A solid anchor rod, a grouting material for the anchor rod, a method for preparing the grouting material, and a surface treatment method for the anchor rod

Abstract

The present application relates to a kind of solid anchor rod, grouting material for anchor rod and the preparation method and surface treatment method of anchor rod of grouting material.The solid anchor rod of the present application includes solid rod body, backing plate, plug, nut, long tube, short tube, self-anchored anchor head, solid rod body includes installation end and connecting end, installation end is installed plug, backing plate and nut;Plug is provided with first installation hole and second installation hole;Backing plate is provided with third installation hole and fourth installation hole;Long tube includes first end and second end, after first end passes through first installation hole and third installation hole, second end is installed on plug and backing plate;Short tube includes third end and fourth end, after third end passes through second installation hole and fourth installation hole, fourth end is installed on plug and backing plate;Self-anchored anchor head includes installation part and flared part, flared part is flared to the direction of plug, flared part includes first inclined plate and second inclined plate, and connecting end is detachably installed on installation part.

Description

Technical Field

[0001] This invention relates to a solid anchor bolt, a grouting material for the anchor bolt, a method for preparing the grouting material, and a surface treatment method for the anchor bolt. Background Technology

[0002] As an important form of geotechnical engineering reinforcement, rock bolt support has been increasingly used in the international geotechnical engineering field due to its advantages such as safety, efficiency, and low cost. Railway tunnel rock bolt support projects utilize solid rock bolts (also known as mortar rock bolts), hollow rock bolts, and combined rock bolts. Solid rock bolts are inexpensive and easy to construct, hollow rock bolts are used for slope and foundation pit support, and combined rock bolts are used for tunnel arch support. Through pressure grouting of the rock bolt body, the fractured rock mass can be consolidated, the rock mass improved, groundwater blocked, and the bolt body protected from corrosion, thus achieving excellent support results.

[0003] Although existing solid anchors have advantages such as low cost and simple construction, their inherent technical defects pose a potential threat to the quality of anchor projects and anchoring effect, which cannot be ignored. The main defects are: (1) The process of grouting first and then inserting the rod is often adopted, and human factors have a great influence on the fullness of grouting; (2) Generally, no pads and nuts are set, so it is impossible to provide support force after the anchor is installed. The role of the anchor is completely passive, which is not conducive to controlling the early loosening and displacement of the rock mass after excavation; (3) Due to the difficulty in controlling the fullness of mortar during anchor construction, the phenomenon of pores, cavities and exposed steel bars in the borehole are often difficult to avoid; (4) When drilling in soft and broken rock masses and other unfavorable geological conditions, the phenomenon of hole collapse often occurs after the drill rod is pulled out. Solid anchors have poor coping ability. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a solid anchor rod, a grouting material for the anchor rod, a method for preparing the grouting material, and a surface treatment method for the anchor rod.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a solid anchor bolt, comprising a solid rod body, a pad, a grout stop plug, a nut, a long tube, a short tube, and a self-anchoring anchor head, wherein:

[0007] The solid rod includes an installation end and a connecting end arranged opposite to each other. The installation end is sequentially fitted with the grout stop plug, the washer plate, and the nut, with the grout stop plug facing the connecting end. The grout stop plug, the washer plate, and the nut are all threaded onto the solid rod.

[0008] The grout stopper is provided with a first mounting hole and a second mounting hole for the long tube and the short tube to pass through, respectively.

[0009] The pad is provided with a third mounting hole and a fourth mounting hole for the long tube and the short tube to pass through respectively;

[0010] The long tube includes a first end and a second end disposed opposite to each other. After the first end passes through the first mounting hole and the third mounting hole, the second end is mounted on the grout stop plug and the gasket.

[0011] The short tube includes a third end and a fourth end arranged opposite to each other. After the third end passes through the second mounting hole and the fourth mounting hole, the fourth end is installed on the grout stop plug and the gasket.

[0012] The self-anchoring anchor head includes an installation part and a flared part. The flared part is flared in the direction of the grout stop plug. The flared part includes a first inclined plate and a second inclined plate. The first inclined plate has a first included angle with the solid rod body, and the second inclined plate has a second included angle with the solid rod body. The connecting end is detachably installed on the installation part.

[0013] Preferably, the first included angle is 10°-30° and the second included angle is 10°-30°.

[0014] Preferably, the outer surfaces of the solid rod, the pad, and the nut are all treated with anti-corrosion measures.

[0015] Preferably, the solid rod is a hot-rolled ribbed steel bar or a fine-rolled threaded steel bar.

[0016] Preferably, the long tube is made of metal or plastic, and the short tube is made of metal or plastic.

[0017] Preferably, the stop plug is made of rubber or plastic.

[0018] Preferably, the material of the pad is 45 steel or Q355 steel.

[0019] Preferably, the pad is a square plate or a round plate.

[0020] Preferably, the nut is made of 45 steel or 40Cr steel.

[0021] Preferably, the connecting end is threaded onto the mounting portion.

[0022] On the other hand, the present invention provides a grouting material for anchor bolts, which is composed of component A and component B. Component A, by mass parts, includes 450-550 parts cement, 450-550 parts sand, 0.1-1.0 parts plastic expansion agent, 10-30 parts expansion agent, 1-5 parts water-reducing agent, 0.2-1.0 parts defoamer, 0.1-1.0 parts stabilizer, 0-5 parts retarder, and 1-10 parts rust inhibitor. Component B is water, by mass parts, comprising 100-160 parts.

[0023] Preferably, component A comprises 460-520 parts cement, 460-530 parts sand, 0.2-0.8 parts plastic expansion agent, 12-28 parts expansion agent, 1.5-4.5 parts water-reducing agent, 0.3-0.9 parts defoamer, 0.2-0.9 parts stabilizer, 0-4.5 parts retarder, and 1-10 parts rust inhibitor.

[0024] Preferably, component B is water, in the form of 110 to 150 parts by mass.

[0025] Preferably, the cement is selected from ordinary Portland cement of grade 42.5 or above, rapid-hardening sulfoaluminate cement of grade 42.5 or above, and ultrafine cement, with ultrafine cement being the most preferred. The grouting material of this invention uses ultrafine cement as the main material. Grout made from this type of ultrafine cement with its small particle size has excellent injectability and can penetrate into rock fissures that are generally considered impenetrable by cement particles. It has good permeability and injectability similar to organic grouts, high strength and durability, significantly increases anchoring force, and improves the bonding force between the anchor bolt and the surrounding rock.

[0026] Preferably, the specific surface area of ​​the ultrafine cement is ≥600m². 2 / kg, with an average particle size of less than 5μm.

[0027] Preferably, the sand is manufactured sand, more preferably it is a blend of manufactured sand of 20 to 40 mesh, greater than 40 to 70 mesh, and greater than 70 to 140 mesh, and even more preferably it is a blend of manufactured sand of 20 to 40 mesh, greater than 40 to 70 mesh, and greater than 70 to 140 mesh in a mass ratio of (10 to 20):(40 to 60):(20 to 30); preferably, the sand has a particle size of less than 0.6 mm and a mud content or stone powder content of less than 1% by weight.

[0028] Preferably, the plasticizing agent is an organic-inorganic composite component capable of generating an inert gas such as nitrogen, and is selected from amine substances.

[0029] Preferably, the expanding agent is a modified ettringite-based expanding agent.

[0030] Preferably, the water-reducing agent is one or more selected from naphthalene-based and polycarboxylate powder water-reducing agents, and more preferably selected from polycarboxylate powder water-reducing agents.

[0031] Preferably, the defoamer is selected from one or more of powdered organophosphates, organosilicon resins, modified organosilicon resins, and silica-organosilicon resin complexes, and is more preferably selected from organosilicon resins.

[0032] Preferably, the stabilizer is selected from one or more of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose ether, and methylcellulose ether; preferably, the stabilizer is hydroxypropyl methylcellulose ether with a viscosity of 50,000 to 100,000 mPa·s.

[0033] Preferably, the retarder is selected from one or more of tartaric acid, boric acid, borax, sodium gluconate and citric acid, more preferably boric acid and / or borax.

[0034] Preferably, the rust inhibitor is selected from one or more of complex amino alcohols, phosphates, fatty acid esters, and silicates. The grouting material of this invention incorporates a rust inhibitor component. During the mortar curing process, the rust inhibitor migrates, adsorbs, and deposits onto the anchor bolt surface, further improving the mortar's density and extending the anchor bolt's service life.

[0035] In another aspect, the present invention provides a method for preparing the above-mentioned grouting material, the method comprising the following steps:

[0036] (1) Add sand, plastic expansion agent, expansion agent, water-reducing agent, defoamer, stabilizer, retarder and rust inhibitor to the mixer in sequence, stir for 5-10 minutes, then add cement and continue stirring for 5-10 minutes.

[0037] (2) Add component B while stirring, and then continue stirring for 3 to 6 minutes, preferably 4 minutes;

[0038] (3) Stop stirring and let stand for 1 to 2 minutes to obtain the product.

[0039] Preferably, in step (1), the stirring speed is 60-100 r / min;

[0040] Preferably, in step (2), the stirring speed is 110-200 r / min, more preferably 150-200 r / min.

[0041] In another aspect, the present invention provides a surface treatment method for anchor bolts, the method comprising infiltrating zinc powder or multi-element powder charge into the surface of the anchor bolt and / or spraying or immersing it in a passivation liquid to form a co-infiltrating layer and a passivation layer.

[0042] Preferably, when co-diffusion with zinc powder or multi-element powder charge, the zinc powder or multi-element powder charge needs to be used together with a diffusion aid, wherein the weight ratio of zinc powder or multi-element powder charge to diffusion aid is 1:(0.05-0.2). The zinc powder, multi-element powder charge and diffusion aid are stored separately and mixed in proportion when needed.

[0043] Preferably, the multi-element powdered furnace charge, by mass percentage, contains 1.5-6.7% Al, 1.4-3.3% Mg, 0.2-1.1% Ni, 0.3-1.2% Cr, 0.1-1.0% Si, 0.1-0.6% rare earth elements, and the balance is zinc. Zn, Ni, and Cr are derived from zinc powder and ZnNi. 20 Cr 30 Powder provided, Al, Si, Mg from AlSi 12 Powder and Al 50 Mg 50 Alloy powder is provided.

[0044] Preferably, the particle size of the zinc powder or multi-element powder furnace charge is 400-450 mesh.

[0045] Preferably, the infiltration aid is composed of NH4Cl and quartz sand, with NH4Cl accounting for 60% to 75% by mass. Ammonium chloride releases nitrogen gas during heating, preventing excessive oxidation of all materials in the furnace. Quartz sand helps to ensure uniform mixing and improves the fluidity of zinc powder or multi-element powder charge on the surface of metal parts during co-infiltration.

[0046] Preferably, the particle size of the quartz sand is 80-100 mesh.

[0047] Preferably, the passivation liquid is selected from one or more of the following: chromium-free environmentally friendly water-based passivation liquid, two-component polyurethane topcoat, water-based polyurethane topcoat, and water-based epoxy paint.

[0048] The surface of the anchor rod undergoes factory anti-corrosion treatment, such as co-diffusion with zinc powder or multi-element powder furnace charge to form a co-diffusion layer, and then is sprayed or immersed in passivation liquid to form a passivation layer. Through composite anti-corrosion treatment, the thickness of the composite anti-corrosion layer of the anchor rod body, pad, and nut is 70-100μm, of which the co-diffusion layer thickness is greater than 60μm and the passivation layer thickness is 5-20μm.

[0049] The surface of the anchor bolt is sequentially treated with zinc powder or multi-element powder furnace charge co-infiltration, followed by passivation liquid spraying or immersion. After factory anti-corrosion treatment, the anchor bolt is installed and grout is injected. The injected grout penetrates into the fissures of the surrounding rock, thus ultimately forming a multi-layered anti-corrosion layer (co-infiltration layer + passivation layer + grout layer), giving the anchor bolt good durability within the surrounding rock and achieving long-term support.

[0050] Preferably, the method for co-diffusion of zinc powder or multi-element powder furnace charge is as follows:

[0051] 1) Remove the oil stains from the surface of the anchor rod and perform shot blasting with steel shot with a diameter of 0.2 to 0.4 mm to expose the metal surface of the anchor rod;

[0052] 2) Add zinc powder and penetration aid or add ZnNi 20 Cr 30 powder, AlSi 12 Powder, Al 50 Mg 50 Alloy powder, rare earth elements, and a seepage aid are placed in a sealed co-diffusion furnace according to a certain ratio. Then, the anchor rods from step 1) are embedded in the furnace charge. Optionally, if the length of the co-diffusion furnace is limited, part of the anchor rods can be embedded in the furnace charge first, and the remaining anchor rods can extend out of the furnace through a pre-drilled hole at the central axis of the co-diffusion furnace. The remaining anchor rods are then processed in the next furnace following the same steps. The rotation speed of the co-diffusion furnace is set to 6-10 r / min. The co-diffusion furnace is equipped with a vacuum treatment device, and the vacuum degree is maintained at 2-5 Pa. The co-diffusion furnace is heated to 360-450°C as indicated by the external temperature display. The temperature of the co-diffusion agent inside the furnace is measured by a temperature sensor to be 370-410°C, and the temperature is maintained for 4-8 hours.

[0053] 3) Turn off the power and allow the temperature inside the co-infiltration furnace to cool to below 100°C. Push the furnace shell out to cool naturally, open the furnace cover, and separate the anchor rod from the furnace charge.

[0054] Preferably, in step 2), the volume ratio of the furnace charge to the co-infiltration furnace is 40-60L:100L;

[0055] Preferably, in step 2), the mass ratio of the furnace charge to the specific surface area ratio of the anchor bolt is 600–1000 kg:1 m². 2 ;

[0056] Preferably, the ZnNi 20 Cr 30 The powder is prepared as follows:

[0057] 1) Prepare zinc ingots and nickel-chromium alloy ingots in a mass ratio of 50:50. 20 Cr 30 ;

[0058] 2) Zinc ingots and nickel-chromium alloy ingots Ni 20 Cr 30 Add it to the melting furnace, heat it to 600-850℃, and after it is completely melted, stir it thoroughly and keep it at the temperature for 15-30 minutes. Remove the surface slag to obtain ZnNiCr alloy liquid.

[0059] 3) Inside the atomizing tank, 99.99% high-purity nitrogen gas at a pressure not less than 0.9 MPa is sprayed at a speed of 200–300 m / s onto the ZnNiCr alloy liquid obtained in step 2). The nitrogen spraying direction is 80°–100° to the flow direction of the ZnNiCr alloy liquid, atomizing the ZnNiCr alloy liquid into micro-droplets. After cooling in a condenser, drying, and sieving, ZnNiCr alloy liquid with a particle size of 400–450 mesh is obtained. 20 Cr 30 pink.

[0060] Preferably, the method of spraying or immersing in the passivation liquid includes the following steps:

[0061] After co-diffusion of zinc powder or multi-element powder charge into the anchor rod, continue to spray or immerse it in passivation liquid for 1 to 5 minutes, and then dry it at 60 to 160°C to obtain the final product.

[0062] Preferably, the passivation liquid is selected from one or more of the following: chromium-free environmentally friendly water-based passivation liquid, two-component polyurethane topcoat, water-based polyurethane topcoat, and water-based epoxy paint.

[0063] Preferably, the thickness of the film layer co-diffused with zinc powder or multi-element powder furnace charge is greater than or equal to 60 μm;

[0064] Preferably, the thickness of the film layer sprayed or immersed in the passivation liquid is 5-20 μm;

[0065] Preferably, the total thickness of the film layer co-diffused with zinc powder or multi-element powder furnace charge and the film layer sprayed or immersed in passivation liquid is 70-100 μm.

[0066] Compared with the prior art, this application has at least the following beneficial technical effects:

[0067] This invention relates to a novel solid anti-corrosion anchor bolt. Unlike existing expansion-shell type anchor bolts with parallel expansion, the anchor bolt of this invention has an angled head that opens outwards, resulting in stronger anchoring force with the surrounding rock and grout. This invention employs a pre-insertion and post-grouting method, leading to high grouting efficiency, easy full grouting, strong permeability, and high anchoring force, solving the problems of incomplete grouting and low work efficiency. For the anti-corrosion steel rod body: for long anchor bolts, a multi-element powder co-infiltration + passivation composite anti-corrosion treatment technology is adopted; for threaded steel solid anchor bolts, finer zinc powder or finer multi-element powder furnace charge is used for co-infiltration. The co-infiltration layer at the threaded section meets the thickness requirements and is uniformly consistent, solving the problem of reduced anchoring force caused by corrosion of steel rods.

[0068] The grouting material of the present invention has good injectability, micro-expansion, high strength, and adjustable setting time, which solves the problems of long setting time and low strength; and the compressive strength and anchoring force of the grouting material at 28 days are far greater than the requirements in the standard.

[0069] To prevent anchor bolt corrosion, this invention treats the anchor bolt surface by co-infiltration with zinc powder or multi-element powder furnace charge and spraying or immersion in passivating liquid. This is the first time that multi-element co-infiltration and passivation anti-corrosion treatment has been applied to tunnel support anchor bolts, resulting in high durability within the surrounding rock and achieving long-term support effects.

[0070] This invention adds elements such as Si and Cr to zinc, which improves the hardness and density of the co-permeation layer and increases the bonding force between the co-permeation layer and the mortar. The passivation solution further seals the surface of the co-permeation layer, making the anchor bolt surface more dense and preventing the penetration of external corrosion products such as water, oxygen, and mortar leachates. Attached Figure Description

[0071] Figure 1 This is a schematic diagram of the solid anchor rod of the present invention.

[0072] Explanation of reference numerals in the attached figures:

[0073] 1: Solid rod body; 2: Pad; 3: Grout stop plug; 4: Nut; 5: Long pipe; 6: Short pipe; 7: Self-anchoring anchor head; 8: Installation end; 9: Connection end; 10: First end; 11: Second end; 12: Third end; 13: Fourth end; 14: Installation part; 15: Flared part; 16: First inclined plate; 17: Second inclined plate. Detailed Implementation

[0074] The present invention will be described below with reference to specific embodiments. Those skilled in the art will understand that these embodiments are for illustrative purposes only and do not limit the scope of the invention in any way.

[0075] In the following embodiments, the same components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0076] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all raw materials and reagents used in the following examples are commercially available products. The purchase details of some reagents and raw materials are as follows:

[0077] Hydroxypropyl methylcellulose ether, viscosity 50,000–100,000 mPa·s: Huizhou Huashengyuan New Materials Co., Ltd.

[0078] Ultrafine cement: 600 mesh and 800 mesh, Lamabel (Beijing) Technology Co., Ltd.;

[0079] Calcium alum-based expanding agent: Tangshan Polar Bear Building Materials Co., Ltd.;

[0080] Plastic expansion agent: Tangshan Polar Bear Building Materials Co., Ltd.;

[0081] Sika Ferror Gard 903 Complex Amino Alcohol Rust Inhibitor: Sika (Sika Corporation)

[0082] Zinc ingots: Dongguan Kaichi Alloy Materials Co., Ltd.;

[0083] Ni-chromium alloy ingots 20 Cr 30 Dongguan Kaichi Alloy Materials Co., Ltd.

[0084] AlSi 12 Powder: Hebei Xinlizhong Nonferrous Metals Group Co., Ltd.;

[0085] Al 50 Mg 50 Alloy powder: Changsha Tianjiu Technology Materials Co., Ltd.;

[0086] ZnNi 20 Cr 30 The powder is prepared as follows:

[0087] 1) Prepare zinc ingots and nickel-chromium alloy ingots in a mass ratio of 50:50. 20 Cr 30 ;

[0088] 2) Zinc ingots and nickel-chromium alloy ingots Ni 20 Cr 30 Add to a melting furnace, heat to 600–850°C, and after complete melting, stir thoroughly and hold at that temperature for 25 minutes. Remove surface slag to obtain ZnNi. 20 Cr 30 Liquid alloy;

[0089] 3) Inside the atomizing tank, 99.99% high-purity nitrogen gas at a pressure of not less than 0.9 MPa is sprayed at a speed of 260 m / s onto the ZnNiCr alloy liquid obtained in step 2). The nitrogen spraying direction is at 85° to the flow direction of the ZnNiCr alloy liquid, atomizing the ZnNiCr alloy liquid into micro-droplets. After cooling in a condenser, drying, and sieving, ZnNiCr alloy liquid with a particle size of 420 mesh is obtained. 20 Cr 30 pink.

[0090] The surface treatment methods for anchor bolts are as follows:

[0091] 1) Surface pretreatment: Remove oil stains from the surface of the anchor rod and perform shot blasting with steel shot with a diameter of 0.3mm to expose the metal surface;

[0092] 2) Add zinc powder and penetration aid or add ZnNi 20 Cr30 powder, AlSi 12 Powder, Al 50 Mg 50 Alloy powder, rare earth and infiltration aid are placed in a sealed co-infiltration furnace in proportion, and then the anchor rod is embedded in the multi-element powder furnace charge. The rotation speed of the co-infiltration furnace is set to 7 r / min. The co-infiltration furnace is equipped with a vacuum treatment device and the vacuum degree is maintained at 3 Pa. The co-infiltration furnace is heated to 410°C as the external temperature display shows. The temperature sensor is set to test the temperature of the co-infiltration agent in the furnace at 385°C and the temperature is maintained for 6 hours.

[0093] 3) Turn off the power and allow the temperature inside the co-infiltration furnace to cool to below 100°C. Push the furnace shell out to cool naturally, open the furnace cover, and separate the anchor rod from the furnace charge.

[0094] In step 2), the mass ratio of the powder to the volume of the co-infiltration furnace is 60L:100L; the mass ratio of the powder to the specific surface area of ​​the anchor rod is 800kg:1m². 2 ;

[0095] In step 3), the thickness of the film layer co-diffused with zinc powder or multi-element powder furnace charge is ≥60μm.

[0096] The method of spraying or immersing the passivation layer includes the following steps:

[0097] After the zinc-infiltrated layer or multi-element powder charge has been co-infiltrated onto the anchor rod, continue to spray or immerse it in passivation liquid for 2 minutes, and then dry it at 70°C to obtain the final product.

[0098] The preparation process of the grouting material is as follows:

[0099] (1) Add sand, plastic expansion agent, expansion agent, water-reducing agent, defoamer, stabilizer, retarder and rust inhibitor to the mixer in sequence, stir for 6 minutes, then add cement and continue stirring for 7 minutes;

[0100] (2) Add component B while stirring, and then continue stirring for 3 to 6 minutes, preferably 4 minutes;

[0101] (3) Stop stirring and let stand for 1.5 minutes to obtain the product.

[0102] In step (1), the stirring speed is 70 r / min;

[0103] In step (2), the stirring speed is 150 r / min.

[0104] Example 1

[0105] like Figure 1As shown, the solid anchor bolt for tunnels provided by the present invention includes a solid rod body 1, a pad 2, a grout stopper 3, a nut 4, a long pipe 5, a short pipe 6, and a self-anchoring anchor head 7. The solid rod body 1 includes an installation end 8 and a connecting end 9 arranged opposite to each other. A grout stopper 3, a pad 2, and a nut 4 are sequentially fitted onto the installation end 8, with the grout stopper 3 facing the connecting end 9. The grout stopper 3, pad 2, and nut 4 are all threaded onto the solid rod body 1. The grout stopper 3 has a first installation hole and a second installation hole for the long pipe 5 and the short pipe 6 to pass through, respectively. The pad 2 has a third installation hole and a fourth installation hole for the long pipe 5 and the short pipe 6 to pass through, respectively. The long pipe 5 includes a first end 10 and a... The second end 11, after the first end 10 passes through the first mounting hole and the third mounting hole, is installed on the grout stop plug 3 and the pad 2; the short pipe 6 includes a third end 12 and a fourth end 13 arranged opposite to each other. After the third end 12 passes through the second mounting hole and the fourth mounting hole, the fourth end 13 is installed on the grout stop plug 3 and the pad 2; the self-anchored anchor head 7 includes a mounting part 14 and a flared part 15. The flared part 15 is flared in the direction of the grout stop plug 3. The flared part 15 includes a first inclined plate 16 and a second inclined plate 17. The first inclined plate 16 has a first included angle with the solid rod body 1, and the second inclined plate 17 has a second included angle with the solid rod body 1. The connecting end 9 is detachably installed on the mounting part 14.

[0106] It should be noted that the long pipe 5 and the short pipe 6 are used together. When one is used as a grouting pipe, the other is used as a ventilation pipe. For example, when the long pipe 5 is selected for grouting, the short pipe 6 can expel the air in the grouting cavity to achieve the effect of full grouting. When the short pipe 6 is selected for grouting, the long pipe 5 can be used as an exhaust pipe. The grout stopper 3 prevents the grout from overflowing out of the grouting cavity after the grout is fully grouted.

[0107] The solid anchor bolt for tunnels provided by this invention includes a solid rod body 1, a pad 2, a grout stopper 3, a nut 4, a long pipe 5, a short pipe 6, and a self-anchoring anchor head 7. By injecting mortar into the long pipe 5 or the short pipe 6, the mortar continuously overflows from the long pipe 5 or the short pipe 6, thereby filling the grouting space. The flared portion 15 in the self-anchoring anchor head 7 is flared with the solid rod body 1, which enhances the anchoring force between the self-anchoring anchor head 7 and the surrounding rock and the injected mortar, thereby improving the anchoring force between the solid anchor bolt for tunnels and the surrounding rock and the injected mortar.

[0108] like Figure 1 As shown, the first included angle is 10°-30°, and the second included angle is 10°-30°. In this embodiment, the first inclined plate 16 and the second inclined plate 17 form a flared structure. The included angle within the above range can better enable the self-anchored anchor head 7 to achieve a stronger anchoring force between the surrounding rock and the grouting mortar, so that the tunnel solid anchor rod is more firmly installed between the surrounding rock and the grouting mortar.

[0109] In one embodiment of the present invention, the outer surfaces of the solid rod 1, the pad 2, and the nut 4 are all treated with anti-corrosion coating. It should be noted that the anti-corrosion treatment can be multi-element co-diffusion anti-corrosion or zinc diffusing anti-corrosion. After anti-corrosion treatment, the solid rod 1, the pad 2, and the nut 4 are less susceptible to corrosion, avoiding the problem of reduced anchoring force caused by corrosion, and improving the anchoring force between the tunnel solid anchor and the surrounding rock and grouting mortar.

[0110] In one embodiment of the present invention, the solid rod 1 is a hot-rolled ribbed steel bar or a finely rolled threaded steel bar. The hot-rolled ribbed steel bar or the finely rolled threaded steel bar has a certain strength, and its surface is rolled with continuous longitudinal ribs and evenly distributed transverse ribs, thereby strengthening the bond between the hot-rolled ribbed steel bar or the finely rolled threaded steel bar and the mortar, and improving the anchoring force between the tunnel solid anchor rod and the surrounding rock and the grouting mortar.

[0111] In one embodiment of the present invention, the long pipe 5 is made of metal or plastic, and the short pipe 6 is also made of metal or plastic. Specifically, the long pipe 5 and the short pipe 6 can also be made of copper or iron. The long pipe 5 and the short pipe 6 made of the above-mentioned materials are wear-resistant, which improves their service life and thus improves the service life of the tunnel solid anchor bolt.

[0112] In one embodiment of the present invention, the grout stopper 3 is made of rubber or plastic. Grout stoppers 3 made of the above-mentioned materials have a longer service life, thus improving the service life of the grout stopper 3 and consequently improving the service life of the tunnel solid anchor bolts.

[0113] In one embodiment of the present invention, the pad 2 is made of 45# steel or Q355 steel. The pad 2 made of the above-mentioned materials has high strength and resistance to deformation, thereby improving the service life of the pad 2 and thus improving the service life of the tunnel solid anchor bolt.

[0114] In one embodiment of the present invention, the pad 2 is a square plate or a round plate. The pad 2 of the above shape is easy to process and produce, reducing the production cost of the pad 2, thereby reducing the production cost of the solid anchor bolt for the tunnel.

[0115] In one embodiment of the present invention, the nut 4 is made of 45# steel or 40Cr steel. Nuts 4 made of the above materials have high strength and resistance to deformation, thereby improving the service life of the nut 4 and further improving the service life of the tunnel solid anchor bolt.

[0116] In one embodiment of the present invention, the connecting end 9 is threaded onto the mounting part 14. The threaded connection is easy to implement and operate, improving the convenience of production and operation of tunnel solid anchor bolts.

[0117] The solid anchor bolt for tunnels provided by this invention includes a solid rod body 1, a pad 2, a grout stopper 3, a nut 4, a long pipe 5, a short pipe 6, and a self-anchoring anchor head 7. By injecting mortar into the long pipe 5 or the short pipe 6, the mortar continuously overflows from the long pipe 5 or the short pipe 6, thereby filling the grouting space. The flared portion 15 in the self-anchoring anchor head 7 is flared with the solid rod body 1, which enhances the anchoring force between the self-anchoring anchor head 7 and the surrounding rock and the injected mortar, thereby improving the anchoring force between the solid anchor bolt for tunnels and the surrounding rock and the injected mortar.

[0118] Grouting materials of Examples 2-4 and Comparative Examples 1-4

[0119] The raw material ratios of the grouting materials in Examples 2-4 are shown in Table 1. They were prepared according to the above method, with component B being water and all other components belonging to component A. Their properties are shown in Table 2.

[0120] Table 1 Raw material ratio of grouting material

[0121]

[0122]

[0123] The performance of the grouting material was tested in accordance with the Technical Specification for Anchor Bolt Support in Railway Tunnels Q / CR9248-2020, and the penetration depth was tested in accordance with the Technical Specification for Corrosion Protection of Concrete Structures in Harbor Engineering JT / J275-2000.

[0124] Table 2 Performance of Grouting Material

[0125]

[0126]

[0127] Examples 1-3 and Comparative Examples 3-4 are ordinary cement mortars with a setting time of 4 hours or more. Examples 4 and Comparative Examples 1-2 are fast-setting cement mortars. The initial setting time of Example 4 is within 1-2 hours. The mortars prepared in Examples 1-4 have higher strength, and the appropriate vertical expansion rate can ensure full mortar filling and high anchoring force in the anchor bolts. The mortar using ultrafine cement in Examples 1-2 has a penetration depth greater than 1 mm, and its permeability is better than that of the comparative examples. With the optimization of the ratio of ultrafine cement, rust inhibitor, and quartz sand, the impermeability of Examples 1-4 is better than that of Comparative Examples 1-4.

[0128] Surface treatment of anchor bolts in Examples 5-9 and Comparative Examples 5-7

[0129] To investigate the effect of surface treatment methods on anchor bolt corrosion, the following experiments were conducted. Based on the anchor bolt from Example 1, zinc powder or multi-element powder co-diffusion and / or passivation liquid were sequentially applied. The compositions of the zinc powder and multi-element powder co-diffusion charge are shown in Table 3, and they were prepared according to the methods described above. The performance is shown in Table 4.

[0130] Table 3. Composition of zinc-diffusion powder and multi-element powder co-diffusion furnace charge

[0131]

[0132]

[0133] Table 4 Performance of Composite Anti-corrosion Coating of Zinc Diffusion Powder, Multi-element Powder Co-diffusion Charge + Passivation Liquid

[0134]

[0135] The Vickers hardness test of the co-permeable layer shall be conducted according to GB / T4340.1; the neutral salt spray resistance test shall be conducted according to GB / T1771; the alkali resistance test shall be conducted according to GB / T1690, and the absence of any change in appearance shall be determined; the co-permeable layer thickness test shall be conducted according to GB / T4956. The bond strength test with mortar shall be conducted according to DL / T5150-2001.

[0136] Comparative Examples 5 and 6 contain high Al content, which leads to the formation of pores at the interface between the anchor rod and the mortar, resulting in low bond strength. Comparative Example 7 lacks Mg and Ni, resulting in poor salt spray performance of both the co-permeation layer and the passivation layer, a shorter time to red rust appearance, and poor corrosion resistance.

[0137] The above description of specific embodiments of the present invention does not limit the present invention. Those skilled in the art can make various changes or modifications based on the invention, and as long as they do not depart from the spirit of the present invention, they should all fall within the scope of the appended claims.

Claims

1. A surface treatment method for an anchor bolt, the method comprising co-diffusion of multi-element powder furnace charge onto the surface of the anchor bolt and / or spraying or immersing in a passivation liquid to form a co-diffusion layer and a passivation layer; in, Multi-element powdered furnace charge is made by using multi-element powdered furnace charge together with a seepage aid, wherein the weight ratio of multi-element powdered furnace charge to seepage aid is 1:(0.05-0.2). The multi-element powder co-infiltration furnace charge, by mass percentage, contains 1.5-6.7% Al, 1.4-3.3% Mg, 0.2-1.1% Ni, 0.3-1.2% Cr, 0.1-1.0% Si, 0.1-0.6% rare earth elements, with the balance being zinc; The passivation liquid is one or more of the following: chromium-free environmentally friendly water-based passivation liquid, two-component polyurethane topcoat, water-based polyurethane topcoat, and water-based epoxy paint. The method for co-infiltration of the multi-element powder co-infiltration furnace charge is as follows: 1) Remove the oil stains from the surface of the anchor rod and perform shot blasting with steel shot with a diameter of 0.2~0.4mm to expose the metal surface of the anchor rod; 2) ZnNi 20 Cr 30 powder, AlSi 12 Powder, Al 50 Mg 50 Alloy powder, rare earth and infiltration aid are placed in a sealed co-infiltration furnace in a certain proportion. Then the anchor rod in step 1) is embedded in the above furnace charge. The rotation speed of the co-infiltration furnace is set to 6~10 r / min. The co-infiltration furnace is equipped with vacuum treatment equipment and the vacuum degree is maintained at 2~5 Pa. The co-infiltration furnace is heated to 360~450℃ as the external temperature display shows. The temperature sensor is set to test the temperature of the co-infiltration agent in the furnace at 370~410℃ and the temperature is maintained for 4~8 hours. 3) Turn off the power and allow the temperature inside the co-infiltration furnace to cool to below 100°C. Push the furnace shell out to cool naturally, open the furnace cover, and separate the anchor rod from the furnace charge.

2. The surface treatment method according to claim 1, characterized in that, The particle size of the multi-element powder co-infiltration furnace charge is 400-450 mesh.

3. The surface treatment method according to claim 1, characterized in that, The penetration aid is composed of NH4Cl and quartz sand, with NH4Cl accounting for 60% to 75% by mass percentage.

4. The surface treatment method according to claim 3, characterized in that, The particle size of the quartz sand is 80-100 mesh.

5. The surface treatment method according to claim 1, characterized in that, In step 2), the volume ratio of the multi-element powder furnace charge to the co-infiltration furnace is 40~60L:100L; The mass ratio of the multi-element powdered furnace charge to the specific surface area of ​​the anchor bolt is 600~1000 kg:1 m³. 2 ; The ZnNi 20 Cr 30 The powder is prepared as follows: 1) Prepare zinc ingots and nickel-chromium alloy ingots in a mass ratio of 50:

50. 20 Cr 30 ; 2) Zinc ingots and nickel-chromium alloy ingots Ni 20 Cr 30 Add it to the melting furnace, heat it to 600~850℃, and after it is completely melted, stir it thoroughly and keep it at the temperature for 15~30 minutes. Remove the surface slag to obtain ZnNiCr alloy liquid. 3) Inside the atomizing tank, 99.99% high-purity nitrogen gas at a pressure not less than 0.9 MPa is sprayed at a speed of 200~300 m / s onto the ZnNiCr alloy liquid obtained in step 2). The nitrogen spraying direction is 80°~100° to the flow direction of the ZnNiCr alloy liquid, atomizing the ZnNiCr alloy liquid into micro-droplets. After cooling in a condenser, drying, and sieving, ZnNiCr alloy liquid with a particle size of 400~450 mesh is obtained. 20 Cr 30 pink.

6. The surface treatment method according to claim 1, characterized in that, The method of spraying or immersing in the passivation liquid includes the following steps: After co-infiltration of multi-element powder furnace charge, continue to spray or immerse the anchor rod with passivation liquid for 1-5 minutes, and then dry it at 60-160℃ to obtain the final product. The thickness of the membrane layer co-infiltrated by the multi-element powder furnace charge is greater than or equal to 60µm; The thickness of the film layer sprayed or immersed in the passivation liquid is 5-20µm; The total thickness of the membrane layer co-infiltrated with the multi-element powder furnace charge and the membrane layer sprayed or immersed in the passivation liquid is 70-100µm.

7. The surface treatment method according to claim 1, characterized in that, The anchor bolt is a solid tunnel anchor bolt, comprising a solid rod body, a pad, a grout stop plug, a nut, a long pipe, a short pipe, and a self-anchoring anchor head, wherein: The solid rod includes an installation end and a connecting end arranged opposite to each other. The installation end is sequentially fitted with the grout stop plug, the washer plate, and the nut, with the grout stop plug facing the connecting end. The grout stop plug, the washer plate, and the nut are all threaded onto the solid rod. The grout stopper is provided with a first mounting hole and a second mounting hole for the long tube and the short tube to pass through, respectively. The pad is provided with a third mounting hole and a fourth mounting hole for the long tube and the short tube to pass through respectively; The long tube includes a first end and a second end disposed opposite to each other. After the first end passes through the first mounting hole and the third mounting hole, the second end is mounted on the grout stop plug and the gasket. The short tube includes a third end and a fourth end arranged opposite to each other. After the third end passes through the second mounting hole and the fourth mounting hole, the fourth end is installed on the grout stop plug and the gasket. The self-anchoring anchor head includes an installation part and a flared part. The flared part is flared in the direction of the grout stop plug. The flared part includes a first inclined plate and a second inclined plate. The first inclined plate has a first included angle with the solid rod body, and the second inclined plate has a second included angle with the solid rod body. The connecting end is detachably installed on the installation part. The first included angle is 10°-30°, and the second included angle is 10°-30°.

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