Anchoring system and method for large diameter fiber composite poles

Abstract

The application discloses an anchoring system and method for a large-diameter fiber composite rod, and relates to the technical field of composite material anchoring, which comprises a large-diameter fiber rod, a stepped inner anchoring cylinder sleeved on an anchoring section of the large-diameter fiber rod, an outer locking sleeve threadedly connected to a small end of an inner diameter of the stepped inner anchoring cylinder, and a centering ring embedded between a large end of the inner diameter of the stepped inner anchoring cylinder and the large-diameter fiber rod; six evenly-distributed slits are formed in an end of the anchoring section of the large-diameter fiber rod along an axial direction, forming a six-petal bifurcated structure, a six-petal gradient hard alloy wedge block is embedded in the center of the six-petal bifurcated structure, and each side edge of the six-petal gradient hard alloy wedge block is correspondingly inserted between two adjacent petals of the large-diameter fiber rod. Through the synergistic innovation of structure, material and process, the application effectively solves the technical problems of stress concentration, low anchoring efficiency, easy damage of the rod body and poor environmental adaptability in the anchoring of the large-diameter fiber composite rod.

Description

Technical Field

[0001] This invention relates to the field of composite material anchoring technology, specifically to an anchoring system and method for large-diameter fiber composite rods. Background Technology

[0002] Large-diameter fiber composites, with their superior specific strength, ultra-high specific modulus, excellent corrosion resistance, and fatigue resistance, have become core materials in various high-end fields. Compared to ordinary fiber-reinforced resin composites, large-diameter fiber composite rods have a denser molecular arrangement and more regular fiber orientation, exhibiting extremely high rigidity under axial loads. However, they also have inherent drawbacks: their transverse strength is only 1 / 10 to 1 / 5 of their axial strength, they are significantly brittle, extremely sensitive to local stress concentration, and have high surface inertia, resulting in poor interfacial compatibility with materials such as metals and resins. These characteristics mean that traditional FRP anchoring technology cannot be directly adapted, necessitating the development of specific anchoring systems.

[0003] Currently, the anchoring methods for composite material rods in engineering mainly follow the four technical routes of ordinary FRP, namely plate anchors, wedge anchors, cone plug anchors and bonded anchors. However, these methods have significant limitations when applied to large-diameter fiber composite rods.

[0004] Plate anchors mainly consist of upper and lower clamping plates, anchor bolts, and bonding resin. Their core design principle is to transfer loads through the synergistic effect of bolt tightening and resin bonding. For ordinary FRP plates, this technology can achieve uniform tensile force transfer. However, when applied to large-diameter fiber rods, the stress concentration problem at the bolt holes is drastically amplified. The brittleness of large-diameter fibers prevents them from dispersing stress through plastic deformation, leading to micro-cracks that easily form and rapidly propagate at the bolt hole edges, causing the rod to fracture at loads far below the design limit. Simultaneously, the bonding strength between ordinary bonding resin and the surface of large-diameter fibers is insufficient. Long-term service creep and aging of the resin further weaken the interfacial properties, making it prone to debonding-slip failure under vibration loads, thus reducing anchoring efficiency.

[0005] The wedge-type anchor consists of an inner conical hole anchor cup, inner wedges, and a soft metal sleeve. It provides anchoring force through the extrusion friction between the wedges and the rod body, and has the advantages of simple installation and high anchoring efficiency. However, the notch effect of this technology is extremely destructive to large-diameter fiber rods. During tensioning, the shear stress at the small end of the wedge can be 3 to 4 times that at the large end, making it very easy for local shear failure to occur at the small end of the wedge. In addition, the point contact characteristics between the wedge and the rod body lead to uneven pressure distribution in the contact area. Although the soft metal sleeve can buffer local stress, it cannot change the brittle characteristics of large-diameter fiber failure. Furthermore, under repeated loading, relative slippage is prone to occur between the wedge and the rod body, resulting in poor fatigue resistance and usually failing to meet the fatigue life requirement of more than 100,000 cycles.

[0006] Conical plug anchors achieve anchoring based on the wedging action of a conical anchor cup and a conical plug. While their anchoring performance for ordinary FRP (fiberglass reinforced plastic) under static loads is acceptable, two major problems arise when applied to large-diameter fiber rods. First, the fixed cone angle of the anchor cup cannot adapt to the elastic characteristics of large-diameter fibers, and the insertion of the conical plug easily creates indentations on the rod surface, leading to localized fiber breakage. Second, stress concentration easily occurs in the conical transition zone at the front of the anchor, preventing the large-diameter fiber rod from fully utilizing its actual load-bearing capacity. Furthermore, even minor defects in this area can rapidly expand under load, causing sudden failure of the anchoring system. Therefore, their application in major engineering projects is limited.

[0007] Bonded anchors consist of an outer sleeve and bonding filler material. Their core advantage is that they cause no mechanical damage to the rod and can achieve centralized anchoring of multiple rods. However, the drawbacks of this technology are particularly prominent when used with large-diameter fiber rods. First, large-diameter fibers have low surface energy, making it difficult for ordinary epoxy resin fillers to fully impregnate them. After injection, air bubbles or voids are easily formed at the interface, leading to large fluctuations in bond strength. Second, the injection process relies on manual operation. The gap between the large-diameter fiber rod and the outer sleeve is usually only 2-5mm, which easily leads to glue breakage or incomplete glue application. Moreover, the glue curing time is as long as 48 hours, affecting construction efficiency. Finally, the load transfer of bonded anchors depends entirely on the filler. The difference in elastic modulus between large-diameter fibers and fillers can be 10-20 times, which easily leads to inconsistent interfacial shear deformation under stress, causing premature failure of the anchoring system.

[0008] While existing improved anchoring technologies have solved the problems of uneven stress and slippage in anchoring ordinary FRP materials, they still have significant shortcomings for large-diameter fiber rods. For example, the number of contact points between the "cross wedge" and the rod is relatively small, failing to effectively disperse the lateral stress of large-diameter fibers; ordinary epoxy resin fillers containing iron sand and steel balls have poor interfacial compatibility with large-diameter fibers and insufficient stiffness matching; and the lack of precise control methods for cutting and assembling large-diameter fibers during construction easily leads to rod damage. Therefore, developing an anchoring system and method that can adapt to the mechanical properties of large-diameter fibers and balance anchoring efficiency and reliability has become a key issue in promoting its large-scale engineering application. Summary of the Invention

[0009] In view of this, the present invention provides an anchoring system and anchoring method for large-diameter fiber composite rods, which solves the problems of stress concentration, low anchoring efficiency and poor anti-slip performance of existing anchoring methods for large-diameter fiber composite rods.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: An anchoring system for a large-diameter fiber composite rod includes: a large-diameter fiber rod, a stepped inner anchoring cylinder fitted on the anchoring section of the large-diameter fiber rod, an outer locking sleeve threaded to the small end of the inner diameter of the stepped inner anchoring cylinder, and a centering ring embedded between the large end of the inner diameter of the stepped inner anchoring cylinder and the large-diameter fiber rod; the end of the anchoring section of the large-diameter fiber rod has six evenly distributed slits along the axial direction to form a six-lobed bifurcated structure, and a six-spoke gradient hard alloy wedge is embedded in the center of the six-lobed bifurcated structure, with each side edge of the six-spoke gradient hard alloy wedge correspondingly inserted between two adjacent lobes of the large-diameter fiber rod; The inner wall of the stepped inner anchoring cylinder has three conical channels. The six-lobed bifurcated structure is inserted into the first-level conical channel, the transition anchoring section of the large-diameter fiber rod is inserted into the second-level conical channel, and the remaining anchoring section is inserted into the third-level conical channel. Modified ceramic particle epoxy resin filler is used to fill the spaces between the six-spoke gradient hard alloy wedge and the first-level conical channel, between each large-diameter fiber rod and the first-level conical channel, between the transition anchoring section and the second-level conical channel, and between the remaining anchoring section and the third-level conical channel. One end of the outer locking sleeve is a closed end, and a tightening bolt is threaded through the closed end. The end of the tightening bolt abuts against the end of the six-spoke gradient hard alloy wedge. The end of the six-lobed bifurcated structure extends out of the stepped inner anchoring cylinder and is located inside the outer locking sleeve.

[0011] Furthermore, the hardness of the six-spoke gradient cemented carbide wedge increases in a gradient from the end to the middle along the axial direction, and the taper of the six-spoke gradient cemented carbide wedge matches the taper of the first-stage tapered channel.

[0012] Furthermore, the inner diameter of the centering ring is equal to the diameter of the large-diameter fiber rod, the outer diameter of the centering ring is equal to the large end of the inner diameter of the stepped inner anchoring cylinder, and an annular guide groove is formed on the inner wall of the centering ring.

[0013] Furthermore, the taper of the first-stage, second-stage, and third-stage tapered channels of the stepped inner anchoring cylinder decreases sequentially, and adjacent channels are transitioned by horizontal sections.

[0014] Furthermore, the modified ceramic particle epoxy resin filler includes an epoxy resin matrix, silicon carbide ceramic particles, alumina short fibers, and lightly calcined magnesium oxide expander; the components by mass percentage are: epoxy resin matrix 65%, silicon carbide ceramic particles 26%, alumina short fibers 8%, and lightly calcined magnesium oxide expander 1%.

[0015] Furthermore, a rectangular sleeve with a length of 20mm is provided at the starting end of the three-stage conical channel to prevent the modified ceramic particle epoxy resin filler from overflowing under tension.

[0016] Furthermore, the slit length on the large-diameter fiber rod is consistent with the length of the six-spoke gradient cemented carbide wedge, and the slit depth is 1 / 4 to 1 / 3 of the diameter of the large-diameter fiber rod.

[0017] An anchoring method for an anchoring system of large-diameter fiber composite rods, comprising: Step 1: Sequentially install the centering ring and the stepped inner anchoring cylinder onto the large-diameter fiber rod, ensuring that the anchoring section of the large-diameter fiber rod protrudes at least 200mm from the stepped inner anchoring cylinder; Step 2: Using laser cutting equipment, six evenly distributed slits are made along the axial direction at the end of the anchoring section of the large-diameter fiber rod. The included angle between the slits is 60°, forming a six-lobed bifurcated structure, ensuring that the length of the slits is consistent with the length of the six-panel gradient cemented carbide wedge. Step 3: Apply modified ceramic particle epoxy resin filler evenly to the side surface of the six-spoke gradient cemented carbide wedge, and use a hydraulic jacking device to slowly press the six-spoke gradient cemented carbide wedge into the center of the six-lobed bifurcated structure along the axis until the end of the six-spoke gradient cemented carbide wedge is flush with the bifurcated end of the large-diameter fiber rod. Step 4: After the modified ceramic particle epoxy resin filler in Step 3 has cured for 24 hours, use two stainless steel cable ties to tie and fix the root of the six-lobed bifurcated structure. Then, apply a 1-2 mm thick layer of modified ceramic particle epoxy resin filler evenly to the outer surface of the six-lobed bifurcated structure and the exposed surface of the six-spoke gradient hard alloy wedge. Step 5: After the modified ceramic particle epoxy resin filler in Step 4 has completely cured, push the stepped inner anchoring cylinder and the centering ring to move towards the anchoring section. The centering ring ensures that the large-diameter fiber rod is coaxial with the stepped inner anchoring cylinder. Tap the large end of the inner diameter of the stepped inner anchoring cylinder to make the first-stage conical channel fit tightly with the outer surface of the six-lobed bifurcated structure, and the end of the six-lobed bifurcated structure extends 15~20mm out of the stepped inner anchoring cylinder. Step 6: Using a high-pressure injection gun, inject the modified ceramic particle epoxy resin filler into the gap between the first-stage conical channel and the large-diameter fiber rod through the injection port at the small end of the inner diameter of the stepped inner anchoring cylinder until the filler overflows from the gap of the first-stage conical channel. Step 7: Remove the centering ring, inject modified ceramic particle epoxy resin filler into the gap between the secondary tapered channel, the tertiary tapered channel and the large-diameter fiber rod through the injection port at the large diameter end of the stepped inner anchoring cylinder, and reset the centering ring before the modified ceramic particle epoxy resin filler cures. Seal the gap between the centering ring and the stepped inner anchoring cylinder with sealing strips. Step 8: Connect the external locking sleeve thread to the small end of the inner diameter of the stepped inner anchoring cylinder, and tighten the top bolt with a torque wrench so that the end of the top bolt is in close contact with the six-spoke gradient carbide wedge. The preload of the top bolt is controlled by torque, and the torque value is determined according to the thread specification and material. The typical value is 60~80 N·m.

[0018] Furthermore, the injection pressure in step six is ​​controlled at 0.8~1.2MPa, and injection is replenished every fifteen minutes during the injection process, for a total of 2~3 times.

[0019] Furthermore, in step four, the minimum binding tension of the stainless steel cable tie is 2kN, and a polytetrafluoroethylene gasket is placed between the stainless steel cable tie and the large-diameter fiber rod.

[0020] The beneficial effects of this invention are as follows: 1. This invention constructs a hierarchical, multi-point distributed force system through the synergistic structure of a three-stage conical channel, a six-spoke gradient wedge, and a six-lobed rod: The taper of the three-stage tapered channel decreases sequentially along the load transfer direction. Combined with the horizontal transition structure, this reduces the stress gradient during the transfer of axial load from the rod to the anchoring cylinder, preventing brittle fracture of the large-diameter fiber rod due to sudden stress changes. At the same time, considering that stress concentration is more pronounced at the rod entry end, three channels are set at this point to effectively alleviate stress concentration through a higher filler content.

[0021] The six side edges of the six-spoke wedge block are precisely matched with the six-lobed rod body, and the number of contact points effectively eliminates rod damage caused by local compression, while generating a certain amount of prestress to improve anchoring efficiency. The threaded connection length of the external locking sleeve is increased to more than 50mm. Combined with the torque control of the tightening bolt, the axial slippage is significantly reduced, and the fatigue resistance is greatly improved.

[0022] 2. This invention overcomes the performance limitations of traditional epoxy resin fillers, effectively improving anchoring efficiency through material innovation and interface optimization: In modified ceramic particle epoxy resin fillers, the synergistic reinforcement of silicon carbide ceramic particles and alumina short fibers significantly improves their compressive strength; the expansion agent can maintain interfacial stability and compensate for the shrinkage during epoxy resin curing, thereby improving the volume stability of the filler.

[0023] The annular guide groove design of the centering ring guides the filler to fully wet the surface of the rod. Combined with the two-end injection and multiple replenishment processes, the filling density is improved, and interface bubbles and voids are effectively eliminated. The stiffness of modified ceramic particle epoxy resin filler can be precisely controlled by the ceramic particle content to achieve stiffness matching with large-diameter fibers, avoiding debonding failure caused by incoordination of interfacial shear deformation, significantly improving anchoring efficiency, and fully leveraging the performance potential of large-diameter fibers.

[0024] 3. This invention standardizes key parameters in the anchoring process, significantly reducing construction difficulty and improving construction quality stability: The application of specialized equipment such as hydraulic jacking devices, high-pressure injection equipment, and torque wrenches has enabled the wedge insertion depth deviation, injection pressure fluctuation, and bolt preload error to be controlled within a smaller range. Clearly defining parameters such as cut depth, extension length, and grouting interval can significantly improve construction quality and reduce quality variations. No custom-made molds are required. By adjusting the wedge size and filler formula, it can be adapted to large-diameter fiber rods with diameters of 10~100mm and moduli of 200~600GPa, making it more widely applicable and stronger in engineering applications.

[0025] 4. Through synergistic innovation in structure, materials, and processes, this invention effectively solves the technical problems of stress concentration, low anchoring efficiency, easy damage to the rod body, and poor environmental adaptability in the anchoring of large-diameter fiber composite rods. Its design is reasonable, its reliability is high, and its construction is controllable. It can be widely used in various fields and provides key technical support for the large-scale application of large-diameter fiber composite materials. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is an overall axial sectional view of the present invention; Figure 2 This is a sectional view of a stepped inner anchoring cylinder; Figure 3 This is a schematic diagram of a six-spoke gradient cemented carbide wedge. Figure 4 This is a cross-sectional view of a large-diameter fiber rod.

[0028] Figure 5 This is a sectional view of the centering ring.

[0029] In the figure: 1-External locking sleeve; 2-Stepped internal anchoring cylinder; 3-Centering ring; 4-Modified ceramic particle epoxy resin filler; 5-Large diameter fiber rod; 6-Six-spoke gradient hard alloy wedge; 7-Tightening bolt; 8-Rectangular sleeve; 9-First-stage conical channel; 10-Second-stage conical channel; 11-Third-stage conical channel. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see the appendix Figure 1-5 This invention provides an anchoring system for a large-diameter fiber composite rod, comprising: a large-diameter fiber rod 5, a stepped inner anchoring cylinder 2 fitted onto the anchoring section of the large-diameter fiber rod 5, an outer locking sleeve 1 threaded to the small end of the inner diameter of the stepped inner anchoring cylinder 2, and a centering ring 3 embedded between the large end of the inner diameter of the stepped inner anchoring cylinder 2 and the large-diameter fiber rod 5; the end of the anchoring section of the large-diameter fiber rod 5 has six evenly distributed slits along the axial direction to form a six-lobed bifurcated structure, and a six-spoke gradient hard alloy wedge 6 is embedded in the center of the six-lobed bifurcated structure, with each side edge of the six-spoke gradient hard alloy wedge 6 correspondingly inserted between two adjacent lobes of the large-diameter fiber rod 5; The inner wall of the stepped inner anchoring cylinder 2 has three conical channels. The six-lobed bifurcated structure is inserted into the first-level conical channel 9. The transition anchoring section of the large-diameter fiber rod 5 is inserted into the second-level conical channel 10. The remaining anchoring section is inserted into the third-level conical channel 11. Modified ceramic particle epoxy resin filler 4 is filled between the six-spoke gradient hard alloy wedge 6 and the first-level conical channel 9, between each large-diameter fiber rod 5 and the first-level conical channel 9, between the transition anchoring section and the second-level conical channel 10, and between the remaining anchoring section and the third-level conical channel 11. One end of the outer locking sleeve 1 is a closed end, and a tightening bolt 7 is threaded through the closed end. The end of the tightening bolt 7 abuts against the end of the six-spoke gradient hard alloy wedge 6. The end of the six-lobed bifurcated structure extends out of the stepped inner anchoring cylinder 2 and is located inside the outer locking sleeve 1. After the tightening bolt 7 is screwed in by the thread, it abuts against the six-spoke gradient hard alloy wedge 6, which can prevent the wedge from sliding out longitudinally along the large-diameter fiber rod 5. By combining the tightening bolt 7 with the six-spoke gradient hard alloy wedge 6 and the modified ceramic particle epoxy resin filler 4, it can be fully ensured that the six-spoke gradient hard alloy wedge 6 and the large-diameter fiber rod 5 share the force during the tensile process. The external load is transferred by compressing the inner wall of the stepped inner anchoring cylinder 2, which further improves the anchoring bearing capacity.

[0032] This invention inserts a six-spoke gradient cemented carbide wedge 6 into a large-diameter fiber rod 5 with a six-lobed bifurcated structure. This ensures that a circumferential contact surface is formed between the six-spoke gradient cemented carbide wedge 6, the large-diameter fiber rod 5, and the first-stage conical channel 9 of the stepped inner anchoring cylinder 2. By increasing the contact area and the number of contact points, stress concentration caused by eccentric compression of the large-diameter fiber rod 5 is avoided. Simultaneously, the six-spoke gradient cemented carbide wedge 6 and the slit-cut large-diameter fiber rod 5 can effectively contact to form an integrated structure, resulting in more uniform and stable force distribution. This prevents the six-spoke gradient cemented carbide wedge 6 from slipping out of the large-diameter fiber rod 5 during stress application, thus avoiding interference with the compression effect or even anchoring failure.

[0033] The force distribution of this anchoring system comprises two parts: First, by cutting the large-diameter fiber rod 5 into a six-lobed structure and adding six-spoke gradient hard alloy wedges 6 to form a gradient, the main anchoring load is provided by compressing the inner wall of the stepped inner anchoring cylinder 2 during the bearing of external loads; second, secondary anchoring load is provided by bonding the large-diameter fiber rod 5 with modified ceramic particle epoxy resin filler 4 filled in the three-stage conical channels 11. The design of the three-stage conical channels 11 ensures that the filler forms a gradient structure, thereby increasing the adhesion between the filler and the rod body, and thus providing a higher anchoring load. The entire anchoring system is subjected to uniform and reasonable force distribution, and the force transmission path is clear.

[0034] The stepped inner anchoring cylinder 2 is designed with three conical channels. On the one hand, this allows for a larger compression area between the large-diameter fiber rod 5 and the inner wall of the stepped inner anchoring cylinder 2, improving the compression anchoring effect. On the other hand, it also increases the contact area between the modified ceramic particle epoxy resin filler 4 and the inner wall of the stepped inner anchoring cylinder 2, further enhancing the reliability of the bonded anchoring and providing greater anchoring load-bearing capacity for the large-diameter fiber rod 5. The horizontal transition structure between adjacent channels effectively optimizes stress distribution, avoids stress peaks at channel bends, and is suitable for the brittle characteristics of large-diameter fibers.

[0035] Preferably, the hardness of the six-spoke gradient cemented carbide wedge 6 increases in a gradient from the end to the middle along the axial direction, and the taper of the six-spoke gradient cemented carbide wedge 6 matches the taper of the first-stage tapered channel 9.

[0036] Preferably, the inner diameter of the centering ring 3 is equal to the diameter of the large-diameter fiber rod 5, both being 30mm, and the outer diameter of the centering ring 3 is equal to the large end of the inner diameter of the stepped inner anchoring cylinder 2, both being 50mm. This ensures that the large-diameter fiber rod 5 is centered in the stepped inner anchoring cylinder 2, avoiding eccentric force caused by positional deviation. The inner wall of the centering ring 3 is provided with an annular guide groove, which can guide the modified ceramic particle epoxy resin filler 4 to flow evenly during the glue pouring process, ensuring dense filling.

[0037] Preferably, the taper of the first-stage conical channel 9, the second-stage conical channel 10, and the third-stage conical channel 11 of the stepped inner anchoring cylinder 2 decreases sequentially. The taper of the first-stage conical channel 9 is 1:10, the taper of the second-stage conical channel 10 is 1:15, and the taper of the third-stage conical channel 11 is 1:20. Adjacent channels are transitioned by a horizontal section with a length of 20mm.

[0038] Preferably, the modified ceramic particle epoxy resin filler 4 comprises an epoxy resin matrix, silicon carbide ceramic particles, alumina short fibers, and lightly calcined magnesium oxide expander; wherein, by mass percentage, the components are: epoxy resin matrix 65%, silicon carbide ceramic particles 26%, alumina short fibers 8%, and lightly calcined magnesium oxide expander 1%; the particle size of the silicon carbide ceramic particles is 50~100 μm, and the length of the alumina short fibers is 1~3 mm. To increase the bonding strength and mechanical properties provided by the filler, the addition of silicon carbide ceramic particles can improve compressive strength and wear resistance, while alumina short fibers can enhance shear strength; by adjusting the particle size and content of ceramic particles and short fibers, fillers with different stiffnesses can be obtained. Fillers with corresponding stiffnesses are used according to the stress state at different locations in the anchorage zone, i.e., a stiffness gradient is formed along the anchorage length, thereby effectively avoiding stress concentration in the filler within the anchorage.

[0039] Preferably, the starting end of the three-stage conical channel 11 is provided with a rectangular sleeve 8 with a length of 20mm to prevent the modified ceramic particle epoxy resin filler 4 from overflowing under tension.

[0040] Preferably, the slit length on the large-diameter fiber rod 5 is consistent with the length of the six-spoke gradient cemented carbide wedge 6, both being 160mm. This ensures that the six-spoke gradient cemented carbide wedge 6 and the large-diameter fiber rod 5 are in close contact to form an integral structure, resulting in more uniform and stable stress distribution. The slit is processed using fiber laser cutting equipment, with the slit width controlled between 0.1 and 0.2mm. Nitrogen gas protection is used during the cutting process to prevent oxidation of the carbon fiber end face, ensuring that the strength of the large-diameter fiber rod 5 is not affected by the cutting process. Furthermore, the slit depth is 1 / 4 to 1 / 3 of the diameter of the large-diameter fiber rod 5.

[0041] An anchoring method for an anchoring system of large-diameter fiber composite rods, comprising: Step 1: Sequentially mount the centering ring 3 and the stepped inner anchoring cylinder 2 onto the large-diameter fiber rod 5, so that the anchoring section of the large-diameter fiber rod 5 protrudes at least 200mm from the stepped inner anchoring cylinder 2, preferably 220mm. Step 2: Using laser cutting equipment, six evenly distributed slits are made along the axial direction at the end of the anchoring section of the large-diameter fiber rod 5. The included angle between the slits is 60°, forming a six-lobed bifurcated structure. Ensure that the length of the slits is consistent with the length of the six-panel gradient hard alloy wedge 6, which is 160mm. Step 3: Apply modified ceramic particle epoxy resin filler 4 evenly to the side surface of the six-spoke gradient cemented carbide wedge 6, and then use a 15kN hydraulic jacking device to slowly press the six-spoke gradient cemented carbide wedge 6 into the six-lobed bifurcated structure along the axis at a pressing speed of 4mm / min until the end of the six-spoke gradient cemented carbide wedge 6 is flush with the bifurcated end of the large-diameter fiber rod 5. Step 4: After the modified ceramic particle epoxy resin filler 4 from Step 3 has cured for 24 hours at 25°C and 65% relative humidity, use two stainless steel cable ties to bind and fix the root of the six-lobed bifurcated structure. Set the binding tension to 2kN. Then, apply a layer of modified ceramic particle epoxy resin filler 4 with a thickness of 1~2mm evenly to the outer surface of the six-lobed bifurcated structure and the exposed surface of the six-spoke gradient hard alloy wedge block 6. Step 5: After the modified ceramic particle epoxy resin filler 4 in Step 4 has been completely cured for 48 hours, push the stepped inner anchoring cylinder 2 and the centering ring 3 to the anchoring section. The centering ring 3 ensures that the large diameter fiber rod 5 is coaxial with the stepped inner anchoring cylinder 2. Gently tap the large inner diameter end of the stepped inner anchoring cylinder 2 with a nylon hammer to make the first-stage conical channel 9 fit tightly with the outer surface of the six-lobed bifurcated structure, and the end of the six-lobed bifurcated structure extends out of the stepped inner anchoring cylinder by 15~20mm, preferably with an exposed length of 18mm. Step 6: Using a high-pressure injection gun, inject the modified ceramic particle epoxy resin filler 4 into the gap between the first-stage conical channel 9 and the large-diameter fiber rod 5 through the injection port at the small end of the inner diameter of the stepped inner anchoring cylinder 2. The injection pressure is controlled at 1.0 MPa. The first injection is performed after 15 minutes, and the second injection is performed after 30 minutes, until the filler overflows from the gap of the first-stage conical channel 9. Step 7: Remove the centering ring 3, inject modified ceramic particle epoxy resin filler 4 into the gap between the secondary conical channel 10, the tertiary conical channel 11 and the large-diameter fiber rod 5 through the injection port at the large diameter end of the stepped inner anchoring cylinder 2, and reset the centering ring 3 before the modified ceramic particle epoxy resin filler 4 has cured. Seal the gap between the centering ring 3 and the stepped inner anchoring cylinder 2 with a sealing strip. Step 8: Thread the outer locking sleeve 1 to the small end of the inner diameter of the stepped inner anchoring cylinder 2, and tighten the top bolt 7 with a torque wrench so that the end of the top bolt 7 is in close contact with the six-spoke gradient hard alloy wedge 6. The preload of the top bolt 7 is controlled by torque. The torque value is determined according to the thread specification and material. The torque is controlled between 60 and 80 N·m, preferably 70 N·m.

[0042] Preferably, the injection pressure in step six is ​​controlled at 0.8~1.2MPa, and injection is repeated every fifteen minutes for a total of 2~3 times to ensure that the modified ceramic particle epoxy resin filler 4 can fully impregnate the gap between the large-diameter fiber rod 5 and the inner wall of the stepped inner anchoring cylinder 2. Injecting glue at both ends can alleviate the uneven glue injection caused by the narrow transition area between the cut and uncut sections of the large-diameter fiber rod 5 during the glue injection process, and reduce the problem of low anchoring efficiency caused by uneven glue injection.

[0043] Preferably, in step four, the minimum binding tension of the stainless steel cable tie is 2kN, and a polytetrafluoroethylene gasket is provided between the stainless steel cable tie and the large-diameter fiber rod 5. The circumferential constraint provided by the stainless steel cable tie is stable and reliable and not easy to loosen. The six-spoke gradient hard alloy wedge 6 and the large-diameter fiber rod 5 are wrapped into a whole and jointly bear the external force, with good overall stress performance.

[0044] This invention features a simple design, convenient manufacturing, and good economic efficiency. Its innovative structure ensures rational internal stress distribution within the anchor, effectively solving the problems of uneven stress, large slippage, and low anchoring efficiency inherent in traditional anchoring systems. Furthermore, thanks to reliable sealing protection and fatigue-resistant design, it can operate stably for extended periods under corrosive environments and repeated loading, providing a practical and highly adaptable solution for the efficient anchoring of large-diameter fiber rods.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. An anchoring system for large-diameter fiber composite rods, characterized in that, include: The large-diameter fiber rod (5), the stepped inner anchoring cylinder (2) fitted on the anchoring section of the large-diameter fiber rod (5), the outer locking sleeve (1) threaded to the small end of the inner diameter of the stepped inner anchoring cylinder (2), and the centering ring (3) embedded between the large end of the inner diameter of the stepped inner anchoring cylinder (2) and the large-diameter fiber rod (5); the end of the anchoring section of the large-diameter fiber rod (5) has six evenly distributed slits along the axial direction to form a six-lobed bifurcated structure, and a six-spoke gradient hard alloy wedge (6) is embedded in the center of the six-lobed bifurcated structure. Each side edge of the six-spoke gradient hard alloy wedge (6) is inserted between two adjacent large-diameter fiber rods (5). The inner wall of the stepped inner anchoring cylinder (2) is provided with three conical channels. The six-lobed bifurcated structure is inserted into the first-level conical channel (9). The transition anchoring section of the large-diameter fiber rod (5) is inserted into the second-level conical channel (10). The remaining anchoring section is inserted into the third-level conical channel (11). Modified ceramic particle epoxy resin filler (4) is filled between the six-spoke gradient hard alloy wedge (6) and the first-level conical channel (9), between each large-diameter fiber rod (5) and the first-level conical channel (9), between the transition anchoring section and the second-level conical channel (10), and between the remaining anchoring section and the third-level conical channel (11). One end of the outer locking sleeve (1) is a closed end, and a tightening bolt (7) is threaded through the closed end. The end of the tightening bolt (7) abuts against the end of the six-spoke gradient hard alloy wedge (6). The end of the six-lobed bifurcated structure extends out of the stepped inner anchoring cylinder (2) and is located inside the outer locking sleeve (1).

2. The anchoring system for large-diameter fiber composite rods according to claim 1, characterized in that, The hardness of the six-spoke gradient cemented carbide wedge (6) increases in a gradient from the end to the middle along the axial direction, and the taper of the six-spoke gradient cemented carbide wedge (6) matches the taper of the first-stage tapered channel (9).

3. The anchoring system for large-diameter fiber composite rods according to claim 1, characterized in that, The inner diameter of the centering ring (3) is equal to the diameter of the large-diameter fiber rod (5), the outer diameter of the centering ring (3) is equal to the large end of the inner diameter of the stepped inner anchoring cylinder (2), and an annular guide groove is provided on the inner wall of the centering ring (3).

4. An anchoring system for large-diameter fiber composite rods according to claim 1, characterized in that, The taper of the first-stage conical channel (9), the second-stage conical channel (10) and the third-stage conical channel (11) of the stepped inner anchoring cylinder (2) decreases sequentially, and the adjacent channels are transitioned by a horizontal section.

5. An anchoring system for large-diameter fiber composite rods according to claim 1, characterized in that, The modified ceramic particle epoxy resin filler (4) includes an epoxy resin matrix, silicon carbide ceramic particles, alumina short fibers, and lightly calcined magnesium oxide expander; the components are as follows by mass percentage: epoxy resin matrix 65%, silicon carbide ceramic particles 26%, alumina short fibers 8%, and lightly calcined magnesium oxide expander 1%.

6. An anchoring system for large-diameter fiber composite rods according to claim 1, characterized in that, The starting end of the three-stage conical channel (11) is provided with a rectangular sleeve (8) with a length of 20mm, which is used to prevent the modified ceramic particle epoxy resin filler (4) from being stretched and overflowing.

7. An anchoring system for large-diameter fiber composite rods according to claim 1, characterized in that, The slit length on the large-diameter fiber rod (5) is consistent with the length of the six-spoke gradient hard alloy wedge (6), and the slit depth is 1 / 4 to 1 / 3 of the diameter of the large-diameter fiber rod (5).

8. An anchoring method for an anchoring system for large-diameter fiber composite rods according to claims 1-7, characterized in that, include: Step 1: Place the centering ring (3) and the stepped inner anchoring cylinder (2) onto the large-diameter fiber rod (5) in sequence, so that the anchoring section of the large-diameter fiber rod (5) protrudes from the stepped inner anchoring cylinder (2) by at least 200mm; Step 2: Using a laser cutting device, six evenly distributed slits are made along the axial direction at the end of the anchoring section of the large-diameter fiber rod (5). The included angle between the slits is 60°, forming a six-lobed bifurcated structure, ensuring that the length of the slits is consistent with the length of the six-panel gradient hard alloy wedge (6). Step 3: Apply modified ceramic particle epoxy resin filler (4) evenly to the side surface of the six-spoke gradient cemented carbide wedge (6), and use a hydraulic jacking device to slowly press the six-spoke gradient cemented carbide wedge (6) into the center of the six-lobed bifurcated structure along the axis until the end of the six-spoke gradient cemented carbide wedge (6) is flush with the bifurcated end of the large-diameter fiber rod (5); Step 4: After the modified ceramic particle epoxy resin filler (4) in Step 3 has cured for 24 hours, use two stainless steel cable ties to tie and fix the root of the six-lobed bifurcated structure. Then, apply a layer of modified ceramic particle epoxy resin filler (4) with a thickness of 1~2mm evenly to the outer surface of the six-lobed bifurcated structure and the exposed surface of the six-width gradient hard alloy wedge (6). Step 5: After the modified ceramic particle epoxy resin filler (4) in Step 4 has been completely cured, push the stepped inner anchor cylinder (2) and the centering ring (3) to move towards the anchoring section. The centering ring (3) ensures that the large diameter fiber rod (5) is coaxial with the stepped inner anchor cylinder (2). The inner diameter of the stepped inner anchor cylinder (2) is struck to make the first-level conical channel (9) fit tightly with the outer surface of the six-lobed bifurcated structure, and the end of the six-lobed bifurcated structure extends 15~20mm out of the stepped inner anchor cylinder (2). Step 6: Use a high-pressure injection gun to inject the modified ceramic particle epoxy resin filler (4) into the gap between the first-stage conical channel (9) and the large-diameter fiber rod (5) from the small-diameter injection port of the stepped inner anchor cylinder (2) until the filler overflows from the gap of the first-stage conical channel (9). Step 7: Remove the centering ring (3), inject modified ceramic particle epoxy resin filler (4) into the gap between the secondary conical channel (10), the tertiary conical channel (11) and the large diameter fiber rod (5) through the injection port at the large diameter end of the stepped inner anchoring cylinder (2), and reset the centering ring (3) before the modified ceramic particle epoxy resin filler (4) has cured. Seal the gap between the centering ring (3) and the stepped inner anchoring cylinder (2) with a sealing strip. Step 8: Connect the outer locking sleeve (1) to the small end of the inner diameter of the stepped inner anchoring cylinder (2) with a threaded connection. Tighten the top bolt (7) with a torque wrench so that the end of the top bolt (7) is in close contact with the six-spoke gradient hard alloy wedge (6). The preload of the top bolt (7) is controlled by torque, and the torque value is determined according to the thread specification and material.

9. The anchoring method according to claim 8, characterized in that, In step six, the injection pressure is controlled at 0.8~1.2MPa, and the injection is replenished every fifteen minutes during the injection process, for a total of 2~3 times.

10. The anchoring method according to claim 8, characterized in that, In step four, the minimum binding tension of the stainless steel cable tie is 2kN, and a polytetrafluoroethylene gasket is placed between the stainless steel cable tie and the large-diameter fiber rod (5).

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