A self-propelled anchor drilling and sealing integrated construction method

Abstract

A self-drilling anchor bolt drilling and grouting integrated construction method utilizes a rod connector to connect the drilling rig and the self-drilling anchor bolt. The drilling rig provides driving force, while a round nut limits the hexagonal nut and transmits torque to the drill bit. Spiral slag removal and chip removal are performed simultaneously using front and rear spiral slag removal channels. The drilling rig is controlled to reverse, and the hexagonal nut presses the torque-regulating plate and anti-shear tray firmly at the borehole opening until a flattened state is achieved, completing the installation of the self-drilling anchor bolt. A grouting pump uses a grouting pipe to deliver grout to the grout mixer, which then injects it into the depth of the borehole through the grouting channel and the drill bit outlet. During this process, the large threaded section in the middle section provides a tight seal to the borehole gaps, maintaining pressure and effectively sealing cracks. When the grouting pressure suddenly increases, the grouting pump is stopped, grouting operations cease, and the grout mixer is then sealed. This method integrates drilling, sealing, and grouting operations.

Description

Technical Field

[0001] This invention belongs to the field of tunnel support technology, specifically relating to an integrated construction method for self-advancing anchor drilling and sealing. Background Technology

[0002] Coal is one of my country's main energy sources, consistently accounting for a significant share of the country's primary energy consumption. During coal mining, a series of roadways need to be excavated. To ensure high-yield and efficient production in coal mines, reliable and stable support is essential for these roadways. Among these roadways, a large proportion are characterized by loose and fractured surrounding rock due to mining activities, geological structures, and the coal-forming environment, making their support challenging and costly. Under current technological conditions, grouting and anchor bolt support methods are commonly used to modify the state of the loose and fractured surrounding rock, transforming it into a more complete structure and thus enabling the surrounding rock to have good load-bearing capacity. In traditional grouting anchoring construction, drilling is often required first. After drilling, grouting anchors are installed in the boreholes, then the boreholes are sealed, and finally, grouting is performed. This method is cumbersome and inefficient. Furthermore, due to the dispersed nature of the processes, the quality control of drilling, anchor installation, borehole sealing, and grouting is poor. This not only fails to meet the current needs for efficient roadway support but also fails to meet the requirements for high-quality support. To effectively overcome these technical problems, there is an urgent need to provide a self-drilling anchor drilling and grouting integrated construction method to ensure safe production in coal mines. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides an integrated construction method for self-drilling anchor bolts, which is simple and convenient to implement. It can complete drilling, sealing, and grouting operations in one integrated manner, greatly simplifying the construction procedures for anchor support and significantly improving the accuracy, efficiency, and safety of anchor construction.

[0004] To achieve the above objectives, this invention provides an integrated construction method for self-drilling anchor bolts, employing self-drilling anchor bolts. The self-drilling anchor bolt includes a rod body, a PDC drill bit, an anti-shear tray, a torque-regulating pressure plate, a hexagonal nut, a round nut, and a grout mixer. The rod body has an axially continuous grouting channel at its axis, and its outer surface has a continuous thread structure, which is divided into a first wavy thread section, a middle large thread section, and a final wavy thread section from the first end to the last end. The outer diameters of both the first and final wavy thread sections are smaller than [a certain value]. The outer diameter of the middle section of the large threaded section; a front spiral slag discharge channel is formed in the first section of the corrugated threaded section; a rear spiral slag discharge channel is formed in the middle section of the large threaded section; the PDC drill bit is installed at the beginning of the rod body, and the beginning of the PDC drill bit has a drill bit outlet that communicates with the grouting channel; at the same time, the outer diameter of the PDC drill bit is larger than the outer diameter of the first section of the corrugated threaded section and smaller than the outer diameter of the middle section of the large threaded section; the central anchor hole of the anti-shear tray is a tubular structure that protrudes axially and has a continuously tapering inner and outer diameter, and the inner diameter of the anchor hole is larger than that of the final section. The outer diameter of the wave-shaped thread section is smaller than that of the middle large thread section. The anti-shear tray is slidably fitted onto the outside of the final wave-shaped thread section through the anchor hole. The torsion plate is a hollow, flat-bottomed spherical crown shape with a mounting hole at its top center. The torsion plate is slidably fitted onto the outside of the final wave-shaped thread section through the mounting hole, and it is closer to the end of the rod than the anti-shear tray. The hexagonal nut is fitted onto the outside of the final wave-shaped thread section through threaded engagement, and it is closer to the end of the rod than the torsion plate. The outer diameter of the circular nut is larger than the outer diameter of the rod. The outer diameter of the slurry mixer is smaller than that of the hexagonal nut. The round nut is coaxially fixed and welded to the end of the rod, and its internal thread cavity is smoothly connected to the grouting channel. The main body of the slurry mixer is a rod-shaped structure, and an external thread structure adapted to the round nut is provided on the outer surface. An axially penetrating mixing cavity is provided at the axis of the slurry mixer, and a cross-shaped partition frame for dividing the radial space of the mixing cavity is fixedly installed inside the mixing cavity. The slurry mixer is connected to the inside of the round nut by a threaded fit, and its head extends into the grouting channel.

[0005] The construction method includes the following steps:

[0006] Step 1: Select the predetermined construction location on the rock mass surface;

[0007] Step 2: Prepare the rod connector and the drilling rig. The rod connector has an internal hexagonal connection hole at the front end of the shaft, and an external hexagonal connector is fixedly connected at the rear end of the shaft. The size of the internal hexagonal connection hole is compatible with the size of the hexagonal nut, the depth of the internal hexagonal connection hole is compatible with the length of the final wave thread section, and the size of the external hexagonal connector is compatible with the size of the internal hexagonal mounting hole at the front end of the drilling rig.

[0008] Step 3: Insert the external hexagonal connector of the rod connector into the internal hexagonal mounting hole on the drilling rig, and then fit the hexagonal connector from the end of the rod onto the outside of the hexagonal nut;

[0009] Step 4: Use the drilling rig to drive the rod connector to rotate, and simultaneously drive the hexagonal nut to rotate clockwise. When the hexagonal nut reaches the end of the rod and abuts against the round nut, the round nut locks the hexagonal nut at the rear limit and transmits the torque acting on the hexagonal nut to the rod and PDC drill bit, thereby driving the rod and PDC drill bit to rotate at high speed simultaneously.

[0010] Step 5: Drilling is performed using a high-speed rotating PDC drill bit. The high-efficiency cutting performance of the PDC drill bit breaks up large coal and rock masses in the direction of travel. The slag and debris formed during drilling enter the front spiral slag discharge channel. Under the action of the clockwise rotation of the rod, the slag and debris are carried out of the hole along the front spiral slag discharge channel. As the drilling operation continues, the rod goes deeper into the hole, and the slag and debris are continuously discharged, thus achieving the initial drilling slag and chip removal operation. This process continues until the first wave-shaped thread section is completely in the hole.

[0011] Step Six: Reduce the drilling rig speed and continue to drive the middle section of the large threaded section slowly into the hole. At the same time, the slag and debris discharged by the front spiral slag discharge channel enter the rear spiral slag discharge channel and are carried out of the hole along the rear spiral channel under the action of rotating the rod in a clockwise direction, realizing the subsequent drilling slag and chip removal operations. After the middle section of the large threaded section has completely entered the hole, proceed to Step Seven.

[0012] Step 7: Control the drill to reverse, so that the drill rod connector synchronously drives the hexagonal nut to rotate in the opposite direction towards the borehole. During the reverse rotation of the hexagonal nut, gradually push the fixed torque pressure plate towards the anti-shear tray, and press the first end of the fixed torque pressure plate firmly against the end of the anti-shear tray, so that the first end of the anti-shear tray firmly against the wall outside the borehole. Continue to apply torque to make the fixed torque pressure plate continue to deform until it reaches the flattened state and reaches the set preload state. Stop applying torque, remove the drill rod connector and drill from the self-advancing anchor rod, and complete the installation of the self-advancing anchor rod.

[0013] Step 8: Thoroughly mix the slurry to ensure that the slurry has the uniformity and fluidity to meet the grouting requirements; connect a pressure gauge to the grouting pipe, and then connect both ends of the grouting pipe to the outlet of the grouting pump and the end of the slurry mixer, respectively.

[0014] Step Nine: Use a grouting pump to pump grout through the grouting pipe into the mixing chamber of the grout mixer. Under the action of the cross-shaped separator, the grout is further mixed evenly in the mixing chamber. Then, it is transported through the grouting channel to the drill bit outlet. Then, it enters the depth of the hole from the drill bit outlet. During this process, the outer edge of the large threaded section in the middle section, which is in close contact with the hole wall, is used to seal the gaps in the hole. This seals the gaps in the hole and plays a role in grouting pressure maintenance. At the same time, the grouting volume is controlled according to the pressure gauge reading. Under the pressure maintenance, the continuously entering grout first fills the entire hole and then gradually enters the deep fissures, achieving effective sealing of the fissures.

[0015] When the grouting pressure displayed on the pressure gauge suddenly increases, control the grouting pump to stop, stop the grouting operation, remove the grouting pipe, and then seal the end of the grout mixer.

[0016] Furthermore, in order to facilitate positioning during assembly, an annular limiting boss is fixedly fitted on the outer end of the slurry mixer.

[0017] Furthermore, in order to reduce the manufacturing cost of the built-in mixer, the slurry mixer is made of nylon and is manufactured as a single piece by injection molding.

[0018] Furthermore, in order to ensure the overall load-bearing strength of the anchor bolt and to ensure the support effect in the later stage, the lengths of the first wave-shaped threaded section, the middle large threaded section and the last wave-shaped threaded section are respectively 3 / 5, 1 / 5 and 1 / 5 of the length of the bolt body.

[0019] Furthermore, in order to improve drilling efficiency, the drill bit is a three-wing drill bit.

[0020] Furthermore, in order to achieve stress homogenization and ensure support effect during long-term use, the perimeter of the anti-shear tray is connected to its anchor hole via a transition section, and the transition section is uniformly provided with 5 to 8 longitudinal ribs in the circumferential direction.

[0021] In this invention, the outer diameter of the drill bit fixedly installed at the head end of the rod is larger than the outer diameter of the first wave-shaped threaded section but smaller than the outer diameter of the middle large threaded section. This allows the drill bit to create a hole diameter relatively larger than the outer diameter of the first wave-shaped threaded section during drilling, effectively reducing friction and resistance between the first wave-shaped threaded section and the hole wall, thus lowering the stress on the first wave-shaped threaded section and ensuring the strength of the rod body in that section. Simultaneously, the high cutting performance of the drill bit is fully utilized to quickly break the coal and rock mass into small particles, and the annular gap between the first wave-shaped threaded section and the hole wall allows for timely transport of slag and debris to the middle large threaded section, thereby improving slag and debris removal efficiency and effectively preventing stuck drill bits due to untimely slag or debris removal, ensuring drilling continuity and efficiency. Meanwhile, the outer edge of the large threaded section in the middle section fully engages with the borehole wall, effectively sealing the borehole. During pumping grouting, this large threaded section effectively seals the grout, preventing leakage and maintaining pressure. This allows the continuously injected grout to extend more efficiently into the surrounding rock fissures, significantly improving the filling effect and resulting in more effective reinforcement. A front spiral-shaped slag discharge channel is formed in the first wavy threaded section, allowing for timely removal of debris and cuttings during initial drilling. A rear spiral-shaped slag discharge channel is formed in the middle threaded section, receiving the debris and cuttings discharged from the front channel during subsequent drilling and carrying them out of the borehole. The coordination of the front and rear spiral-shaped slag discharge channels enables continuous slag and cuttings removal throughout the drilling process. The drill bit has a grout outlet that connects to the grouting channel inside the rod, allowing for convenient subsequent grouting operations after drilling. The anchor hole section of the shear guard plate has a continuously tapering tubular structure, with the anchor hole diameter larger than the outer diameter of the final wave-threaded section. This allows the rod a certain amount of free movement during construction, enabling the angle of the anchor hole to be adjusted to match the bending angle of the rod by rotating the guard plate during drilling. This provides sufficient room for the rod to move, effectively reducing the shear force exerted by the shear guard plate on the rod and providing effective protection. Simultaneously, this structure evenly distributes the stress borne by the anchor hole section to the perimeter of the shear guard plate during support, acting on the rock surface at the borehole opening, increasing the load-bearing capacity of the shear guard plate and achieving stress homogenization. Since the constant torsion pressure plate can achieve a flattened state under the action of the set pre-tightening pressure, setting the constant torsion pressure plate on one side of the end of the anti-shear tray can intuitively determine whether the applied pre-tightening force has reached the set pre-tightening pressure, thus intuitively determining the state of the pre-tightening force, which is conducive to simplifying the construction process.A round nut is fixedly welded to the end of the rod, ensuring smooth connection between the threaded cavity of the round nut and the grouting channel of the rod. Simultaneously, a hexagonal nut is positioned between the torque plate and the round nut. This serves two purposes: firstly, the round nut acts as a limiting block for the hexagonal nut, thereby limiting its backward travel and locking it in place. Thus, when the drilling rig provides clockwise driving force, rotating the hexagonal nut via the rod connector, the round nut can resist and limit the backward travel of the hexagonal nut, and can also continuously reduce its backward travel. Torque acts on the rod and drill bit, enabling drilling operations. Furthermore, after the rod is anchored, the reverse-rotating drill rig can drive the hexagonal nut to reverse, thus pre-tightening the torque plate and anti-shear tray using the hexagonal nut. This design achieves the dual functions of forward drilling and reverse pre-tightening, reducing intermediate steps and significantly improving construction efficiency, ensuring the stability and reliability of the anchor installation process. On the other hand, a built-in mixer with an external thread structure can be inserted into the inner side of the rod end via a threaded connection. The built-in mixer has a mixing chamber with a separating mesh frame. During grouting, the synergistic effect of the separating mesh frame and grouting pressure can be fully utilized to further break up large particles and remix the already mixed grout, resulting in more thorough mixing and significantly increased grout permeability. This prevents grout blockage and facilitates the filling of deeper fissures with the grout. This self-propelled anchor bolt integrates drilling, hole sealing, and grouting reinforcement operations, effectively solving the problem of grout blockage during surrounding rock grouting reinforcement. It also significantly reduces the shear force exerted by the support plate on the bolt. Furthermore, it allows for direct assessment of whether the preload meets requirements, ensuring the strength and effectiveness of the support and providing reliable technical support for the stability control of the surrounding rock. The bolt connector features an internal hexagonal connection hole at the front and an external hexagonal connection head at the rear. This allows for easy fitting of the front end of the bolt connector to the hexagonal nut through the internal hexagonal connection hole, and easy insertion of the rear end of the bolt connector into the internal hexagonal connector at the front of the drilling rig using the external hexagonal connection head. This facilitates a quick and reliable connection between the drilling rig and the bolt. Furthermore, simply starting the drilling rig efficiently drives the self-propelled anchor bolt to rotate, ensuring stability and reliability during the driving process. During the initial drive, the drill rig rotates clockwise, utilizing the locking function of the round nut on the retraction stroke of the hexagonal nut to transmit torque to the drill rod and PDC bit, thus achieving efficient drilling operations. At the end of the drilling phase, the drill rig rotates counterclockwise, pushing the hexagonal nut towards the borehole opening. This presses the torque plate and anti-shear plate firmly against the borehole opening, allowing the application of the set preload. During preload application, the state of the torque plate is observed to determine if the set preload has been reached.Therefore, this invention allows for drilling and pre-tightening operations simply by rotating the drilling rig in both directions, effectively improving the construction efficiency of support structures. After the first section of the corrugated thread is fully drilled, reducing the drilling rig's speed to continue driving the rod ensures more even stress distribution on the rod during drilling using the middle section of the large thread, preventing rod damage and achieving higher-quality boreholes. Throughout the drilling process, real-time slag removal via the front and rear spiral slag removal channels ensures smooth drilling and contributes to improved drilling efficiency. After drilling is completed, the drilling rig and hexagonal connector are removed, and the grouting device is connected to the end of the grout mixer to start grouting. During grouting, the outer edge of the large threaded section in the middle section is used to seal the gap in the hole, which can effectively maintain pressure. This changes the traditional method of sealing the grout in anchor bolt grouting, eliminating the need for a separate hole sealing operation, simplifying the construction process and further improving construction efficiency. After grouting is completed, the end of the grout mixer is sealed to complete the entire operation.

[0022] This method is simple and convenient to implement, and can complete drilling, sealing and grouting operations in one integrated manner, which greatly simplifies the construction process of anchor support and can significantly improve the accuracy, efficiency and safety of anchor construction. Using this method can effectively improve the construction efficiency of support construction and significantly improve the support effect. It has wide applicability and is easy to apply to various engineering support projects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the construction process using a drilling rig and self-propelled anchor bolts according to the present invention.

[0024] Figure 2 This is a schematic diagram of the self-advancing anchor bolt in this invention;

[0025] Figure 3 This is a schematic diagram of the drill bit structure in this invention;

[0026] Figure 4 This is a schematic diagram of the anti-shear pallet in this invention;

[0027] Figure 5 This is a schematic diagram of the structure of the constant torsion pressure plate in this invention;

[0028] Figure 6 This is a schematic diagram of the slurry mixer in this invention;

[0029] Figure 7 This is a schematic diagram of the structure of the rod connector in this invention;

[0030] Figure 8 This is a schematic diagram of the grouting operation in this invention.

[0031] In the diagram: 1. Rod body; 1-1. First section of corrugated thread; 1-2. Middle section of large thread; 1-3. Last section of corrugated thread; 2. PDC drill bit; 2-1. Drill bit grout outlet; 3. Anti-shear tray; 3-1. Anchor hole; 4. Torque plate; 5. Hexagonal nut; 6. Round nut; 7. Grout mixer; 7-1. Cross divider; 7-2. Annular limiting boss; 8. Pressure gauge; 9. Drilling rig; 10. Grouting pump; 11. Rod connector; 11-1. Internal hexagonal connector; 11-2. External hexagonal connector; 12. Grouting pipe. Detailed Implementation

[0032] The invention will now be further described with reference to the accompanying drawings.

[0033] like Figures 1 to 8As shown, this invention provides an integrated construction method for self-drilling anchor bolts, employing self-drilling anchor bolts. The self-drilling anchor bolt includes a rod body 1, a PDC drill bit 2, an anti-shear tray 3, a torque-regulating pressure plate 4, a hexagonal nut 5, a round nut 6, and a grout mixer 7. The rod body 1 has an axially penetrating grouting channel at its axis, and its outer surface has a continuous thread structure, which is divided from the first end to the last end into a first wave-shaped thread section 1-1, a middle large thread section 1-2, and a last wave-shaped thread section 1-3. The outer diameters of the first wave-shaped thread section 1-1 and the last wave-shaped thread section 1-3 are both smaller than the middle large thread section. The outer diameter of section 1-2; a front spiral slag discharge channel is formed in the first section of the wave-shaped thread section 1-1; a rear spiral slag discharge channel is formed in the middle section of the large thread section 1-2; the PDC drill bit 2 is installed at the beginning of the rod body 1, and the beginning of the PDC drill bit 2 has a drill bit outlet 2-1 that communicates with the grouting channel; at the same time, the outer diameter of the PDC drill bit 2 is larger than the outer diameter of the first section of the wave-shaped thread section 1-1 and smaller than the outer diameter of the middle section of the large thread section 1-2; part of the center anchor hole 3-1 of the anti-shear tray 3 is a tubular structure that protrudes axially and has a continuously tapering inner and outer diameter, and the inner diameter of the anchor hole 3-1 is larger than the outer diameter of the first section of the wave-shaped thread section 1-1 and smaller than the outer diameter of the middle section of the large thread section 1-2; The outer diameter of the final wave-shaped threaded section 1-3 is smaller than the outer diameter of the middle large threaded section 1-2. The anti-shear tray 3 is slidably fitted onto the outside of the final wave-shaped threaded section 1-3 through the anchor hole 3-1. The torsion plate 4 is a hollow flat-bottomed spherical crown shape, with a mounting hole at its top center. The torsion plate 4 is slidably fitted onto the outside of the final wave-shaped threaded section 1-3 through the mounting hole, and it is closer to the end of the rod body 1 than the anti-shear tray 3. The hexagonal nut 5 is fitted onto the outside of the final wave-shaped threaded section 1-3 through threaded engagement, and it is closer to the end of the rod body 1 than the torsion plate 4. The outer diameter of the circular nut 6 is... The diameter is larger than the outer diameter of the rod body 1 and smaller than the outer diameter of the hexagonal nut 5. The circular nut 6 is coaxially fixedly welded to the end of the rod body 1, and its internal thread cavity is smoothly connected to the grouting channel. The main body of the grout mixer 7 is a rod-shaped structure, and an external thread structure adapted to the circular nut 6 is provided on the outer surface. The grout mixer 7 has an axially penetrating mixing cavity at its axis, and a cross-shaped divider 7-1 for dividing the radial space of the mixing cavity is fixedly installed inside the mixing cavity. The grout mixer 7 is connected to the inside of the circular nut 6 by a threaded fit, and its head extends into the grouting channel.

[0034] The construction method includes the following steps:

[0035] Step 1: Select the predetermined construction location on the rock mass surface;

[0036] Step 2: Prepare the rod connector 11 and the drilling rig 9. The rod connector 11 has an internal hexagonal connection hole 11-1 at the front end of the shaft, and an external hexagonal connector 11-2 is fixedly connected to the rear end of the shaft. The size of the internal hexagonal connection hole 11-1 is adapted to the size of the hexagonal nut 5, the depth of the internal hexagonal connection hole 11-1 is adapted to the length of the final wave thread section 1-3, and the size of the external hexagonal connector 11-2 is adapted to the size of the internal hexagonal mounting hole at the front end of the drilling rig 9.

[0037] Step 3: Insert the external hexagonal connector 11-2 of the rod connector 11 into the internal hexagonal mounting hole on the drilling rig 9, and then fit the hexagonal connector 11 from the end of the rod body 1 onto the outside of the hexagonal nut 5;

[0038] Step 4: Use the drill rig 9 to drive the rod connector 11 to rotate, and simultaneously drive the hexagonal nut 5 to rotate clockwise. When the hexagonal nut 5 reaches the end of the rod body 1 and abuts against the round nut 6, the round nut 6 locks the hexagonal nut 5 at the rear limit and transmits the torque acting on the hexagonal nut 5 to the rod body 1 and PDC drill bit 2, thereby synchronously driving the rod body 1 and PDC drill bit 2 to rotate at high speed.

[0039] Step 5: Drilling operation is carried out using the high-speed rotating PDC drill bit 2. The high-efficiency cutting performance of the PDC drill bit 2 is used to break up the large coal and rock mass in the direction of travel. The slag and debris formed during the drilling process enter the front spiral slag discharge channel. Under the action of the clockwise rotation of the rod 1, the slag and debris are carried out of the hole along the front spiral slag discharge channel. As the drilling operation continues, the rod 1 continues to penetrate deeper into the hole, and the slag and debris are continuously discharged, thus realizing the initial drilling slag and chip removal operation. This process continues until the first wave-shaped thread section 1-1 completely enters the hole.

[0040] Step Six: Reduce the rotation speed of drill rig 9 and continue to drive the middle section large thread section 1-2 slowly into the hole. At the same time, the slag and debris discharged by the front spiral slag discharge channel enter the rear spiral slag discharge channel. Under the action of the clockwise rotation of rod 1, the slag and debris are carried out of the hole along the rear spiral slag discharge channel, realizing the subsequent drilling slag and chip removal operations. After the middle section large thread section 1-2 has completely entered the hole, proceed to Step Seven.

[0041] Step 7: Control the drill rig 9 to reverse, so that the rod connector 11 synchronously drives the hexagonal nut 5 to rotate in the opposite direction towards the borehole. During the reverse rotation of the hexagonal nut 5, gradually push the fixed torque pressure plate 4 towards the anti-shear tray 3, and press the first end of the fixed torque pressure plate 4 firmly against the end of the anti-shear tray 3, so that the first end of the anti-shear tray 3 firmly presses against the wall outside the borehole. Continue to apply torque to make the fixed torque pressure plate 4 continue to deform until it reaches the flattened state and reaches the set pre-tightening state. Stop applying torque, remove the rod connector 11 and the drill rig 9 from the self-advancing anchor rod, and complete the installation of the self-advancing anchor rod.

[0042] Step 8: Thoroughly mix the slurry to ensure that the uniformity and fluidity of the slurry meet the grouting requirements; connect the pressure gauge 8 to the grouting pipe 12, and then connect both ends of the grouting pipe 12 to the slurry outlet of the grouting pump 10 and the end of the slurry mixer 7, respectively.

[0043] Step 9: Using the grouting pump 10, the grout enters the mixing chamber of the grout mixer 7 through the grouting pipe 12. Under the action of the cross-shaped separator 7-1, the grout is further mixed evenly in the mixing chamber, and then transported to the drill bit outlet 2-1 through the grouting channel. Then, it enters the depth of the hole through the drill bit outlet 2-1. During this process, the outer edge of the middle section of the large thread 1-2, which is in close contact with the hole wall, is used to seal the gap in the hole, thereby playing a role in grouting pressure maintenance during the grouting process. At the same time, the grouting volume is controlled according to the reading of the pressure gauge. Under the pressure maintenance, the continuously entering grout first fills the entire hole, and then gradually enters the deep cracks, achieving effective sealing of the cracks.

[0044] When the grouting pressure displayed on the pressure gauge 8 suddenly increases, control the grouting pump 10 to stop, stop the grouting operation, remove the grouting pipe 12, and then seal the end of the grout mixer 7.

[0045] To facilitate positioning during assembly, an annular limiting boss 7-2 is fixedly fitted on the outer end of the slurry mixer 7.

[0046] To reduce the manufacturing cost of the built-in mixer, the slurry mixer 7 is made of nylon and is manufactured as a single piece using injection molding.

[0047] To ensure the overall load-bearing strength of the anchor bolt and the subsequent support effect, the lengths of the first wave-shaped threaded section 1-1, the middle large threaded section 1-2, and the last wave-shaped threaded section 1-3 are respectively 3 / 5, 1 / 5, and 1 / 5 of the length of the rod body 1.

[0048] To improve drilling efficiency, the drill bit 2 is a three-wing drill bit.

[0049] In order to achieve stress homogenization and ensure the support effect during long-term use, the periphery of the anti-shear tray 3 is connected to the anchor hole 3-1 by a transition section with a variable diameter section, and 5 to 8 longitudinal ribs are evenly arranged in the circumferential direction of the transition section.

[0050] In this invention, the outer diameter of the drill bit fixedly installed at the head end of the rod is larger than the outer diameter of the first wave-shaped threaded section but smaller than the outer diameter of the middle large threaded section. This allows the drill bit to create a hole diameter relatively larger than the outer diameter of the first wave-shaped threaded section during drilling, effectively reducing friction and resistance between the first wave-shaped threaded section and the hole wall, thus lowering the stress on the first wave-shaped threaded section and ensuring the strength of the rod body in that section. Simultaneously, the high cutting performance of the drill bit is fully utilized to quickly break the coal and rock mass into small particles, and the annular gap between the first wave-shaped threaded section and the hole wall allows for timely transport of slag and debris to the middle large threaded section, thereby improving slag and debris removal efficiency and effectively preventing stuck drill bits due to untimely slag or debris removal, ensuring drilling continuity and efficiency. Meanwhile, the outer edge of the large threaded section in the middle section fully engages with the borehole wall, effectively sealing the borehole. During pumping grouting, this large threaded section effectively seals the grout, preventing leakage and maintaining pressure. This allows the continuously injected grout to extend more efficiently into the surrounding rock fissures, significantly improving the filling effect and resulting in more effective reinforcement. A front spiral-shaped slag discharge channel is formed in the first wavy threaded section, allowing for timely removal of debris and cuttings during initial drilling. A rear spiral-shaped slag discharge channel is formed in the middle threaded section, receiving the debris and cuttings discharged from the front channel during subsequent drilling and carrying them out of the borehole. The coordination of the front and rear spiral-shaped slag discharge channels enables continuous slag and cuttings removal throughout the drilling process. The drill bit has a grout outlet that connects to the grouting channel inside the rod, allowing for convenient subsequent grouting operations after drilling. The anchor hole section of the shear guard plate has a continuously tapering tubular structure, with the anchor hole diameter larger than the outer diameter of the final wave-threaded section. This allows the rod a certain amount of free movement during construction, enabling the angle of the anchor hole to be adjusted to match the bending angle of the rod by rotating the guard plate during drilling. This provides sufficient room for the rod to move, effectively reducing the shear force exerted by the shear guard plate on the rod and providing effective protection. Simultaneously, this structure evenly distributes the stress borne by the anchor hole section to the perimeter of the shear guard plate during support, acting on the rock surface at the borehole opening, increasing the load-bearing capacity of the shear guard plate and achieving stress homogenization. Since the constant torsion pressure plate can achieve a flattened state under the action of the set pre-tightening pressure, setting the constant torsion pressure plate on one side of the end of the anti-shear tray can intuitively determine whether the applied pre-tightening force has reached the set pre-tightening pressure, thus intuitively determining the state of the pre-tightening force, which is conducive to simplifying the construction process.A round nut is fixedly welded to the end of the rod, ensuring smooth connection between the threaded cavity of the round nut and the grouting channel of the rod. Simultaneously, a hexagonal nut is positioned between the torque plate and the round nut. This serves two purposes: firstly, the round nut acts as a limiting block for the hexagonal nut, thereby limiting its backward travel and locking it in place. Thus, when the drilling rig provides clockwise driving force, rotating the hexagonal nut via the rod connector, the round nut can resist and limit the backward travel of the hexagonal nut, and can also continuously reduce its backward travel. Torque acts on the rod and drill bit, enabling drilling operations. Furthermore, after the rod is anchored, the reverse-rotating drill rig can drive the hexagonal nut to reverse, thus pre-tightening the torque plate and anti-shear tray using the hexagonal nut. This design achieves the dual functions of forward drilling and reverse pre-tightening, reducing intermediate steps and significantly improving construction efficiency, ensuring the stability and reliability of the anchor installation process. On the other hand, a built-in mixer with an external thread structure can be inserted into the inner side of the rod end via a threaded connection. The built-in mixer has a mixing chamber with a separating mesh frame. During grouting, the synergistic effect of the separating mesh frame and grouting pressure can be fully utilized to further break up large particles and remix the already mixed grout, resulting in more thorough mixing and significantly increased grout permeability. This prevents grout blockage and facilitates the filling of deeper fissures with the grout. This self-propelled anchor bolt integrates drilling, hole sealing, and grouting reinforcement operations, effectively solving the problem of grout blockage during surrounding rock grouting reinforcement. It also significantly reduces the shear force exerted by the support plate on the bolt. Furthermore, it allows for direct assessment of whether the preload meets requirements, ensuring the strength and effectiveness of the support and providing reliable technical support for the stability control of the surrounding rock. The bolt connector features an internal hexagonal connection hole at the front and an external hexagonal connection head at the rear. This allows for easy fitting of the front end of the bolt connector to the hexagonal nut through the internal hexagonal connection hole, and easy insertion of the rear end of the bolt connector into the internal hexagonal connector at the front of the drilling rig using the external hexagonal connection head. This facilitates a quick and reliable connection between the drilling rig and the bolt. Furthermore, simply starting the drilling rig efficiently drives the self-propelled anchor bolt to rotate, ensuring stability and reliability during the driving process. During the initial drive, the drill rig rotates clockwise, utilizing the locking function of the round nut on the retraction stroke of the hexagonal nut to transmit torque to the drill rod and PDC bit, thus achieving efficient drilling operations. At the end of the drilling phase, the drill rig rotates counterclockwise, pushing the hexagonal nut towards the borehole opening. This presses the torque plate and anti-shear plate firmly against the borehole opening, allowing the application of the set preload. During preload application, the state of the torque plate is observed to determine if the set preload has been reached.Therefore, this invention allows for drilling and pre-tightening operations simply by rotating the drilling rig in both directions, effectively improving the construction efficiency of support structures. After the first section of the corrugated thread is fully drilled, reducing the drilling rig's speed to continue driving the rod ensures more even stress distribution on the rod during drilling operations using the middle section of the large thread, preventing rod damage and achieving higher-quality boreholes. Throughout the drilling process, the use of spiral-shaped slag removal channels at the front and rear sections ensures smooth drilling and contributes to improved drilling efficiency. After drilling is completed, the drilling rig and hexagonal connector are removed, and the grouting device is connected to the end of the grout mixer to start grouting. During grouting, the outer edge of the large threaded section in the middle section is used to seal the gap in the hole, which can effectively maintain pressure. This changes the traditional method of sealing the grout in anchor bolt grouting, eliminating the need for a separate hole sealing operation, simplifying the construction process and further improving construction efficiency. After grouting is completed, the end of the grout mixer is sealed to complete the entire operation.

[0051] This method is simple and convenient to implement, and can complete drilling, sealing and grouting operations in one integrated manner, which greatly simplifies the construction process of anchor support and can significantly improve the accuracy, efficiency and safety of anchor construction. Using this method can effectively improve the construction efficiency of support construction and significantly improve the support effect. It has wide applicability and is easy to apply to various engineering support projects.

Claims

1. A self-drilling anchor bolt drilling and grouting integrated construction method, using a self-drilling anchor bolt; the self-drilling anchor bolt includes a rod body (1), a PDC drill bit (2), an anti-shear tray (3), a torsion plate (4), a hexagonal nut (5), a round nut (6), and a grout mixer (7); the rod body (1) has an axially penetrating grouting channel at its axis, and its outer surface has a continuous thread structure, which is divided into a first wave-shaped thread section (1-1), a middle large thread section (1-2), and a last wave-shaped thread section (1-3) from the first end to the last end; the outer diameter of the first wave-shaped thread section (1-1) and the outer diameter of the last wave-shaped thread section (1-3) are both smaller than those of the middle large thread section (1-3). 2) Outer diameter; a front spiral slag discharge channel is formed in the first section of the wave-shaped thread (1-1); a rear spiral slag discharge channel is formed in the middle section of the large thread (1-2); the PDC drill bit (2) is installed at the beginning of the rod (1), and the beginning of the PDC drill bit (2) has a drill bit grout outlet (2-1) that communicates with the grouting channel; at the same time, the outer diameter of the PDC drill bit (2) is larger than the outer diameter of the first section of the wave-shaped thread (1-1) and smaller than the outer diameter of the middle section of the large thread (1-2); the part of the center anchor hole (3-1) of the anti-shear tray (3) is a tubular structure that protrudes axially and has a continuously tapering inner and outer diameter, and the inner diameter of the anchor hole (3-1) is larger than the end The outer diameter of the wave-shaped thread section (1-3) is smaller than that of the middle large thread section (1-2). The anti-shear tray (3) is slidably fitted onto the outside of the final wave-shaped thread section (1-3) through the anchor hole (3-1). The torsion plate (4) is a hollow flat-bottomed spherical crown shape, and a mounting hole is provided at the center of its top. The torsion plate (4) is slidably fitted onto the outside of the final wave-shaped thread section (1-3) through the mounting hole, and it is closer to the end of the rod (1) than the anti-shear tray (3). The hexagonal nut (5) is fitted onto the outside of the final wave-shaped thread section (1-3) through threaded engagement, and it is closer to the end of the rod (1) than the torsion plate (4). The round nut ( The outer diameter of the 6) is greater than that of the rod (1) and less than that of the hexagonal nut (5). The round nut (6) is coaxially fixedly welded to the end of the rod (1), and its internal thread cavity is smoothly connected to the grouting channel. The main body of the slurry mixer (7) is a rod-shaped structure, and an external thread structure adapted to the round nut (6) is provided on the outer surface. The slurry mixer (7) has an axially penetrating mixing cavity at the axis, and a cross divider (7-1) for dividing the radial space of the mixing cavity is fixedly installed inside the mixing cavity. The slurry mixer (7) is connected to the inside of the round nut (6) by threaded connection, and its head extends into the grouting channel. Its features are, Includes the following steps: Step 1: Select the predetermined construction location on the rock mass surface; Step 2: Prepare the rod connector (11) and the drilling rig (9). The rod connector (11) has an internal hexagonal connection hole (11-1) at the front end of the shaft and an external hexagonal connector (11-2) fixedly connected at the rear end of the shaft. The size of the internal hexagonal connection hole (11-1) is compatible with the size of the hexagonal nut (5). The depth of the internal hexagonal connection hole (11-1) is compatible with the length of the last wave-shaped thread section (1-3). The size of the external hexagonal connector (11-2) is compatible with the size of the internal hexagonal mounting hole at the front end of the drilling rig (9). Step 3: Insert the external hexagonal connector (11-2) of the rod connector (11) into the internal hexagonal mounting hole on the drilling rig (9), and then fit the rod connector (11) from the end of the rod body (1) onto the outside of the hexagonal nut (5); Step 4: Use the drill (9) to drive the rod connector (11) to rotate, and simultaneously drive the hexagonal nut (5) to rotate clockwise. When the hexagonal nut (5) reaches the end of the rod (1) and abuts against the round nut (6), the round nut (6) locks the hexagonal nut (5) at the rear limit and transmits the torque acting on the hexagonal nut (5) to the rod (1) and the PDC drill bit (2), thereby simultaneously driving the rod (1) and the PDC drill bit (2) to rotate at high speed. Step 5: Use the high-speed rotating PDC drill bit (2) to carry out drilling operations. The high efficiency of the PDC drill bit (2) is used to break up the large coal and rock mass in the direction of travel. The slag and debris formed during the drilling process enter the front spiral slag discharge channel. Under the action of the clockwise rotation of the rod (1), the slag and debris are carried out of the hole along the front spiral slag discharge channel. As the drilling operation continues, the rod (1) goes deeper into the hole, and the slag and debris are continuously discharged, thus realizing the initial drilling slag and chip removal operation. Continue this process until the first wave-shaped thread section (1-1) completely enters the hole. Step 6: Reduce the speed of the drill (9) and continue to drive the middle section of the large thread (1-2) to slowly enter the hole. At the same time, the slag and debris discharged by the front spiral slag discharge channel enter the rear spiral slag discharge channel. Under the action of rotating the rod (1) in the clockwise direction, they continue to be carried out of the hole along the rear spiral channel to realize the subsequent drilling slag and chip removal operations. After the middle section of the large thread (1-2) has completely entered the hole, proceed to step 7. Step 7: Control the drill (9) to reverse, so that the rod connector (11) drives the hexagonal nut (5) to rotate in the opposite direction towards the hole. During the reverse rotation of the hexagonal nut (5), gradually push the fixed torque plate (4) towards the anti-shear tray (3) and press the first end of the fixed torque plate (4) firmly against the end of the anti-shear tray (3). Press the first end of the anti-shear tray (3) firmly against the wall outside the hole. Continue to apply torque to make the fixed torque plate (4) continue to deform until it reaches the flat state and reaches the set pre-tightening state. Stop applying torque, remove the rod connector (11) and drill (9) from the self-advancing anchor rod, and complete the installation of the self-advancing anchor rod. Step 8: Thoroughly mix the slurry to ensure that the uniformity and fluidity of the slurry meet the grouting requirements; connect the pressure gauge (8) to the grouting pipe (12), and then connect the two ends of the grouting pipe (12) to the slurry outlet of the grouting pump (10) and the end of the slurry mixer (7) respectively. Step 9: Use the grouting pump (10) to bring the grout into the mixing chamber of the grout mixer (7) through the grouting pipe (12). Under the action of the cross divider (7-1), the grout is further mixed evenly in the mixing chamber and then transported to the drill bit outlet (2-1) through the grouting channel. Then, it enters the depth of the hole through the drill bit outlet (2-1). During this process, the outer edge of the middle section of the large thread (1-2) that is in close contact with the hole wall is used to seal the gap of the hole, thereby playing the role of grouting pressure maintenance during the grouting process. At the same time, the grouting volume is controlled according to the reading of the pressure gauge (8). Under the pressure maintenance, the continuously entering grout first fills the entire hole and then gradually enters the deep cracks to achieve effective sealing of the cracks. When the grouting pressure displayed on the pressure gauge (8) suddenly increases, control the grouting pump (10) to stop, stop the grouting operation, remove the grouting pipe (12), and then seal the end of the grout mixer (7).

2. The self-drilling anchor bolt drilling and sealing integrated construction method according to claim 1, characterized in that, The end of the slurry mixer (7) is fixedly fitted with an annular limiting boss (7-2).

3. The self-drilling anchor bolt drilling and sealing integrated construction method according to claim 1, characterized in that, The slurry mixer (7) is made of nylon and is integrally manufactured by injection molding.

4. The self-drilling anchor bolt drilling and sealing integrated construction method according to claim 1 or 2, characterized in that, The lengths of the first wave-shaped thread section (1-1), the middle large thread section (1-2), and the last wave-shaped thread section (1-3) are respectively 3 / 5, 1 / 5, and 1 / 5 of the length of the rod (1).

5. The self-drilling anchor bolt drilling and sealing integrated construction method according to claim 3, characterized in that, The drill bit (2) is a three-wing drill bit.

6. The self-drilling anchor bolt drilling and sealing integrated construction method according to claim 4, characterized in that, The anti-shear tray (3) is connected to its anchor hole (3-1) by a transition section through a variable diameter section, and the variable diameter section is uniformly provided with 5 to 8 longitudinal ribs in the circumferential direction.

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