A method for repairing concrete foundations of substations

Abstract

This application discloses a method for repairing concrete foundations of substations, including the following steps: drilling, pile placement, pouring, protection, and curing. The drilling step involves creating a repair hole at the crack in the concrete foundation of the substation, with the hole size larger than the crack size. The pile placement step involves cleaning the inside and surrounding area of ​​the repair hole, inserting a pile into the hole, and positioning the pile to create gaps between the pile and the inner wall of the hole. The pouring step involves injecting filling grout into the repair hole to fully fill the gaps. The protection step involves laying a protective cloth over the repair hole, filling the gaps between the cloth and the concrete foundation, as well as between the cloth and the pile, with filling grout. The curing step involves curing the repaired area. This method for repairing concrete foundations of substations offers fast repair speed, high repair strength, and good corrosion resistance.

Description

Technical Field

[0001] This application relates to the field of building foundation repair technology, specifically a method for repairing concrete foundations of substations. Background Technology

[0002] Currently, concrete foundations serve as the supporting structure for various equipment in substations (such as transformers, circuit breakers, and disconnectors). They not only provide support but also withstand various loads, such as vibrations during equipment operation, thermal stresses caused by temperature changes, and seismic forces.

[0003] Over time, due to various factors such as environmental erosion, heavy loads, and design and construction defects, concrete foundations may develop defects such as cracks, spalling, carbonation, and steel reinforcement corrosion. These problems not only affect the load-bearing capacity and service life of the foundation itself, but may also affect the stability and safety of the superstructure.

[0004] However, traditional concrete repair materials such as concrete and mortar require a long time to complete, which may lead to prolonged downtime for substations that need to operate continuously. Furthermore, these repair methods are only temporary and cannot fundamentally solve the damage to the concrete foundation; moreover, some repair materials are not well-suited to the original concrete foundation, potentially causing new cracks or damage, and consuming significant human and material resources.

[0005] Therefore, how to improve traditional concrete repair methods to overcome the above-mentioned shortcomings is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] One objective of this application is to provide a method for repairing substation concrete foundations that offers fast repair speed, high repair strength, and good corrosion resistance.

[0007] To achieve the above objectives, the technical solution adopted in this application is: a method for repairing concrete foundations of substations, including drilling steps, pile laying steps, pouring steps, protection steps, and curing steps.

[0008] The drilling step involves drilling a repair hole at a crack in the concrete foundation of the substation, wherein the size of the repair hole is larger than the size of the crack.

[0009] The pile placement steps are as follows: First, clean the residue inside and around the repair hole, then insert the pile rod into the repair hole and position the pile rod so that there is a gap between the pile rod and the inner wall of the repair hole on all sides.

[0010] The pouring step involves injecting filling grout into the repair hole to fully fill the gap.

[0011] The protective step involves laying a protective cloth over the repair hole and filling the space between the protective cloth and the concrete foundation, as well as between the protective cloth and the pile, with the filling grout.

[0012] The maintenance steps include: maintaining the repaired area.

[0013] Preferably, in the hole-making step, the depth of the repair hole is less than the depth of the concrete foundation, and the depth of the repair hole is greater than or equal to 80cm.

[0014] Preferably, in the pouring step, the filling grout is a cement-based grout, and the strength of the cement-based grout is greater than or equal to the strength of the concrete foundation.

[0015] Preferably, in the protective step, the protective fabric is FRP fabric.

[0016] Preferably, during the pile laying step, the outer side wall of the pile rod is provided with a protruding or recessed anti-fall-off part.

[0017] Preferably, in the pile laying step, when cleaning the residue inside and around the repair hole, the clumps of residue are first cleaned manually, then dust particles are cleaned by negative pressure adsorption, then the inside and around the repair hole are flushed by a high-pressure water gun, and finally the water in the repair hole is drained, keeping the inside and around the repair hole moist.

[0018] Preferably, in the pile laying step, at least three flexible support rods are provided at equal intervals along the circumference of the outer wall of the pile rod, and the shape of each support rod is adjusted by bending so that each support rod abuts against the inner wall of the repair hole, thereby achieving the positioning between the pile rod and the inner wall of the repair hole.

[0019] Preferably, the outer wall of the pile is provided with a mounting hole, and one end of the support rod is interference-fitted into the mounting hole.

[0020] Preferably, in the hole-opening step, the repair hole is opened using a circular drill barrel, and the drill barrel is detachably equipped with a grooving device; after the hole is opened using the drill barrel, the grooving device is first assembled onto the drill barrel, and then the drill barrel is screwed into the repair hole from top to bottom, or screwed out of the repair hole from bottom to top, thereby forming a spiral groove on the inner wall of the repair hole.

[0021] Preferably, the slotting device includes an inner core, a drill rod, a spring, and a push rod. The inner core is built into the drill barrel, and its lower end face has an insertion hole. A through hole is horizontally formed through the inner wall of the insertion hole, and a clearance hole is formed through the drill barrel at a position corresponding to the through hole. The drill rod is axially slidably installed in the through hole, and a limiting part is provided at one end of the drill rod near the insertion hole, with an inclined surface formed on the limiting part. The spring is disposed in the through hole and is used to force the drill rod to slide towards the insertion hole, thereby hiding one end of the drill rod away from the insertion hole inside the through hole. The push rod is threaded to the insertion hole, and a conical surface is formed at the upper end of the push rod. A rotating part is provided at the lower end of the push rod, and at least two pins are spaced apart at the lower end of the rotating part. The sum of the heights of the rotating part and the pins is less than or equal to the height difference between the lower end face of the inner core and the lower end face of the drill barrel.

[0022] Preferably, in the drilling step, after drilling is completed, the drill barrel and any residue in the repair hole are removed. Then, the inner core is inserted into the drill barrel, and the through hole is aligned with the clearance hole. Next, the rotating part is rotated, causing the push rod to move upward. The conical surface forces the drill rod into the clearance hole through the inclined surface, thereby limiting the relative displacement between the inner core and the drill barrel. Immediately afterward, before the drill rod exits the clearance hole, the drill barrel is inserted into the repair hole until the pin is inserted to the bottom of the repair hole. The drill barrel is then driven to rotate, causing the push rod to continue moving upward relative to the inner core, thereby allowing the drill rod to exit the clearance hole. Finally, when the pin has fully moved into the drill barrel, the drill rod is in position. The drill barrel is then controlled to rotate out of the repair hole from bottom to top, allowing the drill rod to form the spiral groove on the inner wall of the repair hole.

[0023] Compared with the prior art, the beneficial effects of this application are as follows: (1) This application first opens a repair hole at the crack in the concrete foundation of the substation to remove the inferior foundation in the concrete foundation; then, cleans the inside and around the repair hole of the residue, inserts the pile rod into the repair hole, and makes a gap between the pile rod and the inner wall of the repair hole, and then injects filling grout into the repair hole to fully fill the gap between the pile rod and the inner wall of the repair hole, thereby achieving the purpose of filling; compared with the traditional filling method using concrete, mortar, etc., the filling method of this application uses less filling grout, which can significantly shorten the setting time of the filling grout, that is, the repair speed is faster, which is conducive to shortening the cycle of the entire repair process; in addition, this filling method does not pour a large amount of concrete, mortar, etc. in a large volume area, so its matching after solidification is higher, thus making it less likely to generate new cracks or damage. In addition, the pile rod itself can have high strength, which is conducive to improving the repair strength of the concrete foundation.

[0024] (2) Under the protection step, that is, by laying a protective cloth on the upper part of the repair hole, and filling the gap between the protective cloth and the concrete foundation and the protective cloth and the pile rod with filling grout, the protective cloth is combined with the concrete foundation and the pile rod, which is equivalent to fully filling the gap between the protective cloth and the concrete foundation surface, thereby isolating air and water, so as to improve the anti-corrosion performance of the pile rod (i.e. the repaired foundation) and thus extend the service life of the repaired foundation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the opening for a substation concrete foundation repair method provided in this application.

[0026] Figure 2 A perspective view of a pile rod provided for this application.

[0027] Figure 3 A perspective view of another type of pile provided for this application.

[0028] Figure 4 Provided for this application Figure 3 A magnified view of a portion of point A in the middle.

[0029] Figure 5 A perspective view of yet another type of pile provided in this application.

[0030] Figure 6 A cross-sectional view of a slotting tool provided in this application.

[0031] Figure 7 Provided for this application Figure 6 Assembly process diagram of the slotter and drill barrel.

[0032] Figure 8 Provided for this application Figure 7 Assembly diagram of the grooving tool and drill barrel.

[0033] Figure 9 Provided for this application Figure 8 Diagram showing the grooving tool and drill barrel inserted into the repair hole.

[0034] Figure 10 Provided for this application Figure 9 A diagram showing the state of the drill pipe after it has reached its designated position.

[0035] In the diagram: 1. Pile rod; 11. Anti-fall-off part; 12. Support rod; 13. Mounting hole; 2. Drill barrel; 21. Clearance hole; 3. Grooving tool; 31. Inner core; 311. Insertion hole; 312. Through hole; 32. Drill rod; 321. Limiting part; 322. Inclined surface; 33. Spring; 34. Top rod; 341. Conical surface; 342. Rotating part; 343. Pin; 100. Concrete foundation; 101. Crack; 102. Repair hole. Detailed Implementation

[0036] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0037] In the description of this application, it should be noted that directional terms such as "center," "lateral," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used 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. They should not be construed as limiting the specific scope of protection of this application. The terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "comprising" and "having," and any variations thereof, in the specification and claims of this application, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0038] Reference Figure 1One embodiment of this application provides a method for repairing a substation concrete foundation, including a hole-drilling step, a pile-laying step, a pouring step, a protection step, and a curing step.

[0039] Opening procedure: Open a repair hole 102 at the crack 101 in the concrete foundation 100 of the substation, and the size of the repair hole 102 is larger than the size of the crack 101.

[0040] Piling steps: First, clean the residue inside and around the repair hole 102, then insert the pile rod 1 into the repair hole 102 and position the pile rod 1 so that there is a gap between the pile rod 1 and the inner wall of the repair hole 102.

[0041] Pouring steps: Pour filling grout into the repair hole 102 to fully fill the gap.

[0042] Protection steps: Lay a protective cloth on the upper part of the repair hole 102, and fill the space between the protective cloth and the concrete foundation 100 and between the protective cloth and the pile rod 1 with filling grout.

[0043] Maintenance steps: Perform maintenance on the repaired area.

[0044] The curing time in the maintenance process is typically 12 hours. Of course, the curing time can be increased or decreased depending on the specific repair situation. It should be understood that the specific curing methods used in this process are existing technologies and will not be elaborated upon here.

[0045] As can be seen from the above steps, this application first creates a repair hole 102 at the crack 101 in the concrete foundation of the substation to remove the substandard foundation in the concrete foundation 100. Next, the residue inside and around the repair hole 102 is cleaned, and then a pile rod 1 is inserted into the repair hole 102, creating a gap between the pile rod 1 and the inner wall of the repair hole 102. Then, filling grout is injected into the repair hole 102 to fully fill the gap between the pile rod 1 and the inner wall of the repair hole 102, thus achieving the filling purpose. Compared with traditional filling methods using concrete, mortar, etc., this filling method uses less filling grout, thereby significantly shortening the setting time of the filling grout, resulting in faster repair speed and a shorter overall repair cycle. Furthermore, this filling method does not involve pouring a large amount of concrete or mortar over a large volume, resulting in better compatibility after setting and reducing the likelihood of new cracks 101 or damage. In addition, the pile rod 1 itself can have high strength, which helps to improve the repair strength of the concrete foundation 100. Furthermore, the protective step involves laying a protective cloth on the upper part of the repair hole 102, and filling the gaps between the protective cloth and the concrete foundation 100, as well as between the protective cloth and the pile 1, with filling grout. This allows the protective cloth to bond with both the concrete foundation 100 and the pile 1, effectively filling the gaps between the protective cloth and the surface of the concrete foundation 100. This isolates the pile 1 from air and water, thereby improving its corrosion resistance and extending the service life of the repaired foundation.

[0046] It should be understood that, in order not to damage the underlying structure of the original concrete foundation 100 of the substation, the depth of the repair hole 102 needs to be less than the depth of the concrete foundation 100 during the drilling process. At the same time, to improve the repair strength, the depth of the repair hole 102 should not be too shallow; according to experimental results, a depth of 80cm or more is more suitable.

[0047] It should be understood that this application does not limit the filling grout used in the pouring step, as long as it can adhere the pile rod 1 to the repair hole 102. Since the substation foundation is a concrete foundation 100, in order to improve the repair effect, the filling grout is preferably a cement-based grout, and the strength of the cement-based grout is greater than or equal to the strength of the substation concrete foundation.

[0048] It should be understood that the material of the protective fabric used in the protective steps of this application is not limited, as long as it can provide corrosion protection for the pile 1 and the repaired foundation. However, the preferred material for the protective fabric is FRP (fiber reinforced polymer) fabric. FRP fabric not only provides better corrosion protection but also further enhances the structural stability of the repaired foundation, thereby preventing cracking from recurring.

[0049] In some embodiments of this application, to improve the stability of the repaired pile 1, an anti-detachment portion 11 is provided on the outer side wall of the pile 1, either protruding or recessed. It should be understood that this application does not limit the specific structure of the anti-detachment portion 11; for example, as... Figure 1 As shown, a spiral structure is provided protruding (or recessed) on the outer wall of pile rod 1; or, as... Figure 5 As shown, regular (or irregular) protrusions (or recesses forming grooves) are set on the outer side wall of the pile rod 1.

[0050] In some embodiments of this application, such as Figure 3 As shown, to facilitate the positioning of the pile rod 1, at least three (four in the attached figure) flexible support rods 12 are provided at equal intervals along the circumference of the outer wall of the pile rod 1. During the pile laying process, the shape of each support rod 12 only needs to be adjusted by bending to make each support rod 12 abut against the inner wall of the repair hole 102, thereby achieving positioning between the pile rod 1 and the inner wall of the repair hole 102. The material of the support rods 12 is not limited; for example, iron wire can be used. Furthermore, to facilitate the connection between the support rods 12 and the pile rod 1, the outer wall of the pile rod 1 is provided with mounting holes 13. Assembly is achieved by interfering with one end of the support rod 12 within the mounting hole 13.

[0051] In some embodiments of this application, during the pile laying step, when cleaning the residue inside and around the repair hole 102, the clumps of residue are first manually removed, then dust particles are removed by negative pressure adsorption, followed by flushing the inside and around the repair hole 102 with a high-pressure water gun, and finally the water inside the repair hole 102 is drained, keeping the inside and around the repair hole 102 moist. Maintaining a moist state means that the inside and around the repair hole 102 are damp, but without significant water accumulation.

[0052] In some embodiments of this application, during the drilling step, a repair hole 102 is drilled using a circular drill barrel 2, and the drill barrel 2 is detachably equipped with a grooving device 3. After drilling is completed using the drill barrel 2, the grooving device 3 is first assembled onto the drill barrel 2, and then the drill barrel 2 is screwed into the repair hole 102 from top to bottom, or screwed out of the repair hole 102 from bottom to top, thereby forming a spiral groove on the inner wall of the repair hole 102. The spiral groove serves two purposes: first, it facilitates the entry of filling grout into the gap between the pile rod 1 and the repair hole 102; second, it increases the contact area between the filling grout and the inner wall of the repair hole 102, thereby improving the adhesion between the filling grout and the inner wall of the repair hole 102, thus preventing the pile rod 1 from detaching. This improves the stability and reliability of the connection between the repaired foundation and the original foundation, and helps to extend the service life.

[0053] In some embodiments of this application, such as Figure 6 As shown, the slotting device 3 includes an inner core 31, a drill rod 32, a spring 33, and a push rod 34. The inner core 31 is built inside the drill barrel 2. The lower end of the inner core 31 is provided with an insertion hole 311 facing upward. A through hole 312 is provided horizontally through the inner wall of the insertion hole 311. A clearance hole 21 is provided through the drill barrel 2 at the position corresponding to the through hole 312. The drill rod 32 is axially slidably installed in the through hole 312. A limiting part 321 is provided at one end of the drill rod 32 near the insertion hole 311. An inclined surface 322 is formed on the limiting part 321. The spring 33 is provided in the through hole 312. The spring 33 is used to force the drill rod 32 to slide in the direction close to the insertion hole 311, so that the end of the drill rod 32 away from the insertion hole 311 is hidden inside the through hole 312. The push rod 34 is threaded to the insertion hole 311. The upper end of the push rod 34 has a conical surface 341, and the lower end of the push rod 34 is provided with a rotating part 342. At least two pins 343 are provided at intervals at the lower end of the rotating part 342.

[0054] Reference Figures 6 to 10 The working principle of the slotter 3: In the hole-making process, after the hole is made, the drill barrel 2 and the residue in the repair hole 102 are first removed, and then the inner core 31 is inserted into the drill barrel 2 (e.g., Figure 7 (As shown); when the through hole 312 is aligned with the relief hole 21, the rotating part 342 is rotated, causing the push rod 34 to move upward, and the conical surface 341 can force the drill rod 32 into the relief hole 21 through the inclined surface 322 (as shown); Figure 8 As shown), this restricts the relative displacement between the inner core 31 and the drill barrel 2; then, before the drill rod 32 passes through the relief hole 21, the drill barrel 2 is inserted into the repair hole 102 until the pin 343 is inserted into the bottom of the repair hole 102 (as shown). Figure 9 As shown), when the drill barrel 2 is driven to rotate, the bottom of the repair hole 102 will restrict the rotation of the rotating part 342 (i.e., the push rod 34) to rotate, thereby causing the push rod 34 to continue to move upward relative to the inner core 31, and then causing the drill rod 32 to pass through the clearance hole 21; finally, since the sum of the heights of the rotating part 342 and the insert pin 343 is less than or equal to the height difference between the lower end face of the inner core 31 and the lower end face of the drill barrel 2, when the insert pin 343 has completely moved into the inside of the drill barrel 2, the drill rod 32 moves into place (as shown). Figure 10 As shown, the drill rod 32 will not slide outward, nor will it slide inward under the limiting action of the top rod 34. At this time, the drill barrel 2 is controlled to rotate out of the repair hole 102 from bottom to top, so that the drill rod 32 can form a spiral groove on the inner wall of the repair hole 102.

[0055] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A method of repairing a substation concrete foundation, characterized by, It includes the drilling process, the pile laying process, the pouring process, the protection process, and the curing process; The hole-opening step is as follows: a repair hole (102) is opened at the crack (101) in the concrete foundation (100) of the substation, and the size of the repair hole (102) is larger than the size of the crack (101); the repair hole (102) is opened through a circular drill barrel (2), and the drill barrel (2) is detachably equipped with a slotting tool (3). The pile laying steps are as follows: First, clean the residue inside and around the repair hole (102), then insert the pile rod (1) into the repair hole (102) and position the pile rod (1) so that there is a gap between the pile rod (1) and the inner wall of the repair hole (102) around its perimeter. The pouring step is as follows: filler grout is poured into the repair hole (102) so that the filler grout fully fills the gap; The protective step is as follows: a protective cloth is laid on the upper part of the repair hole (102), and the protective cloth and the concrete foundation (100) and the protective cloth and the pile rod (1) are filled with the filling grout. The maintenance steps include: maintaining the repaired area; The slotting device (3) includes an inner core (31), a drill rod (32), a spring (33), and a push rod (34); the inner core (31) is built inside the drill barrel (2), and the lower end of the inner core (31) is provided with an insertion hole (311) facing upward. A through hole (312) is provided horizontally through the inner side wall of the insertion hole (311), and a clearance hole (21) is provided on the drill barrel (2) corresponding to the position of the through hole (312); the drill rod (32) is axially slidably installed in the through hole. (312) Inside, a limiting part (321) is provided at one end of the drill rod (32) near the insertion hole (311), and a slope (322) is formed on the limiting part (321); the spring (33) is provided in the through hole (312), and the spring (33) is used to force the drill rod (32) to slide towards the insertion hole (311), so that the end of the drill rod (32) away from the insertion hole (311) is hidden inside the through hole (312); The push rod (34) is threaded to the insertion hole (311). The upper end of the push rod (34) has a conical surface (341). The lower end of the push rod (34) is provided with a rotating part (342). At least two pins (343) are spaced apart at the lower end of the rotating part (342). The sum of the heights of the rotating part (342) and the pins (343) is less than or equal to the height difference between the lower end face of the inner core (31) and the lower end face of the drill barrel (2). In the drilling step, after drilling is completed, the drill barrel (2) and the residue in the repair hole (102) are first removed, and then the inner core (31) is inserted into the drill barrel (2), and the through hole (312) is aligned with the relief hole (21); then, the rotating part (342) is rotated, so that the push rod (34) moves upward, and the conical surface (341) forces the drill rod (32) into the relief hole (21) through the inclined surface (322), thereby limiting the relative displacement between the inner core (31) and the drill barrel (2); then, the drill rod (32) is pushed out of the relief hole (21) Before that, insert the drill barrel (2) into the repair hole (102) until the pin (343) is inserted into the bottom of the repair hole (102), drive the drill barrel (2) to rotate, so that the push rod (34) continues to move upward relative to the inner core (31), so that the drill rod (32) passes through the relief hole (21); finally, when the pin (343) has completely moved into the inside of the drill barrel (2), the drill rod (32) moves into place, and then control the drill barrel (2) to rotate out of the repair hole (102) from bottom to top, so that the drill rod (32) can form a spiral groove on the inner wall of the repair hole (102).

2. The method of repairing a substation concrete foundation of claim 1, wherein, In the hole-making step, the depth of the repair hole (102) is less than the depth of the concrete foundation (100), and the depth of the repair hole (102) is greater than or equal to 80cm.

3. The method of repairing a substation concrete foundation of claim 1, wherein, In the pouring step, the filling grout is a cement-based grout, and the strength of the cement-based grout is greater than or equal to the strength of the concrete foundation (100).

4. The method for repairing substation concrete foundations as described in claim 1, characterized in that, In the protective step, the protective fabric is FRP fabric.

5. The method for repairing substation concrete foundations as described in claim 1, characterized in that, In the pile laying step, the outer side wall of the pile rod (1) is provided with a protruding or recessed anti-fall-off part (11).

6. The method for repairing substation concrete foundations as described in claim 1, characterized in that, In the pile laying step, when cleaning the residue inside and around the repair hole (102), the clumps of residue are first cleaned manually, then the dust particles are cleaned by negative pressure adsorption, then the inside and around the repair hole (102) are flushed by a high-pressure water gun, and finally the water in the repair hole (102) is drained, and the inside and around the repair hole (102) are kept moist.

7. The method for repairing concrete foundations of substations as described in any one of claims 1-6, characterized in that, In the pile laying step, at least three flexible support rods (12) are provided at equal intervals along the circumference of the outer wall of the pile rod (1). By bending and adjusting the shape of each support rod (12), each support rod (12) abuts against the inner wall of the repair hole (102), thereby realizing the positioning between the pile rod (1) and the inner wall of the repair hole (102).

8. The method for repairing substation concrete foundations as described in claim 7, characterized in that, The outer wall of the pile (1) is provided with a mounting hole (13), and one end of the support rod (12) is interference-fitted into the mounting hole (13).

9. The method for repairing concrete foundations of substations as described in any one of claims 1-6, characterized in that, In the hole-opening step, after the hole is opened by the drill barrel (2), the slotting device (3) is first assembled onto the drill barrel (2), and then the drill barrel (2) is screwed into the repair hole (102) from top to bottom, or the drill barrel (2) is screwed out of the repair hole (102) from bottom to top, thereby forming a spiral groove on the inner wall of the repair hole (102).

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