Full-closed fixed end structure of slow-bonding prestressed steel strand extrusion anchor

Abstract

The utility model relates to a kind of full-closed fixed end structure of slow-bonding prestressed steel strand extrusion anchorage device, comprising: slow-bonding prestressed steel strand, including prestressed steel strand and the slow-setting adhesive and polyethylene sheath wrapped around prestressed steel strand;Extrusion anchorage device, is sleeved in the end of prestressed steel strand;Cast iron base, is sleeved in prestressed steel strand and extrusion anchorage device;Prestressed steel strand closure cover, one end is sealed connection with polyethylene sheath, the other end is sealed connection with the first end of cast iron base;Extrusion anchor closure cover, cover in the end of prestressed steel strand and the outside of extrusion anchorage device, and with the second end of cast iron base sealed connection, prestressed steel strand closure cover and extrusion anchor closure cover cover inner filling has waterproof adhesive.The full-closed fixed end structure of slow-bonding prestressed steel strand extrusion anchorage device can solve the problem of groundwater through steel strand steel wire gap seepage, can be prefabricated in factory, improve construction efficiency.

Description

Technical Field

[0001] This utility model relates to the field of foundation engineering technology, specifically to a fully enclosed fixed end structure for a slow-bonding prestressed steel strand extrusion anchor. Background Technology

[0002] When slow-bonded prestressed anti-buoyancy anchors (piles) are used for anti-buoyancy in underground structures, there is a widespread problem of structural water seepage, which seriously affects the use of the structure. The main reason for the water seepage of slow-bonded prestressed anti-buoyancy anchors (piles) is the lack of waterproof protection measures at the fixed end. The reasons are: (1) Due to the inherent characteristics of steel strands, there are gaps inside the steel strands after twisting. The fixed end is buried in the concrete of the anchor (pile body). Under the long-term action of high-pressure groundwater, groundwater seeps into the concrete. Due to the lack of waterproof measures at the fixed end, water enters the steel strands from the bottom of the fixed end and rises along the gaps, resulting in water seepage at the tensioning end, which affects the normal use of the structure; (2) Before the concrete pouring of the pile foundation or the grouting of the anchor, the hole is not thoroughly cleaned or the hole collapses during the pouring process, resulting in incomplete anchor grout or pile body concrete, which does not effectively protect the fixed end of the steel strand. The fixed end is directly immersed in the groundwater, and the groundwater seeps up along the gaps between the steel wires.

[0003] In the prior art, the technical solution for sealing the fixed end of prestressed anti-buoyancy anchor rod (pile) has the following problems: (1) The fixed end of the anchor rod is not completely sealed. For example, Chinese patent application No. 202210417364.4 discloses a corrosion-resistant and seepage-resistant anchor rod structure for construction. By putting the extrusion anchor into the sealing cover, the seepage resistance of the fixed end can be improved. However, no seepage-resistant measures are taken at the place where the steel strand passes through the steel pad plate at the upper part of the fixed end, which poses a risk of water seepage. At the same time, the seepage-resistant structure of the fixed end is too complicated and not conducive to construction. (2) The fixed end of the pile is not completely sealed. For example, Chinese patent application No. 202021536346.0 discloses a compression-type pull-out pile. In the patent, the steel strand is placed in the sealing cylinder. The gap between the steel strand and the steel pad plate is not sealed, so there is still a risk of water seepage. Utility Model Content

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a fully enclosed fixed end structure for a prestressed steel strand extrusion anchor, solving the problem of groundwater seepage through the gaps in the steel wires of existing prestressed anchors (piles) due to the lack of sealing at the fixed end of the extrusion anchor. It also solves the problems of complex and cumbersome construction associated with existing sealed fixed end structures. This fully enclosed fixed end structure for prestressed steel strand extrusion anchors can be prefabricated in a factory, improving construction efficiency and ensuring construction quality.

[0005] To achieve the purpose of this utility model, this utility model provides a fully enclosed fixed end structure for a slow-bonding prestressed steel strand extrusion anchor, comprising a slow-bonding prestressed steel strand, wherein the slow-bonding prestressed steel strand includes a prestressed steel strand and a slow-setting adhesive and a polyethylene sheath wrapped around the prestressed steel strand, and the polyethylene sheath and the slow-setting adhesive are removed from the end of the prestressed steel strand; the fully enclosed fixed end structure for the slow-bonding prestressed steel strand extrusion anchor further includes: an extrusion anchor, sleeved on the end of the prestressed steel strand; a cast iron base, sleeved on the prestressed steel strand and disposed on the polyethylene sheath and the extrusion anchor; and a prestressed steel strand enclosure, one end of which is sealed to the polyethylene sheath and the other end of which is sealed to the cast iron base. The first end of the support is sealed. The side wall of the prestressed steel strand enclosure is provided with a first injection hole for injecting waterproof adhesive into the prestressed steel strand enclosure. An extrusion anchor enclosure covers the outer side of the end of the prestressed steel strand and the outer side of the extrusion anchor. The distance between the extrusion anchor enclosure and the extrusion anchor is not less than 2mm, for example, 2mm to 10mm. The extrusion anchor enclosure is filled with waterproof adhesive. The side wall of the extrusion anchor enclosure is provided with a second injection hole for injecting waterproof adhesive into the extrusion anchor enclosure. The extrusion anchor enclosure is sealed to the second end of the cast iron base. A polyethylene weld is used to seal the second injection hole.

[0006] In some embodiments of this utility model, one end of the prestressed steel strand enclosure is connected to the polyethylene sheath via polyethylene welding material.

[0007] In some embodiments of this utility model, the length of the end of the prestressed steel strand after removing the polyethylene sheath and the retarding adhesive is 120mm to 260mm longer than the length of the extrusion anchor.

[0008] In some embodiments of this utility model, the cast iron base includes a plate, a first sleeve disposed at a first end of the plate and a second sleeve disposed at a second end of the plate, the plate having a wire passage hole connecting the first sleeve and the second sleeve, the wire passage hole for the prestressed steel strand to pass through.

[0009] In some embodiments of this utility model, the first sleeve is fitted over the prestressed steel strand, and the other end of the prestressed steel strand enclosure is threadedly connected to the outer wall of the first sleeve.

[0010] In some embodiments of this utility model, the second sleeve is disposed outside the extrusion anchor, and the extrusion anchor enclosure is threadedly connected to the outer wall of the second sleeve.

[0011] In some embodiments of this utility model, the cast iron base also includes a plurality of ribs, which are disposed between the second sleeve and the plate and distributed on the outer periphery of the second sleeve.

[0012] In some embodiments of this utility model, the cast iron base further includes a plurality of pressing protrusions, which are disposed inside the second sleeve and distributed on the inner circumference of the second sleeve, for abutting against the extrusion anchor.

[0013] In some embodiments of this utility model, the pressing protrusion is a protruding longitudinal rib extending axially along the second sleeve, and the protruding longitudinal rib gradually inclines towards the center line of the second sleeve in the direction from the second sleeve to the first sleeve; the outer peripheral wall of the extrusion anchor located inside the second sleeve cooperates with the protruding longitudinal rib, and the depth to which the protruding longitudinal rib is inserted into the outer peripheral wall of the extrusion anchor is 0.5mm~2.0mm.

[0014] In some embodiments of this utility model, the extrusion anchor cover includes a flared portion, and the second end of the cast iron base cooperates with the flared portion.

[0015] In some embodiments of this utility model, the polyethylene sheath includes a sheath body and ribs provided on the sheath body. The corresponding ribs at the ends of the sheath body are melted and then connected to the prestressed steel strand enclosure. The length of the connection between the polyethylene sheath and the prestressed steel strand enclosure is not less than 2 mm.

[0016] In some embodiments of this utility model, the polyethylene sheath extends into the prestressed steel strand enclosure for a length of not less than 0.5 cm.

[0017] In some embodiments of this utility model, the curing time of the waterproof adhesive does not exceed 72 hours.

[0018] In some embodiments of this utility model, the cast iron base is a single-hole or multi-hole structure.

[0019] Compared with the prior art, the present invention can achieve the following beneficial effects: This invention addresses the problem of water seepage along the gaps between the steel wires in existing prestressed anchor (pile) compression anchors due to the lack of sealing. It employs a prestressed steel strand sealing cover that seals and connects the sheath of the prestressed steel strand and the cast iron base at both ends. The compression anchor sealing cover covers the prestressed steel strand and the compression anchor, sealing it with the cast iron base. Waterproof adhesive is injected inside the compression anchor sealing cover, effectively improving the impermeability of the fixed end and providing better load-bearing performance. This fully enclosed fixed end structure solves the problem of complex existing closed fixed end structures, allowing for prefabrication in a factory, improving construction efficiency and ensuring construction quality. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an embodiment of the fully enclosed fixed end structure of the slow-bonding prestressed steel strand extrusion anchor of this utility model.

[0021] Figure 2 yes Figure 1 A magnified schematic diagram of the part circled at point A in the middle.

[0022] Figure 3 yes Figure 1 A magnified schematic diagram of the part circled at point B in the middle.

[0023] Figure 4 yes Figure 1 A magnified schematic diagram of the part circled at point C.

[0024] Figure 5 This is a schematic diagram of the cast iron base structure in an embodiment of the fully enclosed fixed end structure of the slow-bonding prestressed steel strand extrusion anchor of this utility model.

[0025] Figure 6 This is a schematic diagram of the cast iron base from another perspective in an embodiment of the fully enclosed fixed end structure of the slow-bonding prestressed steel strand extrusion anchor of this utility model.

[0026] Figure 7 This is a schematic diagram of the cast iron base in another embodiment of the fully enclosed fixed end structure of the slow-bonding prestressed steel strand extrusion anchor of this utility model.

[0027] In the diagram, 10-slow-setting prestressed steel strand, 11-prestressed steel strand, 12-slow-setting adhesive, 13-polyethylene sheath, 14-sheath body, 15-rib, 20-extrusion anchor, 30-cast iron base, 31-plate, 32-first sleeve, 33-second sleeve, 34-wire hole, 35-rib plate, 36-clamping protrusion, 40-prestressed steel strand enclosure, 50-extrusion anchor enclosure, 51-second injection hole, 52-flared end, 60-waterproof adhesive, 70-polyethylene weld, 80-polyethylene welding material.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0029] like Figures 1 to 7As shown, this utility model provides a fully enclosed fixed-end structure for a slow-bonded prestressed steel strand extrusion anchor, which seals the fixed end of the slow-bonded prestressed anti-buoyancy anchor or pile, effectively preventing water seepage at the fixed end. Using a single-hole or multi-hole cast fixed end can fundamentally meet the impermeability requirements of the fixed end, while also providing better load-bearing performance. The fully enclosed fixed-end structure of the slow-bonded prestressed steel strand extrusion anchor in this embodiment can be prefabricated in a factory, improving construction efficiency and ensuring construction quality.

[0030] Specifically, the fully enclosed fixed end structure of the slow-bonded prestressed steel strand extrusion anchor in this embodiment includes a slow-bonded prestressed steel strand 10, an extrusion anchor 20, a cast iron base 30, a prestressed steel strand enclosure 40, and an extrusion anchor enclosure 50.

[0031] The slow-setting prestressed steel strand 10 includes a prestressed steel strand 11 and a slow-setting adhesive 12 and a polyethylene sheath 13 wrapped around the prestressed steel strand 11. The slow-setting adhesive 12 wraps around the prestressed steel strand 11, and the polyethylene sheath 13 wraps around the outside of the prestressed steel strand 11 and the slow-setting adhesive 12. The polyethylene sheath 13 can be made of polyethylene material and can be used to protect the prestressed steel strand 11 and the slow-setting adhesive 12. The polyethylene sheath 13 and the slow-setting adhesive 12 are removed from the end of the prestressed steel strand 11 to facilitate passing through the central hole of the bearing plate and engaging with the extrusion anchor 20.

[0032] In this embodiment, the slow-bonding prestressed steel strand 10 can be a regular slow-bonding prestressed steel strand or an anti-seepage slow-bonding prestressed steel strand. The diameter and strength of the steel strand can be selected according to the diameter and bearing capacity of the slow-bonding prestressed anti-buoyancy anchor rod.

[0033] The extrusion anchor 20 is fitted onto the end of the prestressed steel strand 11. The extrusion anchor 20 is matched with the prestressed steel strand 11, and the size of the extrusion anchor 20 can be determined according to the diameter and strength of the prestressed steel strand 11.

[0034] The cast iron base support 30 is a cast-type pressure plate with good mechanical properties. The cast iron base support 30 is fitted onto the prestressed steel strand 11 and positioned between the polyethylene sheath 13 and the extruded anchor 20. The dimensions of the cast iron base support 30 can be determined based on the strength, diameter, and quantity of the prestressed steel strand 11.

[0035] One end of the prestressed steel strand enclosure 40 is welded and sealed to the polyethylene sheath 13, and the other end is threaded and sealed to the first end of the cast iron base 30. The prestressed steel strand enclosure 40 has two first injection holes for injecting waterproof adhesive 60 into the enclosure, achieving a seal between the polyethylene sheath 13, the prestressed steel strand 11, and the cast iron base 30. The prestressed steel strand enclosure 40 can be made of polyethylene material. The dimensions of the prestressed steel strand enclosure 40 can be determined based on the diameter of the prestressed steel strand 11.

[0036] The extrusion anchor enclosure 50 covers the outer side of the end of the prestressed steel strand 11 and the outer side of the extrusion anchor 20 to completely seal the end of the prestressed steel strand 11. The extrusion anchor enclosure 50 is threadedly sealed to the second end of the cast iron base 30. The extrusion anchor enclosure 50 is filled with waterproof adhesive 60. The waterproof adhesive 60 can be injected after the extrusion anchor enclosure 50 is installed to the second end of the cast iron base 30, or it can be injected before assembling the extrusion anchor enclosure 50 and the cast iron base 30. The waterproof adhesive 60 can be any existing waterproof adhesive material. The extrusion anchor enclosure 50 can be made of polyethylene. The size of the extrusion anchor enclosure 50 can be determined according to the dimensions of the prestressed steel strand 11 and the extrusion anchor 20. The side wall of the extrusion anchor enclosure 50 has two second injection holes 51 for injecting the waterproof adhesive 60 into the extrusion anchor enclosure 50. The distance between the extrusion anchor enclosure 50 and the extrusion anchor 20 shall not be less than 2mm, for example, the distance can be 2mm~10mm, to leave suitable space for the injection of waterproof adhesive 60. The fully enclosed fixed end structure of the prestressed steel strand extrusion anchor also includes a polyethylene weld 70, which is used to seal the second injection hole 51 on the side wall of the extrusion anchor enclosure 50 and the prestressed steel strand enclosure 40 after the waterproof adhesive 60 is injected.

[0037] As can be seen from the above, the fully enclosed fixed-end structure of the slow-bonded prestressed steel strand extrusion anchor in this embodiment, through the prestressed steel strand sealing cover 40 and the extrusion anchor sealing cover 50 at both ends of the cast iron base 30, and the injection of waterproof adhesive 60, achieves complete sealing of the end of the slow-bonded prestressed steel strand 10. This provides good sealing performance, preventing water from seeping up along the gaps between the steel wires in the steel strand, achieving complete impermeability of the slow-bonded prestressed anchor, and also exhibiting better load-bearing performance. Furthermore, this fully enclosed fixed-end structure of the slow-bonded prestressed steel strand extrusion anchor is structurally simple and can be prefabricated in a factory, improving construction efficiency and ensuring construction quality.

[0038] In some examples, one end of the prestressed steel strand enclosure 40 is connected to the polyethylene sheath 13 via a polyethylene welding material 80, thereby achieving a sealed connection between one end of the prestressed steel strand enclosure 40 and the polyethylene sheath 13. The polyethylene welding material 80 can weld the end of the prestressed steel strand enclosure 40 to the outer surface of the polyethylene sheath 13 together. The polyethylene welding material 80 can be existing materials such as polyethylene welding wire. The polyethylene welding material 80 is used to weld the prestressed steel strand enclosure 40 to the polyethylene sheath 13 of the loosely bonded prestressed steel strand 10, preventing water from seeping in.

[0039] In some examples, the other end of the prestressed steel strand enclosure 40 is threaded to the first end of the cast iron base 30, and waterproof adhesive 60 is injected into the prestressed steel strand enclosure 40 before it is assembled with the cast iron base 30.

[0040] In some examples, the cast iron base 30 includes a plate 31, a first sleeve 32 at a first end of the plate 31, and a second sleeve 33 at a second end of the plate 31. The plate 31 has a wire-passing hole 34 connecting the first sleeve 32 and the second sleeve 33, through which the prestressed steel strand 11 passes. The diameter of the wire-passing hole 34 can be 1 mm to 4 mm larger than the diameter of the prestressed steel strand 11. The end of the loosely bonded prestressed steel strand 10 is exposed from the polyethylene sheath 13, and the exposed length is 120 mm to 260 mm longer than the length of the extruded anchor.

[0041] In some examples, the first sleeve 32 is fitted over the prestressed steel strand 11, and the inner diameter of the first sleeve 32 is 1mm to 4mm larger than the diameter of the prestressed steel strand 11. The other end of the prestressed steel strand enclosure 40 is threaded to the outer wall of the first sleeve 32. The other end of the prestressed steel strand enclosure 40 may have internal threads, and the outer wall of the first sleeve 32 may have external threads. The two fit together, and the threaded connection can serve as a positioning function and has a certain degree of sealing.

[0042] In some examples, the second sleeve 33 is located outside the compression anchor 20, and the inner diameter of the second sleeve 33 is 1.0 mm to 6.0 mm larger than the outer diameter of the compression anchor 20. The inner wall of the second sleeve 33 may be provided with clamping protrusions 36, distributed around the inner circumference of the second sleeve 33. The clamping protrusions 36 abut against the compression anchor 20, allowing the compression anchor 20 to be more securely fixed to the cast iron base 30. The clamping protrusions 36 may be protruding longitudinal ribs extending axially along the second sleeve 33, with the protruding longitudinal ribs extending from the second sleeve 33 towards the first sleeve 32 (i.e.,...). Figure 1 The vertical direction from bottom to top gradually slopes towards the centerline of the second sleeve 33, with an angle of 1.5˚-4.5˚ (i.e., Figure 1The diameter of the extruded anchor 20 is between the upper and lower diameters of the protruding longitudinal ribs of the second sleeve. The rib height of the protruding longitudinal ribs can be 1.0mm to 4.0mm. The extruded anchor 20 can be pushed along the inner wall of the second sleeve 33 towards the first sleeve 32 using an extrusion press, gradually embedding itself into the protruding longitudinal ribs of the inner wall of the second sleeve 33 and tightly fitting with it. The depth to which the protruding longitudinal ribs are squeezed into the outer peripheral wall of the extruded anchor 20 is 0.5mm to 2.0mm. The extruded anchor 20 can be fitted with the second sleeve 33 by extrusion or other means, such as an interference fit, making it difficult for the extruded anchor 20 to detach from the second sleeve 33. The extruded anchor sealing cover 50 is threaded to the outer wall of the second sleeve 33. The inner surface of the extruded anchor sealing cover 50 can have internal threads, and the outer wall of the second sleeve 33 can have external threads. The two fit together, and the threaded connection can serve a positioning function and has a certain degree of sealing.

[0043] In some examples, the cast iron base 30 also includes a plurality of ribs 35 disposed between the second sleeve 33 and the plate 31 and distributed around the outer periphery of the second sleeve 33. The ribs 35 can improve the compressive strength of the plate 31.

[0044] In some examples, the prestressed steel strand enclosure 40 has a through hole through which the polyethylene sheath 13 and the prestressed steel strand 11 pass and accommodate the first end of the cast iron base 30. The prestressed steel strand enclosure 40 is provided with two second injection holes 51. When one end of the prestressed steel strand enclosure 40 is welded to the polyethylene sheath 13 with polyethylene, and the other end of the prestressed steel strand enclosure 40 is threaded to the outer wall of the first sleeve 32, waterproof adhesive 60 is injected into the prestressed steel strand enclosure 40 through the second injection holes. After completion, the second injection holes are sealed with polyethylene welding, thereby further improving the sealing performance.

[0045] In some examples, the compression anchor enclosure 50 includes a flared portion 52, the second end of the cast iron base 30 mates with the flared portion 52, and the bottom end of the flared portion 52 can serve a positioning function.

[0046] In some examples, the polyethylene sheath 13 includes a sheath body 14 and ribs 15 disposed on the sheath body 14. The corresponding ribs 15 at the ends of the sheath body 14 are melted before being connected to the prestressed steel strand enclosure 40. After the corresponding ribs 15 at the ends of the sheath body 14 are melted, the surface of the sheath body 14 is relatively smooth, making it less likely to form pores and increase the possibility of water seepage when it is fitted with the prestressed steel strand enclosure 40. The length of the connection between the polyethylene sheath 13 and the prestressed steel strand enclosure 40 is not less than 2mm, that is, the length of the corresponding ribs 15 at the ends of the sheath body 14 that are melted is not less than 2mm, achieving a stable connection and providing a greater length of waterproof effect.

[0047] In some examples, the polyethylene sheath 13 of the loosely bonded prestressed steel strand 10 extends into the prestressed steel strand enclosure 40 by a length of not less than 0.5 cm, for example, not less than 2 cm, to ensure the connection quality between the polyethylene sheath 13 and the prestressed steel strand enclosure 40.

[0048] In some examples, the cast iron base 30 has a single-hole or multi-hole structure, such as... Figure 5 and 6 As shown, a cast iron base 30 may have only one wire hole 34 for a prestressed steel strand 11 to pass through, or as... Figure 7 As shown, a cast iron base 30 may have multiple wire holes 34 for multiple prestressed steel strands 11 to pass through.

[0049] In some examples, the curing time of the waterproof adhesive 60 does not exceed 72 hours to avoid affecting the waterproofing effect due to excessive curing time. The waterproof adhesive 60 can be any existing adhesive with a curing time not exceeding 72 hours. The waterproof adhesive 60 can be cured at room temperature or by heating.

[0050] In some examples, the preparation method of the fully enclosed fixed end structure of the slow-bonded prestressed steel strand extrusion anchor of this embodiment may mainly include the following steps: (1) Determine the dimensions of the slow-bonded prestressed steel strand 10, the prestressed steel strand enclosure 40, the cast iron base 30, the extrusion anchor enclosure 50, and the extrusion anchor 20 based on the bearing capacity and diameter of the slow-bonded prestressed anchor or pile.

[0051] (2) Remove the polyethylene sheath 13 and the slow-setting adhesive 12 from one end of the slow-bonding prestressed steel strand 10. The length removed is the length of the extrusion anchor 20 + 120mm~260mm. Then, put the prestressed steel strand enclosure 40 into it.

[0052] (3) Insert the prestressed steel strand 11 from the first sleeve 32 into the cast iron base 30 and out from the second sleeve 33. The length of the outgoing strand is not less than the length of the extrusion anchor 20 + 100mm.

[0053] (4) The extrusion anchor 20 and the prestressed steel strand 11 are extruded into one piece by an extrusion press, and then the extrusion anchor is pushed back into the second sleeve 33. The pressing protrusion 36 in the second sleeve 33 is embedded into the extrusion anchor 20, so that the extrusion anchor 20, the prestressed steel strand 11 and the cast iron base 30 are combined into one piece.

[0054] (5) The cast iron base 30 and the prestressed steel strand enclosure 40 are connected as one unit by tightening the threads; the polyethylene sheath 13 of the slow-bonding prestressed steel strand 10 is welded to the prestressed steel strand enclosure 40 using polyethylene welding material 80, and waterproof adhesive 60 is poured into the prestressed steel strand enclosure 40. The injection hole is then sealed with polyethylene welding.

[0055] (6) Connect the extrusion anchor cover 50 to the cast iron base 30 via threads, and simultaneously fill the extrusion anchor cover 50 with waterproof adhesive 60. Then seal the injection hole with polyethylene weld 70.

[0056] Finally, it should be emphasized that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A fully enclosed fixed end structure for a delayed-bonding prestressed steel strand extrusion anchor, comprising a delayed-bonding prestressed steel strand, wherein the delayed-bonding prestressed steel strand includes a prestressed steel strand and a retarding adhesive and a polyethylene sheath wrapped around the prestressed steel strand, wherein the polyethylene sheath and the retarding adhesive are removed from the end of the prestressed steel strand; characterized in that: The fully enclosed fixed end structure of the slow-bonding prestressed steel strand extrusion anchor also includes: An extrusion anchor is fitted onto the end of the prestressed steel strand; A cast iron base is fitted onto the prestressed steel strand and the extrusion anchor. The prestressed steel strand enclosure has one end sealed to the polyethylene sheath and the other end sealed to the first end of the cast iron base. The side wall of the prestressed steel strand enclosure is provided with a first injection hole, which is used to inject waterproof adhesive into the prestressed steel strand enclosure. An extrusion anchor enclosure covers the outer side of the end of the prestressed steel strand and the outer side of the extrusion anchor. The distance between the extrusion anchor enclosure and the extrusion anchor is not less than 2 mm. The extrusion anchor enclosure is filled with waterproof adhesive. A second injection hole is provided on the side wall of the extrusion anchor enclosure for injecting waterproof adhesive into the extrusion anchor enclosure. The extrusion anchor enclosure is sealed to the second end of the cast iron base. Polyethylene welding is used to seal the first injection hole and the second injection hole.

2. The fully enclosed fixed end structure of the prestressed steel strand extrusion anchorage according to claim 1, characterized in that: One end of the prestressed steel strand enclosure is connected to the polyethylene sheath via polyethylene welding material.

3. The fully enclosed fixed end structure of a slow-bonding prestressed steel strand extrusion anchor according to claim 1 or 2, characterized in that: The length of the end of the prestressed steel strand after removing the polyethylene sheath and the retarding adhesive is 120mm to 260mm longer than the length of the extruded anchor.

4. The fully enclosed fixed end structure of a slow-bonding prestressed steel strand extrusion anchor according to claim 1 or 2, characterized in that: The cast iron base includes a plate, a first sleeve at a first end of the plate and a second sleeve at a second end of the plate. The plate has a wire passage hole connecting the first sleeve and the second sleeve, through which the prestressed steel strand passes. The first sleeve is fitted outside the prestressed steel strand, and the other end of the prestressed steel strand enclosure is threaded to the outer wall of the first sleeve. The second sleeve is located outside the extrusion anchor, and the extrusion anchor enclosure is threadedly connected to the outer wall of the second sleeve.

5. The fully enclosed fixed end structure of the prestressed steel strand extrusion anchor according to claim 4, characterized in that: The cast iron base also includes a plurality of ribs, which are disposed between the second sleeve and the plate and distributed on the outer periphery of the second sleeve. The cast iron base also includes a plurality of clamping protrusions, which are located inside the second sleeve and distributed on the inner circumference of the second sleeve, for abutting against the extrusion anchor.

6. The fully enclosed fixed end structure of a slow-bonding prestressed steel strand extrusion anchor according to claim 5, characterized in that: The pressing protrusion is a protruding longitudinal rib extending axially along the second sleeve. The protruding longitudinal rib gradually inclines towards the centerline of the second sleeve in the direction from the second sleeve to the first sleeve. The outer peripheral wall of the extrusion anchor located inside the second sleeve cooperates with the protruding longitudinal rib, and the depth to which the protruding longitudinal rib is inserted into the outer peripheral wall of the extrusion anchor is 0.5mm~2.0mm.

7. The fully enclosed fixed end structure of a slow-bonding prestressed steel strand extrusion anchor according to claim 4, characterized in that: The extrusion anchor enclosure includes a flared section, and the second end of the cast iron base mates with the flared section.

8. The fully enclosed fixed end structure of a slow-bonding prestressed steel strand extrusion anchor according to claim 1 or 2, characterized in that: The polyethylene sheath includes a sheath body and ribs provided on the sheath body. The corresponding ribs at the ends of the sheath body are melted and then connected to the prestressed steel strand enclosure. The length of the connection between the polyethylene sheath and the prestressed steel strand enclosure is not less than 2 mm. The polyethylene sheath extends into the prestressed steel strand enclosure for a length of not less than 0.5 cm.

9. A fully enclosed fixed end structure for a slow-bonding prestressed steel strand extrusion anchor according to claim 1 or 2, characterized in that: The curing time of the waterproof adhesive shall not exceed 72 hours.

10. A fully enclosed fixed end structure for a slow-bonding prestressed steel strand extrusion anchor according to claim 1 or 2, characterized in that: The cast iron base has a single-hole or multi-hole structure.

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