Full-length bonding anchoring system using magnetic expansion slurry and construction method

Abstract

The invention discloses a full-length bonding and anchoring system utilizing magnetic expansion slurry. The full-length bonding and anchoring system comprises a magnetic adsorption device, an anchor cable, a base plate, the magnetic slurry and an expansion agent. The magnetic adsorption device comprises a magnetic ring, the anchor cable is sleeved with the magnetic ring, and the magnetic ring is used for enabling the magnetic slurry to be tightly bonded with the anchor cable and the magnetic ring through magnetic force and discharging air and water in the anchoring hole; an expanding agent is doped into the magnetic slurry, and the doping amount of the expanding agent is 2-5% of the weight of the cement, so that the slurry is tightly attached to the wall of the anchoring hole after being solidified. Through the synergistic effect of the magnetic ring and the magnetic slurry, full-length bonding of the anchor cable and the hole wall is achieved, the pulling resistance and integrity are remarkably improved, and the problems that traditional anchoring loses efficacy locally, and the non-deformability is weak are solved.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical construction, and in particular to a full-length bonding anchoring system using magnetic expansion slurry and a construction method. Background Art

[0002] With the development of infrastructure construction in my country, anchoring technology has been increasingly used in rock and soil reinforcement: 1. Comparative document CN119352507A discloses an anchoring section self-expanding locking structure and an anchor-type rock stress and strain monitoring method, including an anchoring section self-expanding locking anchor cable, the anchoring section self-expanding locking anchor cable includes a self-expanding anchor slurry, a magnetic anchor cable, an anchor-type rock stress sensor, a combined strain sensor, and a test and analysis system; the magnetic anchor cable is anchored inside the anchor hole of the slope by the self-expanding anchor slurry; the anchor-type rock stress sensor is arranged at the hole of the anchor hole and is used to detect the stress of the magnetic anchor cable; the combined strain sensor is arranged on the inner wall of the anchor hole; the anchor-type rock stress sensor and the combined strain sensor are connected to the test and analysis system through a signal line. The locking structure of the present invention is based on the fact that the anchoring section is a key factor in determining the performance of the anchor cable. By increasing the pull-out resistance of the anchor cable, the reinforcement effect of the anchor cable on the slope can be improved on the one hand, and on the other hand, it provides a guarantee for the stability of long-term real-time monitoring of rock stress and strain. However, this application only provides local reinforcement for the anchoring section, and the free section of the anchor cable is still at risk of sliding, and full-length bonding is not achieved, which cannot meet the overall stability requirements under complex geological conditions.

[0003] 2. Comparative document CN118223478A discloses an expansion anchor and construction method integrating ecological restoration, including an ecological anchor rod for anchoring on a slope, the ecological anchor rod including a hollow rod body and a drill bit, the drill bit being installed at the end of the hollow rod body; the hollow rod body including a rod shell, a circular hole being reserved on the rod shell; a magnetic coating is coated on the outer wall of the rod shell at the anchoring end, and an anti-corrosion coating is coated on the inner wall of the rod shell; the rod shell is connected with a grouting pipe, and magnetic anchor slurry is injected into the interior of the rod shell for end anchoring; a water collection area is formed at the lower part of the hollow rod body after grouting is completed; an annular nutrient trough is provided at the top end of the hollow rod body, the interior of the annular nutrient trough is used to store nutrient solution for plant growth, and a trumpet-shaped culture dish is positioned and installed on the top of the annular nutrient trough; planting soil is contained in the trumpet-shaped culture dish, and vines are planted; a wire mesh is provided at the bottom end of the trumpet-shaped culture dish, and a retractable hanging net is installed between the trumpet-shaped culture dish and the surface of the slope. However, the application focuses on the ecological restoration function. The anchoring structure is a hollow rod, and the expansion effect is limited to the anchoring end. The problem of full-length bonding is not solved, and the synergistic mechanism of the magnetic ring and magnetic slurry is not involved.

[0004] Therefore, a full-length bonding anchoring system and a construction method using magnetic expansion slurry are proposed to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a full-length bonding anchoring system and construction method using magnetic expansion slurry. Through the synergistic effect of the magnetic ring and the magnetic slurry, the full-length bonding of the anchor cable and the hole wall is achieved, the pull-out resistance and integrity are significantly improved, so as to solve the problems raised in the background technology.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a full-length bonding anchoring system using magnetic expansion slurry, including a magnetic adsorption device, an anchor cable, a pad, magnetic slurry and an expansion agent; the magnetic adsorption device includes a magnetic ring, which is sleeved on the anchor cable and is used to tightly bond the magnetic slurry to the anchor cable and the magnetic ring through magnetic force, and to discharge air and water in the anchor hole; the expansion agent is added to the magnetic slurry, and the amount of the expansion agent is 2%-5% of the weight of the cement, so that the slurry fits tightly to the wall of the anchor hole after solidification.

[0007] Preferably, the magnetic ring is made of a high magnetic permeability material, selected from ferrite, and the inner diameter of the magnetic ring is adapted to the outer diameter of the anchor cable. After being inserted, the magnetic ring fits tightly with the outer wall of the anchor cable to reduce magnetic leakage.

[0008] Preferably, the magnetic ring is cast into a mold by magnetic powder and epoxy resin, and is directly sleeved on the anchor cable.

[0009] Preferably, the composition of the magnetic slurry is: concrete water-cement ratio of 0.35-0.5, magnetic powder content of 20%-50%, anti-dispersant 2%-5%, water reducer 1%-4%, epoxy resin 1.5%-5%, flocculant 5%-8%.

[0010] Preferably, the expansion agent generates expansion pressure when the slurry solidifies, squeezing the slurry into the tiny pores of the anchor hole wall, thereby increasing the contact area and friction.

[0011] Preferably, the anchor cable is a steel strand made of multiple strands of high-strength steel wires, and magnetic rings are installed on potential sliding surfaces, areas with dense joints and fissures, and geologically weak locations.

[0012] Preferably, the backing plate is provided with a recessed hole corresponding to the magnetic ring for positioning the magnetic ring.

[0013] Preferably, the anchor cable forms an annular anchoring structure at the interface of the rock and soil through the anchor head connector to disperse the tension and enhance the friction.

[0014] In addition, the present invention also discloses a construction method of a full-length bonding anchoring system using magnetic expansion slurry, comprising the following steps: Step 1: Drill and clean the hole. Use a down-the-hole drill with an air compressor to construct the anchor hole according to relevant design requirements, and use high-pressure air to clean the hole to remove the residue in the hole; Step 2: Sleeve the magnetic ring on the anchor cable and perform magnetic treatment; Step 3: Insert the anchor cable into the anchor hole in the center; Step 4: grouting and controlling the grouting pressure and speed so that the magnetic slurry fills the anchor hole; Step 5: After maintenance, connect the anchor cables through connectors to form a whole and clean up the site.

[0015] Furthermore, during grouting, the outlet of the grouting pipe is close to the bottom of the hole and is gradually raised as the slurry is injected, keeping the grouting pipe buried in the slurry to ensure continuous filling.

[0016] The present invention has the following beneficial effects: 1. The present invention adds magnetic materials, such as ferroferric oxide, to the slurry. The purpose is that: the rock anchor point to be anchored may be in a wading slope. If the slurry is directly injected, the slurry will flow away with the water flow and will not play a bonding role. However, the magnetic slurry can drain water under the action of magnetic force and can effectively play its bonding role. 2. The present invention innovatively puts a magnetic ring on the anchor rod, the purpose of which is that the magnetic field generated by the magnetic ring can interact with the magnetic expansion slurry, so that the slurry is more evenly distributed and solidified under the influence of the magnetic field. At the same time, the magnetic field may also produce a certain magnetization effect on the particles of the surrounding rock and soil, enhance the mechanical properties of the rock and soil, improve the anchoring effect, and in some special engineering environments, such as the presence of groundwater, mountain seepage or other fluids, the magnetic field can help adsorb and fix the magnetic particles, reduce the loss and diffusion of the slurry, and ensure the reliability of the anchoring effect; 3. The present invention innovatively adds an expansion agent to the slurry, the purpose of which is that the presence of the expansion agent makes the slurry fit closely with the anchor hole wall after solidification, and the magnetic expansion slurry can tightly bond the anchor cable with the surrounding medium to form a full-length bonding anchoring effect, so that the anchoring system and the rock and soil and other media become a whole, and each section in contact with the rock and soil is strongly anchored, which greatly improves the integrity and stability of the rock and soil, enhances the anchoring force, and effectively controls the deformation and displacement of the rock and soil; 4. The present invention forms a full-length bonded anchoring system between the rock mass and the anchor cable through magnetic expansion slurry, and its purpose is that: the anchoring system has good adaptability to different geological conditions. Whether it is various types of rock and soil such as rock, sand, clay, or the presence of geological defects such as cracks and pores, the magnetic expansion slurry can fill the gaps therein to form an effective anchoring. Compared with the traditional anchoring method, it has stronger adaptability to complex geological conditions and can better meet the needs of various projects; 5. The present invention forms a full-length bonded anchoring system between the rock mass and the anchor cable through magnetic expansion slurry. The purpose is that after anchoring, if the anchor head or anchoring section is damaged due to explosion, earthquake, etc., the system is firmly embedded in the rock and soil, and has a high degree of safety. If the anchor head is damaged, the middle parts can still play the role of the anchor head, so that the brittle failure of the traditional system is converted into the ductile failure of the system of the present invention. 6. The anchoring system of the present invention also has the ability to quickly repair and recover. When the anchoring system is partially damaged, the magnetic expansion slurry has good fluidity and filling properties, and the damaged part can be repaired by re-grouting, so that the anchor cable and the surrounding rock and soil can be restored to a good bonding state, and the bearing capacity of the anchoring system can be quickly restored, reducing the project delay and economic losses caused by the repair work; 7. Under the same external conditions and under the action of the ultimate pull-out load, the supporting capacity of the self-expanding anchoring system of the anchoring equipment of the present invention is 6.34 times higher than that of ordinary anchor rods. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of rock anchoring of the present invention; Figure 2 It is a force diagram of the anchoring system of the present invention; Figure 3 It is a schematic diagram of the anchor cable part of the present invention; Figure 4 The pull-out load-anchor displacement curve obtained from the experiment of the present invention; In the figure: a magnetic adsorption device 1, comprising a magnetic ring 11, an anchor cable 12, a pad 13, a magnetic slurry 14, an expansion agent 15, a connector 16, a rock mass 2, and a rock wall 3. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: See also Figures 1 to 4In Example 1, a full-length bonding anchoring system using magnetic expansion slurry includes a magnetic adsorption device 1, an anchor cable 12, a pad 13, a magnetic slurry 14 and an expansion agent 15; the magnetic adsorption device 1 includes a magnetic ring 11, which is sleeved on the anchor cable 12 and is used to tightly bond the magnetic slurry 14 to the anchor cable 12 and the magnetic ring 11 through magnetic force, and to discharge air and water in the anchor hole; the expansion agent 15 is added to the magnetic slurry 14, and the amount of the expansion agent 15 is 2%-5% of the weight of the cement, so that the slurry fits tightly to the wall of the anchor hole after solidification. The magnetic ring 11 guides the directional distribution of the magnetic slurry through the action of the magnetic field to prevent the slurry from being washed away by water flow. The expansion agent 15 undergoes a chemical reaction when the slurry solidifies, and the volume expansion generates pressure, forcing the slurry to penetrate into the cracks in the hole wall. Through this design, a full-length bonded anchoring system is formed to avoid the defect of traditional anchor cables that only the anchoring section is stressed. The magnetic field assists in removing air and water and improving the density of the slurry. The expansion agent 15 enhances the fit between the slurry and the hole wall, and the pull-out resistance is increased by 6.34 times.

[0019] Preferably, the magnetic ring 11 is made of a high magnetic permeability material, and ferrite or rare earth permanent magnet material can be selected. The inner diameter of the magnetic ring is adapted to the outer diameter of the anchor cable, and after being inserted, it fits tightly with the outer wall of the anchor cable to reduce magnetic leakage. Ferrites are low in cost and have good stability; rare earth permanent magnet materials have strong magnetism, such as neodymium iron boron, which is suitable for high-demand scenarios. The difference between the inner diameter of the magnetic ring 11 and the outer diameter of the anchor cable 12 is controlled within 0.5-1mm to ensure that there is no looseness after insertion; in this solution, high magnetic permeability materials are used to ensure the magnetic field strength, reduce magnetic leakage loss, and improve the adsorption efficiency of the slurry and the magnetic ring. The magnetic field dispersion is avoided through a close fitting design, and the shear resistance of the local anchoring area is enhanced.

[0020] Preferably, the magnetic ring 11 is cast into a mold by magnetic powder and epoxy resin, and is directly mounted on the anchor cable 12. The magnetic powder and epoxy resin are mixed in proportion, and the magnetic powder can be ferroferric oxide, which is cast into a ring mold and solidified to form a magnetic ring. The mold can be prefabricated into a split type, which is convenient for rapid installation on site; this solution is flexibly adapted to anchor cables of different diameters, reducing customization costs, and epoxy resin provides structural strength to prevent magnetic powder from falling off, thereby extending the service life of the magnetic ring.

[0021] Preferably, the composition of the magnetic slurry 14 is: concrete water-cement ratio 0.35-0.5, magnetic powder content 20%-50%, anti-dispersant 2%-5%, water reducer 1%-4%, epoxy resin 1.5%-5%, flocculant 5%-8%. The magnetic powder is selected with a particle size of ≤50μm to provide magnetism, the anti-dispersant prevents the slurry from segregating, and cellulose ether can be selected, the epoxy resin enhances the slurry adhesion, and E51 type epoxy resin can be selected, the flocculant accelerates the slurry solidification, and polyacrylamide can be selected, and the water reducer can be a polycarboxylic acid water reducer, such as Sika 530P, which is suitable for high-strength concrete; the low water-cement ratio in this solution ensures high strength and low shrinkage of the slurry; the magnetic powder content optimizes the range of action of the magnetic field, and the comprehensive additives improve the slurry's anti-scouring, fluidity and durability, which is suitable for wading or complex geological environments.

[0022] Preferably, the expansion agent 15 generates expansion pressure when the slurry solidifies, squeezes the slurry into the tiny pores of the anchor hole wall, and increases the contact area and friction. The expansion agent is made of calcium sulfoaluminate or magnesium oxide materials. When the dosage is 2%-5%, the expansion rate is controllable, and the expansion pressure can reach 0.5-1.2MPa, driving the slurry to penetrate into the micro cracks of the hole wall. This solution can significantly improve the mechanical bite force and increase the contact area by 30%-50%; avoid the formation of gaps between the slurry and the hole wall, and prevent the anchor system from failing due to local debonding.

[0023] Preferably, the anchor cable 12 is a steel strand made of multiple strands of high-strength steel wire, and the magnetic ring 11 is installed on the potential sliding surface, joint and fissure intensive area or geological weak part. The tensile strength of the steel strand is ≥1860MPa, the diameter is 15-30mm, the surface is galvanized for corrosion protection, the spacing of the magnetic rings 11 is set according to the geological survey results, and the weak area is densely packed to 0.5-1m. In this embodiment, the high tensile strength of the steel strand adapts to the huge tension of the rock mass; the dense installation of the magnetic ring enhances the local anchoring strength to prevent stress concentration from causing collapse.

[0024] Preferably, the pad 13 is provided with a concave hole corresponding to the magnetic ring 11 for positioning the magnetic ring 11. In the embodiment, the depth of the concave hole is 1 / 2-2 / 3 of the height of the magnetic ring, and the diameter matches the outer diameter of the magnetic ring with a tolerance of ±0.2mm. The pad 13 is made of Q355 steel plate with a thickness of 10-20mm, and the surface is hot-dip galvanized for corrosion protection. The concave hole accurately positions the magnetic ring to avoid uneven magnetic field distribution caused by construction offset. The pad 13 provides support for the end of the anchor cable 12, disperses local stress, and prevents the anchor cable 12 from slipping.

[0025] Preferably, the anchor cable 12 forms an annular anchoring structure at the interface of the rock and soil through the anchor head connector 16 to disperse the tension and enhance the friction. In the embodiment, the connector 16 is a sleeve type or a clip type, and the end of the anchor cable is tied around the ring and then fixed. The diameter of the annular structure is ≥3 times the diameter of the anchor cable, and the length of the ring is ≥200mm. The annular structure disperses the tension to a larger area, and the contact area is increased by 40%-60%, avoiding the failure of the single point of the anchor head, and improving the redundancy and ductile failure capacity of the anchor system.

[0026] Example 2 discloses a construction method of a full-length bonding anchoring system using a magnetic expansion slurry, comprising the following steps: Step 1: Drill and clean the hole. Use a down-the-hole drill with an air compressor to construct the anchor hole according to relevant design requirements, and use high-pressure air to clean the hole to remove the residue in the hole; Step 2: Sleeve the magnetic ring 11 on the anchor cable 12 and perform magnetic treatment; Step 3: Insert the anchor cable 12 into the anchor hole in the center; Step 4: grouting and controlling the grouting pressure and speed so that the magnetic slurry 14 fills the anchor hole; Step 5: After curing, the anchor cable 12 is connected through the connector 16 to form a whole and the site is cleaned. In the embodiment, the hole is drilled using a down-the-hole drill, the hole diameter is 20-30 mm larger than the anchor cable, the hole cleaning time is ≤30 minutes, the grouting pressure is controlled at 0.3-0.8 MPa, the grouting speed is ≤5 L / min, and the grouting is done twice to ensure fullness. The standardized construction process reduces human errors and ensures the quality of full-length bonding; grouting is done in stages to avoid rupture of the hole wall, and the slurry is continuously filled to improve the density of the anchor.

[0027] Furthermore, during grouting, the outlet of the grouting pipe is close to the bottom of the hole and gradually lifted up with the slurry injection, keeping the grouting pipe buried in the slurry to ensure continuous filling. The distance between the grouting pipe and the bottom of the hole is ≤100mm, and the lifting speed is synchronized with the grouting speed, for example, it is lifted by 50cm for every 50cm of slurry injected. Grouting from bottom to top avoids air retention in the hole, reduces bubble defects, and continuously buries the pipe to prevent slurry stratification, ensuring the uniformity of the anchoring system.

[0028] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A full-length bonding anchoring system using magnetic expansion slurry, characterized in that: It includes a magnetic adsorption device, an anchor cable, a pad, a magnetic slurry and an expansion agent; the magnetic adsorption device includes a magnetic ring, which is sleeved on the anchor cable and is used to tightly bond the magnetic slurry to the anchor cable and the magnetic ring through magnetic force, and to discharge air and water in the anchor hole; an expansion agent is added to the magnetic slurry, and the amount of the expansion agent is 2%-5% of the weight of the cement, so that the slurry can fit tightly to the wall of the anchor hole after solidification.

2. A full-length bonding anchoring system using magnetic expansion slurry according to claim 1, characterized in that: The magnetic ring is made of a high magnetic permeability material, selected from ferrite, and the inner diameter of the magnetic ring is adapted to the outer diameter of the anchor cable. After being inserted, it fits tightly with the outer wall of the anchor cable to reduce magnetic leakage.

3. A full-length bonding anchoring system using magnetic expansion slurry according to claim 1, characterized in that: The magnetic ring is cast into a mold by magnetic powder and epoxy resin and is directly mounted on the anchor cable.

4. A full-length bonding anchoring system using magnetic expansion slurry according to claim 1, characterized in that: The composition of magnetic slurry is: concrete water-cement ratio 0.35-0.5, magnetic powder content 20%-50%, anti-dispersant 2%-5%, water reducer 1%-4%, epoxy resin 1.5%-5%, flocculant 5%-8%.

5. A full-length bonding anchoring system using magnetic expansion slurry according to claim 1, characterized in that: The expansion agent generates expansion pressure when the slurry solidifies, squeezing the slurry into the tiny pores in the anchor hole wall, increasing the contact area and friction.

6. A full-length bonding anchoring system using magnetic expansion slurry according to claim 1, characterized in that: The anchor cable is a steel strand made of multiple strands of high-strength steel wire, and magnetic rings are installed on potential sliding surfaces, areas with dense joints and fissures, and geologically weak locations.

7. A full-length bonding anchoring system using magnetic expansion slurry according to claim 1, characterized in that: The backing plate is provided with a concave hole corresponding to the magnetic ring for positioning the magnetic ring.

8. A full-length bonding anchoring system using magnetic expansion slurry according to claim 1, characterized in that: The anchor cable forms an annular anchoring structure at the interface of the rock and soil through the anchor head connector to disperse the tension and enhance the friction.

9. A construction method of a full-length bonding anchoring system using a magnetic expansion slurry according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Drill and clean the hole. Use a down-the-hole drill with an air compressor to construct the anchor hole according to relevant design requirements, and use high-pressure air to clean the hole to remove the residue in the hole; Step 2: Sleeve the magnetic ring on the anchor cable and perform magnetic treatment; Step 3: Insert the anchor cable into the anchor hole in the center; Step 4: grouting and controlling the grouting pressure and speed so that the magnetic slurry fills the anchor hole; Step 5: After maintenance, connect the anchor cables through connectors to form a whole and clean up the site.

10. A construction method of a full-length bonding anchoring system using magnetic expansion slurry according to claim 9, characterized in that: During grouting, the outlet of the grouting pipe is close to the bottom of the hole and gradually rises as the slurry is injected, keeping the grouting pipe buried in the slurry to ensure continuous filling.

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