Full-length anchoring system and method for graded pumping of anchoring agent and gradient pre-tightening force loading

Abstract

According to the full-length anchoring system and method for graded anchoring agent pumping and gradient pre-tightening force loading, a first filling hole and a second filling hole are formed in the positions, outside an anchor hole, of a tray at intervals, and the first filling hole and the second filling hole are connected with a long grouting pipe and a short grouting pipe; a feeding hole in the bottom of the mixing bin is respectively connected with a discharging hole of the A material bin and a discharging hole of the B material bin through a high-pressure pipeline I and a high-pressure pipeline II; the grouting pumps A and B are connected to the first high-pressure pipeline and the second high-pressure pipeline in series respectively. The first filling pipeline, the second filling pipeline and the third filling pipeline are connected with the first slurry outlet, the second slurry outlet and the third slurry outlet of the mixing bin through the first electric control valve, the second electric control valve and the third electric control valve respectively. The method comprises the steps of drilling and installing the hollow anchor rod; the second electric control valve is opened, and the anchoring agent is injected through the hollow anchor rod; 80% of set pre-tightening force is applied; the first electric control valve is opened, and the anchoring agent is injected through the long grouting pipe; 20% of set pre-tightening force is applied; and the third electric control valve is opened, and the anchoring agent is injected through the short grouting pipe. The system and the method can solve the problem that pretightening force is difficult to effectively apply in full-length anchoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent support for rock engineering, and specifically relates to a full-length anchoring system and method with graded pumping of anchoring agent and gradient pre-tightening force loading. Background Technique

[0002] Conventional resin anchoring agents usually rely on manual stirring or pre-mixed cartridges. If the mixing is uneven, it is easy to cause a decrease in curing strength. At the same time, an A / B two-component independent pumping system is also required. Through the inner cavity of the hollow bolt, a thixotropic anchoring agent is generated by mixing, realizing millimeter-level precise grouting operation without stirring and stopping immediately when the pump stops, and relying on the thixotropic property to precisely control the grouting range; the full-length anchoring method can effectively enhance the integrity of the bolt and surrounding rock. However, in traditional processes, it is easy to form a full-length rigid bond between the bolt, surrounding rock, and anchoring agent, resulting in ineffective application of the pre-tightening force. At the same time, stress concentration is extremely likely to occur at the tail of the bolt; in order to solve the problems that the traditional technology cannot effectively apply the pre-tightening force and stress concentration is likely to occur at the tail of the rod body, it is urgent to provide a full-length anchoring system and method with graded pumping of anchoring agent and gradient pre-tightening force loading, so as to ensure the effect of full-length anchoring in an intelligent manner. At the same time, the pre-tightening force can be effectively converted into the compressive stress of the surrounding rock, providing a reliable guarantee for the safety during coal mine operation. Summary of the Invention

[0003] Aiming at the problems existing in the above-mentioned prior art, the present invention provides a full-length anchoring system and method with graded pumping of anchoring agent and gradient pre-tightening force loading. The system has a simple structure, low manufacturing cost, and high automation. It can greatly improve the application effect of the pre-tightening force by means of segmented anchoring and segmented pre-tightening, ensure that the pre-tightening force is more effectively converted into the compressive stress on the surrounding rock, and is conducive to significantly improving the support strength; the implementation process of the method is simple and has high automation. It can achieve full-length anchoring of the bolt through stages. At the same time, it can solve the problem that it is difficult to apply the pre-tightening force in full-length anchoring by applying the pre-tightening force in a gradient manner, can greatly improve the support effect, and can make the pre-tightening force be more efficiently converted into the compressive stress on the surrounding rock.

[0004] To achieve the above object, the present invention provides a full-length anchoring system with graded pumping of anchoring agent and gradient pre-tightening force loading, including a bolt assembly and a graded pumping mechanism; the bolt assembly includes a hollow bolt, a tray, and a nut. The outer surface of the head end of the hollow bolt is provided with an external thread structure; the center of the tray has an anchor hole adapted to the hollow bolt and is sleeved on the outside of the head end of the hollow bolt through the anchor hole; the nut is sleeved on the outside of the head end of the hollow bolt through thread fit and is located outside the tray;

[0005] The bolt assembly further includes a long grouting pipe and a short grouting pipe; on the tray, a first grouting hole and a second grouting hole are spaced apart outside the anchor hole; the length of the long grouting pipe is longer than that of the short grouting pipe, and the inlet ends of the long grouting pipe and the short grouting pipe are fixedly connected to the first grouting hole and the second grouting hole coaxially respectively;

[0006] The grading pumping mechanism includes a bin for material A, a bin for material B, a mixing bin, a grouting pump A, a grouting pump B, an electric control valve 1, an electric control valve 2, an electric control valve 3, a first grouting pipeline, a second grouting pipeline and a third grouting pipeline; the feed ports at the bottom of the mixing bin are connected to the discharge ports of the bin for material A and the bin for material B through a first high-pressure pipeline and a second high-pressure pipeline respectively, and a first slurry outlet, a second slurry outlet and a third slurry outlet are formed at the top of the mixing bin respectively; the grouting pump A is connected in series on the first high-pressure pipeline; the grouting pump B is connected in series on the second high-pressure pipeline; the inlet ends of the first grouting pipeline, the second grouting pipeline and the third grouting pipeline are connected to the first slurry outlet, the second slurry outlet and the third slurry outlet through the electric control valve 1, the electric control valve 2 and the electric control valve 3 respectively, and check valves are installed at the outlet ends of the first grouting pipeline, the second grouting pipeline and the third grouting pipeline.

[0007] As a preference, the first grouting hole and the second grouting hole are distributed oppositely on both sides outside the anchor hole.

[0008] As a preference, the first grouting pipeline and the third grouting pipeline are of the same length and longer than the second grouting pipeline.

[0009] Furthermore, in order to facilitate the connection between the first grouting pipeline and the first grouting hole, between the second grouting pipeline and the anchor hole, and between the third grouting pipeline and the second grouting hole simultaneously, the first slurry outlet, the second slurry outlet and the third slurry outlet are distributed corresponding to the first grouting hole, the anchor hole and the second grouting hole respectively, and the first grouting pipeline, the second grouting pipeline and the third grouting pipeline are all rigid straight pipelines.

[0010] Furthermore, in order to facilitate the real-time perception of the magnitude of the pre-tightening force, a pressure sensor is further included, and the pressure sensor is sleeved outside the head end of the hollow bolt and located between the nut and the tray.

[0011] Furthermore, in order to facilitate the realization of an automated grouting control process, a controller is further included, and the controller is connected to the pressure sensor, the grouting pump A, the grouting pump B, the electric control valve 1, the electric control valve 2 and the electric control valve 3 respectively.

[0012] Furthermore, in order to facilitate the mixing of material A and material B in a set ratio to form a thixotropic anchoring agent with more stable performance, both the grouting pump A and the grouting pump B are quantitative adjustable grouting pumps.

[0013] In the present invention, a first filling hole and a second filling hole are spaced apart from each other outside the anchor hole on the tray, and a long grouting pipe and a short grouting pipe are correspondingly connected to the first filling hole and the second filling hole. In this way, when the tray is sleeved on the head end of the hollow anchor rod through the anchor hole, a three-stage grouting structure is formed. Among them, the hollow anchor rod serves as the first-stage grouting pipeline. When the hollow anchor rod is installed in the drill hole, its end can extend to a position close to the bottom of the drill hole. In this way, when injecting the thixotropic anchoring agent through the hollow anchor rod, the thixotropic anchoring agent can directly overflow from the bottom of the drill hole and flow down along the annular space between the hole wall and the end section of the hollow anchor rod, so that the outer side of the end section of the hollow anchor rod can be effectively bonded to the surrounding rock, and a bottom anchoring section is formed, thereby realizing the effective anchoring operation of the end section of the hollow anchor rod. The long grouting pipe serves as the second-stage grouting pipeline. After installation, its end can extend to a position close to the middle section of the drill hole. In this way, when injecting the thixotropic anchoring agent by using the long grouting pipe, the thixotropic anchoring agent can directly overflow from the middle section of the drill hole. On the one hand, it can be effectively bonded to the bottom anchoring section, and on the other hand, it can flow down along the annular space between the hole wall and the middle section of the hollow anchor rod, so that the outer side of the middle section of the hollow anchor rod can be effectively bonded to the surrounding rock, and a middle section anchoring section is formed, thereby realizing the effective anchoring operation of the middle section of the hollow anchor rod. Furthermore, the short grouting pipe serves as the third-stage grouting pipeline. After installation, its end is relatively close to the hole mouth. In this way, when injecting the thixotropic anchoring agent by using the short grouting pipe, the thixotropic anchoring agent can overflow from a position close to the hole mouth. On the one hand, it can be effectively bonded to the middle section anchoring section, and on the other hand, the thixotropic anchoring agent can be filled from the side far from the hole mouth to the side close to the hole mouth, ensuring that the first section anchoring section formed at the hole mouth position can be more solidified, effectively improving the anchoring strength of the first section anchoring section near the hole mouth. In addition, since the long grouting pipe and the short grouting pipe are fixedly connected to the inner side of the tray, after the grouting is completed, the long grouting pipe and the short grouting pipe will be left in the drill hole like the hollow anchor rod, thereby significantly improving the shear resistance of the anchor rod assembly. And because the long grouting pipe is longer than the short grouting pipe, the increase range of the shear resistance is different. The increase range of the shear strength of the head section of the hollow anchor rod is better than that of the middle section of the hollow anchor rod, which is beneficial to further improving the support effect of the anchor rod assembly. Thus, through the three-stage grouting structure, the traditional one-stage full-length rigid bonding anchoring process can be segmented in a staged manner, and the corresponding pre-tightening force gradient application operation can be carried out through the staged rigid bonding anchoring process, thereby significantly improving the application effect of the pre-tightening force.Meanwhile, during each rigid bonding and anchoring stage, the injection method is adopted from the side farther away from the hole opening to the side closer to the hole opening. In this way, not only is it conducive to discharging the air between the hole wall and the anchor rod to the outside during the grouting process, ensuring the solidification degree of the anchoring section, but also it can ensure that the anchoring sections formed in each stage can be effectively bonded into a whole, achieving an anchoring effect where the segments are not separated. As a result, the first anchoring section, the middle anchoring section, and the bottom anchoring section can be effectively bonded into a whole anchor body, ensuring the reliability and stability of the full-length anchoring and further ensuring the anchoring effect. Connecting the feed inlet of the mixing bin to the discharge outlets of the A-material and B-material bins through high-pressure pipelines 1 and 2 respectively facilitates directly pumping the A-material and B-material into the mixing bin for mixing to form a thixotropic anchoring agent. On this basis, connecting the mixing bin to the hollow anchor rod through injection pipeline 2, to the long grouting pipeline through injection pipeline 1, and to the short grouting pipeline through injection pipeline 3 can facilitate further promoting the mixing effect of the A-material and B-material by utilizing the internal spaces of the injection pipelines and the hollow anchor rod or the grouting pipeline, so that the formed thixotropic anchoring agent has a better bonding effect. On the top of the mixing bin, slurry outlets 1, 2, and 3 are respectively opened, and injection pipelines 1, 2, and 3 are respectively connected to slurry outlets 1, 2, and 3 through electric control valves 1, 2, and 3. In this way, injection pipeline 1 can be docked with injection hole 1 on the tray, injection pipeline 2 can be docked with the head end of the hollow anchor rod, and injection pipeline 3 can be docked with injection hole 2 on the tray simultaneously, thus establishing three grouting channels between the mixing bin and the borehole at the same time, and the start and stop processes of grouting in the corresponding grouting channels can be controlled through any one of the electric control valves, greatly improving the convenience and efficiency of the staged pumping of the anchoring agent. By installing a grout stop plug at the end of each of injection pipelines 1, 2, and 3, not only can the grout stop plug be used to ensure the sealing performance at the docking part to ensure the smooth grouting process of each grouting channel, but also it is conducive to realizing the precise grouting control process of stopping the grout when the pump stops.

[0014] This system has a simple structure, low manufacturing cost, and high automation degree. It can realize the staged pumping operation of the anchoring agent, and then can realize the staged rigid bonding and anchoring operation. And it can perform gradient loading of the pre-tightening force during the staged rigid bonding and anchoring process. Thus, the application effect of the pre-tightening force can be greatly improved by the method of segmental anchoring and segmental pre-tightening, ensuring that the pre-tightening force can be more effectively converted into the compressive stress on the surrounding rock, which is conducive to significantly improving the support strength. At the same time, it is conducive to avoiding the problem of stress concentration at the tail of the anchor rod, providing a safe and reliable guarantee for the safety production work in coal mines.

[0015] The present invention also provides a full-length anchoring method for staged pumping of the anchoring agent and gradient pre-tightening force loading. Using a full-length anchoring system for staged pumping of the anchoring agent and gradient pre-tightening force loading, it includes the following steps:

[0016] Step 1: Drill holes at the selected construction locations and clean the drilled holes.

[0017] Step 2: Insert the hollow anchor bolt into the drilled hole, and successively install a tray, a pressure sensor, and a nut on the head end of the hollow anchor bolt.

[0018] Step 3: Connect the outlet ends of the first filling pipeline, the second filling pipeline, and the third filling pipeline of the hierarchical pumping mechanism to the first filling hole, the head end of the hollow anchor bolt, and the second filling hole respectively.

[0019] Step 4: Control the electric control valve 2 to open, and respectively control the grouting pump A and the grouting pump B to start working according to the set mixing ratio, pump the material A and the material B into the mixing bin respectively for mixing to generate a thixotropic anchoring agent, then inject it into the hollow anchor bolt through the second filling pipeline, and then overflow from the tail end of the hollow anchor bolt and flow down along the hole wall of the end section of the drilled hole. When the set time A lasts, control the grouting pump A and the grouting pump B to stop. Use the thixotropic anchoring agent to bond and anchor the tail section of the hollow anchor bolt to the surrounding rock, and form a bottom anchoring section at the end section of the drilled hole.

[0020] Step 5: Tighten the nut to apply a primary pre-tightening force to the hollow anchor bolt, and use the pressure sensor to collect the pre-tightening force signal in real time. When the pre-tightening force value reaches 80% of the set pre-tightening force, stop applying the pre-tightening force.

[0021] Step 6: Control the electric control valve 1 to open, and again control the grouting pump A and the grouting pump B to start working, inject the generated thixotropic anchoring agent into the long grouting path through the first filling pipeline, and then overflow from the tail end of the long grouting path and flow down along the hole wall of the middle section of the drilled hole. When the set time B lasts, control the grouting pump A and the grouting pump B to stop. Use the thixotropic anchoring agent to bond and anchor the middle section of the hollow anchor bolt to the surrounding rock, and form a middle anchoring section in the middle section of the drilled hole. At the same time, ensure that the middle anchoring section and the bottom anchoring section are combined into an integral structure.

[0022] Step 7: Tighten the nut again to apply a secondary pre-tightening force to the hollow anchor bolt. When the pre-tightening force value reaches 100% of the set pre-tightening force, stop applying the pre-tightening force.

[0023] Step 8: Control the electric control valve 3 to open, and again control the grouting pump A and the grouting pump B to start working, inject the generated thixotropic anchoring agent into the short grouting pipe through the third filling pipeline, and then overflow from the tail end of the short grouting pipe and flow down along the hole wall of the first section of the drilled hole. When the set time C lasts, control the grouting pump A and the grouting pump B to stop. Use the thixotropic anchoring agent to bond and anchor the first section of the hollow anchor bolt to the surrounding rock, and form a first section anchoring section in the first section of the drilled hole, and ensure that the first section anchoring section and the middle section anchoring section are combined into an integral structure.

[0024] Further, in order to ensure the anchoring effect of the subsequent anchoring agent, in Step 1, drilling operations are carried out according to the design parameters. At the same time, high-pressure air or high-pressure water is used to clean the drilled holes to remove the residues in the holes and ensure the cleanliness of the holes.

[0025] Further, in order to improve the anchoring effect of the segmented anchoring bond, in Step 6, the length of the long grouting path is half of the length of the hollow anchor rod. In Step 8, the length of the short grouting pipe is half of the length of the long grouting path.

[0026] In the present invention, after connecting the first, second, and third filling pipelines to the first filling hole, the head end of the hollow anchor bolt, and the second filling hole respectively, three-stage grouting channels with gradually decreasing lengths can be formed by using hollow anchor bolts, long grouting pipes, and short grouting pipes with different lengths inside the drill hole. During the process of grading and pumping the anchoring agent, first open the second electric control valve, and use the hollow anchor bolt with the longest length to fill the thixotropic anchoring agent, so that the thixotropic anchoring agent can directly overflow from a position close to the bottom of the drill hole, and can flow down along the annular space between the hole wall and the end section of the hollow anchor bolt, thereby effectively bonding the outer side of the end section of the hollow anchor bolt to the surrounding rock and forming a bottom anchoring section, thus realizing the effective anchoring operation of the end section of the hollow anchor bolt. Then, apply a primary pre-tightening force to the hollow anchor bolt by tightening the nut. Since the bottom anchoring section is formed at the end section of the drill hole and mainly acts on the deep stable surrounding rock, in this way, directly applying 80% of the set pre-tightening force during the primary pre-tightening process can effectively ensure the action effect between the end section of the hollow anchor bolt and the deep stable surrounding rock, and can provide a stable and reliable bearing support foundation for the support of the hollow anchor bolt. Then open the first electric control valve, and use the medium-length long grouting pipe to fill the thixotropic anchoring agent, so that the thixotropic anchoring agent can directly overflow from the middle section of the drill hole. On the one hand, it can be effectively bonded to the bottom anchoring section, and on the other hand, it can flow down along the annular space between the hole wall and the middle section of the hollow anchor bolt, thereby effectively bonding the outer side of the middle section of the hollow anchor bolt to the surrounding rock and forming a middle anchoring section, thus realizing the effective anchoring operation of the middle section of the hollow anchor bolt. Then, apply a secondary pre-tightening force to the hollow anchor bolt by tightening the nut. When applying the secondary pre-tightening force, the remaining 20% of the set pre-tightening force is applied at one time, which can effectively ensure the action effect between the middle section of the hollow anchor bolt and the shallow surrounding rock, and can enable the hollow anchor bolt to effectively anchor the shallow surrounding rock and the deep stable surrounding rock into an integral structure, ensuring the stability and reliability of the support. Finally, open the third electric control valve, and use the shortest short grouting pipe to fill the thixotropic anchoring agent, so that the thixotropic anchoring agent overflows from a position close to the hole opening. On the one hand, it can be effectively bonded to the middle anchoring section, and on the other hand, it can make the thixotropic anchoring agent fill from the side far from the hole opening to the side close to the hole opening, ensuring that the first anchoring section formed at the hole opening position is more solid, effectively improving the anchoring strength of the first anchoring section near the hole opening, and greatly improving the support effect near the hole opening. After the anchoring is completed, the long grouting pipe and the short grouting pipe are left inside the drill hole together with the hollow anchor bolt, which can significantly improve the shear resistance of the bolt assembly. And because the long grouting pipe is longer than the short grouting pipe, the increase amplitude of the shear resistance is different. The increase amplitude of the shear strength of the first section of the hollow anchor bolt is better than that of the middle section of the hollow anchor bolt, which is beneficial to further improving the support effect of the bolt assembly.Through the three-stage pumping of anchoring agents and the application of two-stage pre-tightening forces, the present invention can segment the traditional one-stage full-length rigid bonding anchoring process in stages. Through the staged rigid bonding anchoring process, the corresponding pre-tightening force gradient application operation can be carried out, thereby significantly improving the application effect of the pre-tightening force. At the same time, in each rigid bonding anchoring stage, the injection method from the side farther away from the hole mouth to the side closer to the hole mouth is adopted. In this way, it is not only beneficial to discharge the air between the hole wall and the bolt to the outside during the grouting process, ensuring the solidification degree of the anchoring section, but also ensuring that the anchoring sections formed in each stage can be effectively bonded into a whole, achieving the anchoring effect of non-separation in segments. Thus, the first anchoring section, the middle anchoring section, and the bottom anchoring section can be effectively bonded into an integral anchor body, ensuring the reliability and stability of the full-length section anchoring and further ensuring the anchoring effect.

[0027] The implementation process of this method is simple and has a high degree of automation. It realizes the full-length section anchoring of the bolt in a staged manner. At the same time, by applying the pre-tightening force in a gradient, the problem of difficult application of the pre-tightening force in full-length anchoring is solved, greatly improving the support effect and enabling the pre-tightening force to be more efficiently converted into the compressive stress on the surrounding rock. Through the staged process of "pumping - pre-tightening - re-pumping - re-pre-tightening - re-pumping", the bolt completes the rigid bonding of the bolt - surrounding rock - anchoring agent under the pre-tensioned state, ensuring the full-length anchoring effect and effectively converting the pre-tightening force into the compressive stress of the surrounding rock. Brief Description of the Drawings

[0028] Figure 1 is the structural view of the full-length anchoring system in the present invention;

[0029] Figure 2 is the structural view of the bolt assembly in the present invention;

[0030] Figure 3 is the structural view of the staged pumping mechanism in the present invention;

[0031] Figure 4 is the schematic structural view of the tray, long grouting pipe, and short grouting pipe in the present invention;

[0032] Figure 5 is the schematic assembly view of the full-length anchoring system in the state without grouting in the present invention;

[0033] Figure 6 is the schematic assembly view of the full-length anchoring system in the state of completing the first grouting (forming the bottom anchoring section) in the present invention;

[0034] Figure 7 is the schematic assembly view of the full-length anchoring system in the state of completing the secondary grouting (forming the middle anchoring section) in the present invention;

[0035] Figure 8It is an assembly schematic diagram of the full-length anchoring system in the present invention under the state of three-time grouting (forming the first anchoring section);

[0036] Figure 9 It is a principle block diagram of the control part in the full-length anchoring system of the present invention.

[0037] In the figure: 1. Anchor rod assembly, 2. Hollow anchor rod, 3. Tray, 4. Nut, 5. Mixing bin, 6. Bottom anchoring section, 7. Middle anchoring section, 8. First anchoring section, 9. Long grouting pipe, 10. Short grouting pipe, 11. Borehole, 12. First filling hole, 13. Second filling hole, 14. Bin for Material A, 15. Bin for Material B, 16. First high-pressure pipeline, 17. Second high-pressure pipeline, 18. Electric control valve 1, 19. Electric control valve 2, 20. Electric control valve 3, 21. First filling pipeline, 22. Second filling pipeline, 23. Third filling pipeline, 24. Grout stopper, 25. Anchor hole, 26. Grout pump A, 27. Grout pump B, 28. Step-by-step pumping mechanism. Specific embodiments

[0038] The present invention will be further described below in conjunction with the accompanying drawings:

[0039] As Figures 1 to 9 shown, the present invention provides a full-length anchoring system with step-by-step pumping of anchoring agent and gradient pre-tightening force loading, including an anchor rod assembly 1 and a step-by-step pumping mechanism 28. The anchor rod assembly 1 includes a hollow anchor rod 2, a tray 3 and a nut 4. The outer surface of the head end of the hollow anchor rod 2 is provided with an external thread structure; the center of the tray 3 has an anchor hole 25 adapted to the hollow anchor rod 2 and is sleeved on the outside of the head end of the hollow anchor rod 2 through the anchor hole 25; the nut 4 is sleeved on the outside of the head end of the hollow anchor rod 2 by thread fit and is located outside the tray 3;

[0040] The anchor rod assembly 1 further includes a long grouting pipe 9 and a short grouting pipe 10; the tray 3 is provided with a first filling hole 12 and a second filling hole 13 at intervals outside the anchor hole 25; the length of the long grouting pipe 9 is longer than that of the short grouting pipe 10, and the inlet ends of the long grouting pipe 9 and the short grouting pipe 10 are fixedly connected to the first filling hole 12 and the second filling hole 13 coaxially respectively;

[0041] The grading pumping mechanism 28 includes a bin 14 for material A, a bin 15 for material B, a mixing bin 5, a grouting pump A 26, a grouting pump B 27, an electric control valve 18, an electric control valve 19, an electric control valve 20, a filling pipeline 21, a filling pipeline 22, and a filling pipeline 23; the feed inlets at the bottom of the mixing bin 5 are respectively connected to the discharge outlets of the bin 14 for material A and the bin 15 for material B through a high-pressure pipeline 16 and a high-pressure pipeline 17, and the top of the mixing bin 5 is respectively provided with a slurry outlet 1, a slurry outlet 2, and a slurry outlet 3; the grouting pump A 26 is connected in series on the high-pressure pipeline 16; the grouting pump B 27 is connected in series on the high-pressure pipeline 17; the inlet ends of the filling pipeline 21, the filling pipeline 22, and the filling pipeline 23 are respectively connected to the slurry outlet 1, the slurry outlet 2, and the slurry outlet 3 through the electric control valve 18, the electric control valve 19, and the electric control valve 20, and stop grouting plugs 24 are installed at the outlet ends of the filling pipeline 21, the filling pipeline 22, and the filling pipeline 23.

[0042] Among them, the bin 14 for material A is used to load material A (liquid slurry), the bin 15 for material B is used to load material B (liquid slurry), the mixing bin 5 is used to mix the incoming material A (liquid slurry) and material B (liquid slurry), and when material A (liquid slurry) and material B (liquid slurry) are mixed, a thixotropic anchoring agent is generated. The thixotropic anchoring agent has a certain adhesive force. When the grouting pump A 26 and the grouting pump B 27 stop, the stop of the injection of the thixotropic anchoring agent can be realized, which has the effect of stopping the slurry when the pump stops. After the thixotropic anchoring agent enters the drill hole 11, it can effectively bond and anchor the hollow anchor bolt 2 to the surrounding rock.

[0043] As a preference, the filling hole 12 and the filling hole 13 are relatively distributed on both sides outside the anchor hole 25.

[0044] As a preference, the filling pipeline 21 and the filling pipeline 23 have the same length, and are longer than the length of the filling pipeline 22. Further, the length difference between the filling pipeline 21 or the filling pipeline 23 and the filling pipeline 22 is adapted to the length of the exposed section at the head end of the hollow anchor bolt 2.

[0045] In order to facilitate the simultaneous establishment of the connection between the filling pipeline 21 and the filling hole 12, between the filling pipeline 22 and the anchor hole 25, and between the filling pipeline 23 and the filling hole 13, the slurry outlet 1, the slurry outlet 2, and the slurry outlet 3 are respectively distributed corresponding to the filling hole 12, the anchor hole 25, and the filling hole 13, and the filling pipeline 21, the filling pipeline 22, and the filling pipeline 23 are all rigid straight pipelines.

[0046] In order to facilitate the real-time perception of the magnitude of the pre-tightening force, a pressure sensor is further included. The pressure sensor is sleeved outside the head end of the hollow anchor bolt 2 and is located between the nut 4 and the tray 3.

[0047] To facilitate the implementation of an automated grouting control process, a controller is further included. The controller is respectively connected to a pressure sensor, a grouting pump A26, a grouting pump B27, an electric control valve 18, an electric control valve 19, and an electric control valve 20. Further preferably, a display screen is also included. The display screen is connected to the controller. Through the setting of the display screen, when the controller obtains the pre-tightening force value based on the pressure sensor, the pre-tightening force value can be displayed in real time through the display screen. As a preference, the controller is a PLC controller.

[0048] To facilitate the mixing of material A and material B in a set ratio to form a thixotropic anchoring agent with more stable performance, both the grouting pump A26 and the grouting pump B27 are quantitative adjustable grouting pumps.

[0049] In the present invention, a first filling hole and a second filling hole are spaced apart from the outside of the anchor hole on the tray, and a long grouting pipe and a short grouting pipe are correspondingly connected to the first filling hole and the second filling hole. Thus, when the tray is sleeved on the head end of the hollow anchor rod through the anchor hole, a three-stage grouting structure is formed. Among them, the hollow anchor rod serves as the first-stage grouting pipeline. When the hollow anchor rod is installed in the drill hole, its end can extend to a position close to the bottom of the drill hole. Thus, when injecting the thixotropic anchoring agent through the hollow anchor rod, the thixotropic anchoring agent can directly overflow from the bottom of the drill hole and flow down along the annular space between the hole wall and the end section of the hollow anchor rod, so that the outer side of the end section of the hollow anchor rod can be effectively bonded to the surrounding rock, and a bottom anchoring section is formed, thereby realizing the effective anchoring operation of the end section of the hollow anchor rod. The long grouting pipe serves as the second-stage grouting pipeline. After installation, its end can extend to a position close to the middle section of the drill hole. Thus, when injecting the thixotropic anchoring agent by using the long grouting pipe, the thixotropic anchoring agent can directly overflow from the middle section of the drill hole. On the one hand, it can be effectively bonded to the bottom anchoring section, and on the other hand, it can flow down along the annular space between the hole wall and the middle section of the hollow anchor rod, so that the outer side of the middle section of the hollow anchor rod can be effectively bonded to the surrounding rock, and a middle section anchoring section is formed, thereby realizing the effective anchoring operation of the middle section of the hollow anchor rod. Furthermore, the short grouting pipe serves as the third-stage grouting pipeline. After installation, its end is relatively close to the position of the hole opening. Thus, when injecting the thixotropic anchoring agent by using the short grouting pipe, the thixotropic anchoring agent can overflow from a position close to the hole opening. On the one hand, it can be effectively bonded to the middle section anchoring section, and on the other hand, the thixotropic anchoring agent can be filled from the side far from the hole opening to the side close to the hole opening, ensuring that the first section anchoring section formed at the hole opening position can be more solidified, effectively improving the anchoring strength of the first section anchoring section near the hole opening. In addition, since the long grouting pipe and the short grouting pipe are fixedly connected to the inner side of the tray, after the grouting is completed, the long grouting pipe and the short grouting pipe will be left in the drill hole like the hollow anchor rod, thereby significantly improving the shear resistance of the anchor rod assembly. And because the long grouting pipe is longer than the short grouting pipe, the increase amplitude of the shear resistance is different. The increase amplitude of the shear strength of the first section of the hollow anchor rod is better than that of the middle section of the hollow anchor rod, which is beneficial to further improving the support effect of the anchor rod assembly. Thus, through the three-stage grouting structure, the traditional one-stage full-length rigid bonding anchoring process can be segmented in stages, and the corresponding pre-tightening force gradient application operation can be carried out through the staged rigid bonding anchoring process, thereby significantly improving the application effect of the pre-tightening force.Meanwhile, during each rigid bonding and anchoring stage, the injection method is adopted from the side farther away from the hole mouth to the side closer to the hole mouth. In this way, it not only helps to discharge the air between the hole wall and the bolt to the outside during the grouting process, ensuring the solidification degree of the anchoring section, but also ensures that the anchoring sections formed in each stage can be effectively bonded into a whole, achieving the anchoring effect of non-separation in segments. As a result, the first anchoring section, the middle anchoring section, and the bottom anchoring section can be effectively bonded into a whole anchor body, ensuring the reliability and stability of the full-length anchoring and further ensuring the anchoring effect. Connect the feed inlet of the mixing bin to the discharge outlets of the A-material and B-material bins through high-pressure pipelines 1 and 2 respectively, which can facilitate the direct pumping of the A-material and B-material into the mixing bin for mixing to form a thixotropic anchoring agent. On this basis, connect the mixing bin to the hollow bolt through injection pipeline 2, connect it to the long grouting pipeline through injection pipeline 1, and connect it to the short grouting pipeline through injection pipeline 3, which can facilitate the further promotion of the mixing effect of the A-material and B-material by using the internal space of the injection pipeline and the hollow bolt or the grouting pipeline, so that the formed thixotropic anchoring agent has a better bonding effect. Open slurry outlets 1, 2, and 3 respectively at the top of the mixing bin, and connect injection pipelines 1, 2, and 3 to slurry outlets 1, 2, and 3 respectively through electric control valves 1, 2, and 3. In this way, injection pipeline 1 can be docked with injection hole 1 on the tray, injection pipeline 2 can be docked with the head end of the hollow bolt, and injection pipeline 3 can be docked with injection hole 2 on the tray simultaneously, thus establishing three grouting channels between the mixing bin and the borehole at the same time, and the start and stop processes of grouting in the corresponding grouting channels can be controlled through any one of the electric control valves, greatly improving the convenience and efficiency of the staged pumping of the anchoring agent. By installing grout stop plugs at the ends of injection pipelines 1, 2, and 3, not only can the grout stop plugs be used to ensure the sealing performance at the docking place to ensure the smooth grouting process of each grouting channel, but also it is conducive to realizing the precise grouting control process of stopping the grout when the pump stops.

[0050] This system has a simple structure, low manufacturing cost, and high automation degree. It can realize the staged pumping operation of the anchoring agent, and then can realize the staged rigid bonding and anchoring operation, and can perform gradient loading of the pre-tightening force during the staged rigid bonding and anchoring process. Therefore, the application effect of the pre-tightening force can be greatly improved by the method of segmental anchoring and segmental pre-tightening, which can ensure that the pre-tightening force is more effectively converted into the compressive stress on the surrounding rock, is conducive to significantly improving the support strength, and at the same time, is conducive to avoiding the problem of stress concentration at the tail of the bolt, providing a safe and reliable guarantee for the safe production work of coal mines.

[0051] The present invention also provides a full-length anchoring method for staged pumping of anchoring agent and gradient pre-tightening force loading. Using a full-length anchoring system for staged pumping of anchoring agent and gradient pre-tightening force loading, it includes the following steps:

[0052] Step 1: Drill a borehole 11 at the selected construction location and clean the borehole 11;

[0053] Step 2: Insert the hollow anchor rod 2 into the borehole 11, and successively sleeve a tray 3, a pressure sensor, and a nut 4 on the outer side of the head end of the hollow anchor rod 2;

[0054] Step 3: Assemble the grading pumping mechanism 28, and connect the outlet ends of the first injection pipeline 21, the second injection pipeline 22, and the third injection pipeline 23 to the first injection hole 12, the head end of the hollow anchor rod 2, and the second injection hole 13 respectively;

[0055] Step 4: Control the electric control valve II 19 to open. At the same time, close the electric control valve I 18 and the electric control valve III 20, and respectively control the grouting pump A 26 and the grouting pump B 27 to start working according to the set mixing ratio. Pump the material A in the material bin 14 of material A and the material B in the material bin 15 of material B into the mixing bin 5 for mixing to generate a thixotropic anchoring agent, and then inject it into the hollow anchor rod 2 through the second injection pipeline 22. Then, it overflows from the tail end of the hollow anchor rod 2 (corresponding to the deep part of the borehole 11) and flows down along the hole wall of the end section of the borehole 11. When the set time A lasts, control the grouting pump A 26 and the grouting pump B 27 to stop. Use the thixotropic anchoring agent to bond and anchor the tail section of the hollow anchor rod 2 to the surrounding rock, and form a bottom anchoring section 6 at the end section of the borehole 11;

[0056] When the set time A lasts, the thixotropic anchoring agent flowing down along the hole wall of the end section of the borehole 11 reaches a position close to the tail end of the long grouting pipe 9, and there is a certain gap between it and the tail end of the long grouting pipe 9, so that during the subsequent grouting using the long grouting pipe 9, the thixotropic anchoring agent can smoothly overflow from the tail end of the long grouting pipe 9, and it can ensure that the subsequently injected thixotropic anchoring agent can fully contact and combine with the bottom anchoring section 6;

[0057] Step 5: Use a special pre-tightening tool to tighten the nut 4 to apply a primary pre-tightening force to the hollow anchor rod 2. At the same time, use the pressure sensor to collect the pre-tightening force signal in real time and send it to the controller. The controller obtains the pre-tightening force value according to the pre-tightening force signal. At the same time, the pre-tightening force value can be displayed in real time through the display screen, so that the operator can intuitively observe the pre-tightening force situation in real time. When the pre-tightening force value reaches 80% of the set pre-tightening force, stop applying the pre-tightening force;

[0058] Step 6: Control the opening of the first electronic control valve 18. Meanwhile, close the second electronic control valve 19 and the third electronic control valve 20. Then, control the start of the grouting pump A 26 and the grouting pump B 27 again to inject the mixed thixotropic anchoring agent into the long grouting pipe 9 through the first injection pipeline 21. Then, it overflows from the end of the long grouting pipe 9 and flows down along the hole wall in the middle section of the drill hole 11. When the set time B has elapsed, control the grouting pump A 26 and the grouting pump B 27 to stop. Use the thixotropic anchoring agent to bond and anchor the middle section of the hollow anchor rod 2 to the surrounding rock, and form a middle section anchoring section 7 in the middle section of the drill hole 11. At the same time, ensure that the middle section anchoring section 7 and the bottom anchoring section 6 are combined into an integral structure;

[0059] When the set time B has elapsed, the thixotropic anchoring agent flowing down along the hole wall in the middle section of the drill hole 11 reaches a position close to the end of the short grouting pipe 10, and there is a certain gap between it and the end of the short grouting pipe 10, so that during the subsequent grouting process using the short grouting pipe 10, the thixotropic anchoring agent can overflow smoothly from the end of the short grouting pipe 10, and ensure that the subsequently injected thixotropic anchoring agent can be in full contact with and combined with the middle section anchoring section 7;

[0060] Step 7: Use the special pre-tightening tool to tighten the nut 4 again to apply a secondary pre-tightening force to the hollow anchor rod 2. When the pre-tightening force value reaches 100% of the set pre-tightening force, stop applying the pre-tightening force;

[0061] Step 8: Control the opening of the third electronic control valve 20. Meanwhile, close the first electronic control valve 18 and the second electronic control valve 19. Then, control the start of the grouting pump A 26 and the grouting pump B 27 again to inject the mixed thixotropic anchoring agent into the short grouting pipe 10 through the third injection pipeline 23. Then, it overflows from the end of the short grouting pipe 10 and flows down along the hole wall in the first section of the drill hole 11. When the set time C has elapsed, control the grouting pump A 26 and the grouting pump B 27 to stop. Use the thixotropic anchoring agent to bond and anchor the first section of the hollow anchor rod 2 to the surrounding rock, and bond and anchor the first section of the drill hole 11 to the surrounding rock, and form a first section anchoring section 8 at the end section of the drill hole 11, and ensure that the first section anchoring section 8 and the middle section anchoring section 7 are combined into an integral structure.

[0062] When the set time C has elapsed, the thixotropic anchoring agent flowing down along the hole wall in the first section of the drill hole 11 reaches the position of the hole opening. Thus, the full-length anchoring operation is realized by using the thixotropic anchoring agent;

[0063] In order to ensure the anchoring effect of the subsequent anchoring agent, in Step 1, perform the drill hole 11 operation according to the design parameters to ensure that the length of the formed drill hole 11 is adapted to the length of the hollow anchor rod 2, so that when the hollow anchor rod 2 is installed in the drill hole 11 through the tray 3, the end of the hollow anchor rod 2 can be located at a position close to the bottom of the drill hole 11; at the same time, use high-pressure air or high-pressure water to clean the drill hole 11 to remove the residues in the hole and ensure the cleanliness of the hole.

[0064] In order to improve the anchoring effect of sectional anchoring and bonding, in Step 6, the length of the long grouting pipe 9 is half of the length of the hollow anchor rod 2, and in Step 8, the length of the short grouting pipe 10 is half of the length of the long grouting pipe 9.

[0065] In the present invention, after connecting the first, second, and third filling pipelines to the first filling hole, the head end of the hollow bolt, and the second filling hole respectively, three-stage grouting channels with gradually decreasing lengths can be formed by using hollow bolts, long grouting pipes, and short grouting pipes with different lengths inside the drill hole. During the process of grading and pumping the anchoring agent, first open the second electric control valve, and use the hollow bolt with the longest length to inject the thixotropic anchoring agent, which can make the thixotropic anchoring agent directly overflow from a position near the bottom of the drill hole, and can flow down along the annular space between the hole wall and the end section of the hollow bolt, so that the outer side of the end section of the hollow bolt can be effectively bonded to the surrounding rock, and a bottom anchoring section can be formed, thus realizing the effective anchoring operation of the end section of the hollow bolt. Then, apply a primary pre-tightening force to the hollow bolt by tightening the nut. Since the bottom anchoring section is formed at the end section of the drill hole and mainly acts on the deep and stable surrounding rock, in this way, directly applying 80% of the set pre-tightening force during the primary pre-tightening process can effectively ensure the action effect between the end section of the hollow bolt and the deep and stable surrounding rock, and can provide a stable and reliable bearing support foundation for the support of the hollow bolt. Then open the first electric control valve, and use the medium-length long grouting pipe to inject the thixotropic anchoring agent, which can make the thixotropic anchoring agent directly overflow from the middle section of the drill hole. On the one hand, it can be effectively bonded to the bottom anchoring section, and on the other hand, it can flow down along the annular space between the hole wall and the middle section of the hollow bolt, so that the outer side of the middle section of the hollow bolt can be effectively bonded to the surrounding rock, and a middle section anchoring section can be formed, thus realizing the effective anchoring operation of the middle section of the hollow bolt. Then, apply a secondary pre-tightening force to the hollow bolt by tightening the nut. When applying the secondary pre-tightening force, the remaining 20% of the set pre-tightening force is applied at one time, which can effectively ensure the action effect between the middle section of the hollow bolt and the shallow surrounding rock, and can make the hollow bolt effectively anchor the shallow surrounding rock and the deep and stable surrounding rock into an integral structure, ensuring the stability and reliability of the support. Finally, open the third electric control valve, and use the shortest short grouting pipe to inject the thixotropic anchoring agent, which can make the thixotropic anchoring agent overflow from a position near the hole opening. On the one hand, it can be effectively bonded to the middle section anchoring section, and on the other hand, it can make the thixotropic anchoring agent fill from the side far from the hole opening to the side close to the hole opening, ensuring that the first section anchoring section formed at the hole opening position can be more solidified, effectively improving the anchoring strength of the first section anchoring section near the hole opening, and greatly improving the support effect near the hole opening. After the anchoring is completed, the long grouting pipe and the short grouting pipe are left inside the drill hole together with the hollow bolt, which can significantly improve the shear resistance of the bolt assembly. And because the long grouting pipe is longer than the short grouting pipe, the increase amplitude of the shear resistance is different. The increase amplitude of the shear strength of the first section of the hollow bolt is better than that of the middle section of the hollow bolt, which is beneficial to further improving the support effect of the bolt assembly.Through the pumping of three-stage anchoring agents and the application of two-stage pre-tightening forces, the present invention can divide the traditional one-stage full-length rigid bonding anchoring process into stages. Through the staged rigid bonding anchoring process, the operation of applying a pre-tightening force gradient can be carried out accordingly, thereby significantly improving the application effect of the pre-tightening force. At the same time, in each rigid bonding anchoring stage, the injection method from the side farther away from the hole mouth to the side closer to the hole mouth is adopted. In this way, it is not only conducive to discharging the air between the hole wall and the bolt to the outside during the grouting process, ensuring the solidification degree of the anchoring section, but also ensuring that the anchoring sections formed in each stage can be effectively bonded into a whole, achieving the anchoring effect of non-separation of segments. Thus, the first anchoring section, the middle anchoring section, and the bottom anchoring section can be effectively bonded into a whole anchor body, ensuring the reliability and stability of the full-length section anchoring and further ensuring the anchoring effect.

[0066] The implementation process of this method is simple and has a high degree of automation. It realizes the full-length section anchoring of the bolt through a phased manner. At the same time, by applying the pre-tightening force in a gradient, the problem of difficult application of the pre-tightening force in full-length anchoring is solved, greatly improving the support effect and enabling the pre-tightening force to be more efficiently converted into the compressive stress on the surrounding rock. Through the staged process of "pumping - pre-tightening - re-pumping - re-pre-tightening - re-pumping", the bolt completes the rigid bonding of the bolt - surrounding rock - anchoring agent under the pre-tensioned state, ensuring the full-length anchoring effect and effectively converting the pre-tightening force into the compressive stress of the surrounding rock.

Claims

1. A full-length anchoring system capable of graded pumping of anchoring agent and gradient preload, comprising an anchor rod assembly (1), the anchor rod assembly (1) comprising a hollow anchor rod (2), a tray (3) and a nut (4), the head end outer surface of the hollow anchor rod (2) being provided with an external thread structure; the center of the tray (3) having an anchor hole (25) adapted to the hollow anchor rod (2), and being sleeved on the outside of the head end of the hollow anchor rod (2) through the anchor hole (25); the nut (4) being sleeved on the outside of the head end of the hollow anchor rod (2) through threaded matching, and being located on the outside of the tray (3); characterized in that: Also included is a staged pumping mechanism (28); The anchor rod assembly (1) further comprises a long grouting pipe (9) and a short grouting pipe (10); a first grouting hole (12) and a second grouting hole (13) are provided on the tray (3) at intervals outside the anchor hole (25); the length of the long grouting pipe (9) is longer than the length of the short grouting pipe (10), and the inlet end of the long grouting pipe (9) and the inlet end of the short grouting pipe (10) are coaxially fixedly connected to the first grouting hole (12) and the second grouting hole (13) respectively; The grading pumping mechanism (28) comprises an A material silo (14), a B material silo (15), a mixing silo (5), a grouting pump A (26), a grouting pump B (27), an electric control valve 1 (18), an electric control valve 2 (19), an electric control valve 3 (20), a filling pipeline 1 (21), a filling pipeline 2 (22) and a filling pipeline 3 (23); the feed port at the bottom of the mixing silo (5) is connected to the discharge port of the A material silo (14) and the discharge port of the B material silo (15) through a high-pressure pipeline 1 (16) and a high-pressure pipeline 2 (17), respectively; the top of the mixing silo (5) is provided with a slurry discharge port 1, a slurry discharge port 2 and a slurry discharge port 3. The invention relates to a slurry outlet two and a slurry outlet three; the grouting pump A (26) is connected in series to the high-pressure pipeline one (16); the grouting pump B (27) is connected in series to the high-pressure pipeline two (17); the inlet end of the filling pipeline one (21), the inlet end of the filling pipeline two (22), and the inlet end of the filling pipeline three (23) are connected to the slurry outlet one, the slurry outlet two, and the slurry outlet three through the electric control valve one (18), the electric control valve two (19), and the electric control valve three (20), respectively; the outlet end of the filling pipeline one (21), the outlet end of the filling pipeline two (22), and the outlet end of the filling pipeline three (23) are all installed with a slurry stopper (24).

2. A full-length anchoring system with graded pumping of anchoring agent and gradient preload according to claim 1, characterized in that: The first filling hole (12) and the second filling hole (13) are relatively distributed on two sides of the outside of the anchor hole (25).

3. A full-length anchoring system with graded pumping of anchoring agent and gradient preload according to claim 2, characterized in that: The lengths of the filling pipeline one (21) and the filling pipeline three (23) are the same, and are longer than the length of the filling pipeline two (22).

4. A full-length anchoring system with graded pumping of anchoring agent and gradient preload according to claim 3, characterized in that: The slurry outlet one, slurry outlet two and slurry outlet three are respectively distributed corresponding to the filling hole one (12), the anchor hole (25) and the filling hole two (13), and the filling pipeline one (21), the filling pipeline two (22) and the filling pipeline three (23) are all rigid straight-through pipelines.

5. A full-length anchoring system with graded pumping of anchoring agent and gradient preload according to claim 4, characterized in that: It also comprises a pressure sensor, which is sleeved on the outside of the head end of the hollow anchor rod (2) and located between the nut (4) and the tray (3).

6. A full-length anchoring system with graded pumping of anchoring agent and gradient preload according to claim 5, characterized in that: It also includes a controller, which is respectively connected to the pressure sensor, the grouting pump A (26), the grouting pump B (27), the electric control valve 1 (18), the electric control valve 2 (19) and the electric control valve 3 (20).

7. A full-length anchoring system with graded pumping of anchoring agent and gradient preload according to claim 1, characterized in that: The grouting pump A (26) and the grouting pump B (27) are both quantitatively adjustable grouting pumps.

8. A full-length anchoring method with graded pumping of anchoring agent and gradient preload, using a full-length anchoring system with graded pumping of anchoring agent and gradient preload as claimed in any one of claims 4 to 6, characterized in that , including the following steps: Step 1: drilling a borehole (11) at a selected construction location, and cleaning the borehole (11); Step 2: insert the hollow anchor rod (2) into the drill hole (11), and sequentially mount a tray (3), a pressure sensor and a nut (4) on the head end of the hollow anchor rod (2); Step 3: Connect the outlet ends of the filling pipeline 1 (21), the filling pipeline 2 (22) and the filling pipeline 3 (23) of the graded pumping mechanism (28) to the filling hole 1 (12), the head end of the hollow anchor rod (2) and the filling hole 2 (13) respectively; Step 4: Control the electric control valve 2 (19) to open, and control the grouting pump A (26) and the grouting pump B (27) to start working according to the set mixing ratio, respectively pump material A and material B into the mixing chamber (5) for mixing to generate a thixotropic anchoring agent, and then inject it into the hollow anchor rod (2) through the injection pipeline 2 (22), and then overflow from the end of the hollow anchor rod (2) and flow down along the hole wall of the end section of the borehole (11). After the set time A, control the grouting pump A (26) and the grouting pump B (27) to stop, and use the thixotropic anchoring agent to bond and anchor the end section of the hollow anchor rod (2) to the surrounding rock, and form a bottom anchoring section (6) at the end section of the borehole (11); Step 5: Tighten the nut (4) to apply a primary preload force to the hollow anchor rod (2), and use a pressure sensor to collect a preload force signal in real time. When the preload force value reaches 80% of the set preload force, stop applying the preload force; Step 6: Control the electric control valve 1 (18) to open, and control the grouting pump A (26) and the grouting pump B (27) to start working again, and inject the mixed thixotropic anchoring agent into the long grouting path (9) through the injection pipeline 1 (21), and then overflow from the end of the long grouting path (9) and flow down along the hole wall of the middle section of the borehole (11). After the set time B is continued, the grouting pump A (26) and the grouting pump B (27) are controlled to stop, and the thixotropic anchoring agent is used to bond and anchor the middle section of the hollow anchor rod (2) to the surrounding rock, and a middle section anchoring section (7) is formed in the middle section of the borehole (11). At the same time, it is ensured that the middle section anchoring section (7) and the bottom anchoring section (6) are combined into an integrated structure; Step 7: Tighten the nut (4) again to apply a secondary preload force to the hollow anchor rod (2). When the preload force value reaches 100% of the set preload force, stop applying the preload force. Step eight: control the electric control valve three (20) to open, control the grouting pump A (26) and the grouting pump B (27) to start working again, and inject the mixed thixotropic anchoring agent into the short grouting pipe (10) through the injection pipeline three (23), and then overflow from the end of the short grouting pipe (10) and flow down along the hole wall of the first section of the borehole (11). After the set time C, control the grouting pump A (26) and the grouting pump B (27) to stop, use the thixotropic anchoring agent to bond and anchor the first section of the hollow anchor rod (2) to the surrounding rock, and form the first section anchoring section (8) at the first section of the borehole (11), and ensure that the first section anchoring section (8) and the middle section anchoring section (7) are combined into an integrated structure.

9. A full-length anchoring method with graded pumping of anchoring agent and gradient preload according to claim 5, characterized in that: In step one, a drilling operation (11) is performed according to the design parameters, and at the same time, the drilled hole (11) is cleaned using high-pressure air or high-pressure water to remove the residue in the hole and ensure the cleanliness of the hole.

10. A full-length anchoring method with graded pumping of anchoring agent and gradient preload according to claim 9, characterized in that: In step six, the length of the long grouting path (9) is half the length of the hollow anchor rod (2), and in step eight, the length of the short grouting pipe (10) is half the length of the long grouting path (9).

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