A prestressed grouting anchor

Abstract

The present invention relates to the field of geotechnical engineering support technology, and provides a prestressed grouting anchor rod, comprising an anchoring section and a grouting section; the tail of the anchoring section is connected to the head of the grouting section, the anchoring section is used to fix in a borehole, and is consolidated with the surrounding rock at the bottom of the borehole by an anchoring agent, and the grouting section is used to grout into the borehole. The prestressed grouting anchor rod provided by the present invention, by providing a grouting section connected to the anchoring section, realizes full-length anchoring of the prestressed grouting anchor rod on the basis of anchor rod pre-tightening, which not only meets the initial installation pre-tightening conditions for timely support of the surrounding rock, but also can perform grouting and anchoring of the free section, effectively controlling the deformation and damage depth of the tunnel surrounding rock, significantly improving the anchoring stability of the prestressed grouting anchor rod, and ensuring the support safety of the broken surrounding rock of the tunnel under high stress environment.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering support, in particular to a prestressed grouting anchor rod. Background Art

[0002] Prestressed anchor bolting, a primary, safe and efficient method for supporting coal mine roadways, has been widely used in my country. Prestressed anchor bolting involves anchoring one end of the bolt into the coal rock mass, tightening the bolt end nut to apply prestress to the surrounding rock, and using supporting components such as support rails to restrain deformation, delamination, expansion, and slippage of the surrounding rock.

[0003] Figure 1 This is the installation structure of a prestressed anchor support system in existing technology. Prestressed anchor support construction begins with drilling a hole at the anchor installation location on the surface of the tunnel surrounding rock using a drill bit matched to the diameter of the anchor and anchoring agent. Anchoring agent is then added to the borehole and pushed to the bottom. The anchor is then rotated and pushed forward to mix the anchoring agent. After mixing, the anchoring agent solidifies, bonding the anchor to the borehole wall. Finally, metal mesh, steel belts, and other protective components are laid, and the rod end nut is tightened to apply prestress to the surrounding rock. When prestressing the anchor, a certain free length must be left at the borehole end to allow the preload force to be transferred to the surrounding rock. Therefore, prestressed anchor support generally employs end-to-end anchoring or extended anchoring. This involves mixing the anchoring agent and filling a certain length at the bottom of the borehole. This creates an anchor section L2 and a free section L1 within the borehole. The anchor section provides anchoring force to the anchor, while the free section applies prestress to the surrounding rock during prestressing.

[0004] The anchorage length of an anchor bolt affects its anchoring stability. Coal-bearing strata are composed of sedimentary rocks of varying lithology and thickness, such as coal, mudstone, shale, and sandstone. The thickness and strength of the rock formations vary greatly, and their structure is complex. Crustal movement creates numerous geological structures, such as folds and faults, within the strata. Internal bedding and isotropic joints and fissures intersect, resulting in poor structural integrity. After tunnel excavation, under the combined effects of geostress, tectonic stress, and mining dynamic pressure, the surrounding rock inevitably begins to fail at the shallow end. Fractures open, accompanied by deformations such as expansion, expansion, and slippage. Over time, the extent of the damage gradually deepens. The higher the stress in the surrounding rock, the greater the depth of the deformation and failure. With the continuous increase in coal mining depth and mining intensity, there are more and more high-stress environments such as deep wells and strong mining, and the deformation and damage depth of tunnel surrounding rocks is also getting deeper and deeper, especially in complex and difficult tunnel surrounding rocks such as high stress, broken surrounding rocks, isolated island working faces, and adjacent goafs. The damage range often reaches or even exceeds the anchoring depth of the anchor rod, causing the anchoring force of the anchor rod to decrease or even lose the anchoring force, resulting in instability or even complete failure of the support system, which seriously threatens the safety of the tunnel. Summary of the Invention

[0005] (1) Technical issues to be solved

[0006] The present invention provides a prestressed grouting anchor rod to solve the technical problems in the prior art of low anchoring reliability and unstable supporting effect of the prestressed anchor rod in high-stress tunnel surrounding rock.

[0007] (2) Technical solution

[0008] In order to solve the above technical problems, an embodiment of the present invention provides a prestressed grouting anchor rod, including an anchoring section and a grouting section; the tail of the anchoring section is connected to the head of the grouting section, the anchoring section is used to be fixed in the borehole, and is consolidated with the surrounding rock at the bottom of the borehole through an anchoring agent, and the grouting section is used to grout into the borehole.

[0009] Among them, the prestressed grouting anchor rod also includes a connecting head; the connecting head is a tubular structure, and a first grouting hole is opened on the tube wall of the connecting head. One end of the connecting head is connected to the tail of the anchoring section, and the other end is connected to the head of the grouting section.

[0010] Among them, the prestressed grouting anchor rod also includes a sealing rubber tube, a rubber tube locking ring and a positioning clip; the grouting section is a tubular structure, the pipe wall of the grouting section is provided with a second grouting hole, and the sealing rubber tube is sleeved on the grouting section with the second grouting hole; rubber tube locking rings are sleeved on both ends of the sealing rubber tube; the positioning clip is sleeved on the grouting section, and the positioning clip cooperates with the rubber tube locking ring provided near the tail of the grouting section to fix one end of the sealing rubber tube near the tail of the grouting section.

[0011] Wherein, the prestressed grouting anchor rod further comprises an elastic inner sealing sleeve; the elastic inner sealing sleeve is sleeved on the grouting section where the second grouting hole is located.

[0012] Among them, the prestressed grouting anchor rod also includes a sealing plate and a sealing plate pressure ring; the inner tube wall of the connecting head is provided with a stepped hole, and the first grouting hole is located in the area between the stepped hole and the anchoring section; the sealing plate and the sealing plate pressure ring are sequentially clamped in the inner cavity of the connecting head through the stepped hole.

[0013] Wherein, the sealing sheet and the sealing sheet pressure ring are both made of metal sheets.

[0014] Among them, the prestressed grouting anchor rod also includes at least one stirring rib; the anchoring section is a solid columnar structure, and the stirring rib is spirally wound around the outer wall of the anchoring section.

[0015] The prestressed grouting anchor rod further comprises a plurality of retaining rings which are sleeved on the outside of the stirring ribs at intervals along the axial direction of the anchoring section.

[0016] Among them, the prestressed grouting anchor rod also includes a tray, a self-aligning spherical washer and a locking nut at the end of the rod, which are sequentially sleeved on the tail of the grouting section. The tray surface is set towards the rock wall and is used to tighten the surface of the tunnel surrounding rock.

[0017] The prestressed grouting anchor rod further includes a one-way check valve sleeved at the tail of the grouting section to prevent slurry backflow.

[0018] (3) Beneficial effects

[0019] The prestressed grouting anchor provided by the present invention can inject grout when the anchor is in a pre-tightened state by providing a grouting section connected to the anchoring section, which not only meets the prestressed anchor support requirements during the excavation process, but also can perform grouting and anchoring on the free section. The anchor and the surrounding rock in the grouting section are combined into anchor piles, and the radial size of the anchoring structure is enlarged and the stability is enhanced. At the same time, grouting reinforces the tunnel surrounding rock in situ, improves the surrounding rock structure, and can effectively control the deformation and damage depth of the tunnel surrounding rock, ensuring the support safety of the broken tunnel surrounding rock under high stress environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of tunnel surrounding rock support structure in the prior art;

[0021] Figure 2 Schematic diagram of the tunnel surrounding rock support structure provided by the present invention;

[0022] Figure 3 A schematic structural diagram of an embodiment of an anchoring section in a prestressed grouting anchor provided by the present invention;

[0023] Figure 4 A schematic structural diagram of an embodiment of a connector in a prestressed grouting anchor provided by the present invention;

[0024] Figure 5 A schematic structural diagram of an embodiment of a grouting section in a prestressed grouting anchor provided by the present invention;

[0025] Figure 6 A schematic structural diagram of an embodiment of a one-way check valve in a prestressed grouting anchor provided by the present invention;

[0026] In the figure, 1-tunnel surrounding rock; 2-anchoring agent; 3-drilling hole; 4-anchoring section; 5-connector; 6-grouting section; 7-one-way check valve; 8-stirring rib; 9-retaining ring; 10-first grouting hole; 11-sealing plate; 12-sealing plate pressure ring; 13-sealing rubber cylinder; 14-rubber cylinder locking ring; 15-positioning clamp; 16-elastic inner sealing sleeve; 17-second grouting hole; 18-tray; 19-self-aligning spherical washer; 20-rod tail locking nut. DETAILED DESCRIPTION

[0027] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0028] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0029] like Figure 2 As shown, an embodiment of the present invention provides a prestressed grouting anchor rod, including an anchoring section 4 and a grouting section 6; the tail of the anchoring section 4 is connected to the head of the grouting section 6, the anchoring section 4 is used to be fixed in the borehole 3, and is consolidated with the surrounding rock at the bottom of the borehole through the anchoring agent 2, and the grouting section 6 is used to grout into the borehole 3.

[0030] Specifically, for example, the anchoring section 4 can be made of steel bars, and the grouting section 6 can be made of steel pipe. During use, the anchoring section 4 is inserted into the borehole 3, and the anchoring agent 2 is rotated and stirred to fill the bottom section of the borehole 3 tightly. The anchoring agent 2 consolidates the anchor rod with the surrounding rock of the hole wall. The rod end nut is tightened to apply prestress, and the tray presses against the surrounding rock surface. Then, grouting section 6, connected to an external grouting machine, can be used to inject slurry into the borehole 3. After the slurry solidifies, a free-section anchoring structure is formed, achieving full-length anchoring of the prestressed grouting anchor rod. The anchoring agent 2 can be made of resin.

[0031] The prestressed grouting anchor provided by the present invention realizes full-length anchoring of the prestressed grouting anchor by setting a grouting section 6 connected to the anchoring section 4, grouting in the pre-tightened state of the anchor, which not only meets the initial installation pre-tightening conditions of the entire anchor support, but also can perform grouting and anchoring on the free section. The slurry injected into the borehole 3 penetrates into the internal cracks of the surrounding rock, the radial dimension of the anchoring structure is increased, and at the same time the structural integrity of the surrounding rock is improved, the deformation and damage depth of the tunnel surrounding rock 1 is effectively controlled, the anchoring stability of the prestressed grouting anchor is significantly improved, and the support safety of the broken surrounding rock of the tunnel in a high-stress environment is ensured.

[0032] like Figure 4 As shown, further, the prestressed grouting anchor rod also includes a connecting head 5; the connecting head 5 is a tubular structure, and a first grouting hole 10 is opened on the tube wall of the connecting head 5. One end of the connecting head 5 is connected to the tail of the anchoring section 4, and the other end is connected to the head of the grouting section 6.

[0033] Specifically, for example, an internal thread can be provided on the inner side wall of the connector 5 for threaded connection with the tail of the anchoring section 4 and the head of the grouting section 6 respectively; for example, the first grouting hole 10 can be provided directly through the connector 5, which is conducive to smoother injection of the slurry into the borehole 3; wherein, since the connector 5 transmits the force of the anchor rod, the connector 5 can be made of high-strength alloy steel.

[0034] like Figure 5 As shown, further, the prestressed grouting anchor rod also includes a sealing rubber tube 13, a rubber tube locking ring 14 and a positioning clip 15; the grouting section 6 is a tubular structure, and the pipe wall of the grouting section 6 is provided with a second grouting hole 17, and the sealing rubber tube 13 is sleeved on the grouting section 6 with the second grouting hole 17; rubber tube locking rings 14 are sleeved on both ends of the sealing rubber tube 13; the positioning clip 15 is sleeved on the grouting section 6, and the positioning clip 15 cooperates with the rubber tube locking ring 14 provided near the tail of the grouting section 6 to fix one end of the sealing rubber tube 13 near the tail of the grouting section 6.

[0035] Specifically, for example, in order to prevent the slurry injected into the borehole 3 from leaking, a sealing rubber sleeve 13 can be set on the grouting section 6. The sealing rubber sleeve 13 is a hollow sleeve made of high-elastic rubber. When in use, the sealing rubber sleeve 13 is sleeved on the outside of the grouting section 6, and it is necessary to make each second grouting hole 17 wrapped by the sealing rubber sleeve 13, so that the slurry flowing out of the second grouting hole 17 flows to the area between the inner wall of the sealing rubber sleeve 13 and the outer wall of the grouting section 6; for example, the rubber sleeve locking ring 14 can be made of stainless steel or other alloy materials, and the rubber sleeve locking ring 14 is sleeved on both ends of the sealing rubber sleeve 13 to prevent the slurry from overflowing from both ends of the sealing rubber sleeve 13; at the same time, as the inner wall of the sealing rubber sleeve 13 and the injection The slurry between the outer walls of the slurry section 6 increases, causing the sealing rubber sleeve 13 to expand under force, thereby blocking the gap between the outer walls of the drill hole 3 and the grouting section 6; for example, the positioning clamp 15 can be sleeved or welded on the pipe body of the grouting section 6, so that the outer wall of the grouting section 6 forms an annular protrusion. After the sealing rubber sleeve 13 is sleeved on the outer surface of the grouting section 6, the positioning clamp 15 is wrapped inside, and the rubber sleeve locking ring 14 near the tail of the grouting pipe 6 is located on the outside of the positioning clamp 15. The two respectively fix the sealing rubber sleeve 13 on the grouting section 6 from the inside and outside. When the sealing rubber sleeve 13 is expanded under force, it can only be shortened in the direction close to the positioning clamp 15, which can avoid leakage caused by the reverse shrinkage of the rubber sleeve when the grouting pressure in the hole increases.

[0036] Furthermore, the prestressed grouting anchor rod further includes an elastic inner sealing sleeve 16; the elastic inner sealing sleeve 16 is sleeved on the grouting section 6 at the location of the second grouting hole 17, and the elastic inner sealing sleeve 16 is tightly wrapped around the outer surface of the grouting section 6. Specifically, for example, the elastic inner sealing sleeve 16 can be an annular structure made of highly elastic rubber. When in use, the elastic inner sealing sleeve 16 is sleeved on the tube body of the grouting section 6 and blocks the second grouting hole 17. When the pressure of the slurry in the tube body of the grouting section 6 exceeds a certain critical value, the elastic inner sealing sleeve 16 can be propped up, and the slurry flows out through the gap between the inner side wall of the elastic inner sealing sleeve 16 and the grouting section 6.

[0037] Furthermore, the prestressed grouting anchor rod also includes a sealing plate 11 and a sealing plate pressure ring 12; the inner tube wall of the connecting head 5 is provided with a stepped hole, and the first grouting hole 10 is located in the area between the stepped hole and the anchoring section 4; the sealing plate 11 and the sealing plate pressure ring 12 are sequentially clamped in the inner cavity of the connecting head 5 through the stepped groove.

[0038] Specifically, for example, the sealing sheet 11 and the sealing sheet pressure ring 12 are both made of metal sheets, and their outer diameters are slightly smaller than the inner diameter of the connector 5 to facilitate installation. When the grouting section 6 is connected to the connector 5, the front end surface of the grouting section 6 pushes the annular sealing sheet pressure ring 12, pressing the circular sealing sheet 11 against the stepped hole end surface of the connector 5. When the pressure of the slurry increases to a certain critical value, the sealing sheet 11 can be torn, and the slurry flows out through the inner hole of the sealing sheet pressure ring 12 and the torn notch of the sealing sheet 11, and then flows into the borehole 3 through the first grouting hole 10 on the connector 5 until the grouting is completed.

[0039] Furthermore, the sealing sheet 11 and the sealing sheet pressure ring 12 are made of metal sheets of different thicknesses and materials.

[0040] like Figure 3 As shown, further, the prestressed grouting anchor rod also includes at least one stirring rib 8; the anchoring section 4 is a solid columnar structure, and the stirring rib 8 is spirally wound around the outer wall of the anchoring section 4.

[0041] Specifically, for example, two stirring ribs 8 can be set, and the stirring ribs 8 are made of thin steel bars. The diameter of the stirring ribs 8 is smaller than the diameter of the anchoring section 4. The stirring ribs 8 can be welded to the outer wall of the anchoring section 4, or the stirring ribs 8 can be fastened and fixed with the help of a retaining ring 9, wherein the retaining ring 9 can be a metal ring, and retaining rings 9 are set at both ends of the stirring rib 8. The number of retaining rings 9 in the middle can be selected according to the length of the stirring rib 8; with such a setting, the anchoring agent 2 can be stirred more evenly, and the reliability of the initial anchoring can be improved. At the same time, the retaining ring 9 can also prevent the anchoring agent 2 from overflowing during the stirring process.

[0042] Furthermore, the prestressed grouting anchor rod further includes a plurality of retaining rings 9 which are sleeved on the outside of the stirring ribs 8 at intervals along the axial direction of the anchoring section 4 .

[0043] Furthermore, the prestressed grouting anchor rod also includes a tray 18, a self-aligning spherical washer 19 and a rod tail locking nut 20 which are sequentially sleeved on the tail of the grouting section 6. The disk surface of the tray 18 is set towards the rock wall and is used to press the surrounding rock surface when the prestressed grouting anchor rod is installed.

[0044] Specifically, for example, the tray 18, the self-aligning spherical washer 19 and the rod tail locking nut 20 are all connected with the Figure 1 The structures and installation methods of the tray 18, the self-aligning spherical washer 19 and the rod tail locking nut 20 in the prior art are the same and will not be repeated here.

[0045] like Figure 6 As shown, the prestressed grouting anchor further includes a one-way check valve 7 sleeved on the tail of the grouting section 6 to prevent the slurry from flowing back.

[0046] Specifically, for example, an external thread can be provided at the tail of the grouting section 6 and connected to the internal thread on the one-way check valve 7. The one-way check valve 7 only allows the slurry in the grouting machine to enter the grouting section 6. After the grouting is completed, the one-way check valve 7 can be removed after the slurry solidifies for recycling, which is conducive to reducing construction costs.

[0047] The following is a description of the specific construction and use process:

[0048] 1. Anchoring with anchoring agent

[0049] Taking the resin anchor 2 as an example, during the anchoring process, the grouting section 6 is rotated and advanced, driving the anchor section 4 through the connector 5 to stir the anchor 2. The portion of the anchor section 4 within the anchor 2 is the length between the frontmost retaining ring 9 and the rearmost retaining ring 9. The maximum diameter of the anchor 2 does not exceed the diameter of the borehole 3. During the anchoring process, the stirring ribs 8 stir the anchor 2 and push it into the borehole 3. At the same time, the retaining ring 9 prevents the anchor 2 from flowing toward the orifice of the borehole 3, filling the anchor section 4 densely.

[0050] 2. Grouting anchoring

[0051] After the anchoring agent is anchored, the anchor rod is pre-tightened first, and then a one-way check valve 7 is installed at the tail end of the grouting section 6 and connected to the grouting machine through the grouting pipe. The slurry enters the inner cavity of the grouting section 6 through the one-way check valve 7 and flows forward to the connector 5. Under the obstruction of the sealing seal 11, the inner cavity pressure of the grouting section 6 increases, and the slurry squeezes the elastic inner sealing sleeve 16 and flows through the second grouting hole 17 to the cavity between the sealing rubber cylinder 13 and the grouting section 6. As the amount of slurry in the cavity increases, the sealing rubber cylinder 13 expands radially and slides and shrinks unidirectionally toward the tail direction of the grouting section 6. After the sealing rubber cylinder 13 tightens the wall of the drilled hole 3, the slurry pressure increases, and the force of the slurry in the connector 5 squeezing the sealing seal 11 increases until the sealing seal 11 is sheared and broken along the edge of the center hole of the connector 5. At this time, the elastic inner sealing sleeve 16 contracts and closes the second grouting hole 17. The slurry pressure in the cavity between the sealing rubber cylinder 13 and the grouting section 6 is the grouting sealing pressure, which is the same as the grouting pressure when the sealing seal 11 breaks. At this point, the grouting system for tunnel surrounding rock 1 is established. Slurry flows through the center hole of sealing plate pressure ring 12 and then through first grouting hole 10 into borehole 3. Grouting continues until a certain pressure is reached, filling borehole 3 and the surrounding rock fissures. The slurry in borehole 3 and the cracks in tunnel surrounding rock 1 solidifies to form a stone body, improving the surrounding rock structure in situ and completing the full-length anchoring of the prestressed grouting anchor rod in borehole 3. After the grout solidifies, the one-way check valve 7 is removed for reuse.

[0052] From the above embodiments, it can be seen that the prestressed grouting anchor provided by the present invention has the following beneficial effects:

[0053] 1. The original prestressed anchor support construction process remains unchanged; the tunnel surrounding rock can be promptly and actively supported during the excavation process, which is beneficial to improving the stress state of the initial support tunnel surrounding rock and giving full play to the bearing capacity of the tunnel surrounding rock;

[0054] 2. Grouting is performed while the anchor bolts are in the prestressed support state. The slurry is injected into the boreholes and surrounding rock cracks to reinforce the tunnel surrounding rock in situ, effectively controlling the deformation process and damage range of the tunnel surrounding rock. The slurry fills the cracks opened by the tunnel surrounding rock excavation, forming a continuous force transmission structure, improving the integrity of the tunnel surrounding rock and enhancing the bearing capacity. Grouting reinforcement of the tunnel surrounding rock is completed simultaneously with anchoring and grouting. In particular, when high-strength, high-toughness, and high-adhesion chemical materials are used for grouting, the integrity of the tunnel surrounding rock is significantly improved.

[0055] 3. The slurry fills the internal cracks of the borehole and surrounding roadway surrounding rock to form a network of stone bodies. The prestressed grouting anchor rods, roadway surrounding rock, and slurry stone bodies form an integrated anchor pile structure, increasing the radial dimension of the anchor structure and enhancing stability. Moreover, the prestressed grouting anchor rods are wrapped in the slurry stone body along the entire length of the borehole, significantly improving the shear resistance to prevent slippage between rock layers.

[0056] 4. The sealing sheet cooperates with the elastic inner sealing sleeve to complete the sealing and grouting processes in one go. By changing the thickness of the sealing sheet or the diameter of the center hole of the connector, the expansion pressure of the sealing rubber sleeve can be changed, thus ensuring the sealing effect of high-pressure grouting.

[0057] 5. Resin anchoring not only provides initial anchoring force for prestressed support, but also axially tightens the prestressed grouting anchor rod during grouting to maintain the stability of the support system. During grouting and anchoring, the slurry pressure acting on the sealing rubber cylinder makes the prestressed grouting anchor rod bear the pulling force along the axial direction of the borehole, and the anchoring section stabilizes the prestressed grouting anchor rod in the borehole;

[0058] 6. The pipe bodies of the connector and grouting section are both high-strength thick-walled structures, and the bearing capacity matches that of the anchoring section, ensuring consistent overall bearing capacity of the prestressed grouting anchor rod, high bearing capacity, and strong ability to adapt to deformation of the surrounding rock of the tunnel;

[0059] 7. Prestressed support and grouting anchoring can be organized in parallel without affecting the speed of tunnel excavation construction. Grouting anchoring allows the prestressed support construction to be delayed to a certain extent without affecting the support effect.

[0060] 8. Grouting materials of different properties can be used, including high-strength cement slurry and chemical slurry, and a wide range of grouting materials can be used.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A prestressed grouting anchor rod, comprising an anchoring section, characterized in that: It also includes the grouting section; The tail of the anchoring section is connected to the head of the grouting section. The anchoring section is used to be fixed in the borehole and consolidated with the surrounding rock at the bottom of the borehole through an anchoring agent. The grouting section is used to grout into the borehole. The connector further comprises a connecting head, a sealing sheet and a sealing sheet pressure ring; the connecting head is a tubular structure, a first grouting hole is opened in the wall of the connecting head, one end of the connecting head is connected to the tail of the anchoring section, and the other end is connected to the head of the grouting section; the inner wall of the connecting head is provided with a stepped hole, and the first grouting hole is located in the area between the stepped hole and the anchoring section; the sealing sheet and the sealing sheet pressure ring are sequentially clamped in the inner cavity of the connecting head through the stepped hole; It also includes a tray, a self-aligning spherical washer and a rod tail locking nut which are sequentially sleeved on the tail of the grouting section, wherein the tray is arranged with its disk surface facing the rock wall and is used to press the surrounding rock surface when the prestressed grouting anchor rod is installed; It also includes a sealing rubber sleeve, a rubber sleeve locking ring, a positioning clamp ring and an elastic inner sealing sleeve; the grouting section is a tubular structure, the pipe wall of the grouting section is provided with a second grouting hole, and the sealing rubber sleeve is sleeved on the grouting section with the second grouting hole; the rubber sleeve locking ring is sleeved on both ends of the sealing rubber sleeve; the positioning clamp ring is sleeved on the grouting section, and the positioning clamp ring cooperates with the rubber sleeve locking ring provided near the tail of the grouting section to fix the end of the sealing rubber sleeve near the tail of the grouting section; the elastic inner sealing sleeve is sleeved on the grouting section where the second grouting hole is located; It also includes at least one stirring rib; the anchoring section is a solid columnar structure, and the stirring rib is spirally wound around the outer wall of the anchoring section; and it also includes a plurality of retaining rings that are spaced apart and sleeved on the outer side of the stirring rib along the axial direction of the anchoring section; During the anchoring process, the grouting section is rotated and pushed forward, and the grouting section drives the anchoring section to stir the anchoring agent through the connector. The stirring ribs stir the anchoring agent and push the anchoring agent into the borehole. At the same time, the retaining ring blocks the anchoring agent from flowing toward the orifice side of the borehole, so that the anchoring section is filled densely. After the anchoring of the anchoring agent is completed, the locking nut at the rod tail is tightened to apply prestress to ensure that the tray is pressed against the surrounding rock surface to complete the installation pre-tightening of the anchor rod, and then grouting is injected into the grouting pipe through the grouting machine. The slurry enters the inner cavity of the grouting section through the one-way check valve and flows forward to the connecting head. Under the obstruction of the sealing seal, the pressure in the inner cavity of the grouting section increases, and the slurry squeezes the elastic inner sealing sleeve and flows through the second grouting hole to the cavity between the sealing rubber cylinder and the grouting section. As the amount of slurry in the cavity increases, the sealing rubber cylinder expands the wall of the borehole, and the slurry pressure increases until the sealing seal is sheared and broken along the edge of the center hole of the connecting head. At this time, the elastic inner sealing sleeve shrinks and closes the second grouting hole, and the tunnel surrounding rock grouting system is formed. The slurry flows through the center hole of the sealing ring and then enters the borehole through the first grouting hole. Continuous grouting to a certain pressure fills the borehole and the surrounding rock cracks.

2. The prestressed grouting anchor rod according to claim 1, characterized in that: The sealing sheet and the sealing sheet pressure ring are both made of metal sheets.

3. The prestressed grouting anchor rod according to claim 1, characterized in that: It also includes a one-way check valve sleeved on the tail of the grouting section to prevent the slurry from flowing back.

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