A reverse circulation drilling tool

Abstract

The application belongs to the technical field of reverse drilling construction, and specifically provides a reverse drilling tool, which comprises multiple center shafts sequentially connected from top to bottom, and multiple reaming units corresponding to the center shafts, wherein the reaming diameters of the multiple reaming units distributed from top to bottom increase, and when reverse drilling reaming construction is performed, small-diameter reaming units located at the top first contact the rock stratum, and large-diameter reaming units located at the bottom contact the rock stratum later. The multiple reaming units are arranged on the multiple center shafts respectively, and the reaming units on each center shaft are only responsible for cutting the corresponding circle of rock, so that the total cutting force is dispersed to the multiple center shafts, and the risk of fracture of the center shaft due to excessive torque or impact load when large-diameter reaming is performed is reduced.

Description

Technical Field

[0001] This application belongs to the field of reverse drilling construction technology, specifically a reverse drilling tool. Background Technology

[0002] Raise-the-well drilling rigs, as efficient and safe equipment for vertical and inclined shaft construction, are widely used in the construction of ventilation shafts, pipeline shafts, and safety escape routes in coal mines, hydropower projects, and other fields. The raise-the-well drilling process consists of two stages: first, a pilot hole is drilled from top to bottom using a directional drill bit until it connects to the lower horizontal roadway; then, the pilot hole drill bit is replaced with a reaming drill bit, and the hole is reamed from bottom to top to ultimately form the shaft of the required diameter. In this process, the reaming drill bit used for reverse reaming is the key component of the entire system, and its performance directly determines the efficiency, cost, and safety of the project.

[0003] Currently, the reaming drill bit widely used in reverse drilling projects uses a large cutterhead to carry all the rock-breaking drill blocks. The cutterhead is detachably connected to the bottom drill rod. During the reaming operation, the cutterhead is fixed to the drill rod, and the drill rod is raised while driving the cutterhead to rotate, so that the drill blocks break the rock formation.

[0004] The diameter of the reamer is significantly different from that of the drill pipe. When drilling large-diameter wells (such as 2-3m), the cutterhead diameter is large and the torque required to break the rock is also large. In the existing technology, the entire cutterhead is fixed on a drill pipe, which is subjected to large torque and impact loads, making it prone to breakage due to excessive instantaneous load. Summary of the Invention

[0005] Based on the above-mentioned technical problems, this application provides a reverse drilling tool to solve the problem in the prior art that when the diameter of the reaming drill bit is large, the drill pipe is subjected to large torque and is prone to breakage and damage.

[0006] To achieve the above objectives, the technical solution adopted in this application is: to provide a raise boring tool, comprising:

[0007] Multiple central shafts are connected sequentially from top to bottom, and adjacent central shafts are threaded together; and

[0008] Multiple hole-expanding units are arranged one-to-one on the central axis, and the hole-expanding diameters of the multiple hole-expanding units distributed from top to bottom increase.

[0009] In one possible implementation, the uppermost central axis is defined as the first central axis. The interior of the first central axis is hollow and forms a slurry channel. A water outlet box is installed above the hole-expanding unit. The water outlet box is arranged around the first central axis. The inner cavity of the water outlet box is connected to the slurry channel. A water outlet hole is opened at the bottom of the water outlet box. A plurality of water outlet holes are spaced apart along the circumference of the water outlet box.

[0010] In one possible implementation, the uppermost hole-reducing unit is defined as the first hole-reducing unit, which includes:

[0011] An enlarged-hole bracket, disposed on the first central axis and located below the water outlet box, has multiple mounting blocks evenly spaced along the circumference of the central axis. Adjacent mounting blocks form chip removal grooves, and each chip removal groove has at least one water outlet corresponding to its upper surface.

[0012] Multiple first drill bits are respectively located at the end of the mounting block away from the first central axis.

[0013] In one possible implementation, the bottommost central axis is defined as the second central axis, and the bottommost reaming unit is defined as the second reaming unit, which includes:

[0014] Multiple radial adjustment components are respectively disposed on the second central axis and evenly distributed along the circumference of the second central axis; the radial adjustment components are capable of extending and retracting along the radial direction of the second central axis; and

[0015] Multiple drill blocks, with at least one drill block provided on each of the radial adjustment components.

[0016] In one possible implementation, the outer wall of the second central axis is provided with two fixed supports spaced apart from top to bottom, and the fixed supports are provided with a plurality of fixed rods at equal intervals along the circumferential direction of the second central axis, and the fixed rods extend outward radially along the second central axis;

[0017] The radial adjustment component includes:

[0018] The upper connecting rod has one end hinged to the fixed rod located above, and the other end inclined downwards, with the drill block located on the upper connecting rod;

[0019] The lower connecting rod has one end hinged to the fixed rod located below, and the other end inclined downwards and parallel to the upper connecting rod; and

[0020] A vertical rod, the upper end of which is hinged to the end of the upper connecting rod away from the fixed rod, and the lower end of which is hinged to the end of the lower connecting rod away from the fixed rod.

[0021] In one possible implementation, each of the upper connecting rods is provided with a plurality of drill blocks spaced apart along its own length direction, and the drill blocks of the plurality of upper connecting rods are staggered with each other so that the movement path of the plurality of drill blocks covers the entire cross-section of the borehole.

[0022] In one possible implementation, the upper connecting rod is provided with a mounting base, the drill block is cylindrical or conical, the drill block and the mounting base are rotatably engaged along an axis parallel to the length direction of the upper connecting rod, and the outer surface of the drill block is provided with multiple breaking teeth.

[0023] In one possible implementation, a gauge block is provided on the side of the vertical rod away from the second central axis, the sidewall of the gauge block is provided with a plurality of gauge teeth, and a second drill bit is provided on the top of the gauge block.

[0024] In one possible implementation, the bottom of the vertical rod is provided with a fixing part below the hinge position of itself and the lower connecting rod, and the radial adjustment assembly further includes a fixing ring, which is concentrically arranged with the second central axis and is detachably connected to the fixing part.

[0025] In one possible implementation, a positioning plate is provided at the center of the fixed ring, the positioning plate is connected to the outer ring of the fixed ring by a rib, a first positioning hole is provided at the bottom of the second central shaft, and a second positioning hole is provided on the positioning plate.

[0026] The radial adjustment assembly further includes a connecting rod, which passes through the second positioning hole and is threaded into the first positioning hole. The bottom of the connecting rod has a stop portion that abuts against the positioning plate.

[0027] Compared with existing technologies, the beneficial effects of the riser tool provided in this application are:

[0028] The reverse drilling tool provided in this application includes multiple central shafts connected sequentially from top to bottom, and multiple reaming units corresponding to each of the central shafts. The reaming diameters of the multiple reaming units distributed from top to bottom increase. During reverse drilling reaming operations, the smaller diameter reaming unit located at the top contacts the rock formation first, and the larger diameter reaming unit located at the bottom contacts the rock formation later.

[0029] From the perspective of the stress on the central shaft during the reverse drilling process, this application sets multiple reaming units on multiple central shafts respectively. Each reaming unit on the central shaft is only responsible for cutting its corresponding ring of rock, distributing the total cutting force to multiple central shafts, thereby reducing the risk of the central shaft breaking due to excessive torque or impact load during large-diameter reaming.

[0030] From the perspective of cuttings removal and cooling effects during raise boring, the rock cuttings generated by the reaming unit are at different heights, allowing the drilling fluid to more smoothly and promptly remove the cuttings generated from each layer. The distribution of multiple reaming units at different heights also facilitates heat dissipation, thus improving the cuttings removal performance and cooling efficiency of the raise boring tool.

[0031] From the perspective of drilling accuracy during reverse drilling, the diameter of the reaming units increases from top to bottom. The smallest diameter reaming unit at the top acts as a guide drill bit, which can first form a small guide hole. Subsequent reaming units gradually increase the drilling diameter along this guide hole, making the drilling process more stable and the drilling trajectory less prone to deviation, which helps to improve the straightness accuracy of the drilling. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 Schematic diagram of the structure of the riser provided in the embodiments of this application Figure 1 ;

[0034] Figure 2 Schematic diagram of the structure of the riser provided in the embodiments of this application Figure 2 ;

[0035] Figure 3 An exploded view of the assembly of the riser provided in the embodiments of this application;

[0036] Figure 4 This is a schematic diagram of the structure of the first central shaft and the first hole-expanding unit;

[0037] Figure 5 This is a front view of the second central axis and the second hole-expanding unit;

[0038] Figure 6 This is a top view of the second central axis and the second hole-expanding unit;

[0039] Explanation of reference numerals in the attached figures:

[0040] 10. First central shaft; 11. Water outlet box; 111. Water outlet hole; 20. First reaming unit; 21. Reaming bracket; 211. Mounting block; 22. First drill bit; 30. Second central shaft; 31. Fixed bracket; 40. Second reaming unit; 41. Radial adjustment assembly; 411. Upper connecting rod; 4111. Mounting seat; 412. Lower connecting rod; 413. Vertical rod; 4131. Gauge block; 4132. Second drill bit; 4133. Fixing part; 42. Drill block; 43. Fixing ring; 431. Positioning plate; 4311. Second positioning hole; 44. Connecting rod. Detailed Implementation

[0041] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0042] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0043] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0046] Please refer to the following: Figures 1 to 6 The following describes the riser tool provided in the embodiments of this application.

[0047] Please see Figures 1 to 3The raise boring tool provided in this application includes multiple central shafts and multiple reaming units. The central shafts are connected sequentially from top to bottom, with adjacent central shafts threaded together. The multiple reaming units are correspondingly located on the central shafts, and the reaming diameter of the multiple reaming units increases from top to bottom.

[0048] The central shaft can be made from drill pipe. There can be two or more central shafts. Considering the limited space within the horizontal tunnel, the length of the central shaft should not be too long; it should be less than the height of the horizontal tunnel, specifically 2 meters. During raise boring, a small-diameter pilot hole is first drilled in the rock strata using a raise boring rig, drill pipe, and pilot drill bit. After the pilot hole connects to the horizontal tunnel, the pilot drill bit is removed from the horizontal tunnel, and the uppermost central shaft is connected to the drill pipe.

[0049] It is important to note that when the horizontal tunnel is relatively low, the uppermost center shaft and its corresponding reaming unit can be installed first, and then the raise boring machine can be started to drill upwards. Once the upper reaming unit has drilled into the rock strata to a suitable depth, there will be ample space below the center shaft, at which point the next center shaft and its corresponding reaming unit can be installed.

[0050] The central shaft at the top is used to connect to the drill pipe of the raise boring machine. There are no specific restrictions on the length, diameter, and material of the central shaft; users can choose according to their actual needs. The reaming unit can be an existing drill bit such as a roller cone drill or a PDC drill, or it can be any other structure capable of breaking up rock.

[0051] Optionally, multiple reaming units can use the same type of drill bit, differing only in diameter; alternatively, multiple reaming units can use different types of drill bits, as long as they can drill smoothly into the rock.

[0052] The diameter of the reaming units increases from top to bottom, with the diameter of the bottommost reaming unit being the diameter of the well shaft to be constructed. There are no specific restrictions on the spacing between two adjacent reaming units, such as a spacing of 50-100 cm.

[0053] Compared with the prior art, the beneficial effects of the riser tool provided in this application are:

[0054] The reverse drilling tool provided in this application includes multiple central shafts connected sequentially from top to bottom, and multiple reaming units corresponding to each central shaft. The reaming diameter of the multiple reaming units distributed from top to bottom increases. During reverse drilling reaming construction, the smaller diameter reaming unit located at the top contacts the rock formation first, and the larger diameter reaming unit located at the bottom contacts the rock formation later.

[0055] When encountering the problem of central shaft breakage, designers typically try to make the central shaft thicker or use higher-strength steel, which increases the weight or cost of the central shaft. This application optimizes the stress distribution on the central shaft by placing multiple reaming units on multiple central shafts. Each reaming unit on a central shaft is only responsible for cutting its corresponding ring of rock, thus distributing the total cutting force across multiple central shafts. This reduces the risk of the central shaft breaking due to excessive torque or impact loads during large-diameter reaming.

[0056] In traditional integrated cutterheads, multiple drill blocks 42 are mounted on a single cutterhead, resulting in a compact design that hinders the flow of cuttings and drilling fluid. In this embodiment, the cuttings generated by the reaming unit are distributed at different heights, allowing the drilling fluid to more smoothly and promptly remove cuttings from each layer. The distribution of multiple reaming units at different heights also facilitates heat dissipation, improving the cuttings removal performance and cooling efficiency of the raiseshare.

[0057] In traditional integrated cutterheads, multiple drill bits 42 are positioned on the same horizontal plane, simultaneously cutting a flat surface of rock during upward drilling. This can easily lead to deviation when encountering uneven strata. In this embodiment, the borehole diameters of multiple reaming units are designed to increase progressively from top to bottom. The smallest diameter reaming unit at the top drills into the rock strata first, acting as a guide bit to form a small pilot hole. Subsequent reaming units gradually increase the borehole diameter along this pilot hole, resulting in a more stable drilling process, less likelihood of deviation from the drilling trajectory, and improved straight-line accuracy of the borehole.

[0058] In summary, the raise boring tool provided in this application has optimizations in terms of central shaft stress, cuttings removal and cooling effect, and drilling straightness accuracy compared with the existing one-piece cutterhead raise boring tool. This helps to reduce the probability of central shaft breakage and improve the service life of the raise boring tool.

[0059] Please see Figures 1 to 4 During borehole reaming, drilling fluid needs to be supplied to cool the reaming unit and remove the cuttings. The uppermost central axis is defined as the first central axis 10. The interior of the first central axis 10 is hollow, forming a slurry channel. A water outlet box 11 is installed above the reaming unit on the first central axis 10, surrounding the first central axis 10. The inner cavity of the water outlet box 11 is connected to the slurry channel. A water outlet hole 111 is opened at the bottom of the water outlet box 11, with multiple water outlet holes 111 spaced apart along the circumference of the water outlet box 11. Drilling fluid can be ejected through the water outlet holes 111.

[0060] In order to increase the area of ​​the chip removal groove and improve the chip removal efficiency, in this embodiment, the water outlet box 11 and the hole expansion unit are spaced a certain distance apart in the axial direction. The bottom of the chip removal groove can be opened to a position adjacent to the first central axis 10. The size of the chip removal groove is not affected by the water outlet box 11 and can be designed to be larger.

[0061] Please see Figures 1 to 4 The uppermost reaming unit is defined as the first reaming unit 20. The first reaming unit 20 includes a reaming bracket 21 and a first drill bit 22. The reaming bracket 21 is located on the first central axis 10 and below the water outlet box 11. The reaming bracket 21 has multiple mounting blocks 211 evenly spaced along the circumference of the central axis. Adjacent mounting blocks 211 form chip removal grooves, and each chip removal groove has at least one water outlet hole 111 above it. Multiple first drill bits 22 are correspondingly located at the end of the mounting block 211 away from the first central axis 10.

[0062] The first drill bit 22 can be a roller cone drill, PDC drill, or similar structure. The first drill bit 22 is mounted on the mounting block 211 by bolts or welding. The water outlet 111 can be fitted with a water nozzle at a specific angle. The water nozzle can control the spray angle of the drilling fluid and increase the spray pressure, so that the drilling fluid is sprayed directly onto the first drill bit 22, washing away the mud or rock cuttings on the surface of the first drill bit 22 and preventing mud packing from forming on the first drill bit 22.

[0063] Please see Figures 1 to 3 , Figure 5 and Figure 6 The lowermost central axis is defined as the second central axis 30, and the lowermost reaming unit is defined as the second reaming unit 40. The second reaming unit 40 includes a radial adjustment assembly 41 and a drill block 42. Multiple radial adjustment assemblies 41 are respectively disposed on the second central axis 30 and are evenly distributed along the circumference of the second central axis 30. The radial adjustment assemblies 41 can extend and retract along the radial direction of the second central axis 30. Each radial adjustment assembly 41 is provided with at least one drill block 42. The horizontal position of the drill block 42 is adjusted by the radial adjustment assembly 41, thereby changing the reaming diameter of the raise boring tool.

[0064] The radial adjustment component 41 can be an existing adjustment device capable of realizing radial movement of the borehole, such as a hydraulic telescopic rod, an electric telescopic rod, etc.

[0065] like Figures 1 to 3As shown, the outer wall of the second central shaft 30 is provided with two fixed supports 31 spaced apart from top to bottom. Each fixed support 31 has multiple fixed rods evenly spaced along the circumference of the second central shaft 30, and these fixed rods extend radially outwards along the second central shaft 30. The radial adjustment assembly 41 includes an upper connecting rod 411, a lower connecting rod 412, and a vertical rod 413. The upper connecting rod 411 is parallel to the lower connecting rod 412, and the vertical rod 413 is parallel to the second central shaft 30. The upper connecting rod 411, the vertical rod 413, the lower connecting rod 412, and the second central shaft 30 form a parallelogram.

[0066] One end of the upper connecting rod 411 is hinged to the fixed rod located above, and the other end is inclined downwards. The drill block 42 is located on the upper connecting rod 411. One end of the lower connecting rod 412 is hinged to the fixed rod located below, and the other end is inclined downwards and parallel to the upper connecting rod 411. The upper end of the vertical rod 413 is hinged to the end of the upper connecting rod 411 away from the fixed rod, and the lower end of the vertical rod 413 is hinged to the end of the lower connecting rod 412 away from the fixed rod.

[0067] A drill block 42 is provided on the upper connecting rod 411. By changing the tilt angle of the upper connecting rod 411, the diameter of the enlarged hole can be changed. The tilt angle of the upper connecting rod 411 can be driven by a hydraulic cylinder, an electric telescopic rod, or a manually adjustable screw.

[0068] It is important to note that the positions of the drill blocks 42 on different upper connecting rods 411 should be staggered to ensure that the drill blocks 42 can break rocks at different locations. For improved breaking efficiency, please refer to [link / reference needed]. Figure 6 Each upper connecting rod 411 is provided with multiple drill blocks 42 at intervals along its own length direction. The drill blocks 42 of the multiple upper connecting rods 411 are staggered with each other so that the movement path of the multiple drill blocks 42 covers the entire cross-section of the borehole.

[0069] Please see Figure 5 and Figure 6 The upper connecting rod 411 is provided with a mounting base 4111. The drill block 42 is cylindrical or conical. The drill block 42 and the mounting base 4111 rotate and cooperate along an axis parallel to the length direction of the upper connecting rod 411. The outer surface of the drill block 42 is provided with multiple breaking teeth. The breaking teeth are made of a highly wear-resistant material and can break rocks during the movement of the drill block 42.

[0070] To improve the hole formation quality on the wellbore sidewall, a gauge block 4131 is provided on the side of the vertical rod 413 away from the second central axis 30. The sidewall of the gauge block 4131 has multiple gauge-keeping teeth, which can be made of PDC material. A second drill bit 4132 is located on the top of the gauge block 4131. The second drill bit 4132 can be a PDC drill bit or a roller cone drill bit. The breaking diameter of the second drill bit 4132 is the maximum breaking diameter of the raise boring tool.

[0071] Please see Figure 5 and Figure 6 In order to improve the overall rigidity of the second hole expansion unit 40, a fixing part 4133 is provided at the bottom of the vertical rod 413 below the hinge position of itself and the lower connecting rod 412. The radial adjustment assembly 41 also includes a fixing ring 43, which is concentrically arranged with the second central shaft 30 and is detachably connected to the fixing part 4133.

[0072] There are multiple retaining rings 43, each with a different diameter, such as 2.0m, 2.2m, 2.5m, 3m, etc. The appropriate retaining ring 43 is selected based on the required wellbore diameter and connected to the fixing part 4133 using bolts. Changing the retaining ring 43 to a different diameter allows adjustment of the reaming diameter of the second reaming unit 40. The retaining ring 43 is annular and will not affect the discharge of cuttings and drilling fluid.

[0073] After installation, the retaining ring 43 is located below the second central shaft 30. To improve the torsional strength of the radial adjustment assembly 41, the retaining ring 43 and the second central shaft 30 can be connected as a single unit. To achieve a detachable connection between the retaining ring 43 and the second central shaft 30, such as... Figure 2 , Figure 3 and Figure 5 As shown, a positioning plate 431 is provided at the center of the fixed ring 43. The positioning plate 431 is connected to the outer ring of the fixed ring 43 by ribs. A first positioning hole is provided at the bottom of the second central shaft 30, and a second positioning hole 4311 is provided on the positioning plate 431. The radial adjustment assembly 41 also includes a connecting rod 44. The connecting rod 44 passes through the second positioning hole 4311 and is threadedly engaged with the first positioning hole. The connecting rod 44 is similar in shape to a bolt. The bottom of the connecting rod 44 has a stop that abuts against the positioning plate 431. After tightening the connecting rod 44, the positioning plate 431 and the second central shaft 30 can be connected as a whole, thereby improving the overall torsional strength.

[0074] It should be noted that, in order to prevent the connecting rod 44 from loosening during construction, the connecting rod 44 and the bottom of the second central shaft 30 can be temporarily fixed by common anti-loosening measures such as anti-loosening nuts and spot welding.

[0075] It is understood that the parts in the above embodiments can be freely combined or deleted to form different combined embodiments. The specific contents of each combined embodiment will not be repeated here. After this description, it can be considered that the present invention specification has recorded each combined embodiment and can support different combined embodiments.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A raise boring tool, characterized in that, include: Multiple central shafts are connected sequentially from top to bottom, and adjacent central shafts are threaded together. as well as Multiple hole-expanding units are arranged one-to-one on the central axis, and the hole-expanding diameter of the multiple hole-expanding units distributed from top to bottom increases. Among them, the central axis located at the top is the first central axis (10). The interior of the first central axis (10) is hollow and forms a slurry channel. A water outlet box (11) is installed above the corresponding hole expansion unit. The water outlet box (11) is arranged around the first central axis (10). The inner cavity of the water outlet box (11) is connected to the slurry channel. A water outlet hole (111) is opened at the bottom of the water outlet box (11). Multiple water outlet holes (111) are spaced apart along the circumference of the water outlet box (11). The uppermost hole-expanding unit is the first hole-expanding unit (20), which includes: An enlarged hole bracket (21) is disposed on the first central axis (10) and located below the water outlet box (11). The enlarged hole bracket (21) has multiple mounting blocks (211) evenly spaced along the circumference of the central axis. Adjacent mounting blocks (211) form chip removal grooves, and each chip removal groove has at least one water outlet hole (111) above it. Multiple first drill bits (22) are respectively disposed at one end of the mounting block (211) away from the first central axis (10); Among them, the central axis located at the bottom is the second central axis (30), and the hole-expanding unit located at the bottom is the second hole-expanding unit (40), which includes: Multiple radial adjustment components (41) are respectively disposed on the second central axis (30) and evenly distributed along the circumferential direction of the second central axis (30). The radial adjustment components (41) are capable of extending and retracting along the radial direction of the second central axis (30); and Multiple drill blocks (42), each of the radial adjustment components (41) is provided with at least one of the drill blocks (42); The outer wall of the second central shaft (30) is provided with two fixed supports (31) from top to bottom. The fixed supports (31) are provided with multiple fixed rods at equal intervals along the circumferential direction of the second central shaft (30). The fixed rods extend outward along the radial direction of the second central shaft (30). The radial adjustment assembly (41) includes: The upper connecting rod (411) is hinged at one end to the fixed rod located above, and the other end is inclined downward. The drill block (42) is located on the upper connecting rod (411). The lower connecting rod (412) has one end hinged to the fixed rod located below, and the other end inclined downwards and parallel to the upper connecting rod (411); and A vertical rod (413) is hinged at its upper end to the end of the upper connecting rod (411) away from the fixed rod, and at its lower end to the end of the lower connecting rod (412) away from the fixed rod. Each of the upper connecting rods (411) is provided with a plurality of drill blocks (42) spaced apart along its own length direction. The drill blocks (42) of the plurality of upper connecting rods (411) are staggered with each other so that the movement path of the plurality of drill blocks (42) covers the entire cross-section of the borehole. A gauge block (4131) is provided on the side of the vertical rod (413) away from the second central axis (30). The side wall of the gauge block (4131) is provided with multiple gauge teeth, and the top of the gauge block (4131) is provided with a second drill bit (4132). The bottom of the vertical rod (413) is provided with a fixing part (4133) below the hinge position of itself and the lower connecting rod (412). The radial adjustment assembly (41) also includes a fixing ring (43). The fixing ring (43) is concentrically arranged with the second central axis (30). The fixing ring (43) and the fixing part (4133) are detachably connected.

2. The raise boring tool according to claim 1, characterized in that, The upper connecting rod (411) is provided with a mounting base (4111), the drill block (42) is cylindrical or conical, the drill block (42) and the mounting base (4111) are rotated and engaged along an axis parallel to the length direction of the upper connecting rod (411), and the outer surface of the drill block (42) is provided with multiple breaking teeth.

3. A raise boring tool according to claim 1, characterized in that, A positioning plate (431) is provided at the center of the fixed ring (43). The positioning plate (431) is connected to the outer ring of the fixed ring (43) by ribs. A first positioning hole is provided at the bottom of the second central shaft (30), and a second positioning hole (4311) is provided on the positioning plate (431). The radial adjustment assembly (41) further includes a connecting rod (44), which passes through the second positioning hole (4311) and is threadedly engaged with the first positioning hole. The bottom of the connecting rod (44) has a stop portion that abuts against the positioning plate (431).

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