Automatic grout leakage prevention stop-grouting plug and using method thereof

Abstract

The invention discloses an automatic grout leakage prevention stop-grouting plug and a using method thereof. The automatic grout leakage prevention stop-grouting plug comprises a hollow barrel-shaped stop-grouting plug body, and the barrel-shaped stop-grouting plug body is sequentially divided into a front reaction activation area, a middle mechanical anchoring area and a rear limiting locking area from top to bottom; the front reaction activation area is of a cylindrical structure, an annular containing cavity is formed in the cylindrical structure, and plugging particles are contained in the annular containing cavity; the whole middle mechanical anchoring area is of a conical structure, and spiral protruding ribs are arranged on the outer wall face of the conical structure. The rear limiting and locking area is of a step-shaped annular structure, and the outer diameter of the rear limiting and locking area is larger than that of the middle mechanical anchoring area. Through the three-section structural design of the front reaction activation area, the middle mechanical anchoring area and the rear limiting locking area, the cooperative functions of automatic plugging, effective grout stopping and reliable limiting in the grouting process are achieved.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering construction equipment technology, specifically to an automatic anti-grout leakage plug and its usage method. Background Technology

[0002] As important underground engineering structures, mine tunnels have a significant impact on mine production and personnel safety. Grouting reinforcement is a widely used support measure in mine tunnel construction, which aims to enhance the overall stability of the tunnel by injecting grout into rock fissures and pores to improve the density and bearing capacity of the rock mass.

[0003] In grouting construction, the grout stopper is a crucial device for preventing grout backflow and leakage, and its performance directly affects the grouting effect and construction quality. Existing traditional grout stoppers mostly employ mechanical sealing structures, such as rubber sealing rings or conical plugs, to achieve sealing. However, these traditional grout stoppers generally have the following shortcomings: 1. Limited sealing effect. Mechanical seals rely on close contact between the grout stopper and the borehole wall. During construction, installation errors, irregular borehole walls, or wear can easily lead to incomplete sealing, failing to effectively prevent grout leakage. 2. Poor adaptability. Traditional grout stoppers have a rigid structure, making it difficult to adapt to the diverse pore and fracture morphologies of rock masses, and unable to effectively seal fine fractures around the borehole opening. 3. Complex construction. Some grout stoppers require on-site adjustment or multiple replacements, increasing construction difficulty and time, and reducing construction efficiency. 4. Difficulty in maintaining grouting pressure. Grout leakage makes it difficult to maintain grouting pressure, affecting the grout filling effect, and consequently affecting the reinforcement effect and the long-term stability of tunnel support. Therefore, existing traditional grout stoppers are unable to meet the dual requirements of sealing effect and construction convenience in mining tunnel construction. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an automatic anti-grout leakage plug and its usage method, which is mainly applicable to underground rock mass grouting and reinforcement projects such as mine tunnels. It can actively seal the orifice and surrounding fissures under complex geological conditions such as high water permeability and developed fissures, ensuring the density of grouting and the continuity of pressure transmission.

[0005] The technical solution of the present invention is as follows: In a first aspect of the present invention, an automatic anti-grout leakage plug is provided, comprising a hollow cylindrical plug body, wherein the cylindrical plug body is divided from top to bottom into a front reaction activation zone, a middle mechanical anchoring zone, and a rear limiting and locking zone; the front reaction activation zone is a cylindrical structure, wherein an annular cavity is provided inside the cylindrical structure, and the annular cavity is filled with sealing particles; the middle mechanical anchoring zone is generally conical, wherein a spiral rib is provided on the outer wall surface of the conical structure; the rear limiting and locking zone is a stepped annular structure, wherein the outer diameter of the rear limiting and locking zone is larger than the outer diameter of the middle mechanical anchoring zone.

[0006] In some embodiments of the present invention, the cylindrical structure with annular cavity is made of a water-soluble membrane, and the bottom of the cylindrical structure is fixed to the top of the central mechanical anchoring zone by adhesion.

[0007] In some embodiments of the present invention, the particle size of the sealing particles is controlled between 0.3 and 2.5 mm, and the composition of the sealing particles includes modified bentonite, superabsorbent polymer, mineral micro powder and cellulose composite material, and quartz sand inert aggregate.

[0008] In some embodiments of the present invention, the height of the spiral ribs on the central mechanical anchoring zone is 2.5 to 4.0 mm, the pitch is 10 to 12 mm, and each turn of the ribs is continuously connected to form an equidistant interlocking thread structure.

[0009] In some embodiments of the present invention, the total number of spiral turns is 4 to 6, and the spiral angle is controlled between 15° and 25°.

[0010] In some embodiments of the present invention, the stepped annular structure is an outwardly expanding flange provided at the tail of the grout stopper, so that the grout stopper forms a limiting stop after reaching a predetermined advancing depth. There are 2 to 5 equidistant reinforcing ribs or flanges above the step, with a height of 1 to 2 mm.

[0011] In some embodiments of the present invention, the outer diameter of the step is 38-45 mm, which is larger than the outer diameter of the stop plug body, thereby forming a shoulder limit at the orifice or sleeve edge, and the thickness of the step is 4-6 mm.

[0012] In some embodiments of the present invention, the central mechanical anchoring area and the rear limiting and locking area are made of the same polymer-based material and are formed into an integral structure by one-time injection molding or mechanical splicing.

[0013] In some embodiments of the present invention, the axial length of the front reaction activation zone is greater than the axial length of the middle mechanical anchoring zone, and the axial length of the middle mechanical anchoring zone is greater than the axial length of the rear limiting and locking zone.

[0014] In a second aspect of the present invention, a method for using an automatic anti-grout leakage plug is provided, comprising the following steps: The grout stopper, as a pre-installed component of the grouting anchor, is inserted into the borehole along the anchor and sleeved on the outside of the anchor body, near the grout outlet. It seals the position of the grouting anchor and the borehole opening. The spiral ribs form an interference fit with the inner wall of the borehole to achieve structural positioning and preliminary sealing. The blocking particles in the pre-reaction activation zone are in a stable and sealed state before they come into contact with the slurry; When grouting begins, the cement-based grout enters the internal channel of the grouting anchor rod. The grout flows out from the grout outlet of the anchor rod and comes into contact with the front reaction activation zone, releasing sealing particles that enter the surrounding area of ​​the hole wall for sealing.

[0015] One or more technical solutions of the present invention have the following beneficial effects: (1) The automatic anti-slurry-running plug provided by the present invention achieves a multi-synergistic sealing mechanism through the setting of a front reaction activation zone, a middle mechanical anchoring zone and a rear limiting and locking zone; wherein, the annular cavity of the front reaction activation zone is pre-filled with sealing particles, which expand and fill the micro-cracks of the orifice under the trigger of slurry, solving the defect that traditional mechanical seals are difficult to adapt to irregular orifice walls; the spiral protrusions of the middle mechanical anchoring zone provide active screw-in anchoring, resisting slippage in high-pressure grouting, while the spiral structure guides the slurry vortex and promotes uniform distribution of particles; the stepped structure of the rear limiting and locking zone forms a physical anti-retraction barrier to prevent the plug body from shrinking due to slurry back pressure.

[0016] (2) The automatic anti-slurry stop plug provided by the present invention is made of a water-soluble membrane in the front reaction activation zone. The water-soluble membrane decomposes rapidly after contacting the slurry, so that the functional plugging particles are released into the surrounding area of ​​the borehole wall for plugging, thereby achieving a rapid response in the plugging process.

[0017] (3) The present invention uses modified bentonite in the plugging particles as the main expansion substrate, which has natural expansion properties and good interfacial compatibility; the super absorbent polymer can improve the reaction rate and expansion ratio, and the dosage should be controlled during use to avoid adverse effects on the bonding strength; the mineral micro powder-cellulose composite material can enhance the adhesion and anti-dispersion properties, and can form a three-dimensional support structure after expansion, thereby improving the overall strength of the plugging.

[0018] (4) By limiting the parameters of the spiral ribs, this invention enables the spiral rib structure to play a "screw-in guide" role during the grouting process. Driven by the flow of grout, it can automatically complete the "tightening" anchoring, enhancing the mechanical engagement force between the grout stop plug and the borehole wall. At the same time, the central mechanical anchoring area is conical, which can significantly improve its pull-out resistance, avoid the back pressure caused by grout, and effectively improve the grouting efficiency and sealing performance.

[0019] (5) This invention is a pre-installed component of a grouting anchor system. No additional operations or modifications to the conventional grouting process are required during construction, ensuring the convenience of construction and the adaptability of the project. It is suitable for application in various geotechnical engineering scenarios such as mine roadways, tunnel initial support, and slope grouting reinforcement. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the automatic anti-grout leakage plug of the present invention; Figure 2This is a cross-sectional schematic diagram of the automatic anti-grout leakage plug of the present invention.

[0021] In the diagram: 1. Front reaction activation zone; 101. Annular cavity; 102. Sealing particles; 103. Anchor bolt channel; 104. Water-soluble membrane; 2. Middle mechanical anchoring zone; 201. Spiral rib; 3. Rear limiting and locking zone; 301. Reinforcing rib; 302. Limiting step. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Example 1 In a typical embodiment of the present invention, an automatic anti-grout leakage plug is provided, such as... Figure 1 and Figure 2 As shown, the device includes a hollow cylindrical grout stopper body, which is divided into a front reaction activation zone 1, a middle mechanical anchoring zone 2, and a rear limiting and locking zone 3 from top to bottom. The front reaction activation zone 1 has a cylindrical structure with an annular cavity 101 inside, which is filled with sealing particles 102. The middle mechanical anchoring zone 2 has a conical structure, and the outer wall of the conical structure is provided with spiral protrusions 201. The rear limiting and locking zone 3 has a stepped annular structure, and the outer diameter of the rear limiting and locking zone 3 is larger than the outer diameter of the middle mechanical anchoring zone 2.

[0024] The automatic anti-slurry leakage plug provided by this invention achieves a multi-layered synergistic sealing mechanism through a front reaction activation zone 1, a middle mechanical anchoring zone 2, and a rear limiting and locking zone 3. Specifically, the annular cavity 101 of the front reaction activation zone 1 is pre-filled with sealing particles 102, which expand and fill the micro-cracks in the orifice when triggered by slurry, solving the problem of traditional mechanical seals being unable to adapt to irregular orifice walls. The spiral ribs 201 of the middle mechanical anchoring zone 2 provide active screw-in anchoring, resisting slippage during high-pressure grouting, while the spiral structure guides the slurry vortex, promoting uniform particle distribution. The stepped structure of the rear limiting and locking zone 3 forms a physical backlash barrier, preventing slurry back pressure from causing the plug to retract.

[0025] In this embodiment, the front reaction activation zone 1 is located at the very front of the grout plug structure and is the key part for realizing the directional release of functional sealing particles 102 and automatic grout leakage prevention. Structurally, it is a hollow annular cavity 101 that covers the outer wall of the hollow anchor rod, forming a cylindrical structure, and is pre-loaded with intelligent sealing particles 102. To meet the requirements of effective release and distribution under complex fracture conditions, the cylindrical structure with the annular cavity 101 is made of a water-soluble membrane 104. The bottom of the cylindrical structure is fixed to the top of the central mechanical anchoring zone 2 by adhesion, and can quickly dissolve and release the particles through hydration reaction after the grouting liquid enters the cavity. Specifically, after the grouting begins, the grout flows into the hollow anchor rod and passes through the cylindrical structure of the annular cavity 101. After the grout comes into contact with the sealing particles 102, the sealing particles 102 expand rapidly within 30 to 90 seconds (volume expansion rate of 500% to 1000%) and form an interlocking cementitious body with the cement-based grout. The expansion process is mainly concentrated in the release cavity and the fracture area directly in front of it, forming the first "active" sealing barrier to prevent excessive loss of grout into the deep rock mass and improve the effective filling rate and pressure retention capacity of the grout.

[0026] In this embodiment, the length of the front reaction activation zone 1 is determined based on the sealing requirements. Under normal working conditions, it can be controlled at 50-100 mm to ensure a compact structure and convenient construction. Under complex geological conditions such as fracture development and severe grout leakage, the length is designed to be 100-200 mm to ensure the effective release of sealing particles 102 and the sealing coverage. The length of the front reaction activation zone 1 is determined proportionally to the sealing requirements and the total length of the grout stopper, and it is recommended to occupy 1 / 2-2 / 3 of the total length of the grout stopper.

[0027] In one specific embodiment of this example, taking a hollow grouting anchor bolt with a diameter of Φ25mm as an example, the front reaction activation zone 1 is designed to be 100mm to 200mm long, and the total length of the grout plug is typically 200 to 350m. This ensures that the sealing particles 102 have sufficient deployment distance and spatial distribution capability in the flow path, adapting to the dimensional inhomogeneity of rock mass fissures or pore structures. Simultaneously, this length range can accommodate the effective storage and release coverage capacity of the sealing particles 102 without affecting the mechanical interlocking performance of the central anchoring zone. The inner diameter of the cylindrical structure is 27.5mm to 28.0mm, tightly fitting with the hollow anchor bolt; the outer diameter is controlled at 32mm to 38mm to ensure good mechanical embedding and flow resistance guiding performance.

[0028] In this embodiment, the particle size of the sealing particles 102 is controlled between 0.3-2.5 mm, and the composition of the sealing particles 102 includes modified bentonite, superabsorbent polymer, mineral micro powder and cellulose composite material, and quartz sand inert aggregate.

[0029] Modified bentonite, as the main expansion substrate, possesses natural expansibility and good interfacial compatibility. Superabsorbent polymers (SAPs) can improve the reaction rate and expansion ratio; however, the dosage must be controlled during use to avoid adversely affecting the bonding strength. Mineral micropowder-cellulose composite materials can enhance adhesion and anti-dispersion properties, and after expansion, they can form a three-dimensional support structure, improving the overall sealing strength.

[0030] Quartz sand inert aggregate: provides skeletal support and enhances the material's resistance to shear, compression and rheology.

[0031] In this embodiment, the sealing material is formulated into granules according to the following weight ratios: 45-50 parts by weight of modified bentonite; 5-10 parts by weight of superabsorbent polymer (SAP); 10-15 parts by weight of mineral micropowder and cellulose composite material; and 10-30 parts by weight of quartz sand inert aggregate. Preferably, 50 parts by weight of modified bentonite serves as the main expansion matrix, providing rapid water absorption and expansion, and basic sealing performance. 10 parts by weight of superabsorbent polymer (SAP) is used to enhance the initial rapid water absorption reaction and increase the volume expansion ratio. 15 parts by weight of mineral micropowder and cellulose composite material forms a three-dimensional skeleton structure during expansion, improving the support and anti-dispersion properties between particles. 25 parts by weight of quartz sand inert aggregate serves as a skeleton filler, improving the shear, compressive, and rheological resistance of the sealing body and preventing the expanded body from being dispersed.

[0032] Furthermore, the modified bentonite can be a sodium-based bentonite product coupled with an organosilane coupling agent, which can improve its water absorption rate and swelling stability. The highly absorbent polymer is preferably partially hydrolyzed sodium polyacrylate, which has a high water absorption ratio and good alkali resistance, making it suitable for cement-based slurry environments. The mixing ratio of the mineral powder and cellulose is 1:1; the mineral powder is preferably metakaolin powder, used to improve the density of the slurry; the cellulose is preferably sodium carboxymethyl cellulose (CMC), which enhances bonding and anti-dispersion properties; the inert quartz sand aggregate is preferably dried natural quartz sand with a particle size range of 0.2–1.0 mm, used to form a particle skeleton and improve the shear and rheological properties of the expanded body.

[0033] The particle size of the plugging particles 102 is controlled between 0.3 mm and 2.5 mm, exhibiting continuous gradation characteristics to improve adaptability to cracks of different sizes and filling efficiency. To enhance the stability of the plugging structure, 10% to 30% by mass of quartz sand particles with a particle size of 0.1 mm to 1.0 mm are mixed into the particle system to construct an interparticle support framework, thereby improving the material's compressive strength and erosion resistance.

[0034] The aforementioned plugging particles 102 have the following characteristics: 1. Expansion and stability: The particles can rapidly expand within 30-90 seconds after contact with free water or cement slurry, with a volume expansion ratio of 500%-1000% of the original volume. After expansion, they form a flexible, structurally stable, and insoluble filler, enabling adaptive embedding and sealing of complex cracks. Quartz sand aggregate plays a role in resisting stress concentration and providing stable support during the expansion process, preventing structural damage or loss of the expanded body.

[0035] 2. Cementitious compatibility: The surface of the sealing particles 102 is modified with hydrophilicity, giving them good interfacial activity and enabling them to form an interlocking structure with cement-based grouting materials. After grouting, they harden together with the grout within 6–12 hours to form a monolithic sealing cementitious body with a compressive strength ≥3MPa, exhibiting excellent sealing and long-lasting anchoring performance.

[0036] 3. It has environmental adaptability. The sealing particles 102 can exist stably in an alkaline grouting environment with pH=10 to 12 without degradation. It has good resistance to water seepage, shear and chemical erosion, and is suitable for complex geological environments with high water content and obvious crack development.

[0037] In this embodiment, the water-soluble membrane 104 is a polyvinyl alcohol water-soluble membrane 104.

[0038] In this embodiment, the central mechanical anchoring zone 2 is the main sealing and anchoring function bearing area for the grout plug. Its structure is an annular sleeve-type outer shell with continuous spiral ribs on the outer wall, evenly distributed along the anchor rod axis, resembling a screw thread. This section achieves effective embedding and grout stopping of the grout plug through mechanical engagement and interfacial friction with the grouting hole wall or the inner wall of the casing. Specifically, under grouting pressure, the grout continuously enters from the front end. The spiral ribs 201 structure provide high mechanical engagement to prevent slippage of the grout plug; on the other hand, they form small vortex zones locally, which help to agitate the grout and ensure uniform particle distribution, enhancing the grout stopping effect.

[0039] In one specific embodiment of this invention, taking a hollow grouting anchor bolt with a diameter of Φ25mm as an example, the axial length of the central mechanical anchoring zone 2 is 30mm to 50mm to ensure sufficient anchoring force and shear resistance during on-site grouting operations. This length setting can effectively improve the pressure-bearing stability of the grout plug in a high-pressure grouting environment, preventing axial slippage or rotational detachment under grouting pressure, and is particularly suitable for grouting operations in weak surrounding rock or fractured strata.

[0040] The structural parameters of the spiral rib 201 are optimized based on the diameter of the matching anchor rod and the grouting construction conditions. The outer diameter of the base material is 26.5mm to 27.0mm, the height of the spiral rib 201 is 2.5mm to 4.0mm, and the pitch is 10mm to 12mm. Each turn of the rib is continuously connected to form an equidistant interlocking thread structure, with a total of 4 to 6 spiral turns. The helix angle is controlled between 15° and 25° to balance the pushing resistance and the anti-backward ability.

[0041] The spiral rib 201 structure acts as a "screw-in guide" during grouting, automatically completing a "tightening" anchorage under the drive of grout flow, enhancing the mechanical engagement force between the grout stop plug and the borehole wall. Simultaneously, the reverse angled structure significantly improves its pull-out resistance, preventing backflow caused by grout back pressure, effectively enhancing grout stopping efficiency and sealing performance.

[0042] In terms of material selection, high-strength engineering plastics (such as glass fiber reinforced polypropylene, polyamide PA66, or HDPE) are chosen, which have good hydrolysis resistance, pressure resistance, and grout compatibility. To further enhance anchoring performance, the outer surface can be provided with micro-rough texture or additional reinforcing ribs 301 to improve interfacial shear strength.

[0043] In this embodiment, the rear limiting and locking zone 3 is located at the very end of the grout stop plug, serving as the final line of defense for the axial anti-retraction structure. It takes the form of a stepped annular structure, with an outwardly expanding flange at the tail of the grout stop plug. This allows the grout stop plug to form a limiting and anti-retraction mechanism after reaching the predetermined advancement depth, preventing it from retracting or slipping due to reverse pressure during grouting. Above the step, there are 2-5 rings of equidistant reinforcing ribs 301 or flanges, 3mm wide and 1-2mm high, to improve the frictional contact strength of the anchoring section. Specifically, after grouting is completed, the grout solidifies behind the limiting step 302, forming a secondary anti-retraction platform, achieving an integrated "limiting-anti-retraction-sealing" effect for the grout stop plug, ensuring that the grout stop plug is stably and reliably positioned at the predetermined location throughout the grouting process.

[0044] In one specific embodiment of this example, taking a hollow grouting anchor bolt with a diameter of Φ25mm as an example, the axial length of the rear limiting and locking zone 3 is 8mm to 10mm, and the outer diameter of the step is designed to be 38mm to 45mm, significantly larger than the outer diameter of the grout stop plug, thereby forming a "shoulder limiting" at the orifice or casing edge; the step thickness is 4mm to 6mm, forming an anti-reverse effect. The outer edge of the step can be designed as a blunt edge to enhance the limiting effect and adapt to the irregularity of the inner wall of the casing.

[0045] Furthermore, the central mechanical anchoring zone 2 and the rear limiting and locking zone 3 are made of the same polymer-based material and are formed into an integral structure through one-time injection molding or mechanical splicing, ensuring good mechanical connection and sealing continuity between them and the main body. If necessary, a back pressure channel or pressure relief hole can be provided to prevent air blockage or impact damage during grouting.

[0046] In this embodiment, the axial length of the front reactive activation zone 1 is greater than the axial length of the middle mechanical anchoring zone 2, and the axial length of the middle mechanical anchoring zone 2 is greater than the axial length of the rear limiting and locking zone 3. This ensures that the sealing particles 102 in the front reactive activation zone 1 have sufficient diffusion space, the anchoring section in the middle mechanical anchoring zone 2 provides the dominant anti-slip force, and the rear limiting and locking zone 3 minimizes the structural size of the rear limiting area.

[0047] The working process of the automatic anti-grout leakage plug provided in this embodiment is as follows: 1. Initial assembly and installation positioning The grout stopper, as a pre-installed component of the anchor bolt system, is inserted into the borehole along the anchor bolt and fitted onto the outside of the anchor bolt body, near the grout outlet. The grout stopper achieves structural positioning and initial sealing by interfering with the inner wall of the borehole through spiral ribs 201 on its outer wall. A pre-reaction activation zone 1 is formed at the front end, filled with functional sealing particles 102. These particles 102 are coated with a water-soluble membrane 104 and remain in a stable, sealed state before contact with the grout.

[0048] 2. Grouting Initiation and Trigger Response When grouting begins, cement-based grout is injected into the hole through the internal channel of the anchor bolt. The grout flows out from the grout outlet of the anchor bolt and is first intercepted by the grout stop plug structure. At the same time, the grout comes into contact with the front reaction activation zone 1, and the encapsulated water-soluble membrane 104 begins to decompose upon contact with the water-containing grout, releasing the functional sealing particles 102 into the area surrounding the hole wall.

[0049] 3. Hydration expansion and embedding of sealing particles 102 The plugging particles 102 rapidly absorb water and expand in a hydrated environment, with a volume expansion rate of up to 1000% within 30 to 90 seconds. The expanded particles possess excellent flexibility and deformability, enabling them to effectively embed into micro-cracks and fissures in the pore wall, achieving adaptive plugging of multi-scale pores, while simultaneously forming local backfill and blocking the slurry backflow channel.

[0050] 4. Interface bonding and secondary grouting The surface of the sealing particles 102 is modified with hydrophilicity, enabling them to participate in the hydration and bonding reaction with cement grout, forming a structurally continuous interlocking cementitious body within 6–12 hours. This cementitious body has a compressive strength of not less than 3 MPa and possesses excellent compressive strength, shear strength, and sealing performance, further enhancing the stability and overall density of the grout-stopping area.

[0051] 5. The synergistic effect of multiple sealing mechanisms is achieved. The grout-stopping plug achieves a multiple grout-stopping mechanism: structural sealing, material response, and interfacial bonding. Structural sealing involves primary blocking through the interference fit between the plug body and the borehole wall; material response utilizes the adaptive expansion and embedding of the plugging particles 102; and interfacial bonding provides secondary stabilization and long-term sealing. These three mechanisms work synergistically to effectively inhibit grout leakage, improve grouting efficiency, and enhance anchoring quality.

[0052] The automatic anti-grout leakage plug provided in this embodiment achieves a dual effect of mechanical sealing and material adaptive expansion sealing through improvements in the plug structure and the inclusion of sealing particles 102. During grouting, the plug body completes primary sealing and positioning, while the front reaction activation zone 1 releases intelligent sealing particles 102. These particles hydrate and expand upon contact with water or grouting fluid, dynamically filling the borehole and fissures. This meets the sealing requirements for different anchor bolt diameters and fissure structures, significantly improving the grouting reinforcement effect and pressure stability. No additional construction steps are required; functional upgrades can be achieved simply by replacing the plug, demonstrating good engineering feasibility.

[0053] Example 2 In a typical embodiment of the present invention, a method for using an automatic anti-grout leakage plug is provided, comprising the following steps: The grout stopper, as a pre-installed component of the grouting anchor, is inserted into the borehole along the anchor and sleeved on the outside of the anchor body, near the grout outlet. It seals the position of the grouting anchor and the borehole opening. The spiral protrusions form an interference fit with the inner wall of the borehole to achieve structural positioning and preliminary sealing. The blocking particles in the pre-reaction activation zone are in a stable and sealed state before they come into contact with the slurry; When grouting begins, the cement-based grout enters the internal channel of the grouting anchor rod. The grout flows out from the grout outlet of the anchor rod and comes into contact with the front reaction activation zone, releasing sealing particles that enter the surrounding area of ​​the hole wall for sealing.

[0054] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An automatic anti-grout leakage stopper, characterized in that, The device includes a hollow cylindrical grout stopper body, which is divided into a front reaction activation zone, a middle mechanical anchoring zone, and a rear limiting and locking zone from top to bottom. The front reaction activation zone has a cylindrical structure with an annular cavity inside, which is filled with sealing particles. The middle mechanical anchoring zone has a conical structure, and the outer wall of the conical structure is provided with spiral ribs. The rear limiting and locking zone has a stepped annular structure, and the outer diameter of the rear limiting and locking zone is larger than the outer diameter of the middle mechanical anchoring zone.

2. The automatic anti-grout leakage stopper as described in claim 1, characterized in that, The cylindrical structure with an annular cavity is made of a water-soluble membrane, and the bottom of the cylindrical structure is fixed to the top of the central mechanical anchoring zone by adhesion.

3. The automatic anti-grout leakage plug as described in claim 1, characterized in that, The particle size of the sealing particles is controlled between 0.3 and 2.5 mm. The components of the sealing particles include modified bentonite, superabsorbent polymer, mineral micro powder and cellulose composite material, and quartz sand inert aggregate.

4. The automatic anti-grout leakage stopper as described in claim 1, characterized in that, The height of the spiral protrusions in the central mechanical anchoring zone is 2.5 to 4.0 mm, and the pitch is 10 to 12 mm. Each turn of the protrusions is continuously connected to form an equidistant interlocking thread structure.

5. The automatic anti-grout leakage stopper as described in claim 4, characterized in that, The total number of spiral turns is 4 to 6, and the spiral angle is controlled between 15° and 25°.

6. The automatic anti-grout leakage plug as described in claim 1, characterized in that, The stepped annular structure is an outwardly expanding flange provided at the tail of the grout stopper, which causes the grout stopper to form a limiting stop after reaching the predetermined advancement depth. There are 2 to 5 equidistant reinforcing ribs or flanges above the step, with a height of 1 to 2 mm.

7. The automatic anti-grout leakage plug as described in claim 1, characterized in that, The outer diameter of the step is 38-45mm, which is larger than the outer diameter of the stop plug body, thus forming a shoulder limit at the orifice or the edge of the casing. The thickness of the step is 4-6mm.

8. The automatic anti-grout leakage plug as described in claim 1, characterized in that, The central mechanical anchoring area and the rear limiting and locking area are made of the same polymer-based material and are formed into an integral structure through one-time injection molding or mechanical splicing.

9. The automatic anti-grout leakage stopper as described in claim 1, characterized in that, The axial length of the front reaction activation zone is greater than the axial length of the middle mechanical anchoring zone, and the axial length of the middle mechanical anchoring zone is greater than the axial length of the rear limiting and locking zone.

10. A method of using the automatic anti-grout leakage plug as described in any one of claims 1-9, characterized in that, Includes the following steps: The grout stopper, as a pre-installed component of the grouting anchor, is inserted into the borehole along the anchor and sleeved on the outside of the anchor body, near the grout outlet. It seals the position of the grouting anchor and the borehole opening. The spiral protrusions form an interference fit with the inner wall of the borehole to achieve structural positioning and preliminary sealing. The blocking particles in the pre-reaction activation zone are in a stable and sealed state before they come into contact with the slurry; When grouting begins, the cement-based grout enters the internal channel of the grouting anchor rod. The grout flows out from the grout outlet of the anchor rod and comes into contact with the front reaction activation zone, releasing sealing particles that enter the surrounding area of ​​the hole wall for sealing.

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