A coal mine hard rock roadway tunneling method

Abstract

The application discloses a coal mine hard rock roadway tunneling method, comprising the following steps: first, a center free circular surface drilling and expansion area is demarcated, dense drilling and expansion are carried out in the free circular surface drilling and expansion area, and drilling and expansion are carried out on the circumference; then, a plurality of circles larger than the center free surface are drawn by taking the center of the center free surface as the center, an expanded contour drilling and expansion area is demarcated, drilling and expansion are carried out on each circle, and the rock between adjacent circles is stripped; finally, a peripheral forming drilling and expansion area is determined, the outer contour of the roadway is reduced to several contour lines in proportion, drilling and expansion are carried out on the contour lines, and the rock between adjacent circles is stripped. The application can easily strip the rock with large hardness, and the rock pieces cannot fly randomly, so that the safety of equipment and people is not endangered, and the work efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of mine roadway excavation technology, specifically to a method for excavating hard rock roadways. Background Technology

[0002] Currently, there are three main methods for tunneling in underground coal mines in my country: blasting, fully mechanized tunneling, and tunnel boring machine (TBM) method. All three methods have drawbacks in hard rock tunneling, making it difficult to excavate hard rock tunnels flexibly, efficiently, and safely. For example, in mine tunneling, the fully mechanized tunneling method is currently one of the more intelligent methods, using a cantilevered TBM to cut the rock face and remove fallen rock. However, when cutting hard rock tunnels with a hardness greater than f6, the wear of the cutting teeth of the tunnel boring machine (TBM) increases dramatically. When the hardness of the surrounding rock exceeds f8, the TBM cannot cut the cross-section. When the cross-section does not meet the conditions for fully mechanized tunneling, the drill-and-blast method is required for rock breaking. The drill-and-blast method can break hard rock that the TBM cannot cut, but it has drawbacks such as long single-foot cycle time, easy over- and under-cutting, and the generation of flyrock and harmful gases. Mining full-face tunnel boring machines (MTBMs) can automatically cut high-hardness rock cross-sections, but they are huge, have fixed cross-section contours, and lack the flexibility to turn or tilt, making them unsuitable for tunneling small-sized, short-to-medium-distance tunnels. Therefore, a flexible, effective, and safe tunneling method is urgently needed in the field of hard rock tunnel excavation. Summary of the Invention

[0003] The purpose of this invention is to provide a method for tunneling hard rock tunnels to solve the above-mentioned problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides a method for tunneling hard rock roadways in coal mines, comprising the following steps:

[0005] Step 1: Determine the central free surface drilling expansion zone on the cross-section of the target roadway. The central free surface drilling expansion zone is a circular surface. Use a drilling expansion rig to drill holes at certain intervals along the edge of the central free surface drilling expansion zone and expand and crack each hole one by one. Then, drill densely inside the edge and expand and crack each hole one by one to peel off the rock in the central free surface drilling expansion zone and form a cylindrical concave expanded and cracked free surface.

[0006] Step 2: Draw an enlarged outline drilling expansion zone outside the edge of the central free surface drilling expansion zone. Using the center of the central free surface drilling expansion zone as the center point, draw multiple circles that increase in size outward to form an enlarged outline drilling expansion zone. Each circle is an enlarged expansion crack circle. On the outer side of the middle of the central free surface drilling expansion zone, drill continuous interlocking boreholes in the horizontal direction towards both sides of the target roadway to form a pressure relief free surface. The two ends of the pressure relief free surface fall on the edge of the outermost enlarged expansion crack circle. Then, using a drilling expansion rig, drill holes at certain intervals on each edge of the enlarged outline drilling expansion zone, starting from the inner circle and working outward. After drilling is completed, expand and crack the boreholes from the inner circle outward, and peel off the rock between adjacent connecting lines to form a disc-shaped concave expanded cracked area.

[0007] Step 3: Delineate the section between the outer contour of the target tunnel and the expanded contour drilling area as the peripheral forming drilling area, and proportionally reduce the outer contour of the target tunnel to draw multiple peripheral expansion cracks inward; Before constructing the peripheral drilling area, first create control free surfaces. Along the two bottom corners of the target tunnel section towards the center of the central free surface drilling area, drill two continuous interlocking control free surfaces, ending at the outer perimeter of the expanded contour drilling area; along the top corner or inflection point of the target tunnel section towards the center of the central free surface drilling area, drill two continuous interlocking control free surfaces, ending at the outer perimeter of the expanded contour drilling area; then, from the inside out, drill holes at equal intervals on each peripheral expansion crack and expand crack, and peel off the rock within two adjacent peripheral expansion crack circles to finally form the concave surface of the target tunnel section;

[0008] Step 4: Mill and level the over- and under-excavated areas of the formed roadway outline, remove the fractured rock and trimmed stone from the working face, inspect the surrounding rock and equipment at the working face, and proceed with the next round of drilling and excavation to achieve continuous drilling and excavation.

[0009] Furthermore, the diameter of the expansion zone on the central free face is less than the difference between 15 times the diameter of the expansion device and 2 times the allowable hole distance of the expansion device; the drilling depth on the free face is greater than or equal to the working depth of the expansion device.

[0010] Furthermore, in step 2, the spacing between the drill holes on each enlarged expansion ring is less than 5 times the diameter of the expansion device.

[0011] Furthermore, when the distance between the outermost edge of the expanded contour drilling expansion zone and the target roadway contour is close to 2 to 3 times the allowable hole distance of the expansion device, it enters the peripheral forming drilling expansion zone.

[0012] Furthermore, the drilling direction of the expansion holes formed on the outermost periphery is at an angle of 5° to 15° to the ideal profile surface.

[0013] Beneficial technical effects of the present invention:

[0014] (1) This invention uses mechanized excavation of hard rock tunnels to divide the tunnel cross-section into a central free surface drilling expansion zone, an expanded outline drilling expansion zone, and a peripheral shaped drilling expansion zone. From the inside out, the rock of the cross-section is gradually and layer by layer peeled off by drilling first and then expanding and cracking. This achieves efficient crushing of rocks with a hardness grade greater than f 8 in the tunnel cross-section.

[0015] (2) The drilling expansion tunneling technology used in this invention has the advantages of not generating impact disturbance, falling rocks, or harmful gases when tunneling hard rock. After the expansion is completed and the working face is cleaned, the next cycle of drilling expansion tunneling can be carried out directly, avoiding the ventilation work of drilling and blasting tunneling and realizing continuous drilling expansion tunneling.

[0016] (3) By defining three regions and creating a pressure relief free surface and a control free surface, the present invention can achieve directional rock breaking, more accurately control the roadway forming profile, and reduce over-excavation and under-excavation. Attached Figure Description

[0017] Figure 1 This is a diagram showing the cross-sectional area division and borehole layout of the target roadway working face;

[0018] Figure 2 It is a diagram showing the center free surface of the target tunnel cross-section and the borehole layout.

[0019] Figure 3 It is an enlarged outline of the target tunnel cross-section, the drilling expansion zone, and the borehole layout diagram;

[0020] Figure 4 It is a diagram showing the surrounding drilling expansion zone and borehole layout of the target tunnel cross-section;

[0021] Figure 5 This is a diagram showing the drilling and expansion scheme for the outer layer of the target tunnel cross-section.

[0022] Figure 6 It is a cross-sectional view of the outer borehole of the target tunnel section, showing the surrounding contour of the tunnel section.

[0023] Figure 7 This is a structural diagram of the double-arm drilling expansion trolley proposed in this invention;

[0024] In the diagram: 1-Cross-section of the tunnel, 2-Central free face drilling expansion zone, 3-Enlarged contour drilling expansion zone, 3-1-Pressure relief free face, 4-Peripheral forming drilling expansion zone, 4-1-Control free face, 4-2-Outer periphery forming expansion crack contour, 4-3-Outer periphery expansion crack hole, 5-Drilling expansion trolley, 5-1-Integrated drilling and expansion device, 5-2-Drilling expansion working arm, 5-3-Hydraulic pump station, 5-4-Electrical control box, 5-5-Traveling track, 5-6-Outrigger. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] First, let's clarify the meanings of some terms used in this technical solution: 1. Over-excavation / Under-excavation: This is a technical engineering term. Based on the designed excavation outline, the portion of the actual excavated cross-section outside the outline is called over-excavation, and the portion inside the outline is called under-excavation. 2. Inflection point: Since the shape of the tunnel cross-section to be excavated can vary, such as rectangular or arched cross-sections, when it's an arched cross-section, the two points where the upper arc intersects the lower rectangle are called inflection points. Similarly, the two lower endpoints of the arc forming the inner contour of the tunnel cross-section, which is proportionally reduced inward, are also called inflection points. 3. Permissible hole distance of the fracturing device: This refers to the maximum hole distance that a fracturing device with a certain working pressure, fracturing distance, and other capabilities can complete fracturing; that is, fracturing can be completed within this distance range.

[0027] like Figure 1 As shown, the tunnel cross-section 1 is arched. First, the central free surface drilling expansion zone 2 is determined on the tunnel cross-section 1. The central free surface drilling expansion zone is a circular surface. The center of the free surface is generally determined at the intersection of the two diagonals of the rectangle below the arch (upper semicircle + lower rectangle). This method uses a drilling expansion rig, which is existing technology and has the functions of drilling holes and expanding and fracturing the drill holes. First, the drilling expansion rig is used to drill holes at certain intervals on the outer circle of the central free surface, and each drill hole is expanded and fractured. Then, multiple drill holes are densely drilled inside the circular surface, and each drill hole is expanded and fractured. In this way, the rock in the central free surface drilling expansion zone can be peeled off, and finally a cylindrical concave expanded and fractured free surface is formed. The drilling arrangement of the central free surface drilling expansion zone 2 is as follows. Figure 2 As shown.

[0028] Extend the outer ring of the central free surface drilling expansion zone 2 outwards, drawing multiple concentric circles. The area between the outermost circle and the central free surface is defined as the expanded outline drilling expansion zone 3, as shown below. Figure 3 As shown. Since the rock within the central free surface has been stripped away, the expanded contour drilling zone has the shape of a large ring. On both sides of the middle of the central free surface drilling zone 2, continuous interlocking boreholes are drilled outwards to form the pressure-relieving free surface 3-1, as shown. Figure 2 As shown. A so-called interlocking borehole refers to a borehole with no gap between adjacent boreholes. The pressure relief free surface 3-1 divides this ring into upper and lower parts. Its function is to reduce the drilling pressure and fracturing pressure during drilling, thereby reducing wear on the drilling rig and facilitating the stripping of hard rocks.

[0029] On multiple circles of the expanded contour drilling expansion zone 3, starting from the innermost circle, boreholes are drilled outwards at certain intervals. Then, the boreholes are expanded and fractured. After all the boreholes on all circles have been expanded and fractured, the rock in the adjacent circles is stripped. After the stripping work is completed, the expanded contour drilling expansion zone and the fractured central free surface together form a concave disc-shaped cross-section.

[0030] like Figure 4 As shown, after the rock on the expanded contour expansion zone is stripped away, the surrounding shaped expansion zone is delineated. The surrounding shaped expansion zone is the area between the outer contour of the tunnel cross-section and the outermost circle of the expanded contour expansion zone. This invention uses an arched cross-section as an example; therefore, the surrounding shaped expansion zone also includes the upper semi-circular cross-section. The delineation method is to proportionally reduce the outer contour of the tunnel cross-section to form several reduced-size outer contour lines. First, control free surface 4-1 is manufactured. The manufacturing method for control free surface 4-1 is as follows: Since the lower half of the arched cross-section is a rectangular surface, lines are first drawn from the two bottom corners of the outermost rectangular outline of the tunnel cross-section towards the circular line of the central free surface. The endpoint of the line segment falls on the outermost circle of the expanded outline drilling expansion zone. Interlocking drill holes are then drilled and expanded on these two line segments. Next, the rectangular line in the innermost outline of the peripheral forming drilling expansion zone is connected from its apex (also the inflection point) to the center of the free central surface. The endpoint also lies on the outermost circle of the expanded outline drilling expansion zone. Interlocking drill holes are then drilled and expanded on these two line segments. Additionally, interlocking drill holes are also drilled between the innermost and outermost inflection points in the horizontal direction.

[0031] 4-1 After the construction of the free surface is completed, drill holes at certain intervals along the outer contour lines of different sizes and proportions, and then crack the drill holes. Figure 5 As shown.

[0032] Setting the free surface 4-1 can make drilling and cracking of the outer contour easier and more convenient to implement. On the other hand, it can effectively control the shape of the roadway cross section, prevent accidents, and ensure that the drilled cross section is not an arched cross section.

[0033] All the boreholes drilled during the above construction were perpendicular to the cross-section. However, the outer perimeter expansion hole 4-3 on the inner side of the outer contour line of the tunnel cross-section, i.e., the outer perimeter expansion hole 4-3 on the outer perimeter expansion contour 4-2, was not perpendicular to the cross-section, but was drilled at an inward angle of 5-15 degrees. Figure 6 As shown, since the tunnel advances in successive advances, a working space is needed around the drilling equipment. Due to the presence of surrounding rock, it is impossible to drill along the outline. To avoid the outline becoming smaller with each advance, it is necessary to drill at an angle so that the cross-sectional area of ​​the newly formed borehole is equal to that of the previous advance.

[0034] Of course, after drilling and cracking work is completed, there may still be areas of over- or under-excavation. These areas of over- or under-excavation in the formed roadway outline need to be milled and leveled.

[0035] Finally, the fractured rock and trimmed stone are removed from the working face, the surrounding rock and equipment are inspected, and the rock stripping work of one round of drilling is completed. Then, the next round of drilling and fracture is carried out, thus achieving continuous drilling and excavation.

[0036] In this embodiment, the diameter of the central free face should be less than the difference between 15 times the diameter of the fracturing device and 2 times the allowable hole distance of the fracturing device, and the drilling depth of the free face should be slightly greater than the working depth of the fracturing device. The spacing between each enlarged contour fracturing hole area should be less than the allowable hole distance of the fracturing device, and the drilling depth should be greater than the drilling depth of the free face. The upper and lower drilling expansion areas of the innermost fracturing hole area should contain at least 3 fracturing holes. The hole spacing between each enlarged contour fracturing hole area should be less than 5 times the diameter of the fracturing device. When the distance between the enlarged contour fracturing profile and the target roadway profile is close to 2 to 3 times the allowable hole distance of the fracturing device, the hole layout scheme is changed, and the peripheral fracturing stage is entered. The spacing between each peripheral fracturing hole area should be less than the allowable hole distance of the fracturing device. The hole spacing between each peripheral fracturing hole area should be less than 5 times the diameter of the fracturing device. After one round of drilling and expansion, the hole depth and number are adjusted in a timely manner according to the rockfall diameter and the advance.

[0037] The drilling rig used in the hard rock tunnel excavation method of this invention is a double-arm drilling rig, such as... Figure 7 As shown, the system includes a drilling and expansion trolley 5-1, a drilling and expansion working arm 5-2, a hydraulic pump station 5-3, an electrical control box 5-4, crawler tracks 5-5, and outriggers 5-6. The drilling and expansion working arm 5-2 is the working device for completing the drilling and expansion work, and has the functions of lateral movement, height adjustment, and propulsion. The drilling and expansion trolley 5-1 is mounted on the drilling and expansion working arm 5-2 via a rotary support, and has the functions of drilling, rotation, and expansion fracturing. This invention uses a double-arm drilling and expansion trolley for drilling and expansion fracturing operations, which greatly improves rock breaking efficiency.

[0038] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes that can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention are all within the protection scope of the claims of the present invention.

Claims

1. A method for tunneling hard rock roadways in coal mines, characterized in that, Includes the following steps: Step 1: Determine the central free surface drilling expansion zone on the cross-section of the target roadway. The central free surface drilling expansion zone is a circular surface. Use a drilling expansion rig to drill holes at certain intervals along the edge of the central free surface drilling expansion zone and expand and crack each hole one by one. Then, drill densely inside the edge and expand and crack each hole one by one to peel off the rock in the central free surface drilling expansion zone and form a cylindrical concave expanded and cracked free surface. Step 2: Draw an enlarged outline drilling expansion zone outside the edge of the central free surface drilling expansion zone. Using the center of the central free surface drilling expansion zone as the center point, draw multiple circles that increase in size outward to form an enlarged outline drilling expansion zone. Each circle is an enlarged expansion cracking circle. On the outer side of the middle of the central free surface drilling expansion zone, drill continuous interlocking boreholes in the horizontal direction towards both sides of the target roadway to form a pressure relief free surface. The two ends of the pressure relief free surface fall on the edge of the outermost enlarged expansion cracking circle. Then, using a drilling expansion rig, drill holes at certain intervals on each edge of the enlarged outline drilling expansion zone, starting from the inner circle and working outward. After drilling is completed, expand and crack the boreholes from the inner circle outward, and peel off the rock between adjacent connecting lines to form a disc-shaped concave expanded cracking area. Step 3: Delineate the section between the outer contour of the target tunnel and the expanded contour drilling area as the peripheral forming drilling area, and proportionally reduce the outer contour of the target tunnel to draw multiple peripheral expansion cracks inward; Before constructing the peripheral drilling area, first create control free surfaces. Along the two bottom corners of the target tunnel section towards the center of the central free surface drilling area, drill two continuous interlocking control free surfaces, ending at the outer perimeter of the expanded contour drilling area; along the top corner or inflection point of the target tunnel section towards the center of the central free surface drilling area, drill two continuous interlocking control free surfaces, ending at the outer perimeter of the expanded contour drilling area; then, from the inside out, drill holes at equal intervals on each peripheral expansion crack and expand crack, and peel off the rock within two adjacent peripheral expansion crack circles to finally form the concave surface of the target tunnel section; Step 4: Mill and level the over- and under-excavated areas of the formed roadway outline, remove the fractured rock and trimmed stone from the working face, inspect the surrounding rock and equipment at the working face, and proceed with the next round of drilling and excavation to achieve continuous drilling and excavation.

2. The method for tunneling hard rock roadways in coal mines according to claim 1, characterized in that, The diameter of the expansion zone on the central free face is less than the difference between 15 times the diameter of the expansion device and 2 times the allowable hole distance of the expansion device; the drilling depth on the free face is greater than or equal to the working depth of the expansion device.

3. The method for tunneling hard rock roadways in coal mines according to claim 1, characterized in that, In step 2, the spacing between the drill holes on each enlarged expansion ring is less than 5 times the diameter of the expansion device.

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