Grouting anchor rod with built-in plugging particles and working method of grouting anchor rod

Abstract

The invention discloses a grouting anchor rod with built-in plugging particles and a working method thereof.The grouting anchor rod comprises a hollow anchor rod body, the anchor rod body is installed in a drill hole, and the anchor rod body and an orifice of the drill hole are plugged through a stop-grouting plug; the interior of the anchor rod serves as a slurry channel, a plurality of slurry outlet holes are formed in the anchor rod in the axial direction at intervals, plugging particles wrapped by a water-soluble film are arranged on the inner wall face of the anchor rod, after slurry enters the anchor rod, the water-soluble film dissolves and releases the plugging particles, and the plugging particles flow out of the anchor rod along with the slurry through the slurry outlet holes for plugging; the blocking particles are self-expanding particles; the grouting anchor rod structure is improved, in the grouting process, grout can carry plugging particles with specific response performance to enter cracks and automatically expand and condense, a stable and compact flow blocking structure is formed, and the grouting efficiency, the supporting quality and the engineering safety are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical engineering construction devices, in particular to an internal plugging particle grouting anchor and a working method thereof. BACKGROUND

[0002] In the process of geotechnical engineering construction, grouting anchoring technology, as an important means to improve the stability of stratum, control deformation and prevent water seepage, has been widely used in various engineering fields such as tunnels, slopes, foundation pits, hydraulic engineering and mines. The grouting anchor support structure realizes the filling, cementation and anchoring of rock mass fissures by injecting cement-based slurry into the pre-set borehole or structural plane, thereby enhancing the integrity and bearing capacity of the rock-soil body.

[0003] The existing grouting anchor technology has the following problems: 1. Only relying on mechanical plugging plugs or external plugging materials to plug the anchor and the hole position, which easily leads to hole sealing failure, slurry escaping from the anchor-hole wall interface, fissures not being effectively filled, poor sealing of the anchoring boundary, and high risk of long-term water seepage; 2. In the fissure developed or high permeability stratum, the slurry easily flows away along the hole, surrounding rock fissures, resulting in insufficient grouting amount and incomplete anchoring body; 3. Running slurry leads to the inability to maintain system pressure, and slurry preferentially flows to low resistance paths (such as existing fissures) rather than unfilled areas, resulting in low grouting efficiency, repeated grouting, uneven slurry distribution, large dispersion of anchoring body strength, and affecting the reliability of support; 4. The traditional slurry is only cement-based material without active plugging function, and cannot adaptively fill the fissures; additional plugging agents or multiple grouting are required, which is high in cost and uncontrollable in effect. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides an internal plugging particle grouting anchor and a working method thereof. Through improvement of the structure of the grouting anchor, in the grouting process, the slurry can carry the plugging particles with specific response performance into the fissures and automatically expand and coagulate, forming a stable and dense flow resistance structure, which greatly improves the grouting efficiency, support quality and engineering safety.

[0005] The technical scheme of the present application is as follows: In the first aspect of the present application, an internal plugging particle grouting anchor is provided, which comprises a hollow anchor rod installed in a borehole, the anchor rod and the hole of the borehole are plugged by a plugging plug at the hole, the inside of the anchor rod serves as a slurry channel, a plurality of slurry outlets are arranged on the anchor rod along the axial direction, plugging particles wrapped by a water-soluble film are arranged on the inner wall surface of the anchor rod, the water-soluble film dissolves to release the plugging particles after the slurry enters the anchor rod, the plugging particles flow out of the anchor rod through the slurry outlets for plugging; the plugging particles are self-expanding particles.

[0006] In some embodiments of the present application, the slurry outlet hole comprises a plurality of main slurry outlet holes and a plurality of auxiliary slurry outlet holes, the main slurry outlet holes and the auxiliary slurry outlet holes are staggered, the axis of the main slurry outlet hole is perpendicular to the axis of the anchor rod, and the axis of the auxiliary slurry outlet hole is arranged at an angle of 25-30° with the axis of the anchor rod.

[0007] In some embodiments of the present application, the axial distance between the main slurry outlet hole and the auxiliary slurry outlet hole is greater than 15 cm.

[0008] In some embodiments of the present application, the main slurry outlet hole is symmetrically arranged in the circumferential direction, and the auxiliary slurry outlet hole is asymmetrically distributed in the circumferential direction. In some embodiments of the present application, one end of the anchor rod serves as a grouting hole, the other end extends into the borehole and is fixed to the surrounding rock through anchoring agent, and is sealed by a plug. In some embodiments of the present application, the grouting hole is connected with a grouting assembly.

[0009] In some embodiments of the present application, the grouting plug is locked by a gasket and a nut, and the nut is installed on the anchor rod by threads.

[0010] In some embodiments of the present application, the particle size of the self-expanding particles is controlled to be 0.3-2.5 mm, and the composition of the self-expanding particles includes modified bentonite, superabsorbent polymer, mineral micro-powder and cellulose composite, and quartz sand inert aggregate.

[0011] In some embodiments of the present application, the water-soluble film is a polyvinyl alcohol water-soluble film, the thickness of the water-soluble film is 20-50 μm, and the water-soluble film is fixed on the inner wall surface of the anchor rod by adhesion.

[0012] In the second aspect of the present application, a working method of a grouting anchor rod with built-in sealing particles is provided, comprising the following steps: The anchor rod with built-in sealing particles is installed in the borehole, and a grouting assembly is connected; The cement slurry is gradually injected into the anchor rod by grouting, the slurry washes and dissolves the water-soluble film to release the sealing particles; The sealing particles flow to the orifice or the fracture with the slurry, and expand to form a physical barrier when meeting water; After sealing, the system pressure rises, and the slurry continues to fill the unsaturated area; The sealing particles and the cement slurry harden together to form an integral anchoring body. The technical scheme of the present application has the following advantages: (1) The grouting anchor rod with built-in plugging particles provided by the present application sets the plugging particles wrapped by a water-soluble film in the interior of the anchor rod, when the slurry diffuses to the surrounding rock fissures and the anchor hole through the grouting hole, the plugging particles can expand rapidly after meeting water, and embed into the slurry running channel under the action of pressure, forming an initial closed barrier, significantly improving the anti-slurry running capacity in the grouting process, realizing self-adaptive flow guiding and leakage blocking of the slurry, effectively solving the problems of "slurry loss" and "hole orifice cannot be closed" of the traditional grouting anchor rod when encountering high permeable fissures or hole edge loose zone.

[0013] (2) The grouting anchor rod with built-in plugging particles provided by the present application sets the main grouting hole and the auxiliary grouting hole on the anchor rod, the main grouting hole releases the slurry and the plugging particles, and the auxiliary grouting hole plays a pressure guiding and shunting role, which can realize the responsive agility of the plugging particles, can close the orifice free surface, and can further penetrate and expand into the surrounding fissures, fill and solidify in the hole edge gap, has excellent three-dimensional plugging capacity, and adapts to the diversity requirements of different rock-soil structures, and enhances the boundary sealing property of the anchoring system.

[0014] (3) The grouting anchor rod with built-in plugging particles provided by the present application, the large aperture of the main grouting hole guarantees the smooth output of the slurry main body, the small aperture of the auxiliary grouting hole realizes fine shunting, in combination with the limitation of axial spacing ≥10 cm, avoiding the turbulent flow of slurry caused by too close double holes, ensuring that the particles are stably transported to the target area in a laminar flow state, and in addition, the spacing control avoids the accumulation of particles between the holes.

[0015] (4) The modified bentonite in the plugging particle composition is used as the main swelling base material, which has natural swelling property and good interface compatibility; the superabsorbent polymer (SAP) can improve the reaction rate and swelling ratio, and the dosage needs to be controlled during use to avoid adverse effects on the cementing strength; the mineral powder-cellulose composite material can enhance the adhesion and anti-dispersion performance, and can form a three-dimensional support structure after swelling, improving the overall strength of plugging.

[0016] (5) The grouting anchor rod with built-in plugging particles provided by the present application can realize the passive response plugging mechanism only by improving the structure, and can realize automatic start without relying on complex monitoring or external excitation conditions, which is suitable for anchoring construction under complex rock-soil conditions such as abundant underground water, joint fissure development and unstable stratum, and reduces the technical dependence on construction personnel and the complexity of operation.

[0017] (6) The grouting anchor rod with built-in plugging particles provided by the present application can flexibly select the existing standard anchor rod pipe material according to engineering needs, the grouting hole can be optimally arranged in position and size according to different engineering grouting amount and pressure conditions, and the plugging particles can also be graded according to the performance of the slurry, which has good universality and generalizability, and is suitable for large-scale rock-soil anchoring engineering popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 This is a schematic diagram of the grouting anchor bolt with built-in sealing particles of the present invention before grouting; Fig. 2 This is a schematic diagram of the grouting anchor bolt with built-in sealing particles of the present invention during the grouting process; Fig. 3 This is a schematic diagram of the grouting anchor bolt with built-in sealing particles of the present invention after grouting.

[0019] In the diagram: 1. Anchor bolt; 101. Grout channel; 102. Anchor bolt wall; 103. Main grout outlet; 104. Secondary grout outlet; 105. Grouting hole; 2. Plug; 3. Anchoring agent; 4. Sealing particles coated with water-soluble film; 5. Grout stop plug; 6. Gasket; 7. Nut; 8. Sealing particles; 9. Expanded sealing particles. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Example 1 In a typical embodiment of the present invention, a grouting anchor bolt with built-in sealing particles is proposed, such as... Figs. 1 to 3 As shown, the device includes a hollow anchor rod 1, which is installed inside a borehole. The anchor rod 1 and the borehole opening are sealed by a grout stopper 5. The interior of the anchor rod 1 serves as a grout channel 101. Multiple grout outlet holes are arranged axially at intervals on the anchor rod wall 102. Sealing particles 4, which are coated with a water-soluble film, are provided on the inner wall of the anchor rod. After the grout enters the anchor rod, the water-soluble film dissolves and releases the sealing particles. The sealing particles flow out of the anchor rod through the grout outlet holes with the grout to seal the hole. The sealing particles 8 are self-expanding particles.

[0022] Anchor rod 1 is a hollow rod, which can be made of alloy steel, galvanized steel, or other high-strength metal tubing. The diameter of the grout outlet holes on the anchor rod is generally controlled between φ5mm and φ8mm, and the hole density and distribution location are determined based on the length of the anchoring section and the grouting requirements. The placement of the grout outlet holes ensures that the grout can be fully released into the target fracture while also controlling the flow path of the sealing particles.

[0023] Furthermore, the grout outlet includes multiple main grout outlets 103 and multiple secondary grout outlets 104, which are staggered. The axis of the main grout outlet is perpendicular to the axis of the anchor rod, and the axis of the secondary grout outlet is at an angle of 25-30° to the axis of the anchor rod. The inner diameter of the main grout outlet 103 is larger than the inner diameter of the secondary grout outlet 104. The axial distance between the main grout outlet 103 and the secondary grout outlet 104 is greater than 15cm. The main grout outlets 103 are symmetrically arranged in the circumferential direction, and the secondary grout outlets 104 are asymmetrically distributed in the circumferential direction.

[0024] In one specific implementation of the embodiment, the diameter of the main slurry outlet hole is 8 mm, and the diameter of the auxiliary slurry outlet hole is 5 mm. The auxiliary slurry outlet hole mainly functions as a pressure guide and shunt, guiding part of the slurry horizontally into the gap of the anchor wall, reducing the instantaneous impact pressure near the main slurry outlet hole by 30%-40%, and effectively reducing the risk of particle accumulation and blockage near the main hole. The main slurry outlet hole and the auxiliary slurry outlet hole work together to help achieve stable release of slurry and sealing particles and permeation of fractures. It is suitable for complex scenes such as broken rock strata and high water pressure strata, significantly improving the bearing capacity of the anchor rod and the construction efficiency. The axis of the auxiliary slurry outlet hole is arranged at an angle of 25-30° with the axis of the anchor rod. This angle range can ensure that the slurry is smoothly deviated to the anchor wall and diffused along the fracture, and can effectively weaken the pressure peak of the main hole and reduce the probability of collision and blockage. The auxiliary slurry outlet hole is arranged in a staggered manner with the main slurry outlet hole, with an axial distance of >15 cm, and adjacent holes are arranged in a staggered manner as much as possible to avoid local slurry collision.

[0025] In the embodiment, one end of the anchor rod serves as a grouting hole 105, the other end extends into the borehole and is fixed to the surrounding rock through an anchoring agent 3, and is sealed by a plug. The grouting hole 105 is connected with a grouting assembly. The grouting assembly system is a key structural part for realizing directional grouting and preventing slurry running, mainly including: a grouting port rigging, a slurry stopper, an anchor rod tail plug, a slurry conveying pipe interface, a flow guide copper strand (or steel strand), etc., and its structure layout and functions are as follows: The grouting port rigging is installed at the front end of the anchor rod grouting hole, and is a standard detachable connection structure, composed of an internal threaded connector, a grouting connector, a sealing washer, and a flow limiting guide pipe. The grouting port is connected with an external slurry conveying device (such as a grouting pump) through a quick plug or a threaded connection, and forms a high-pressure sealed environment through a sealing washer, effectively preventing slurry leakage. The connector material is made of high-strength corrosion-resistant alloy steel or nylon reinforced composite material, which has good impact resistance and wear resistance.

[0026] The slurry stopper is arranged at the junction of the grouting port and the anchor rod cavity, and is made of a conical rubber or polyurethane elastomer structure. It is tightly attached to the inner wall by using elastic restoring force to realize one-way sealing function, preventing slurry from flowing back to the rigging part after grouting, and improving the grouting pressure maintaining efficiency. Its design refers to the related requirements of anchoring sealing components in “GB / T 50086-2015 Technical Code for Anchor Jet Grouting Support”. The slurry stopper 5 is locked by a gasket 6 and a nut 7, and the nut is installed on the anchor rod through threads.

[0027] The plug 2 is located at the tail end of the hollow anchor rod, and is a whole metal closed plug or an inflatable compression end cap, which has good air and water tightness, preventing slurry from escaping in the opposite direction along the rod body, and can also be used as a limiting end piece after the anchor rod is tensioned.

[0028] After the slurry enters through the rigging, it is guided along the cable to the rod body and released at each slurry hole, while carrying functional blocking particles to diffuse into the surrounding rock cracks and orifices. When the blocking particles swell upon contact with water and form a preliminary seal, the remaining slurry can continue to advance to the anchoring depth, forming a complete and continuous anchoring structure.

[0029] In this embodiment, the particle size of the self-expanding particles is controlled to be 0.3-2.5mm, and the components of the self-expanding particles include modified bentonite, superabsorbent polymer, mineral powder and cellulose composite, and quartz sand inert aggregate.

[0030] Among them, the modified bentonite as the main swelling base material has natural swelling property and good interface compatibility; the superabsorbent polymer (SAP) can improve the reaction rate and swelling ratio, and the dosage needs to be controlled to avoid adverse effects on the cementing strength. Mineral powder-cellulose composite can enhance the adhesion and dispersion resistance, and after swelling, it can form a three-dimensional support structure to improve the overall strength of the block.

[0031] Quartz sand inert aggregate: provides skeletal support, enhances the shear resistance, compressive strength and rheological resistance of the material.

[0032] In this embodiment, the blocking material is made into granules according to the following weight ratio: modified bentonite 45~50 parts by weight; superabsorbent polymer 5~10 parts by weight; mineral powder and cellulose composite 10~15 parts by weight; quartz sand inert aggregate 10~30 parts by weight. Preferably, the modified bentonite is 50 parts by weight, which serves as the main swelling matrix, providing rapid water absorption and swelling and basic blocking performance. The superabsorbent polymer (SAP) is 10 parts by weight, which is used to enhance the initial rapid water absorption reaction and improve the volume expansion ratio. The mineral powder and cellulose composite is 15 parts by weight, which forms a three-dimensional skeletal structure during the swelling process, improving the support and dispersion resistance between particles. The quartz sand inert aggregate is 25 parts by weight, which serves as a skeletal filler material to improve the shear resistance, compressive strength and rheological resistance of the blocking body, preventing the swelling body from being washed away.

[0033] Further, the modified bentonite can be sodium-based bentonite treated with an organosilane coupling agent to improve its water absorption rate and swelling stability. The superabsorbent polymer is preferably partially hydrolyzed sodium polyacrylate, which has high water absorption ratio and good alkali resistance, and is suitable for cement-based slurry environment. The mixing ratio of mineral powder and cellulose is 1:1; the mineral powder is preferably metakaolin powder, which is used to improve the density of the slurry; the cellulose is preferably carboxymethyl cellulose sodium (CMC), which enhances the adhesion and dispersion resistance, and the quartz sand inert aggregate is preferably natural quartz sand treated by drying, with a particle size range of 0.2~1.0mm, which is used to form a particle skeleton to improve the shear resistance and rheological resistance of the swelling body.

[0034] The particle size of the plugging particles is controlled at 0.3 mm to 2.5 mm, and has a continuous grading characteristic, so as to improve the adaptability to different scale fractures and filling efficiency. In order to enhance the stability of the plugging body structure, 10% to 30% of quartz sand particles with a particle size of 0.1 mm to 1.0 mm are mixed in the particle system by mass ratio, a support skeleton between particles is constructed, and the compressive strength and the anti-scouring ability of the material are improved.

[0035] The plugging particles have the following characteristics: 1. The plugging particles have expansion performance and stability: the particles can rapidly expand within 30 to 90 seconds after contacting with free water or cement slurry, and the volume expansion ratio is 500% to 1000% of the original volume; after expansion, a filling body with good flexibility, stable structure and non-dissolution is formed, which can realize self-adaptive embedding and plugging of complex fractures. The quartz sand aggregate plays a role of stress concentration resistance and stable support in the expansion process, and prevents the structure of the expanded body from being damaged or lost.

[0036] 2. The plugging particles have cementing compatibility: the surface of the plugging particles is subjected to hydrophilic modification treatment, has good interfacial activity, and can form a mutual embedding-mutual locking structure with the cement-based grouting material. Within 6 to 12 hours after grouting is completed, the plugging particles and the slurry are hardened together to form an integrated plugging cementing body with a compressive strength of ≥3 MPa, which has good sealing and durable anchoring performance.

[0037] 3. The plugging particles have environmental adaptability, and can stably exist in an alkaline grouting environment with a pH value of 10 to 12 without degradation, have good water permeation resistance, shear resistance and chemical corrosion resistance, and are suitable for complex geological environments with high water content and obvious fracture development.

[0038] In the embodiment, the water-soluble film is a polyvinyl alcohol water-soluble film, and the thickness of the water-soluble film is 20-50 μm. The water-soluble film is fixed on the inner wall surface of the anchor rod in an adhering manner.

[0039] The plugging particles are pre-filled in the specified section of the grouting channel in the manufacturing link; a polyvinyl alcohol (PVA) water-soluble film is used for packaging to form a controllable release wrapping layer: thickness: 20-50 μm; dissolution time: 30-300 s (adjusted according to the type of film); and adhering manner: hot sealing, film pressing or glue spraying to adhere to the inner wall.

[0040] The use method of the grouting anchor rod with the built-in plugging particles provided in the embodiment is as follows: 1. Pre-provision before grouting: Particle pre-provision: the plugging particles wrapped by the water-soluble film are adhered in the grouting channel of the hollow anchor rod. The water-soluble film is a light controllable release cavity, which can stably fix a certain amount of intelligent plugging particles. In this stage, the particles are not in contact with water, and are in a dry dormant state, have good storage and pre-grouting stability, and will not affect the normal flow of the slurry.

[0041] Anchor rod installation: Install the hollow grouting anchor rod in the pre-drilled anchor hole, ensure the axial positioning and end sealing of the anchor rod, and meet the design length and angle requirements of construction.

[0042] Pre-installation of grouting components: Grouting port rigging, grouting stopper, tail plug, and copper wire guide are sequentially installed in the corresponding positions of the hollow anchor rod to form a complete and sealed grouting channel.

[0043] 2. Grouting stage Slurry introduction: The composite grouting slurry is injected into the hollow anchor rod cavity through the grouting pump and grouting rigging. The slurry flows directionally along the copper wire channel under the driving of pump pressure.

[0044] Path allocation: The slurry first fills the anchor rod cavity, then enters the surrounding rock fissures through multiple slurry outlets evenly distributed on the surface of the anchor rod, achieving comprehensive grouting of the anchoring area.

[0045] Flow rate control and flow limiting adjustment: A flow limiting structure or stopper is installed at the grouting port to effectively adjust the grouting flow rate, control the slurry front advance rhythm, and avoid "rapid escape" or "cavity not filled".

[0046] Grouting activated sealing particles: When the grouting operation starts, the grouting liquid enters the anchor rod cavity under the action of pump pressure and washes the water-soluble membrane containing particles. The containing device uses a soluble membrane, which quickly releases particles when the slurry flows through. The released sealing particles immediately react with water, start to swell, and are transported to the target sealing site along with the slurry flow to the main and auxiliary slurry outlets and fissure areas.

[0047] 3. Automatic anti-run grouting response mechanism stage Water-swelling reaction: Functional sealing particles in the grouting liquid contact free water sources (such as groundwater, capillary water) at the orifice or fissure, rapidly undergo hydration swelling reaction, and significantly increase in volume within 30-90 seconds, embedding in the fissure or orifice cavity.

[0048] Initial sealing formation: The swelling particles are forced to squeeze into small gaps and orifice edge spaces under pressure, forming a physical barrier, and partially absorbing water from the slurry to undergo a bonding reaction with the slurry, initially preventing further slurry leakage.

[0049] Pressure recovery feedback: As the resistance of the sealing point increases, the local pressure relief path of the slurry is blocked, the internal pressure of the system rises, prompting the slurry to be injected again into other unsaturated areas, improving grouting efficiency.

[0050] Stable condensation process: the expansion particles and the cement paste co-react and solidify to form high-strength embedded bodies, which gradually transform into continuous and stable "plugging-anchoring integrated bodies" within 12-24 hours, and realize interface interlocking with the anchor body and the surrounding rock hole wall. The plugging particles have the ability to react with the cement paste to form high-strength hardened bodies, and ultimately form an overall dense structure with the cement paste. This structure not only has the filling effect of the expansion particles on the micro cracks, but also has the bonding and bearing characteristics of the cement paste, realizing the engineering effect of "material complementation-structure unification-performance enhancement", which can effectively replace the conventional anchoring and grouting system and improve the long-term bearing and stability performance of the anchoring body.

[0051] 4. Grouting completion and support formation stage System closure: after grouting is completed, pumping is stopped, grouting pipes are removed, and grouting port plugs are used to achieve self-closing; anchor rod tail plugs prevent backflow of the slurry, and the entire system remains in a closed state.

[0052] Structure bearing formation: the slurry hardens in the surrounding rock, and the expansion particles and the cement co-form dense and strong anchoring bodies with good adhesion, shear resistance and durability.

[0053] Pressure capacity improvement: the plugging effect enables the grouting pressure to be maintained, the slurry fully fills the hole cavity and the surrounding rock micro cracks, significantly improving the mechanical coupling performance of the anchor body and the surrounding rock, and further enhancing the overall stability of the support structure.

[0054] The grouting anchor with built-in plugging particles provided in the embodiment realizes directional grouting and synchronous plugging of the crack area inside the anchor hole and outside the hole, can automatically plug the grouting path of the hole or cracks during the flow of the slurry, forms a dense anchoring body, improves grouting efficiency and support effect, and is suitable for complex geological environments with high requirements for support quality and compactness in various geotechnical engineering.

[0055] The grouting anchor with built-in plugging particles provided in the embodiment has wide engineering application prospects, can be used for crack plugging and support behind the working face, surrounding rock and lining in underground tunnels and space engineering; in deep foundation pit and slope engineering, can be used for slope stability control and grouting anchoring of slip zone; in water conservancy and hydropower engineering, is suitable for anti-seepage reinforcement of dam foundation, cofferdam and water conveyance tunnel structures; in the field of foundation treatment, is suitable for reinforcement of loose soil, sandy soil and strongly weathered rock with strong water permeability; and is also suitable for mine roadway and tunnel surrounding rock support, especially in environments with high risk of rock burst or surrounding rock loosening, can significantly improve the stability and reliability of the support system.

[0056] Embodiment 2 In a typical embodiment of the present application, a working method of a grouting anchor with built-in plugging particles is provided, including the following steps: The anchor rod with the built-in blocking particles is installed in the borehole, and the grouting assembly is connected; The cement slurry is gradually injected into the anchor rod by grouting, and the slurry washes and dissolves the water-soluble film to release the blocking particles; The blocking particles flow with the slurry to the orifice or the fracture, and expand to form a physical barrier when encountering water; After the blocking, the system pressure rises, and the slurry continues to fill the unsaturated area; The blocking particles and the cement slurry jointly harden to form an integrated anchoring body.

[0057] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications or changes made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A grouting anchor bolt with built-in sealing particles, characterized in that, The device includes a hollow anchor bolt installed inside a borehole. The anchor bolt and the borehole opening are sealed with a grout stopper. The interior of the anchor bolt serves as a grout channel, and multiple grout outlet holes are arranged axially along the anchor bolt. Sealing particles coated with a water-soluble film are provided on the inner wall of the anchor bolt. After the grout enters the anchor bolt, the water-soluble film dissolves and releases the sealing particles, which flow out of the anchor bolt through the grout outlet holes to seal the grout. The sealing particles are self-expanding particles.

2. The grouting anchor bolt with built-in sealing particles as described in claim 1, characterized in that, The grout outlet includes multiple main grout outlets and multiple secondary grout outlets, which are arranged alternately. The axis of the main grout outlet is perpendicular to the axis of the anchor rod, and the axis of the secondary grout outlet is at an angle of 25-30° to the axis of the anchor rod.

3. The grouting anchor bolt with built-in sealing particles as described in claim 2, characterized in that, The inner diameter of the main slurry outlet is larger than the inner diameter of the secondary slurry outlet, and the axial distance between the main slurry outlet and the secondary slurry outlet is greater than 15cm.

4. The grouting anchor bolt with built-in sealing particles as described in claim 2, characterized in that, The main slurry outlet holes are symmetrically arranged in the circumferential direction, while the auxiliary slurry outlet holes are asymmetrically distributed in the circumferential direction.

5. The grouting anchor bolt with built-in sealing particles as described in claim 1, characterized in that, One end of the anchor rod serves as a grouting hole, while the other end extends into the borehole and is fixed to the surrounding rock using an anchoring agent, and then sealed with a plug.

6. The grouting anchor bolt with built-in sealing particles as described in claim 5, characterized in that, The grouting hole is connected to the grouting assembly.

7. The grouting anchor bolt with built-in sealing particles as described in claim 1, characterized in that, The grout stop plug is locked in place by a gasket and a nut, the nut being threaded onto the anchor bolt.

8. The grouting anchor bolt with built-in sealing particles as described in claim 1, characterized in that, The particle size of the self-expanding particles is controlled between 0.3-2.5 mm. The composition of the self-expanding particles includes modified bentonite, superabsorbent polymer, mineral micro powder and cellulose composite material, and quartz sand inert aggregate.

9. The grouting anchor bolt with built-in sealing particles as described in claim 1, characterized in that, The water-soluble membrane is made of polyvinyl alcohol and has a thickness of 20-50 μm. It is fixed to the inner wall of the anchor rod by adhesion.

10. A method for operating a grouting anchor bolt with built-in sealing particles as described in any one of claims 1-9, characterized in that, Includes the following steps: Anchor bolts with built-in sealing particles are installed in the borehole and connected to the grouting assembly; Cement grout is gradually injected into the anchor bolt through grouting. The grout washes away and dissolves the water-soluble film, releasing the sealing particles. The sealing particles flow with the slurry to the orifice or fissure, where they expand upon contact with water to form a physical barrier. After the blockage, the system pressure rises, and the grout continues to fill the unsaturated area; The sealing particles and cement slurry harden together to form an integral anchor body.

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