting pressure relief zone 13. The top boundary is the top boundary of the blasting pressure relief rock layer. The bottom boundary of the blasting pressure relief zone 13 can be determined based on its height.

[0036] S4: Detonate within the determined detonation range using blasting decompression drilling.

[0037] S41: Construct pressure relief borehole 14 from the blasting pressure relief zone 13 in the self-recovery roadway 6 direction, charge the pressure relief borehole portion within the blasting pressure relief zone 13 with explosives, seal the pressure relief borehole portion between the blasting pressure relief zone and the slip body (coal seam side slip body 11 or coal pillar or roadway filling body side slip body 12); and carry out blasting;

[0038] S42: Grouting reinforcement of the side slip body 11 of the coal seam, the side slip body 12 of the coal pillar or roadway filling body, and the pressure relief borehole section.

[0039] While the present invention has been described above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for preventing floor heave in coal mine roadways based on floor blasting pressure relief, characterized in that, Includes the following steps: S1: Determine the coal seam side support pressure curve and the coal pillar or roadway backfill side support pressure curve of the mining roadway; introduce Rankine earth pressure theory to analyze the stress characteristics of the mining roadway floor, and determine the range of coal seam side slip and the range of coal pillar or roadway backfill side slip. S2: Identify the blasting and decompression rock strata in the bottom plate S21: First, identify the thick, hard base strata in the base plate; S22: Next, select the hard floor rock layer that is closest to the coal seam lateral slip body and the coal pillar or roadway filling body lateral slip body and does not intersect as the blasting decompression rock layer; S3: Determine the blasting pressure relief range S31: Calculate the area of ​​coal seam lateral slip body S 1. and the area of ​​the side slip body of the coal pillar or roadway filling body. S 2; S32: Determine the energy released by the floor heave deformation of a unit area of ​​coal seam side slip body. E 1. Determine the energy released by the deformation of the bottom heave of the side slip body of the coal pillar or roadway backfill per unit area. E 2. Determine the compressive deformation capacity that the unit area of ​​the blasting relief zone can absorb. E ; S33: Determine the area of ​​the blasting decompression zone S = ( E 1× S 1+ E 2× S 2) / E ; S34: Determine the boundary of the blasting pressure relief zone on the coal seam side, wherein the boundary of the coal seam side should reach or exceed the peak position of the coal seam side support pressure curve; determine the boundary of the blasting pressure relief zone on the coal pillar or roadway filling body side, wherein the boundary of the coal pillar or roadway filling body side should reach or exceed the peak position of the coal pillar or roadway filling body side support pressure curve; then determine the left and right widths of the blasting pressure relief zone, based on the area of ​​the blasting pressure relief zone. S The height of the blasting decompression zone can be determined. S35: Determine the top boundary of the blasting pressure relief zone. The top boundary is the top boundary of the blasting pressure relief rock layer. The bottom boundary of the blasting pressure relief zone can be determined based on the height of the blasting pressure relief zone. S4: Blasting within the defined pressure relief range using blasting pressure relief boreholes; including S41: constructing pressure relief boreholes from the mining roadway to the blasting pressure relief zone, loading explosives into the pressure relief borehole portion within the blasting pressure relief zone, sealing the pressure relief borehole portion between the blasting pressure relief zone and the slip body; and then blasting; S42: grouting to reinforce the pressure relief borehole section in the side slip body of the coal seam, coal pillar, or roadway filling body.

2. The method for preventing floor heave in coal mine roadways according to claim 1, characterized in that, In step S21, the thick and hard base rock layer is determined based on the critical layer theory, or by selecting a rock layer with a larger thickness and harder lithology based on experience.

Images