Tensile and shear resistant steel wire composite anchor

Abstract

This invention discloses a tensile and shear-resistant steel wire composite anchor, which is composed of basalt fiber, carbon fiber, steel wire, and a prepared epoxy resin matrix. The volume ratio of basalt fiber, carbon fiber, and steel wire composite is 5-8:1:1, and the volume of the prepared epoxy resin matrix accounts for 20%-25% of the total volume of the basalt fiber, carbon fiber, and steel wire composite anchor. This steel wire composite anchor is manufactured using a pultrusion-winding process, involving yarn threading, resin impregnation, pultrusion winding, heat curing, stretching and calendering, cutting, and finishing. The steel wire composite anchor provided by this invention exhibits superior mechanical properties such as shear strength and tensile strength compared to basalt fiber anchors, effectively overcoming the low shear strength defect of ordinary basalt fiber anchors, making it widely applicable in geotechnical engineering support structures. It also has advantages such as being lightweight and easy to operate, and can replace traditional steel anchors, showing good market prospects.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation, specifically relating to a tensile and shear-resistant steel wire composite anchor rod made using basalt fiber, carbon fiber and steel wire reinforcement materials. Background Technology

[0002] The current development of infrastructure construction and underground space utilization in my country will inevitably promote the rapid development of soil and rock anchoring technology. Compared with traditional support methods (such as wooden scaffolding, concrete support, hydraulic prop support, and steel arch support), anchor support has significant technical and economic advantages, and its effectiveness in improving the stress state of soil and rock, enhancing the integrity, bearing capacity, and stability of the soil and rock mass has been proven by numerous engineering practices. Steel anchors are widely used in anchor support projects; however, existing steel anchors suffer from problems such as rapid corrosion, insufficient steel strength, and low construction reliability. Furthermore, blindly increasing the density of steel anchors to improve reinforcement effects can lead to excessive density, affecting the construction speed and cost of the support system.

[0003] Basalt fiber anchors possess excellent physicochemical properties, such as resistance to acid and alkali corrosion. Their strength is more than twice that of ordinary steel, while their weight is only one-quarter. Furthermore, they are widely available and inexpensive. As a completely green material, they have broad prospects for engineering applications and can effectively replace steel anchors. However, basalt fiber anchors have poor shear resistance. This is because within soil and rock masses, basalt fiber anchors are subjected not only to tensile forces but also to shear forces along the joint surfaces of the soil and rock fracture zones, especially in situations like slope landslides and soil displacement. The anchors exert a reaction force on the surrounding rock. Due to the anisotropy of the composite material and the low transverse shear strength of basalt fibers, basalt fiber anchors undergo almost no plastic deformation during shear stress, making them more prone to brittle shear failure compared to metal anchors. This limits the application of basalt fiber anchors in geotechnical engineering support structures.

[0004] The prior art, Chinese invention application publication number CN111501383A, published on April 8, 2020, discloses a novel basalt fiber composite reinforcement, its preparation method, and its application. It proposes to use a resin matrix to heat and solidify a steel wire rope and several basalt fibers surrounding the steel wire rope through a pultrusion mold to produce a novel basalt fiber composite reinforcement. This solves the problem that the longitudinal and transverse thermal expansion coefficients of the basalt fiber composite reinforcement are relatively small, which leads to cracking of the basalt fiber composite reinforcement due to changes in ambient temperature. However, the basalt fiber composite bar production process used in this method is pultrusion-compression molding. The interface between the composite bar and the threaded structure produced by this process is bonded with resin, resulting in low overall shear strength. The production process is complex and cannot achieve automated integration. In addition, this method only studies the problem of cracking caused by changes in ambient temperature, which leads to small differences in the longitudinal and transverse thermal expansion coefficients of the basalt fiber composite bar. It does not study the problem of basalt fiber anchor rods being sheared along the joint surfaces of the rock and soil fracture zone due to slope landslides and rock and soil displacement, leading to rod fracture.

[0005] Chinese invention patent application CN117108330A, published on November 24, 2023, discloses a composite material anchor rod and its manufacturing method, as well as a composite material anchor rod, to address the mismatch between the tensile strength, torsional strength, and transverse shear performance of the composite material anchor rod in existing technologies. However, this patented technology has certain drawbacks. First, the manufacturing process of this patented technology is relatively complex. On the one hand, it requires the preparation of the anchor rod core material first, and then the external fibers are woven and / or wound once or multiple times on the surface of the core material to form the external structure. This makes it difficult to automate the production equipment and process. Furthermore, it places high demands on the production equipment and workers, affecting the market application of this patented technology. On the other hand, this patented technology is mainly applied in the field of coal mine roadway support, therefore, it requires the addition of additives such as curing agents, flame retardants, antistatic agents, toughening agents, and accelerators during its preparation process, which also increases the number of preparation steps and production costs. Secondly, this patented technology proposes adding a fiber braided layer and / or winding layer to the unidirectional fiber main structure, completing the material selection and fiber orientation design of the composite anchor fiber, and realizing the directional application of high-strength and tough fibers in the key stress-bearing parts of the anchor. However, this method has been widely used in the manufacturing process of composite materials, such as in various engineering fields that require improved shear strength, such as aerospace and automotive manufacturing. Therefore, the innovation and advancement of this patented technology cannot be proven or inspired. Finally, although the patented technology mentions that basalt fiber can be used in the raw materials of the composite anchor, it mentions very little about the role of basalt fiber in the composite anchor and provides no relevant examples, lacking relevant theoretical and data support. At the same time, the patented technology only vaguely mentions which fibers basalt fiber can be compounded with when used as the core material and external fibers of the anchor body, but does not mention the compounding effect of basalt fiber with other fibers or the reinforcement mechanism of the composite anchor. Therefore, this patented technology lacks scientific validity and practical guiding significance.

[0006] A prior art Chinese invention patent, CN1962731A, published on November 8, 2005, discloses a fiber-reinforced resin anchor bolt. This invention proposes a basalt fiber-reinforced resin anchor bolt with high tensile strength and strong anchoring force, incorporating carbon fibers. It also exhibits excellent shear strength, compressive strength, and flexural strength, with carbon fibers comprising 10% to 50% of the total reinforcement mass. However, this patented technology has certain drawbacks. First, it does not mention the manufacturing process and related process parameters for this fiber-reinforced resin anchor bolt. Existing processes such as pultrusion-molding and pultrusion-winding can affect the performance of fiber-reinforced resin anchor bolts due to differences in process parameters. Secondly, the patented technology only mentions the advantages of high tensile strength of carbon fiber (2800MPa-3800MPa) and high elongation at break of basalt fiber (2.2% for basalt fiber and 1.7% for carbon fiber) in terms of the reinforcement mechanism of resin by basalt fiber and carbon fiber. It also states that compared to resin anchors reinforced with basalt fiber alone, the tensile strength can reach approximately 1.2 to 1.5 times, and the elongation at break is also somewhat improved. However, the high tensile strength of carbon fiber and the high elongation at break of basalt fiber lack relevant theoretical and data support for improving the shear strength of resin anchors. This is because high tensile strength of carbon fiber does not improve the shear strength of resin anchors, only the tensile strength. Similarly, the high elongation at break of basalt fiber does not contribute to improving the shear strength of resin anchors. This is because the elongation at break of basalt fiber refers to the ratio of the elongation at break to its original length, reflecting the ductility or toughness of basalt fiber. This indicator is mainly affected by the raw materials, preparation process, microstructure, processing history, and environmental factors of the fiber. Shear strength, on the other hand, is the ability of a resin anchor to resist shear force; that is, the maximum shear stress per unit area when the resin anchor fails under shear action. It is related to the internal structure, chemical composition, and external stress state of the material. The elongation at break of basalt fiber and the shear strength of the resin anchor are two different mechanical performance indicators, reflecting different properties of the material under different stress states. Fiber elongation at break mainly focuses on the ductility of the material under tension, while shear strength focuses on the strength performance of the material under shear stress. Therefore, there is no direct connection or correlation between the two. Furthermore, this patented technology makes it difficult to see how the mixture of carbon fiber and basalt fiber improves the shear strength, compressive strength, and flexural strength of the resin anchor, and the extent of the performance improvement is difficult to quantify. Therefore, this patented technology lacks practical guiding significance, and the related technological innovation and advancement cannot be proven or inspired. Finally, in this patented technology, the mass ratio of carbon fiber is more than 10% of the total mass of the reinforcement, and in some cases even reaches 50%. Since carbon fiber is expensive, it will increase the price of the fiber-reinforced resin anchor rod, and the market competitiveness of related products will be greatly reduced.

[0007] The existing technology, Chinese invention patent application CN114017086A, published on February 8, 2022, discloses a tensile-shear continuous basalt fiber composite anchor bolt adapted to large deformations of surrounding rock. This bolt retains the good tensile properties of the original basalt fiber composite anchor bolt while possessing stronger elongation and shear resistance to large deformations. However, this patented technology has certain drawbacks. First, the tensile-shear continuous basalt fiber composite anchor bolt is composed of a basalt fiber reinforced resin composite core, a steel spiral sleeve, a basalt fiber reinforced resin composite protective layer, a carbon fiber mesh layer, a threaded steel sleeve, a tray, and a nut. It is constructed using a "bamboo shoot"-like structure with layers spirally wound, making its manufacturing process complex, impossible to automate, and requiring high-level production equipment and skilled workers, which may hinder the market application of this patented technology. Secondly, while the tensile-shear continuous basalt fiber composite anchor incorporates multiple layers of steel spiral sleeves to enhance its shear strength, this method significantly increases its weight, negating the lightweight advantage of basalt fiber reinforcement over steel. This is particularly problematic in inaccessible mountainous or remote areas, increasing transportation and installation costs. Furthermore, the use of steel spiral sleeves reduces the anchor's corrosion and weather resistance, hindering the full realization of these advantages and severely impacting its service life and reliability in corrosive environments such as acids, alkalis, salts, and organic solvents, as well as its reliability and safety in engineering geological applications. Finally, this patented technology proposes that when the shear stress of the tensile-shear continuous basalt fiber composite anchor is below the ultimate shear stress, the structure is in an elastic deformation stage, where the shear stress is primarily borne by the outer threaded steel sleeve. When large shear deformation occurs, the inner basalt fiber composite material will fracture first. The carbon fiber mesh in the interlayer provides structural flexibility and shear buffering. As deformation continues to increase, the outer threaded steel sleeve fractures under shear, while the implanted steel spiral sleeve continues to ensure structural continuity, maintaining the effect of shear without breaking. The invention is mentioned in its embodiments as having a tensile strength similar to that of a single continuous basalt fiber composite anchor, but due to its ability to withstand continuous loads after fracture, it proves that the design can overcome the problem of high brittleness in basalt fiber composites and has a certain ability to resist large deformations. However, this claim lacks relevant theoretical and data support. This is because the shear strength of a basalt fiber composite anchor mainly depends on the material's ability to resist shear force, while the ability to withstand continuous loads after fracture is not directly related to shear strength. Shear strength is a mechanical property index of a material under shear stress, reflecting its ability to resist shear deformation or failure. The ability to withstand continuous loads after fracture is more related to the material's ductility, toughness, and other properties, which, while related to strength, are not directly equivalent to shear strength.In practical applications, the shear strength of materials is determined using standardized testing methods that take into account material properties, test conditions, and engineering application requirements. Therefore, while the sustained load-bearing capacity of this tensile-shear continuous basalt fiber composite anchor after fracture is related to the material's strength, it does not directly prove its high shear strength. Evaluating the shear strength of basalt fiber composite anchors requires determination using standard mechanical testing methods. Summary of the Invention

[0008] To address the issue of low shear strength in existing basalt fiber anchors, this invention aims to provide a tensile and shear-resistant composite steel wire anchor. Due to the reinforcement of basalt fibers by carbon fiber and steel wire, this anchor exhibits superior mechanical properties such as shear strength and tensile strength compared to ordinary basalt fiber anchors, effectively overcoming the low shear strength defect of conventional basalt fiber anchors and enabling its widespread application in geotechnical engineering support structures. Furthermore, because this invention employs a pultrusion-winding production process to manufacture the composite anchor of basalt fiber, carbon fiber, and steel wire, it boasts a high degree of integration between the anchor body and the threaded structure, excellent shear resistance, and is easy to operate with a high degree of automation, improving the cost-effectiveness of anchor manufacturing, effectively reducing product costs, and enhancing its practical value.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] A tensile and shear resistant steel wire composite anchor bolt is made by combining basalt fiber, carbon fiber, and steel wire. The process involves impregnating the basalt fiber, carbon fiber, and steel wire with a prepared resin matrix, then drawing them into a winding machine for pultrusion winding, and finally curing them in a five-stage heating and curing device. The volume ratio of the basalt fiber to the carbon fiber and steel wire composite is 5–8:1:1, and the volume of the prepared epoxy resin matrix accounts for 20%–25% of the total volume of the basalt fiber, carbon fiber, and steel wire composite anchor bolt.

[0011] The specific steps are as follows:

[0012] (1) Yarn threading: The basalt fiber, carbon fiber and steel wire placed on the yarn rack are extracted according to the required number of strands by volume ratio, and then passed through the yarn separating plate into the impregnation tank.

[0013] (2) Impregnation: The prepared resin matrix is ​​sent into the impregnation tank, so that the basalt fiber, carbon fiber and steel wire surface that enter through the yarn separating plate are evenly wrapped and impregnated by the resin matrix in the impregnation tank.

[0014] (3) Pultrusion winding: The basalt fiber, carbon fiber and steel wire after impregnation are pulled by the traction machine and enter the bundler to form a mixed filament bundle. Then, they enter the winding device and are wound with nylon rope to form threads on the surface of the mixed filament bundle to obtain a pre-formed anchor rod. The width of the nylon rope is 2.8 mm, the traction speed of the traction machine is 32 cm / min, and the winding speed of the winding device is 13-15 r / min.

[0015] (4) Heating and curing: Under the traction of the traction machine, the preformed anchor rod obtained after pultrusion and winding enters the five-stage heating and curing device to cure and form the preformed anchor rod. The temperature of the first heating stage is 100℃, the temperature of the second heating stage is 120℃, the temperature of the third heating stage is 150℃, the temperature of the fourth heating stage is 160℃, and the temperature of the fifth heating stage is 170℃.

[0016] (5) Stretching and calendering: The formed anchor rod is pulled into the stretching and calendering equipment under the traction of the traction machine, wherein the clamping force of the stretching and calendering machine is 0.2MPa;

[0017] (6) Cutting: The stretched and calendered anchor rod is pulled into the cutting machine by the traction machine to cut the anchor rod;

[0018] (7) Finishing: After cutting, the anchor rods are pulled by the traction machine and enter the post-processing machine to correct the thread accuracy and remove burrs and paint, so as to obtain the finished basalt fiber, carbon fiber and steel wire composite anchor rods.

[0019] Furthermore, the basalt fiber is made from basalt ore from Liupanshui, Guizhou Province. After crushing, the basalt ore is added to a melting furnace and melted at 1450-1500℃. The basalt fiber filaments are then drawn through a platinum-rhodium alloy spun yarn. The basalt fiber filaments are then impregnated with a sizing agent and twisted together. Because they are not twisted, they are referred to as basalt untwisted roving. The fiber diameter is 17μm, the tensile strength is 2200MPa, and the elastic modulus is 85GPa.

[0020] Furthermore, the carbon fiber is Zhongfu Shenying carbon fiber purchased from Shenzhen Jusheng Carbon Fiber Co., Ltd., model: SYT45S-12K, with a fiber diameter of 7um, tensile strength greater than 4500MPa, and elastic modulus of 220~260GPa.

[0021] Furthermore, the steel wire is a stainless steel wire purchased from Hongguo Stainless Steel Products Factory in Xinghua City, Jiangsu Province. The wire diameter is 0.6 mm, the tensile strength is 1960 MPa, and the elastic modulus is 200 GPa.

[0022] Furthermore, the prepared resin matrix is ​​obtained by mixing LY-EP618A resin and LY-EP618B curing agent purchased from Futian Chemical Industry Co., Ltd. of Zhaoqing City, Guangdong Province, in a mixer at a weight ratio of 3:2, and stirring at a stirring speed of 1300-1400 r / min for 40-50 minutes.

[0023] Compared with the prior art, the present invention has significant advantages and beneficial effects. As can be seen from the above technical solution, the present invention has the following characteristics:

[0024] (1) This invention is the first to use basalt fiber, carbon fiber, and steel wire to prepare composite anchors. Specifically, a certain volume fraction of carbon fiber and steel wire are added during the production of basalt fiber anchors. Based on the principle of hybridization, basalt fiber, carbon fiber, and steel wire are mixed. The high tensile strength of carbon fiber is used to improve the tensile strength of the basalt fiber anchor, while the high modulus of carbon fiber and steel wire is used to increase the modulus value of the basalt fiber anchor, thereby enhancing its resistance to deformation. In this process, the relatively small diameter of carbon fiber facilitates its dispersion in the composite material, avoiding stress concentration caused by fiber aggregation. Furthermore, under the induction of an external force field, it easily forms a regular orientation distribution, which has a good promoting effect on improving the tensile strength and shear strength of the composite anchor. Meanwhile, the steel wire used in this invention is a soft steel wire with high toughness, and it forms an internally interwoven multi-layered network structure with basalt fiber and carbon fiber, which enhances the adhesion between the steel wire, basalt fiber and carbon fiber and the resin matrix, making the internal structure of the composite anchor more compact. When subjected to shear stress, it can quickly transmit stress internally, and during the fracture process, it is necessary to destroy the entanglement points of the steel wire, basalt fiber and carbon fiber, which consumes a certain amount of extra work, thus improving the shear strength of the composite anchor.

[0025] (2) This invention employs a novel pultrusion-winding process to prepare composite anchors made of basalt fiber, carbon fiber, and steel wire. The composite anchors prepared using this process exhibit a high degree of integration between the anchor body and the threaded structure, good shear resistance, and are simple to operate and highly automated. The technological innovations of this invention are mainly reflected in the following three points:

[0026] First, this invention, in the composite anchor manufacturing process, combines the ratio of basalt fiber, carbon fiber, and steel wire, as well as the reinforcement effect of carbon fiber and steel wire on basalt fiber. It adjusts the number of strands of basalt fiber, carbon fiber, and steel wire, and optimizes their yarn distribution on the yarn separating plate. This ensures uniform impregnation of basalt fiber, carbon fiber, and steel wire in the resin matrix, improving their compatibility with the resin matrix and enhancing the strength of the composite anchor. Simultaneously, it ensures uniform distribution of carbon fiber and steel wire in the outer yarn portion of the basalt fiber, while achieving concentrated twisting in the central yarn portion, solving the problem of the high load on the central part of the basalt fiber anchor due to its low material strength.

[0027] Secondly, the present invention employs a five-stage heating and curing molding process in the composite anchor bolt preparation process, which ensures that the pre-formed anchor bolt obtained after pultrusion winding has sufficient curing time and appropriate curing temperature during the curing process, resulting in continuous enhancement of the anchor bolt strength.

[0028] Third, in the composite anchor manufacturing process, the present invention performs stretching and calendering on the cured anchor, which further improves the ductility and density of the material, and also promotes the improvement of the shear strength and tensile strength of the anchor.

[0029] (3) The basalt fiber, carbon fiber and steel wire composite anchor prepared by the present invention has the advantages of simple production process, low price, easy cutting, explosion-proof and anti-static, high strength and corrosion resistance, and lightweight and easy operation. It can replace traditional steel anchors and be used for support in geotechnical engineering, mines, roadways and slopes, etc., with good social benefits and market prospects. Detailed Implementation

[0030] The following detailed description, in conjunction with preferred embodiments, details the specific implementation methods, features, and effects of a basalt fiber, carbon fiber, and steel wire composite anchor bolt and its preparation method based on the present invention.

[0031] A tensile and shear resistant steel wire composite anchor bolt is made by combining basalt fiber, carbon fiber, and steel wire. The process involves impregnating the basalt fiber, carbon fiber, and steel wire with a prepared resin matrix, then drawing them into a winding machine for pultrusion winding, and finally curing them in a five-stage heating and curing device. The volume ratio of the basalt fiber to the carbon fiber and steel wire composite is 5–8:1:1, and the volume of the prepared epoxy resin matrix accounts for 20%–25% of the total volume of the basalt fiber, carbon fiber, and steel wire composite anchor bolt.

[0032] The basalt fiber is made from basalt ore from Liupanshui, Guizhou Province. After crushing, the basalt ore is added to a melting furnace and melted at 1450-1500℃. The basalt fiber filaments are then drawn through a platinum-rhodium alloy spun yarn. The basalt fiber filaments are then impregnated with a sizing agent and twisted together. Because they are not twisted, they are referred to as basalt untwisted roving. The fiber diameter is 17μm, the tensile strength is 2200MPa, and the elastic modulus is 85GPa.

[0033] The carbon fiber in question is Zhongfu Shenying carbon fiber (model: SYT45S-12K) purchased from Shenzhen Jusheng Carbon Fiber Co., Ltd., with a fiber diameter of 7µm, a tensile strength greater than 4500MPa, and an elastic modulus of 220-260GPa.

[0034] The steel wire was purchased from Hongguo Stainless Steel Products Factory in Xinghua City, Jiangsu Province. The wire diameter is 0.6 mm, the tensile strength is 1960 MPa, and the elastic modulus is 200 GPa.

[0035] The prepared resin matrix is ​​obtained by mixing LY-EP618A resin and LY-EP618B curing agent purchased from Futian Chemical Industry Co., Ltd. of Zhaoqing City, Guangdong Province, in a mixer at a weight ratio of 3:2, and stirring at a stirring speed of 1300-1400 r / min for 40-50 minutes.

[0036] Specifically, the following steps are included:

[0037] (1) Yarn threading: The basalt fiber, carbon fiber and steel wire placed on the yarn rack are extracted according to the required number of strands by volume ratio, and then passed through the yarn separating plate into the impregnation tank.

[0038] (2) Impregnation: The prepared resin matrix is ​​sent into the impregnation tank, so that the basalt fiber, carbon fiber and steel wire surfaces that enter through the yarn separating plate are evenly wrapped and impregnated by the resin matrix in the impregnation tank.

[0039] (3) Pultrusion winding: The basalt fiber, carbon fiber and steel wire after impregnation are pulled by the traction machine and enter the bundler to form a mixed filament bundle. Then, they enter the winding device and are wound with nylon rope to form threads on the surface of the mixed filament bundle to obtain a pre-formed anchor rod. The width of the nylon rope is 2.8mm, the traction speed of the traction machine is 32cm / min, and the winding speed of the winding device is 13~15r / min.

[0040] (4) Heating and curing: Under the traction of the traction machine, the preformed anchor rod obtained after pultrusion and winding enters the 5-section heating and curing device to cure and form the anchor rod. The temperature of the first heating section is 100℃, the temperature of the second heating section is 120℃, the temperature of the third heating section is 150℃, the temperature of the fourth heating section is 160℃, and the temperature of the fifth heating section is 170℃.

[0041] (5) Stretching and calendering: The formed anchor rod is pulled into the stretching and calendering equipment under the traction of the traction machine, wherein the clamping force of the stretching and calendering machine is 0.2MPa.

[0042] (6) Cutting: The stretched and calendered anchor rod is pulled into the cutting machine by the traction machine to cut the anchor rod.

[0043] (7) Finishing: After cutting, the anchor rods are pulled by the traction machine and enter the post-processing machine to correct the thread accuracy and remove burrs and paint, so as to obtain the finished basalt fiber, carbon fiber and steel wire composite anchor rods.

[0044] Example 1:

[0045] A tensile and shear resistant steel wire composite anchor rod, wherein the volume ratio of basalt fiber, carbon fiber and steel wire composite is 5:1:1, and the volume of the prepared epoxy resin matrix accounts for 20% of the total volume of the basalt fiber, carbon fiber and steel wire composite anchor rod.

[0046] Its preparation method includes the following steps:

[0047] (1) Yarn threading: The basalt fiber, carbon fiber and steel wire placed on the yarn rack are extracted according to the required number of strands by volume ratio, and then passed through the yarn separating plate into the impregnation tank.

[0048] (2) Impregnation: The prepared resin matrix is ​​sent into the impregnation tank, so that the basalt fiber, carbon fiber and steel wire surface that enter through the yarn separating plate are evenly wrapped and impregnated by the resin matrix in the impregnation tank.

[0049] (3) Pultrusion winding: The basalt fiber, carbon fiber and steel wire after impregnation are pulled by the traction machine and enter the bundler to form a mixed braided filament bundle. Then, they enter the winding device and are wound with nylon rope to form threads on the surface of the mixed braided filament bundle to obtain a pre-formed anchor rod. The width of the nylon rope is 2.8mm, the traction speed of the traction machine is 32cm / min, and the winding speed of the winding device is 13r / min.

[0050] (4) Heating and curing: Under the traction of the traction machine, the preformed anchor rod obtained after pultrusion and winding enters the 5-section heating and curing device to cure and form the preformed anchor rod. The temperature of the first heating section is 100℃, the temperature of the second heating section is 120℃, the temperature of the third heating section is 150℃, the temperature of the fourth heating section is 160℃, and the temperature of the fifth heating section is 170℃.

[0051] (5) Stretching and calendering: The formed anchor rod is pulled into the stretching and calendering equipment under the traction of the traction machine, wherein the clamping force of the stretching and calendering machine is 0.2MPa;

[0052] (6) Cutting: The stretched and calendered anchor rod is pulled into the cutting machine by the traction machine to cut the anchor rod;

[0053] (7) Finishing: After cutting, the anchor rods are pulled by the traction machine and enter the post-processing machine to correct the thread accuracy and remove burrs and paint, so as to obtain the finished basalt fiber, carbon fiber and steel wire composite anchor rods.

[0054] The inventors compared the basalt fiber / carbon fiber / steel wire composite anchor rod from Example 1 with a basalt fiber anchor rod (an anchor rod obtained by replacing carbon fiber and steel wire with the same proportion of basalt fiber under the same process parameters and flow). The tensile and shear strengths of the basalt fiber / carbon fiber / steel wire composite anchor rod and the basalt fiber anchor rod were tested according to the relevant standards of "Test Methods for Basic Mechanical Properties of Fiber Reinforced Composite Reinforcement" (GB / T30022-2013). The relevant test data are shown in Table 1. (Note: The diameter of both the composite anchor rod obtained in Example 1 and the basalt fiber anchor rod used for comparison is 18 mm.)

[0055] Table 1. Test data of anchor bolt mechanical properties

[0056]

[0057] As shown in Table 1, the basalt fiber, carbon fiber, and steel wire composite anchor bolts produced by this invention exhibit significantly improved tensile and shear strengths compared to basalt fiber anchor bolts, demonstrating superior mechanical properties. The tensile strength of Example 1 is 38.3% higher than that of the basalt fiber anchor bolts, and the shear strength is 66.5% higher. This effectively overcomes the low shear strength of ordinary basalt fiber anchor bolts, enabling their widespread application in geotechnical engineering support structures and achieving the objectives of this invention.

[0058] Example 2:

[0059] A tensile and shear resistant steel wire composite anchor rod, wherein the volume ratio of basalt fiber, carbon fiber and steel wire composite is 6:1:1, and the volume of the prepared epoxy resin matrix accounts for 22% of the total volume of the basalt fiber, carbon fiber and steel wire composite anchor rod;

[0060] Its preparation method includes the following steps:

[0061] (1) Yarn threading: The basalt fiber, carbon fiber and steel wire placed on the yarn rack are extracted according to the required number of strands by volume ratio, and then passed through the yarn separating plate into the impregnation tank.

[0062] (2) Impregnation: The prepared resin matrix is ​​sent into the impregnation tank, so that the basalt fiber, carbon fiber and steel wire surface that enter through the yarn separating plate are evenly wrapped and impregnated by the resin matrix in the impregnation tank.

[0063] (3) Pultrusion winding: The basalt fiber, carbon fiber and steel wire after impregnation are pulled by the traction machine and enter the bundler to form a mixed braided filament bundle. Then, they enter the winding device and are wound with nylon rope to form threads on the surface of the mixed braided filament bundle to obtain a pre-formed anchor rod. The width of the nylon rope is 2.8mm, the traction speed of the traction machine is 32cm / min, and the winding speed of the winding device is 14r / min.

[0064] (4) Heating and curing: Under the traction of the traction machine, the preformed anchor rod obtained after pultrusion and winding enters the five-stage heating and curing device to cure and form the preformed anchor rod. The temperature of the first heating stage is 100℃, the temperature of the second heating stage is 120℃, the temperature of the third heating stage is 150℃, the temperature of the fourth heating stage is 160℃, and the temperature of the fifth heating stage is 170℃.

[0065] (5) Stretching and calendering: The formed anchor rod is pulled into the stretching and calendering equipment under the traction of the traction machine, wherein the clamping force of the stretching and calendering machine is 0.2MPa;

[0066] (6) Cutting: The stretched and calendered anchor rod is pulled into the cutting machine by the traction machine to cut the anchor rod;

[0067] (7) Finishing: After cutting, the anchor rods are pulled by the traction machine and enter the post-processing machine to correct the thread accuracy and remove burrs and paint, so as to obtain the finished basalt fiber, carbon fiber and steel wire composite anchor rods.

[0068] The inventors compared the basalt fiber / carbon fiber / steel wire composite anchor rod from Example 2 with a basalt fiber anchor rod (an anchor rod obtained by replacing carbon fiber and steel wire with the same proportion of basalt fiber under the same process parameters and flow). The tensile and shear strengths of the basalt fiber / carbon fiber / steel wire composite anchor rod and the basalt fiber anchor rod were tested according to the relevant standards of "Test Methods for Basic Mechanical Properties of Fiber Reinforced Composite Reinforcement" (GB / T30022-2013). The relevant test data are shown in Table 2. (Note: The diameter of both the composite anchor rod obtained in Example 2 and the basalt fiber anchor rod used for comparison is 18 mm.)

[0069] Table 2. Anchor Bolt Mechanical Performance Test Data

[0070]

[0071] As shown in Table 2, the basalt fiber, carbon fiber, and steel wire composite anchor bolts produced by this invention exhibit significantly improved tensile and shear strengths compared to basalt fiber anchor bolts, demonstrating superior mechanical properties. The tensile strength of Example 2 is 34.8% higher than that of the basalt fiber anchor bolts, and the shear strength is 73.4% higher. This effectively overcomes the low shear strength of ordinary basalt fiber anchor bolts, enabling their widespread application in geotechnical engineering support structures and achieving the objectives of this invention.

[0072] Example 3:

[0073] A tensile and shear resistant steel wire composite anchor rod, wherein the volume ratio of basalt fiber, carbon fiber and steel wire composite is 8:1:1, and the volume of the prepared epoxy resin matrix accounts for 25% of the total volume of the basalt fiber, carbon fiber and steel wire composite anchor rod;

[0074] Its preparation method includes the following steps:

[0075] (1) Yarn threading: The basalt fiber, carbon fiber and steel wire placed on the yarn rack are extracted according to the required number of strands by volume ratio, and then passed through the yarn separating plate into the impregnation tank.

[0076] (2) Impregnation: The prepared resin matrix is ​​sent into the impregnation tank, so that the basalt fiber, carbon fiber and steel wire surface that enter through the yarn separating plate are evenly wrapped and impregnated by the resin matrix in the impregnation tank.

[0077] (3) Pultrusion winding: The basalt fiber, carbon fiber and steel wire after impregnation are pulled by the traction machine and enter the bundler to form a mixed braided filament bundle. Then, they enter the winding device and are wound with nylon rope to form threads on the surface of the mixed braided filament bundle to obtain a pre-formed anchor rod. The width of the nylon rope is 2.8mm, the traction speed of the traction machine is 32cm / min, and the winding speed of the winding device is 15r / min.

[0078] (4) Heating and curing: Under the traction of the traction machine, the preformed anchor rod obtained after pultrusion and winding enters the five-stage heating and curing device to cure and form the preformed anchor rod. The temperature of the first heating stage is 100℃, the temperature of the second heating stage is 120℃, the temperature of the third heating stage is 150℃, the temperature of the fourth heating stage is 160℃, and the temperature of the fifth heating stage is 170℃.

[0079] (5) Stretching and calendering: The formed anchor rod is pulled into the stretching and calendering equipment under the traction of the traction machine, wherein the clamping force of the stretching and calendering machine is 0.2MPa;

[0080] (6) Cutting: The stretched and calendered anchor rod is pulled into the cutting machine by the traction machine to cut the anchor rod;

[0081] (7) Finishing: After cutting, the anchor rods are pulled by the traction machine and enter the post-processing machine to correct the thread accuracy and remove burrs and paint, so as to obtain the finished basalt fiber, carbon fiber and steel wire composite anchor rods.

[0082] The inventors compared the basalt fiber / carbon fiber / steel wire composite anchor rod from Example 3 with a basalt fiber anchor rod (an anchor rod obtained by replacing carbon fiber and steel wire with the same proportion of basalt fiber under the same process parameters and flow). The tensile and shear strengths of the basalt fiber / carbon fiber / steel wire composite anchor rod and the basalt fiber anchor rod were tested according to the relevant standards of "Test Methods for Basic Mechanical Properties of Fiber Reinforced Composite Reinforcement" (GB / T30022-2013). The relevant test data are shown in Table 3. (Note: The diameter of both the composite anchor rod obtained in Example 3 and the basalt fiber anchor rod used for comparison is 18 mm.)

[0083] Table 3. Test data of anchor bolt mechanical properties

[0084]

[0085] As shown in Table 3, the basalt fiber, carbon fiber, and steel wire composite anchor bolts produced by this invention exhibit significantly improved tensile and shear strengths compared to basalt fiber anchor bolts, demonstrating superior mechanical properties. In Example 3, the tensile strength was increased by 32.1% compared to basalt fiber anchor bolts, and the shear strength was increased by 61.2%. This effectively overcomes the low shear strength of ordinary basalt fiber anchor bolts, enabling their widespread application in geotechnical engineering support structures and achieving the objectives of this invention.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments without departing from the technical essence of the present invention shall still fall within the scope of the present invention.

Claims

1. A tensile and shear resistant steel wire composite anchor bolt, characterized in that: Made from a composite of basalt fiber, carbon fiber, and steel wire, the process involves impregnating basalt fiber, carbon fiber, and steel wire with a prepared resin matrix, then drawing them into a winding machine for pultrusion winding, and finally curing them in a five-stage heating and curing device. The volume ratio of the basalt fiber to the carbon fiber and steel wire composite is 5–8:1:1, and the volume of the prepared epoxy resin matrix accounts for 20%–25% of the total volume of the basalt fiber, carbon fiber, and steel wire composite anchor. The specific steps are as follows: (1) Yarn threading: The basalt fiber, carbon fiber and steel wire placed on the yarn rack are pulled out according to the required number of strands by volume ratio, and passed through the yarn separating plate into the impregnation tank. (2) Impregnation: The prepared resin matrix is ​​sent into the impregnation tank, so that the basalt fiber, carbon fiber and steel wire surfaces that enter through the yarn separating plate are evenly wrapped and impregnated by the resin matrix in the impregnation tank. (3) Pultrusion winding: The basalt fiber, carbon fiber and steel wire after impregnation are pulled by the traction machine and enter the bundler to form a mixed braided filament bundle. Then, they enter the winding device and are wound with nylon rope to form threads on the surface of the mixed braided filament bundle to obtain a pre-formed anchor rod. The width of the nylon rope is 2.8 mm, the traction speed of the traction machine is 32 cm / min, and the winding speed of the winding device is 13-15 r / min. (4) Heating and curing: Under the traction of the traction machine, the preformed anchor rod obtained after pultrusion and winding enters the five-stage heating and curing device to cure and form the preformed anchor rod. The temperature of the first heating stage is 100℃, the temperature of the second heating stage is 120℃, the temperature of the third heating stage is 150℃, the temperature of the fourth heating stage is 160℃, and the temperature of the fifth heating stage is 170℃. (5) Stretching and calendering: The formed anchor rod is pulled into the stretching and calendering equipment under the traction of the traction machine, wherein the clamping force of the stretching and calendering machine is 0.2MPa; (6) Cutting: The stretched and calendered anchor rod is pulled into the cutting machine by the traction machine to cut the anchor rod; (7) Finishing: After cutting, the anchor rods are pulled by the traction machine and enter the post-processing machine to correct the thread accuracy and remove burrs and paint, so as to obtain the finished basalt fiber, carbon fiber and steel wire composite anchor rods.

2. The tensile and shear resistant steel wire composite anchor bolt as described in claim 1, characterized in that: The basalt fiber is made from basalt ore as raw material. After crushing, the basalt ore is added to a melting furnace and melted at 1450-1500℃. The basalt fiber filaments are then drawn through a platinum-rhodium alloy filament drawing stencil. The basalt fiber filaments are then impregnated with a sizing agent and twisted together. Because they are not twisted, they are referred to as basalt untwisted roving. The fiber diameter is 17μm, the tensile strength is 2200MPa, and the elastic modulus is 85GPa.

3. The tensile and shear resistant steel wire composite anchor bolt as described in claim 1, characterized in that: The carbon fiber, model SYT45S-12K, has a fiber diameter of 7µm, a tensile strength greater than 4500MPa, and an elastic modulus of 220-260GPa.

4. The tensile and shear resistant steel wire composite anchor bolt as described in claim 1, characterized in that: The steel wire is stainless steel wire with a diameter of 0.6 mm, a tensile strength of 1960 MPa, and an elastic modulus of 200 GPa.

5. The tensile and shear resistant steel wire composite anchor bolt as described in claim 1, characterized in that: The prepared resin matrix is ​​obtained by mixing LY-EP618A resin and LY-EP618B curing agent in a mixer at a weight ratio of 3:2 and stirring at a stirring speed of 1300-1400 r / min for 40-50 minutes.

Images