Layout method for roadway in water control and scour prevention area

Abstract

The invention discloses a roadway layout method in a water control and scour prevention area, which belongs to the field of roadway safety optimization and comprises the following steps of: dividing a coal seam into a small panel with the maximum panel size of less than or equal to 600m and a large coal pillar with the isolation coal pillar width of more than or equal to 200m; the method comprises the following steps: firstly, calculating the panel scale and the coal pillar width according to a water pressure value P of an extremely thick aquifer and a coal seam impact tendency index K; then, mining roadways and connection roadways are arranged in all panels, micro-seismic monitoring sensors and seepage pressure testing meters are arranged on goaf top plates, large coal pillars and the ground surface, and stress and permeability are monitored in real time; an interval jump mining mode is adopted, and the interval between adjacent panels is larger than or equal to 6 months. On-site contrast tests show that compared with a traditional'large panel-small coal pillar ', the method has the advantages that the frequency, permeability and water inrush risk of micro-seismic events are remarkably reduced, and the collaborative effectiveness of the layout on scour prevention and water control is verified.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of roadway safety optimization, and particularly relates to a water control and burst prevention regional roadway layout method. BACKGROUND

[0002] In the mining of coal seams under thick aquifers, the chain induction of rock burst and water inrush disasters has become a major problem threatening mine safety. The traditional roadway layout generally adopts a "large panel and small coal pillar" mode (panel size > 800 m, and isolation coal pillar width < 50 m). Although this mode can improve resource recovery rate, it has the intrinsic defects of easy induction of key layer breakage in traditional large-scale panel mining, leading to double risks of rock burst and water channeling, and the small coal pillar cannot effectively block the seepage pressure of the aquifer, causing water inrush risk.

[0003] At the same time, the excessive panel size leads to an over-limit suspended span of the overburden key layer, and when it breaks, the released elastic energy exceeds 106J, inducing strong mine earthquake or even rock burst. Moreover, the excessively narrow isolation coal pillar (< 50 m) undergoes hydraulic fracturing under the action of high water pressure (often up to 4-8 MPa), and the permeability increases from the initial value of 10-15m2 to 10-12m2 (1000 times), losing the water blocking ability. The dynamic stress wave generated by rock burst can accelerate the expansion of coal pillar fractures, while the water inrush seepage weakens the strength of the coal pillar, forming a vicious cycle of "rock burst → water channeling → rock burst again". Therefore, it is urgent to invent a technical method that combines rock burst prevention and water control functions to fundamentally break the occurrence of disasters. SUMMARY

[0004] To solve the above technical problems, the application provides a water control and burst prevention regional roadway layout method, which comprises:

[0005] determining the maximum allowable size of the panel according to the water pressure value of the thick aquifer and the rock burst tendency index of the coal seam;

[0006] determining the minimum width of the isolation coal pillar according to the water pressure value of the thick aquifer;

[0007] dividing the coal seam into a plurality of independent panels and setting an isolation coal pillar between adjacent panels according to the maximum allowable size of the panel and the minimum width of the isolation coal pillar;

[0008] arranging the mining roadway and the connecting roadway in each panel to form a roadway system;

[0009] arranging a sensor array in the roadway system to monitor the stress and permeability in real time and control the mining according to the stress and permeability.

[0010] Optionally, the water pressure value of the thick aquifer is obtained based on the static water pressure, the disturbed water pressure and the tectonic water pressure.

[0011] The static water pressure is measured by a hydrological borehole;

[0012] The disturbed water pressure is obtained by embedding a seepage pressure gauge in a pre-mining area;

[0013] The tectonic water pressure is obtained by a fault permeability coefficient.

[0014] Optionally, the calculation expression of the coal seam impact tendency index is:

[0015]

[0016] Wherein, DT is a dynamic failure time; WCF is an elastic energy index; and KEI is an impact energy index.

[0017] Optionally, the calculation expression of the size of the panel is:

[0018]

[0019] Wherein, P is a water pressure of a thick aquifer; K is a coal seam impact tendency index; L max is a size of the panel.

[0020] Optionally, the calculation expression of the minimum width of the coal pillar is:

[0021]

[0022] Wherein, W min is the minimum width of the coal pillar.

[0023] Optionally, the maximum allowable size of the panel is not greater than 600 m, and the minimum width of the isolation coal pillar is not less than 200 m.

[0024] Optionally, the width-height ratio of the isolation coal pillar is greater than 8:1 and the integrity coefficient is greater than 0.9.

[0025] Optionally, the sensor array comprises microseismic sensors and seepage pressure gauges, and the distance between adjacent sensors is not greater than 50 m.

[0026] The stress threshold obtained by monitoring is not greater than 0.6 times the uniaxial compressive strength of the coal pillar.

[0027] In another aspect, the present application also provides an electronic device, comprising a memory, a processor, and a calculation program stored in the memory and executable on the processor, wherein the processor executes the calculation program to realize the method.

[0028] In another aspect, the present application also provides a computer readable storage medium, which stores a computer program, wherein the computer program is executed by a processor to realize the method.

[0029] Compared with the prior art, the present application has the following advantages and technical effects:

[0030] 1. Source disaster suppression mechanism: propose "small panel area + large coal pillar" collaborative layout, i.e. panel area size ≤600m (preferably 400-600m), and isolated coal pillar width ≥200m (preferably 200-250m); small panel area suppresses the impact, by setting the panel area size ≤600m (preferably 400-600m), the key layer breakage step distance is controlled, so that the frequency of rock burst is greatly reduced; large coal pillar resists seepage, by setting ≥200m wide isolated coal pillar, a low-permeability water-blocking barrier is formed, and the water inrush probability is greatly reduced; by setting "small panel area + large coal pillar" collaborative layout, the frequency of rock burst is greatly reduced, the average number of microseismic events is reduced from 180 before using the technology to 50 after using the technology, the frequency ratio is reduced from 10% to 3.5%, and the occurrence of rock burst accidents is effectively suppressed. In addition, the permeability of the overlying strata of the goaf is greatly reduced, from high permeability 102 and 62.3 (unit: 10 -13 m 2 ) before using the technology to low permeability 18.6 (unit: 10 -13 m 2 ) after using the technology, respectively decreased by 83.4 and 43.7, forming a low-permeability water-blocking barrier, effectively reducing the occurrence of water inrush accidents.

[0031] 2. Dual-disaster prevention and control mechanism: small panel area limits the key layer overhanging span, reduces the breakage energy, and reduces the development depth of mining-induced fissures; large coal pillar as a stress buffer absorbs impact energy and forms a high-pressure water-resistant barrier. By using the coal pillar to simultaneously realize stress buffering and water pressure regulation, the coal pillar is regulated, and at the same time, the propagation path of the impact wave and the water channel are blocked, which cooperatively prevents the occurrence of impact and water disaster accidents.

[0032] 3. Safe and efficient production: in the mining of coal seams under thick aquifer, the method of the invention can effectively control the roadway deformation, key layer suspended span and the probability of water inrush accidents. The large coal pillar can absorb 80% of the dynamic load stress, the stress concentration coefficient is reduced from 2.5 to 1.2, the roadway deformation is reduced from 300-420mm of the traditional layout method to less than 50mm, and the improvement rate is as high as 85%; The key layer breaking geometry is limited to ≤600m, the key layer suspended span is reduced from 350-400m of the traditional layout method to less than 220m, and the improvement rate is 38%; The coal pillar ≥200m makes the permeability of the overlying strata decrease significantly, and the probability of water inrush accidents is reduced from 28% per year of the traditional layout to less than 5%. Based on the above advantages, the cumulative deformation of the roadway is reduced by 85%, the repair rate is reduced by 80% (the floor displacement rate is reduced from 8mm / day to 1.5mm / day), the service life is increased from 2-3 years to more than 6 years, the disaster prevention cost per ton of coal is reduced from 38 yuan / ton to 15 yuan / ton, the service life is increased by 3 times, and the disaster prevention cost per ton of coal is reduced by more than 50%. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of this application illustrated in the drawings, and their description, are presented to explain the application and are not intended to limit the application. In the drawings:

[0034] Figure 1 Layout mode diagram of the water control and scour prevention area roadway system of the embodiment of the invention;

[0035] Figure 2 Layout method flow chart of the water control and scour prevention area roadway system of the embodiment of the invention;

[0036] Figure 3 Stratigraphic section view of the mine and microseismic sensor array of the embodiment of the invention;

[0037] Figure 4 "Small panel-large coal pillar" water control and scour prevention effect display diagram of the embodiment of the invention;

[0038] Figure 5 Another display diagram of the "small panel-large coal pillar" water control and scour prevention effect of the embodiment of the invention;

[0039] Among them, 1. The original first panel area - large panel area; 2. The original second panel area - large panel area; 3. The third panel area - small panel area; 4. Small panel area - large coal pillar layout; 5. 101 working face; 6. 102 working face; 7. 103 working face; 8. 104 working face; 9. 201 working face; 10. 202 working face; 11. 203 working face; 12. 204 working face; 13. 205 working face; 14. Large coal pillar; 15. 301 working face; 16. 302 working face; 17. 303 working face; 18. Various types of coal mine tunnels; 19. Microseismic monitoring sensors; 20. Medium sandstone; 21. Mudstone; 22. Aquifer; 23. Fine and coarse sandstone; 24. Sandy mudstone; 25. Wide coal pillar; 26. Goaf. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0042] Example 1

[0043] like Figure 1 As shown, this embodiment provides a method for laying out laneways in a water control and anti-scouring area, including:

[0044] Determine the maximum allowable size of the panel area based on the water pressure value of the thick aquifer and the coal seam impact tendency index;

[0045] Determine the minimum width of the isolated coal pillar based on the water pressure value of the thick aquifer;

[0046] Divide the coal seam into several independent panels and leave isolation coal pillars between adjacent panels based on the maximum allowable panel size and the minimum width of the isolation coal pillars;

[0047] Arrange mining tunnels and connecting tunnels in each panel area to form a tunnel system;

[0048] A sensor array is arranged in the tunnel system to monitor stress and permeability in real time and control mining based on the stress and permeability.

[0049] Specifically:

[0050] Step 1: Divide the mining units. Combined with geological exploration data, determine the water pressure value P (MPa) of the thick aquifer and the coal seam impact tendency index K. Then, calculate the maximum allowable scale of the panel area (no more than 600m) according to the formula.

[0051] Step 2, isolated coal pillar parameter design. According to the water pressure value P of the thick aquifer, the minimum coal pillar width (width ≥ 200 m) is obtained by using the coal pillar width calculation formula.

[0052] Step 3, roadway system layout. According to the maximum allowable size of the panel calculated in the above steps, the coal seam is divided into several independent mining panels, and the length of a single panel along the strike is ≤600 m; a rectangular isolated coal pillar with a width ≥200 m is left between adjacent panels; and the extraction roadway and the connecting roadway are arranged in each panel.

[0053] Step 4, mining and monitoring cooperative control. Microseismic sensor arrays and seepage pressure gauges are arranged in the goaf roof and coal pillars, and a reasonable mining mode is adopted to monitor the roof and coal pillar stress and permeability threshold in real time.

[0054] Further, the determination of the water pressure value P of the thick aquifer in step 1 includes the following steps:

[0055] 1. The static water pressure P0 is measured through the hydrological borehole;

[0056] 2. The seepage pressure gauge is buried in the pre-mining area to monitor the mining disturbance water pressure Pd;

[0057] 3. The fault permeability coefficient is used to calculate the tectonic water pressure Ps;

[0058] 4. The maximum values of P0, Pd and Ps are multiplied by the disturbance coefficient to calculate the water pressure value of the aquifer (1.2 when the buried depth is ≤600 m, and 1.5 when the buried depth is >600 m).

[0059] Further, the calculation method of the coal seam impact tendency index K in step 1 is:

[0060]

[0061] DT is the dynamic failure time;

[0062] WCF is the elastic energy index;

[0063] KEI is the impact energy index.

[0064] Further, the maximum allowable size of the panel (not greater than 600 m) in step 1 is mainly based on the fact that when the panel size is small, the key layer breakage step distance can be controlled, the internal energy storage of the roof is reduced, and the probability of rock burst is greatly reduced. The specific panel size calculation formula is:

[0065]

[0066] P is the water pressure of the thick aquifer;

[0067] K is the coal seam impact tendency index.

[0068] Further, considering that the coal pillar needs to have integrity, the fissure development density is ≤3 lines / 10m, and the integrity coefficient is >0.9, the isolation coal pillar width is set to be not less than 200m.

[0069] Further, the coal pillar width calculation formula in step 2 is:

[0070]

[0071] P is the water pressure of the thick aquifer.

[0072] Further, the reasonable mining mode in step 4 is the interval skip mining mode, and the interval between adjacent panels is ≥6 months, and the mining is continued after the mine pressure of the interval working face is stable.

[0073] Further, the width-height ratio of the isolation coal pillar is >8:1, and the integrity coefficient is >0.9.

[0074] Further, the interval between the microseismic sensor array arranged in the goaf roof and the seepage pressure test gauge is less than or equal to 50m, which ensures that the roof and coal pillar stress state and permeability change can be monitored in real time, the coal pillar stress threshold is ≤0.6 times the uniaxial compressive strength, and the permeability threshold is ≤10 -14 m 2 , to prevent stress and permeability values from changing suddenly (mine earthquake and water inrush accidents).

[0075] Further, the panel mining sequence adopts the interval skip mining mode, and the interval time between adjacent panels is ≥6 months.

[0076] Example Two

[0077] The embodiment provides a water control and impact prevention regional roadway layout method, which comprises:

[0078] As shown in Figure 1 , the original one panel-large panel 1 is located at the lower left side of the drawing, the panel strike length is about 800m, and four working faces 101 working face 5, 102 working face 6, 103 working face 7 and 104 working face 8 are arranged in sequence inside, and various types of roadways 18 and connecting roads of the coal mine are arranged between and on both sides of the working faces.

[0079] The original two panels-large panel 2 is located in the middle of the drawing and slightly to the right, the panel strike length is about 900m, and five working faces 201 working face 9, 202 working face 10, 203 working face 11, 204 working face 12 and 205 working face 13 are arranged in sequence inside, and various types of roadways 18 of the coal mine are also connected.

[0080] The third panel-small panel 3 is located at the rightmost side of the drawing, the panel trend length is about 550m, the internal is arranged 301 working face 15, 302 working face 16, 303 working face 17 three working faces in turn, and the working faces are connected by various types of roadways 18 in the coal mine. The small panel-large coal pillar arrangement 4 refers to the layout mode of “small panel-large coal pillar” between the third panel-small panel 3 and the adjacent panel, that is, the scale of the third panel itself is less than or equal to 600m, and a large coal pillar 14 is left between the third panel and the adjacent panel.

[0081] The large coal pillar 14 is located between the original second panel-large panel 2 and the third panel-small panel 3, with a width of about 210m, in the form of a rectangular strip, and plays a role in isolation and water prevention and control. The wide coal pillar 25 refers to the ordinary coal pillar left between the original first panel-large panel 1 and the original second panel-large panel 2, and between the original first panel-large panel 1 and the third panel-small panel 3, and the width is obviously smaller than that of the large coal pillar 14. Various types of roadways 18 in the coal mine pass through each panel, including recovery roadways, transportation roadways, connecting roadways and the like, connecting each working face to form a complete production system. Microseismic monitoring sensors 19 are arranged in the surface, underground roadways and coal pillars at an interval of less than or equal to 50m, for real-time monitoring of the stress and permeability changes of the roof and coal pillars.

[0082] As shown in Figure 3 , the microseismic monitoring sensors 19 are arranged on the surface at a certain grid, for receiving roof breaking signals. The medium sandstone 20 is located below the surface and is one of the key layers of overburden rock, which is prone to breaking due to large-scale panel mining.

[0083] The mudstone 21 is located below the medium sandstone and plays a role in local water isolation, with a relatively thin thickness. The aquifer 22 is a thick aquifer, with a vertical depth of about 400-550m from the working face cut; the water pressure is high, with a measured value of 4-8MPa, which is the main source of water inrush disasters. Microseismic monitoring sensors 19 are also arranged in the aquifer and near the upper and lower interfaces, for monitoring the aquifer rupture and seepage pressure changes. The fine and coarse sandstone 23 is located below the aquifer and has a relatively hard lithology, which is prone to water flowing fractured. The sandy mudstone 24 is located below the fine and coarse sandstone and has a relatively soft lithology, which serves as the direct roof or false roof of the coal seam. The coal seam is located below the sandy mudstone 24 and is the layer where the working face is located. The goaf 26 is the cavity formed after the coal seam has been mined and is located below the coal seam and expands with the advancement of the working face.

[0084] Example Three

[0085] In this embodiment, a water control and rock burst prevention regional roadway layout method is provided, which comprises:

[0086] To verify the effectiveness of the water control and rock burst prevention regional roadway layout method provided in this embodiment, a field comparison effect verification example of the coal pillar setting mode under different panel arrangement modes in the same mine is provided, which verifies the characteristics of the key layer breaking, the synergistic isolation and crack control and the seepage resistance and pressure regulation effects, as shown in Figure 4 andFigure 5 as shown.

[0087] The present embodiment arranges the original first panel-large panel 1 in the southeast area of the minefield, the panel span is 800m, which is greater than 600m, adopts the "large panel-small coal pillar" regional roadway layout method, and is composed of 4 working faces of 101 working face 5, 102 working face 6, 103 working face 7 and 104 working face 8; the two sides of each working face are arranged with recovery roadway and transportation roadway 18, and the roadways are communicated with each other through the connecting roadway 18. The original second panel-large panel 2 is arranged in the middle of the minefield, the panel span is 900m, which can be greater than 600m, and also adopts the "large panel-small coal pillar" layout method, and is composed of 201 working face 9, 202 working face 10, 203 working face 11, 204 working face 12 and 205 working face 13; the preparation roadway 18 is arranged between the original first panel 1 and the original second panel 2, and the area is isolated by the wide coal pillar 25. The three panels-small panel 3 is arranged in the northwest area of the minefield, the panel span is 550m, which can be less than 600m, adopts the "small panel-large coal pillar" layout method, and is composed of 301 working face 15, 302 working face 16 and 303 working face 17; the wide coal pillar 14 with a width of 210m is arranged between the original second panel 2 and the three panels 3.

[0088] The mine stratum and the microseismic sensor array profile view is as shown in Figure 3 : The thick aquifer 22 is located at a vertical depth of 400-550m from the working face cut, and the water-conducting fissures are densely distributed in it; the microseismic monitoring sensors 19 and the seepage pressure gauges 19 are simultaneously arranged on the ground, above the working faces of the original first panel-large panel 1, the original second panel-large panel 2 and the three panels-small panel 3, and in the recovery roadway and the transportation roadway 18 on both sides underground, to form a three-dimensional monitoring network with a vertical and strike interval ≤50m, so as to improve the accuracy of the seismic source positioning.

[0089] As shown in Figure 4 and Figure 5 : The microseismic monitoring sensors 19 and the seepage pressure gauges 19 are simultaneously arranged on the ground and in the roadway 18 underground of the original first panel-large panel 1, the original second panel-large panel 2 and the three panels-small panel 3, to monitor the stress and permeability of the post-mining roof and the large coal pillar 14 / wide coal pillar 25 in real time; among them, the original first panel 1 and the original second panel 2 each collect a set of data, and the three panels 3 collect three sets of data according to the "small panel-large coal pillar" layout method. The monitoring results show that the number of microseismic events, frequency ratio and permeability of the original first panel 1 and the original second panel 2 using the "large panel-small coal pillar" are significantly higher than those of the three panels 3 using the "small panel-large coal pillar", which verifies the effectiveness of the regional roadway layout method of controlling water and preventing impact ground pressure.

[0090] In another aspect, the embodiment further provides an electronic device, comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein the processor implements the method when executing the computing program.

[0091] In another aspect, the embodiment further provides a computer readable storage medium, which stores a computer program, wherein the computer program is executable on a processor to implement the method.

[0092] The above merely shows the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for laying out laneways in a water control and anti-scouring area, characterized in that: include: Determine the maximum allowable size of the panel area based on the water pressure value of the thick aquifer and the coal seam impact tendency index; Determine the minimum width of the isolated coal pillar based on the water pressure value of the thick aquifer; Divide the coal seam into several independent panels and leave isolation coal pillars between adjacent panels based on the maximum allowable panel size and the minimum width of the isolation coal pillars; Arrange mining tunnels and connecting tunnels in each panel area to form a tunnel system; A sensor array is arranged in the tunnel system to monitor stress and permeability in real time and control mining based on the stress and permeability.

2. The method according to claim 1, characterized in that The water pressure value of the thick aquifer is obtained based on static water pressure, disturbed water pressure and tectonic water pressure; Wherein, the static water pressure is measured by hydrological drilling; The disturbed water pressure is obtained by burying a piezometer in the pre-mining area; The structural water pressure is obtained through the fault permeability coefficient.

3. The method according to claim 1, characterized in that The calculation expression of the coal seam impact tendency index is: Among them, DT is the dynamic failure time; WCF is the elastic energy index; KEI is the impact energy index.

4. The method according to claim 1, wherein The calculation expression of the size of the disk area is: Among them, P is the water pressure of the thick aquifer; K is the coal seam impact tendency index, L max is the panel size.

5. The method according to claim 1, wherein The calculation expression of the minimum width of the coal pillar is: Among them, W min is the minimum width of the coal pillar.

6. The method according to claim 1, characterized in that The maximum allowable scale of the panel area is not more than 600m, and the minimum width of the isolation coal pillar is not less than 200m.

7. The method according to claim 1, characterized in that The width-to-height ratio of the isolated coal pillar is greater than 8:1 and the integrity coefficient is greater than 0.

9.

8. The method according to claim 1, characterized in that The sensor array includes microseismic sensors and seepage pressure testers, and the distance between adjacent sensors is no more than 50m; The stress threshold obtained by monitoring is no more than 0.6 times the uniaxial compressive strength of the coal pillar.

9. An electronic device comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein: When the processor executes the computing program, the method according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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