Tunnel face gas pumping and draining drilling positioning instrument and construction method

Abstract

The invention provides a tunnel face gas pumping and draining drilling positioning instrument and a construction method, and the tunnel face gas pumping and draining drilling positioning instrument mainly comprises a host, a projection wide-angle lens, a touch control panel, a tripod, a horizontal bead level, a lithium battery and the like. After tunnel shape parameters are input through a touch control panel to form a tunnel face contour line, the number of drainage holes is set according to construction specifications, the positions of the drainage holes and inspection holes are determined by selecting a drilling layout area and the number of horizontal and vertical rows of drilling holes through a touch screen of a drilling positioning instrument, and the drilling positioning instrument is debugged on a construction site. And the drilling point projected on the tunnel face is more accurate through the horizontal bead level. And after the projection picture is projected on the tunnel face, a constructor uses a corresponding seal buckling device to mark on the tunnel face. By adopting the equipment, the layout construction of the gas pumping and draining drill holes on the tunnel face is more convenient, the workload of hole distribution is greatly reduced, the drill hole construction time is shortened, and the working efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, and in particular to a tunnel face gas extraction drilling locator and a construction method. Background Art

[0002] The through-layer grid pre-extraction of coal seam gas is to set up a drill site in the excavated rock tunnel or in the excavation working face before the tunnel opens the coal layer. A grid of drill holes are arranged on the heading face. The drill site drills holes into the coal seam through the heading face and penetrates the coal seam. The gas in the coal seam is pre-extracted through the drill holes. This is gas extraction from undepressurized coal seams.

[0003] By utilizing the negative air pressure generated by the extraction pump, the gas in the coal seams that are not affected by mining or have not been artificially loosened and depressurized is extracted through tunnels and boreholes, and the gas in the coal stratum section in front of the tunnel face is extracted and discharged outside the cave at one time for high-altitude discharge.

[0004] When implementing the through-layer grid pre-extraction coal seam gas technology, it is necessary to design the tunnel face hole layout. Since manual measurement to determine the drilling position will cause inaccurate hole layout, too long operation time, and possible mechanical damage during the operation, therefore, it is urgent to design a tunnel face gas extraction drilling locator to solve the above problems. Summary of the invention

[0005] In view of this, the present invention proposes a tunnel face gas extraction drilling locator and a construction method to solve the problem of marking drilling positions on the tunnel face.

[0006] On the one hand, to achieve the above-mentioned purpose, the present invention proposes a tunnel face gas extraction drilling locator, comprising a rocker, a lifting rod, a level bead level, a locator host, and a control panel display area;

[0007] The rocker and the lifting rod are used to control the height of the drilling locator;

[0008] The horizontal bead level is used to keep the drilling locator parallel to the upper step bottom line;

[0009] The locator host is used to calculate the tunnel face contour shape and the location of the drainage hole;

[0010] The control panel display area is used to divide the drilling areas and display the distribution and quantity of drilling holes in each drilling area.

[0011] Furthermore, a tripod is provided on the outer side of the lifting rod, and the height of the drilling locator is controlled by the tripod. When the height of the tripod cannot reach the optimal projection position, the height of the drilling locator is controlled by controlling the rocker and the lifting rod.

[0012] Furthermore, the water drop in the horizontal bead leveler is always in the most central position, so that the drilling locator remains relatively parallel to the upper step bottom line, and the projected image completely covers the coal seam gas extraction area.

[0013] Furthermore, the control panel display area displays several drilling area division methods, and a suitable division method is determined according to the construction conditions.

[0014] Furthermore, the boundaries of the drainage holes are determined by clicking on the four corners of the drilling area within the tunnel contour in the display area of ​​the control panel, and the number of columns and rows of the drilling holes is input. After calculation by the locator host, the position of the drainage hole is displayed in the drilling area of ​​the tunnel face contour through the display area of ​​the control panel, and the number of drilling holes in the drilling area is displayed at the same time.

[0015] On the other hand, in order to achieve the above-mentioned purpose, the present invention proposes a construction method based on the above-mentioned tunnel face gas extraction drilling locator, comprising the following steps:

[0016] Input tunnel shape parameters into the image display part, determine the coordinates of the upper step bottom line, input the coordinates of the upper step bottom line into the locator host, and obtain the contour shape of the tunnel face;

[0017] The number of coal seam gas extraction drilling holes is determined based on the construction specifications, and the drilling area of ​​the tunnel face is divided. The area division method is determined based on the actual construction situation;

[0018] Determine the extraction hole position and the inspection hole position in the drilling area respectively;

[0019] Determine the placement height of the drilling locator and the distance from the tunnel face according to the contrast on the drilling locator;

[0020] Control the drilling locator to keep it parallel to the bottom line of the upper step;

[0021] Mark the locations of the extraction holes and inspection holes on the tunnel face.

[0022] Furthermore, in the process of determining the positions of the drainage holes and inspection holes, a single row of odd-numbered holes and a single row of even-numbered holes are staggered so that the coal seam in front of the tunnel heading is completely within the drainage area, and triangular marks are set in the gaps between the drainage holes to represent the inspection holes.

[0023] Furthermore, the process of determining the placement height of the drilling locator and the distance from the tunnel face according to the contrast on the drilling locator includes:

[0024] Set the ratio of the projected image to the tunnel face contour line in the projector control panel, turn on the drilling locator and adjust its position according to the image position, and control the height of the drilling locator by adjusting the three brackets of the projection device tripod. When the bracket height cannot reach the optimal projection position, control the height of the drilling locator by controlling the joystick and lifting rod.

[0025] Furthermore, the process of controlling the drilling locator to remain parallel to the upper step bottom line includes:

[0026] Use the horizontal bead level on the top of the drilling locator to keep the drilling locator parallel to the bottom line of the upper step, control the water drop in the horizontal bead level to the center, and keep the projector relatively parallel to the bottom line of the upper step so that the projected image completely covers the coal seam gas extraction area.

[0027] Furthermore, the process of marking the positions of the drainage holes and the inspection holes on the tunnel face includes:

[0028] The extraction holes and inspection holes are marked with painted stamps of different shapes.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention uses projection equipment and methods to mark the drilling positions on the tunnel face to make the hole layout more regular, determine the shape of the tunnel face on the touch screen 5 of the drilling locator, and according to the "Technical Specifications for Design and Construction of Highway Gas Tunnels" and other regulations, formulate the number of coal seam gas extraction drilling holes n. Determine the spacing between the boreholes on the premise of ensuring the number of boreholes. The drilling locator is kept horizontal by the level bead level 6, so that the drilling points projected on the tunnel face are more accurate. According to the height of the drilling locator above the ground and the distance between the equipment and the tunnel face, the boreholes fully and evenly cover the coal seam gas extraction area.

[0031] The present invention adopts a tunnel gas extraction drilling locator to enable constructors to more accurately locate the drilling points of the tunnel face. On the premise of determining the size of the face, the fixed area can be fixed to make the layout of the openings on the face more regular, and the drilled holes can fully and evenly cover the coal seam gas extraction area. At the same time, the use of this equipment can make the layout construction of the gas extraction drilling holes on the tunnel face more convenient, greatly reduce the workload of hole layout, shorten the drilling time, and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0033] Figure 1 It is a schematic diagram of the structure of a gas extraction drilling locator for a tunnel face in an embodiment of the present invention;

[0034] Figure 2 It is a projected tunnel face front view used for positioning of gas extraction drilling holes in a tunnel face in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the initial page of the tunnel face gas extraction drilling locator in an embodiment of the present invention;

[0036] Figure 4 The tunnel face contour line of the tunnel face gas extraction drilling locator in the embodiment of the present invention;

[0037] Figure 5 It is a drilling area setting page of the tunnel face gas extraction drilling locator in the embodiment of the present invention;

[0038] Figure 6 This is a page for designing the arrangement of drilling holes for a gas extraction drilling locator for a tunnel face in an embodiment of the present invention;

[0039] Figure 7 It is a drilling position marking seal snapping device in the embodiment of the present invention;

[0040] Figure 8 The top view and side view of the construction site of the tunnel face gas extraction drilling locator in the embodiment of the present invention;

[0041] Fig. 9 It is an overall operation flow chart of the tunnel face gas extraction drilling locator in an embodiment of the present invention;

[0042] Fig.10 This is a flow chart of the drilling position operation of the tunnel face gas extraction drilling locator in an embodiment of the present invention;

[0043] Among them: 1. Projection equipment joystick; 2. Lifting rod controlled by the projection equipment joystick; 3. Tripod connecting projector joint; 4. Projection lens; 5. Projector control panel; 6. Level bead level; 7. Positioning instrument host; 8. Control panel image display area; 9. Coordinate axis; 10. Upper step bottom plate line; 11. Stamping plate knob of stamper; 12. Stamping plate card slot of stamper; 13. Extraction hole; 14. Inspection hole. DETAILED DESCRIPTION

[0044] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] The pre-extraction of coal seam gas through the interlayer grid is to set up a drilling site in the excavated rock tunnel or in the excavation working face before the tunnel uncovers the coal layer, and arrange grid-shaped boreholes on the face. The drilling site drills holes through the face and penetrates the coal seam, and then pre-extracts the gas in the coal seam through the boreholes. This is the gas extraction of undepressurized coal seams. The negative air pressure generated by the extraction pump is used to extract the gas in the coal seams that are not affected by mining or artificially loosened and depressurized through the tunnel and the borehole, and the gas in the coal formation section in front of the tunnel face is extracted and discharged outside the cave at one time for high-altitude discharge. When implementing the through-layer grid pre-extraction of coal seam gas technology, it is necessary to design the hole layout of the face. Since the drilling position is determined by manual measurement, the hole layout will be inaccurate, the operation time will be too long, and the operation process may cause mechanical damage, which may easily cause a blank area at the final hole position in the coal seam in front of the tunnel face or damage between the drill holes, resulting in incomplete gas extraction in the coal seam. The appearance of blank areas for gas extraction in some coal seams has a great impact on the construction. This embodiment solves the problem of marking the drilling position of the tunnel face by projection of a drilling locator, so that the layout of the openings on the face is more regular, and the drill holes fully and evenly cover the coal seam gas extraction area; at the same time, the use of this equipment can make the layout construction of the gas extraction drilling holes in the tunnel face more convenient, greatly reduce the workload of hole layout, shorten the drilling time, and improve work efficiency.

[0046] This embodiment provides a tunnel face gas extraction drilling locator and construction method, wherein the structure of the drilling locator is as follows: Figure 1 As shown, it includes: a projection device joystick 1; a lifting rod 2 controlled by the projection device joystick; a tripod connecting projector joint 3; a projector projection lens 4; a projector control panel 5; a level bead level 6; and a positioning instrument host 7;

[0047] The construction process of the gas extraction drilling locator for the tunnel face is as follows: according to the tunnel design document, the tunnel shape parameters (R1, R2, R3) are input through the touch screen control panel 5 of the drilling locator to form the tunnel face contour line, and then the number of coal seam gas extraction drilling holes n is planned according to the "Technical Specifications for Design and Construction of Highway Gas Tunnels" and other regulations, and the drilling layout area n0 is selected through the touch screen of the drilling locator to determine the location of the extraction drilling holes and input the horizontal arrangement number (l1, l2, l3) and vertical row number (m1, m2, m3) of the drilling holes in the corresponding areas (Ⅰ, Ⅱ, Ⅲ) in turn. After the location of the extraction hole 13 is determined, the location of the inspection hole 14 is determined by clicking between the extraction holes 13 in the corresponding area through the touch screen control panel 5. After the contrast is determined in the control panel, the drilling locator is debugged at the construction site to determine the height and the optimal distance from the face, and is kept level by the level bead leveler 6 to make the drilling point projected on the face more accurate. After the projection image is projected onto the tunnel face, the construction workers use the corresponding stamp device to mark the face.

[0048] The construction method comprises:

[0049] (I) Determine the tunnel face profile on the borehole locator control panel 5

[0050] The initial interface is as follows Figure 3 As shown, click on the face contour line in the control panel 5, and four conceptual diagrams of the tunnel face are displayed in the control panel image display part 8. Click (R1, R2, R3) in the diagram, enter the corresponding tunnel parameters, and after the information is transmitted to the host 7 for calculation, the image display part 8 displays the contour line of the same shape as the tunnel face (such as Figure 4 As shown), the placement position of the drilling locator in the tunnel is on the upper step bottom plate line 10, and the coordinate value of the upper step bottom plate line 10 is determined on the negative semi-axis of the Y axis of the coordinate axis 9 of the fourth image in the image display area 8 to form the upper step bottom plate line 10 parallel to the X axis, and the position of the upper step bottom plate line 10 is determined, and the overall tunnel face contour is displayed on the control panel 5;

[0051] (II) Determine the number of holes drilled on the tunnel face

[0052] Since the boundary of the gas drainage area is not less than 12m away from the tunnel contour line, the drainage radius of the final hole is determined to be 2.5m. According to the "Technical Specifications for Design and Construction of Highway Gas Tunnels" and other regulations, the number of coal seam gas drainage drilling holes n is proposed. In order to eliminate the existence of blank zones at the final hole, a single row of odd-numbered holes and a single row of even-numbered holes are staggered to ensure that the coal seam in front of the tunnel face is completely within the drainage area;

[0053] (III) Determine the drilling position on the drilling locator control panel 5

[0054] 3.1, such as Fig. 9 , Fig.10 As shown, the tunnel face drilling area division is performed first, and the drilling setting is clicked in the control panel 5, and three types of drilling area division diagrams are displayed in the image display part 8 (such as Figure 5 As shown in the figure, select the one that best suits the actual construction situation for drilling setting, minimize the blank area of ​​the tunnel face, and evenly distribute the drill holes on the tunnel face to avoid cross damage between drill holes in the coal seam ahead of the tunnel face and the appearance of white areas in the coal seam gas extraction holes, which will cause incomplete coal seam gas extraction;

[0055] 3.2. After the setting of the drilling area of ​​the tunnel face is completed, the position of the drainage hole 13 in the first area I is determined on the tunnel face. The drainage hole command in the image display part 8 is clicked. The four corners of the first area I in the tunnel contour line in the image display part 8 of the drilling locator control panel 5 are clicked to determine the boundary of the drainage hole 13 in the first area I. The number of columns l1 and the number of rows m1 of the drilling holes are displayed in the lower right corner of the image display part 8. Enter the corresponding parameters and click Start. After the host 7 calculates, the position of the drainage hole 13 in the image display part 8 of the control panel is displayed in the first area I of the tunnel face contour line. The number of drilling holes n in the lower right corner of the corresponding image display part will also display the number of drilling holes n1 in the first area I (such as Figure 6 shown);

[0056] 3.3, determine the position of the second area II drainage hole 13 at the step position in the tunnel (repeat step 3.2 process).

[0057] 3.4. Determine the location of the third zone III drainage hole 13 at the step position in the tunnel (repeat step 3.2).

[0058] 3.5, click the inspection hole command in the image display part 8 to determine the positions of the inspection holes 14 in the first area I, the second area II and the third area III in the control panel of the drilling locator. According to the "Interim Provisions on the Compliance of Coal Mine Gas Extraction Standards" and the "Detailed Rules for the Prevention and Control of Coal and Gas Outbursts", when inspecting the coal seam gas area burst prevention measures in the coal tunnel and coal tunnel uncovering area through-layer drilling pre-extraction, at least 4 inspection test points are arranged, which are respectively located in the middle of the tunnel and the upper part and both sides outside the tunnel contour line. In the present invention, only the tunnel face in the first area I, II and III is inspected. The inspection holes 14 in the second area II and the third area III are positioned, and triangular marks are set in the gaps between the extraction holes 14 to represent the inspection holes. Two are set in the first area I, three are set in the second area II, and five are set in the third area III. In the first area: in the second quadrant, one inspection hole 14 position is determined between the second and third rows from top to bottom in the horizontal row and the third and fourth columns from left to right in the vertical row; in the first quadrant, the second inspection hole 14 position is determined between the second and third rows from top to bottom in the horizontal row and the fourth and fifth columns from left to right in the vertical row. Second area: the position of the first inspection hole 14 is determined between the second and third rows from top to bottom in the horizontal row of the positive semi-axis of the Y axis; the position of the second inspection hole 14 is determined between the second and third rows from top to bottom in the second quadrant, and between the fourth and fifth columns from left to right in the vertical row; the position of the third inspection hole 14 is determined between the second and third rows from top to bottom in the first quadrant, and between the sixth and seventh columns from left to right in the vertical row; Third area: the position of the first inspection hole 14 is determined between the third and fourth rows from top to bottom in the horizontal row of the negative semi-axis of the Y axis; the position of the third inspection hole 14 is determined between the second and third rows from top to bottom in the horizontal row of the third quadrant The second inspection hole 14 is located between the second and third rows from the bottom and the fourth and fifth columns from the left to the right in the vertical column; the third quadrant horizontally from the top to the bottom of the fifth and sixth rows, the third inspection hole 14 is located between the fourth and fifth columns from the left to the right in the vertical column; the fourth quadrant horizontally from the top to the bottom of the second and third rows, the fourth inspection hole 14 is located between the eighth and ninth columns from the left to the right in the vertical column; the fourth quadrant horizontally from the top to the bottom of the fifth and sixth rows, the fifth inspection hole 14 is located between the eighth and ninth columns from the left to the right in the vertical column. Click the corresponding position, click the start command, and the triangular inspection hole 14 is displayed in the image, as shown in the following figure: Figure 2 As shown;

[0059] (IV) Determine the height of the drilling locator and the distance from the tunnel face

[0060] After the data parameters of the borehole locator control panel 5 are input and calculated to form an image, the height of the borehole locator and the distance from the tunnel face are determined by the contrast on the borehole locator. The ratio of the projected image to the tunnel face contour line of the image display 8 in the borehole locator is set in the borehole locator control panel 5. After turning on the borehole locator, the position of the borehole locator is adjusted according to the position of the image. The height of the borehole locator can be controlled by the three brackets of the tripod of the projection device. When the height of the bracket cannot reach the optimal position for projection, the height of the borehole locator can be determined by controlling the shaking rocker 1 above the three brackets to control the lifting rod 2 to ensure that the projection covers the coal seam gas extraction area comprehensively and evenly.

[0061] Alternatively, the height of the borehole locator and the distance between the borehole locator and the tunnel face may be determined first, and then the contrast on the borehole locator may be determined to ensure that the projection fully and completely covers the coal seam gas extraction area (the specific operation steps are the same as above);

[0062] (V) Control the drilling locator to keep it parallel to the upper step bottom line 10

[0063] After ensuring that the projected image completely covers the entire face and the distance and height between the borehole locator and the face are determined, since the projected image cannot completely match the face, it is also necessary to control the borehole locator to remain parallel to the upper step bottom line 10. The horizontal bead level 6 on the top of the borehole locator is used to keep the borehole locator parallel to the upper step bottom line 10. The water drop in the horizontal bead level 6 is controlled in the center. After the projector remains relatively parallel to the upper step bottom line 10, the projected image ensures that the projection fully and completely covers the coal seam gas extraction area.

[0064] (VI) Marking the positions of the drainage hole 13 and the inspection hole 14 on the tunnel face

[0065] like Figure 7 As shown, by using a painted seal to mark the drilled hole displayed on the tunnel face, the pumping hole 13 is marked with a painted circular seal, and the inspection hole 14 is marked with a painted triangular seal, so that the pumping hole 13 and the inspection hole 14 are easier to distinguish. Apply red paint on the marking plate, put it into the sealer, connect it with the knob 11 on the marking plate through the card slot 12, and fix the marking plate on the sealer. When marking the drilling position, the construction personnel press the sealer at the corresponding drilling position on the projection screen of the tunnel face to apply the corresponding marking symbol on the tunnel face. Before using the sealer, distinguish the type of drilling used to avoid marking errors, make construction more convenient, greatly reduce the workload of hole arrangement, shorten the drilling time, and improve work efficiency.

[0066] The top and side views of the construction site of the gas extraction drilling locator at the tunnel face are as follows: Figure 8 As shown, it can be understood that the use of the tunnel gas extraction drilling locator provided by the present invention can make the layout of the openings on the face more regular, and the drilled holes can fully and evenly cover the coal seam gas extraction area; at the same time, the use of this equipment can make the layout construction of the gas extraction drilling holes on the tunnel face more convenient, greatly reduce the workload of hole layout, shorten the drilling time, and improve work efficiency.

[0067] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can still modify the technical solutions described in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or perform equivalent replacements on some of the technical features thereof; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. They should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A tunnel face gas extraction drilling locator, characterized in that: It includes a rocker (1), a lifting rod (2), a level bead level (6), a positioning instrument host (7), and a control panel display area (8); The rocker (1) and the lifting rod (2) are used to control the height of the drilling locator; The horizontal bead level (6) is used to keep the drilling locator parallel to the upper step bottom plate line (10); The positioning device host (7) is used to calculate the contour shape of the tunnel face and the position of the drainage hole; The control panel display area (8) is used for dividing the drilling areas and displaying the distribution and quantity of drilling holes in each drilling area.

2. The tunnel face gas extraction drilling locator according to claim 1, characterized in that: A tripod is provided on the outside of the lifting rod (2), and the height of the drilling locator is controlled by the tripod. When the height of the tripod cannot reach the optimal projection position, the height of the drilling locator is controlled by controlling the rocker (1) and the lifting rod (2).

3. The tunnel face gas extraction drilling locator according to claim 1, characterized in that: The water drop in the horizontal bead leveler (6) is always in the most central position, so that the drilling locator and the upper step bottom plate line (10) remain relatively parallel, and the projected image completely covers the coal seam gas extraction area.

4. The tunnel face gas extraction drilling locator according to claim 1, characterized in that: The control panel display area (8) displays several drilling area division methods, and a suitable division method is determined according to the construction conditions.

5. The tunnel face gas extraction drilling locator according to claim 1, characterized in that: The boundaries of the drainage holes are determined by clicking on the four corners of the drilling area within the tunnel contour line in the control panel display area (8), and the number of columns and rows of the drilling holes is input. After calculation by the locator host (7), the position of the drainage hole is displayed in the drilling area of ​​the tunnel face contour line through the control panel display area (8), and the number of drilling holes in the drilling area is displayed at the same time.

6. A construction method based on the tunnel face gas extraction drilling locator according to claims 1-5, characterized in that: The following steps are involved: Input tunnel shape parameters into the image display part (8), determine the coordinates of the upper step bottom line (10), input the coordinates of the upper step bottom line (10) into the positioning device host (7), and obtain the contour shape of the tunnel face; The number of coal seam gas extraction drilling holes is determined based on the construction specifications, and the drilling area of ​​the tunnel face is divided. The area division method is determined based on the actual construction situation; Determine the extraction hole position and the inspection hole position in the drilling area respectively; Determine the placement height of the drilling locator and the distance from the tunnel face according to the contrast on the drilling locator; Controlling the drilling locator to remain parallel to the upper step bottom plate line (10); Mark the locations of the extraction holes and inspection holes on the tunnel face.

7. The construction method according to claim 6, characterized in that: In the process of determining the positions of the drainage holes and inspection holes, a single row of odd-numbered holes and a single row of even-numbered holes are staggered so that the coal seam in front of the tunnel heading is completely within the drainage area, and triangular marks are set in the gaps between the drainage holes to represent the inspection holes.

8. The construction method according to claim 6, characterized in that: The process of determining the placement height of the borehole locator and the distance from the tunnel face according to the contrast on the borehole locator includes: The ratio of the projected image to the tunnel face contour line is set on the projector control panel (5); after turning on the drilling locator, the position of the drilling locator is adjusted according to the position of the image; the height of the drilling locator is controlled by adjusting the three brackets of the projection device tripod; when the bracket height cannot reach the optimal projection position, the height of the drilling locator is controlled by controlling the joystick (1) and the lifting rod (2).

9. The construction method according to claim 6, characterized in that: The process of controlling the drilling locator to maintain parallelism with the upper step bottom plate line (10) includes: The drilling locator is kept parallel to the upper step bottom line (10) through the horizontal bead level (6) on the top of the drilling locator, and the water drop in the horizontal bead level (6) is controlled to be at the center. After the projector is kept relatively parallel to the upper step bottom line (10), the projected image completely covers the coal seam gas extraction area.

10. The construction method according to claim 6, characterized in that: The process of marking the locations of drainage holes and inspection holes on the tunnel face includes: The extraction holes and inspection holes are marked with painted stamps of different shapes.

Images