Double-layer anti-corrosion pre-stressed anchor rod achieved by controlling crack width through pre-grouting

Abstract

The utility model provides a double-layer anti-corrosion pre-stressed anchor rod realized by controlling crack width through pre-grouting, a double-layer plastic sleeve is arranged on the periphery of a free section, the inner layer is a plastic corrugated sleeve, and the outer layer is a plastic smooth sleeve; a single-layer plastic corrugated sleeve is arranged on the periphery of the anchoring section; the space between the plastic corrugated sleeve and the anchor rod body is filled with non-shrinkage cement paste solidification bodies in a factory in advance, the width of a crack generated by the cement paste solidification bodies in the plastic corrugated sleeve is not larger than 0.1 mm, so that the crack becomes an anti-corrosion protection layer of the anchor rod body, and the portion, on the outer side of the anchoring section, of the single-layer plastic corrugated sleeve serves as another anti-corrosion protection layer. And the plastic corrugated sleeve and the plastic smooth sleeve of the free section form double-layer corrosion prevention. Double-layer corrosion prevention of the pre-stressed anchor rod is achieved, only a single-layer sleeve is needed, cracks can be conveniently and effectively controlled, multiple protection effects can be achieved on a prefabricated structure, and the prefabricated structure is prevented from being damaged during transportation and installation; after factory prefabrication, on-site grouting is conducted, the on-site grouting procedure is simple, and the diameter of a drilled hole can be reduced.

Description

Technical Field

[0001] The utility model relates to a double - layer anti - corrosion prestressed anchor rod that controls crack width by pre - grouting, which is mainly applicable to underground engineering, foundation pit engineering, retaining wall engineering and slope engineering under temporary reinforcement or permanent reinforcement conditions in moderately or strongly corrosive strata. Background Technique

[0002] The prestressed anchor rod is a rigid rod - shaped member that actively bears tension. It fixes the stress - bearing tendon in the stratum through drilling and applies prestress during the installation stage, so as to achieve the purpose of stabilizing the reinforced body and restricting its deformation. The prestressed anchor rod consists of an anchor head, a free section, an anchorage section and accessories. With the development of anchoring technology, the requirements for the reliability and durability of anchor rods are getting higher and higher, and more and more precise. Especially for permanent buildings, permanent protective anchor rods are required. For anchor rods in corrosive strata, special anti - corrosion designs are needed to ensure the durability of the anchor rods. The anchor rod is buried in the stratum. When the soil or groundwater is corrosive, corrosion is likely to occur. The corrosion of the anchor rod body is the biggest threat factor affecting the life of the anchor rod. Accidents caused by corrosion due to improper design and construction of the anti - corrosion protection structure of anchor rods occur frequently at home and abroad. Content of the Utility Model

[0003] The purpose of the utility model is to provide a double - layer anti - corrosion prestressed anchor rod that controls crack width by pre - grouting, so as to improve the anti - corrosion performance of the prestressed anchor rod. The technical solution adopted by the utility model is as follows:

[0004] A double - layer anti - corrosion prestressed anchor rod that controls crack width by pre - grouting, including an anchor rod body, the anchor rod body includes an anchorage section and a free section, and is characterized in that,

[0005] The anchor head part includes a nut, a bearing plate, an epoxy resin cushion layer and a concrete base;

[0006] A double-layer plastic casing is provided around the free section of the bolt rod body. The inner layer is a plastic corrugated casing, and the outer layer is a plastic smooth casing. A single-layer plastic corrugated casing is arranged around the anchoring section. The space between the plastic corrugated casing and the bolt rod body is pre-filled with a non-shrinking cement slurry solid in the factory. The crack width of the cement slurry solid inside the plastic corrugated casing is not greater than 0.1 mm, forming an anti-corrosion protection layer for the bolt rod body. The single-layer plastic corrugated casing outside the anchoring section serves as another anti-corrosion protection layer. The plastic corrugated casing and the plastic smooth casing in the free section form a double-layer anti-corrosion structure. An isolation frame is provided between the plastic smooth casing and the bolt hole wall and between the single-layer plastic corrugated casing and the bolt hole wall, and it is filled with cement slurry solid. An anti-corrosion cap is provided at the rear end of the single-layer plastic corrugated casing. A sealing ring is arranged between the anti-corrosion cap and the single-layer plastic corrugated casing. A post heat shrinkable sleeve is also sleeved outside the connection between the anti-corrosion cap and the corrugated casing. The front end of the single-layer plastic corrugated casing and the plastic smooth casing are connected and sealed by a middle heat shrinkable sleeve. An extension sleeve is provided at the rear side of the bearing plate. The extension sleeve passes through the hole on the concrete pedestal and is inserted into the bolt hole. The front end of the plastic smooth casing is inserted into the extension sleeve, and a sealing ring is arranged between them. The part of the bolt rod body extending out of the plastic smooth casing is protected by the bearing plate, the extension sleeve and the concrete inside. The space between the bearing plate and the bolt hole orifice is sealed by an epoxy resin cushion layer.

[0007] After the bolt rod body is tensioned, its front end is connected and fixed with a nut, a bearing plate, an epoxy resin cushion layer, a concrete pedestal and the bolt hole orifice. An anchor head plastic cap is also provided at the anchor head part. The anchor head plastic cap covers the end of the bolt rod body, the nut and the nut washer at the anchor head, and is filled with a rust inhibitor inside to achieve the sealing of the integrity of the bolt rod body.

[0008] On the basis of adopting the above technical solutions, the present invention can also adopt the following further technical solutions, or use these further technical solutions in combination:

[0009] The plastic corrugated casing outside the free section and the single-layer plastic corrugated casing around the anchoring section are composed of the same plastic corrugated casing.

[0010] The nut washer includes a hemispherical washer, and the opening of the bearing plate fits the shape of the hemispherical washer. An epoxy resin cushion layer is provided at the bottom of the bearing plate to achieve spatial closure together with the concrete pedestal and prevent external corrosive substances from invading. A guiding sleeve is also provided for the double-layer anti-corrosion prestressed bolt. The guiding sleeve extends from the through hole on the concrete pedestal to the orifice of the bolt hole.

[0011] All the anchor head components of the bolt adopt a galvanized or epoxy anti-corrosion coating, providing an additional anti-corrosion layer for the anchor head and the front part of the rod body.

[0012] The bolt body is composed of several sections of bolt bodies connected together, and adjacent sections of bolt bodies are connected by a connector, so that the bolt can be further lengthened.

[0013] A grouting pipe and a slurry return pipe are provided between the plastic smooth casing and the single-layer plastic corrugated casing and the hole wall of the bolt hole.

[0014] The concrete base structure can be designed with different inclination angles. The bottom of the concrete base is a concrete cushion layer or a shotcrete layer. The bearing plate cooperates with the concrete base surface and the epoxy resin coating; the bearing plate and the hemispherical washer are provided with openings for the grouting pipe and the slurry return pipe to pass through.

[0015] Isolation frames are arranged between the plastic corrugated casing outside the free section and the single-layer plastic corrugated casing around the anchorage section and the bolt body, and between the plastic corrugated casing outside the free section and the plastic smooth casing. A precast filled cement slurry solid is filled and compacted between the plastic corrugated casing outside the free section and the plastic smooth casing.

[0016] Due to the adoption of the technical solution of the present utility model, the present utility model can be applied to prestressed bolts, realizing double-layer anti-corrosion of prestressed bolts and only requiring a single-layer casing, and can conveniently and effectively control cracks, and has multiple protection effects on precast structures, avoiding damage during transportation and installation; from factory prefabrication to the site, the on-site grouting procedure is simple, and the drilling diameter can be reduced. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of an embodiment of the present utility model.

[0018] Figure 2 is a schematic cross-sectional structural diagram of A-A of an embodiment of the present utility model. Detailed Embodiments

[0019] The present utility model will be further described below with reference to the drawings.

[0020] As Figure 1 shown, the double-layer anti-corrosion prestressed bolt using pre-grouting to control the crack width provided by the present utility model includes a bolt body. The bolt body includes an anchorage section and a tension section. The anchor head part includes a nut 304, a bearing plate 305, an epoxy resin cushion layer 203 and a concrete base 201.

[0021] A double-layer plastic casing is provided around the free section of the anchor rod body. The inner layer is a plastic corrugated casing 505, and the outer layer is a plastic smooth casing 506. A single-layer plastic corrugated casing 504 is provided around the anchoring section. Between the plastic corrugated casing (plastic corrugated casing 505 and single-layer plastic corrugated casing 504) and the anchor rod body, a non-shrinkage cement slurry solid 205 is pre-poured and filled in the factory and the thickness of the cement slurry solid is ensured by a spacer 603, which plays a supporting and centering function. The crack width generated by the cement slurry solid inside the plastic corrugated casing is not greater than 0.1 mm, thus becoming an anti-corrosion protection layer for the anchor rod body. The plastic corrugated casing not only serves as another anti-corrosion protection layer and provides sufficient anchoring friction in the anchoring section, but also protects the prefabricated body inside it, effectively ensuring the crack control result of the factory prefabricated body. In the free section, the plastic corrugated casing 505 and the plastic smooth casing 506 form a double-layer anti-corrosion structure, and the smooth plastic casing 506 allows the rod body in the free section to slide freely. A centering support 601 is provided between the plastic smooth casing 506 and the wall of the anchor hole 102 and filled with a cement slurry solid 204, and a centering support is provided between the single-layer plastic corrugated casing 504 and the wall of the anchor hole 102 and filled with a cement slurry solid 204 to ensure the thickness of the cement slurry outside the casing, playing a supporting and centering function, avoiding the displacement of the anchor rod structure during the grouting process, which may lead to the non-uniformity of the anti-corrosion protection structure, and improving the anti-corrosion protection effect and the overall mechanical properties. A centering support 602 is provided between the inner corrugated casing 505 and the outer smooth casing 506 and filled with a cement slurry solid 206, which is prefabricated and filled in the factory.

[0022] An anti-corrosion cap 508 is provided at the rear end of the single-layer plastic corrugated casing 504. A sealing ring 507 is provided between the anti-corrosion cap 508 and the single-layer plastic corrugated casing 504. A rear heat shrinkable sleeve 510 is also sleeved outside the connection between the anti-corrosion cap 508 and the single-layer plastic corrugated sleeve 504. The front end of the single-layer plastic corrugated casing 504 and the plastic smooth casing 506 are connected and sealed by a middle heat shrinkable sleeve 511. An extension sleeve 802 is provided at the rear side of the bearing plate 305. The extension sleeve 802 passes through the hole in the concrete base 201 and is inserted into the anchor hole 102. The front end of the plastic smooth casing 506 is inserted into the extension sleeve 802 and a sealing ring 502 is provided between them. The part of the anchor rod body extending out of the plastic smooth casing 506 is protected by the bearing plate 305, the extension sleeve 802 and the concrete inside it. The gap between the bearing plate 305 and the orifice of the anchor hole 102 is sealed by an epoxy resin cushion layer 203.

[0023] The plastic corrugated casing 505 outside the free section and the single-layer plastic corrugated casing 504 around the anchoring section are composed of the same plastic corrugated casing.

[0024] The bonding force between the prestressed anchor rod and the hole wall of the anchor hole corresponding to the single-layer corrugated casing 504 is the inner-end anchoring force. After the anchor rod body is tensioned, its front end is connected and fixed to the orifice of the anchor hole with the nut 304, the bearing plate 305, the epoxy resin cushion layer 203, and the concrete base 201.

[0025] An anchor head plastic cap 900 is also provided at the anchor head part. The anchor head plastic cap 900 covers the end of the anchor rod body of the anchor head, the nut 304, and the nut washer 303. The inside is filled with a rust inhibitor 901 to achieve the enclosure of the integrity of the anchor rod body. The plastic cap 900 can be filled with the rust inhibitor 901 through the opening 902. There is an epoxy resin cushion layer 203 at the anchor head part to achieve the enclosure between the bearing plate 305 and the concrete base 201, and the concrete base 201 can be cast in an inclined shape.

[0026] The nut washer 303 can be a hemispherical washer, and the opening 3051 of the bearing plate 305 fits the shape of the hemispherical washer; an epoxy resin cushion layer 203 is provided at the bottom of the bearing plate 305 to, together with the concrete base 201, achieve spatial enclosure and prevent external corrosive substances from invading.

[0027] The concrete base structure 201 can be designed with different inclination angles to compensate for the inclination angle of the axis of the anchor hole at the orifice of the anchor hole, so as to deal with anchor rods with different inclinations and make the anchor rod more stably in a reasonable position. The bearing plate 305 and the hemispherical washer are provided with openings for the grouting pipe or the return slurry pipe to pass through.

[0028] All anchor head metal components such as the nut 304, the bearing plate 305, and the nut washer 303 are galvanized or coated with epoxy in the factory. A guide pipe 801 is also provided at the orifice section to provide a guiding function for the prestressed anchor rod.

[0029] The anchor rod body is composed of two rod bodies 301 and 302 connected (it can also be a single section or multiple sections of rod bodies connected). The adjacent rod bodies are connected by a connector 701, so that the anchor rod can be further lengthened. The connector 701 is a metal connection sleeve, and the connecting ends of the two rod bodies 301 and 302 are threaded 702 and are threadedly connected to the connector 701.

[0030] The grouting between the plastic smooth casing 506 and the single-layer plastic corrugated casing 504 and the hole wall of the anchor hole is realized through the grouting pipe 402 and the return slurry pipe 403. The grouting pipe 402 and the return slurry pipe 403 pass through the openings on the bearing plate 305 and enter the space between the plastic smooth casing 506 and the single-layer plastic corrugated casing 504 and the hole wall of the anchor hole. Among them, the outlet of the grouting pipe 402 is located at the inner end of the anchor hole, and the inlet of the return slurry pipe 403 is close to the outer end of the anchor hole.

[0031] The implementation steps of this embodiment are as follows: After the pre-grouted anchor rod forms a prefabricated body (including the anchor rod body, plastic smooth casing 506, single-layer plastic corrugated casing 504, heat shrinkable sleeve, anticorrosion cap at the front end, and the solidified cement slurry inside), it is transported to the site. After the drilling and hole cleaning are completed on site, the cushion layer 202, concrete base 201, and epoxy resin cushion layer 305 are poured. The prefabricated body is placed into the anchor rod hole 102, and pure cement slurry is injected through the grouting pipe 402, with the return pipe 403 discharging air. After the upper orifice of the external return pipe 403 has stable return slurry, the grouting is stopped.

[0032] When the grouting slurry reaches the specified strength, prestress is applied, and the nut 304 is tightened to lock the anchor head. Finally, the anchor head is sealed with the anchor head plastic cap 900 and rust inhibitor 901.

[0033] The grouting and return pipes in the description of this embodiment and the attached drawings correspond to the case where the anchor rod hole is a downward hole. For an upward hole, the functions of the grouting and return pipes are correspondingly swapped, that is, the grouting pipe of the downward hole is used as the return pipe of the upward hole, and the return pipe of the downward hole is used as the grouting pipe of the upward hole.

[0034] The above are only specific implementation cases of the utility model. The technical features of the utility model are not limited thereto. Any changes or modifications made by those skilled in the relevant art within the field of the utility model are covered by the protection scope of the utility model.

Claims

1. A double - layer anti - corrosion prestressed anchor rod that controls crack width by pre - grouting, comprising an anchor rod body. The anchor rod body includes an anchorage section and a free section, and is characterized in that the anchor head part includes a nut, a bearing plate, an epoxy resin cushion layer, and a concrete pedestal; a double - layer plastic sleeve is provided on the outer periphery of the free section of the anchor rod body. The inner layer is a plastic corrugated sleeve, and the outer layer is a plastic smooth sleeve; a single - layer plastic corrugated sleeve is arranged on the outer periphery of the anchorage section; the space between the plastic corrugated sleeve and the anchor rod body is filled with a non - shrinkage cement slurry solid in the factory. The crack width of the cement slurry solid inside the plastic corrugated sleeve is not greater than 0.1 mm, forming an anti - corrosion protection layer of the anchor rod body. The single - layer plastic corrugated sleeve outside the anchorage section serves as another anti - corrosion protection layer. The plastic corrugated sleeve and the plastic smooth sleeve in the free section form a double - layer anti - corrosion; an isolation frame is arranged between the plastic smooth sleeve and the hole wall of the anchor hole and filled with a cement slurry solid; an anti - corrosion cap is provided at the rear end of the single - layer plastic corrugated sleeve. A sealing ring is arranged between the anti - corrosion cap and the single - layer plastic corrugated sleeve, and a post - heat - shrinkable sleeve is also sleeved outside the connection between the anti - corrosion cap and the single - layer plastic corrugated sleeve; the front end of the single - layer plastic corrugated sleeve and the plastic smooth sleeve are connected and sealed by a middle heat - shrinkable sleeve; an extension sleeve is arranged at the rear side of the bearing plate. The extension sleeve passes through the hole on the concrete pedestal and inserts into the anchor hole. The front end of the plastic smooth sleeve inserts into the extension sleeve and a sealing ring is arranged between them. The part of the anchor rod body extending out of the plastic smooth sleeve is protected by the bearing plate, the extension sleeve and the concrete inside it. The space between the bearing plate and the hole opening of the anchor hole is sealed by the epoxy resin cushion layer; after the anchor rod body is tensioned, its front end is connected and fixed to the hole opening of the anchor hole by the nut, the bearing plate, the epoxy resin cushion layer, and the concrete pedestal; an anchor head plastic cap is also arranged at the anchor head part. The anchor head plastic cap covers the end of the anchor rod body, the nut, and the nut washer at the anchor head, and is filled with a rust inhibitor inside to achieve the sealing of the integrity of the anchor rod body.

2. The double-layer anti-corrosion prestressed anchor rod using pre-grouting to control crack width as claimed in claim 1, wherein The plastic corrugated sleeve outside the free section and the single - layer plastic corrugated sleeve outside the anchorage section are composed of the same plastic corrugated sleeve.

3. A double-layer anti-corrosion prestressed anchor rod using pre-grouting to control crack width as claimed in claim 1, characterized in that, The nut washer includes a hemispherical washer. The opening of the bearing plate fits the shape of the hemispherical washer; an epoxy resin cushion layer is arranged at the bottom of the bearing plate. Together with the concrete pedestal, it realizes spatial closure to prevent external corrosive substances from invading; a guiding sleeve is also arranged on the double - layer anti - corrosion prestressed anchor rod. The guiding sleeve extends from the through - hole on the concrete pedestal to the inside of the hole opening of the anchor hole.

4. A double-layer anti-corrosion prestressed anchor rod that uses pre-grouting to control crack width as described in claim 1, characterized in that, All the anchor head components of the anchor rod adopt a galvanized or epoxy anti - corrosion coating, providing an additional anti - corrosion layer for the anchor head and the front part of the rod body.

5. A double-layer anti-corrosion prestressed anchor rod that uses pre-grouting to control crack width as described in claim 1, characterized in that, The anchor rod body is composed of several sections of rod bodies connected together. Adjacent rod bodies are connected by a connector, so that the anchor rod can be further lengthened.

6. A double-layer anti-corrosion prestressed anchor rod using pre-grouting to control crack width as described in claim 1, characterized in that, A grouting pipe and a return slurry pipe are arranged between the plastic smooth sleeve and the single - layer plastic corrugated sleeve and the hole wall of the anchor hole.

7. A double-layer anti-corrosion prestressed anchor rod that uses pre-grouting to control crack width as described in claim 3, characterized in that: The bearing plate, hemispherical washer, guide pipe and extension casing are protected against corrosion by galvanizing or epoxy coating. The concrete base structure can be designed with different inclination angles, and the bottom of the concrete base is a concrete cushion layer or a shotcrete layer. The bearing plate is matched with the concrete base surface and the epoxy resin coating. The bearing plate and the hemispherical washer are provided with openings for the grouting pipe and the return grouting pipe to pass through.

8. A double-layer anti-corrosion prestressed anchor rod that uses pre-grouting to control crack width as described in claim 1, characterized in that, Isolation frames are arranged between the plastic corrugated casing outside the free section and the single-layer plastic corrugated casing around the anchorage section and the anchor rod body, and between the plastic corrugated casing outside the free section and the plastic smooth casing. A precast filled cement slurry solid is filled and compacted between the plastic corrugated casing outside the free section and the plastic smooth casing.

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