A construction method for replacing unbonded steel strands with pressure oil injection

Abstract

The present invention discloses a construction method for replacing bondless steel strands with pressure oil injection, which belongs to the technical field of bondless prestressed systems and solves the problem that bondless steel strands in existing prestressed anchoring systems cannot be replaced or are difficult to replace. The method is to dismantle the original prestressed anchor, connect the new steel strand to one end of the steel strand to be replaced in the bondless reinforcement, pull the other end of the steel strand to be replaced, and inject oil into the new steel strand at the same time until the new steel strand is completely pulled into place and tensioning is completed. The construction method for replacing bondless steel strands of the present invention can realize the rapid replacement of steel strands, solve the problem that bondless steel strands in prestressed anchoring systems cannot be replaced or are difficult to replace, and effectively extend the life cycle of the prestressed system.

Description

Technical Field

[0001] The invention relates to the technical field of unbonded prestressed system, and more specifically to a construction method for replacing unbonded steel strands with pressure oil injection. Background Art

[0002] At present, the prestressed anchoring system is mainly divided into bonded and non-bonded systems. The bonded anchoring system uses grouting to bond the steel strands to the structure to form a whole structure. The non-bonded anchoring system uses non-bonded bars. The outer PE sleeve of the non-bonded bars is filled with grease, so that the steel strands can slide in the PE, which can achieve a smaller friction loss. However, conventional non-bonded bars need to be cast together with concrete, which has a greater impact on large components or components cast in sections. In short, the friction loss of bonded prestressing is large, and the non-bonded construction is inconvenient.

[0003] In the field of civil engineering, especially in the field of third-generation nuclear power prestressed containment technology, the use of a non-bonded prestressing system can reduce the friction resistance of the prestressed beam, increase the effective prestress in the component, and shorten the nuclear power construction period. During the operation period of the component, if the steel strands are loose, the prestressed beams can be re-tensioned to extend the life cycle of the containment.

[0004] However, as time goes by, the steel strand will gradually relax due to the characteristics of the material, so that the component no longer has the original mechanical properties; during the life cycle of the steel strand, it may also break due to overload or the steel strand itself, which poses a safety hazard. Therefore, how to replace the steel strand without bonding has become a problem that needs to be solved urgently. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. The purpose of the present invention is to provide a construction method for replacing unbonded steel strands with pressure oil injection, so as to solve the problem that unbonded steel strands in prestressed anchoring systems cannot be replaced or are difficult to replace, thereby effectively extending the life cycle of the prestressed system.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a construction method for replacing unbonded steel strands with pressure oil injection. The method is to dismantle the original prestressed anchor, connect the new steel strand to one end of the steel strand to be replaced in the unbonded reinforcement, pull the other end of the steel strand to be replaced, and inject oil into the new steel strand at the same time until the new steel strand is fully pulled into place and tensioning is completed.

[0007] As a further improvement, the method comprises the following steps:

[0008] S1. Release the unbonded prestressed tendons and remove the anchor plates and clips at both ends of the prestressed tendons;

[0009] S2. Put the sealing device on the new steel strand and connect the sealing device to the oil injection machine;

[0010] S3, firmly connect the new steel strand to the steel strand to be replaced, and the traction steel strand of the traction machine to the steel strand to be replaced;

[0011] S4, sealingly connecting the other end of the sealing device to the PE sleeve in the unbonded reinforcement, and sealingly connecting one end of the sealing device to the new steel strand;

[0012] S5. Start the oil injection machine until the sealing device is filled with grease and maintain the oil injection pressure of 0.1 to 20 bar;

[0013] S6, start the traction machine, pull out the steel strand to be replaced, until the new steel strand completely replaces the steel strand to be replaced, remove the sealing device, disconnect the new steel strand from the steel strand to be replaced, disconnect the traction steel strand from the steel strand to be replaced, and cut off the new steel strand;

[0014] S7, repeating steps S3-S6 until all the steel strands to be replaced in the prestressed duct are replaced;

[0015] S8. Install anchors at both ends and tension and anchor the new steel strands to complete the replacement of the unbonded steel strands.

[0016] Furthermore, the sealing device comprises a sealing cylinder, the inner diameter of which is larger than the outer diameter of the new steel strand, one end of which is provided with a first sealing structure, and the other end of which is provided with a second sealing structure, the sealing cylinder is provided with an oil inlet pipe and an oil return pipe respectively, and the oil inlet pipe or the oil return pipe is provided with a pressure valve;

[0017] The step S2 comprises the following specific steps:

[0018] S2.1. Put the sealing tube onto the new steel strand;

[0019] S2.2. Connect the oil inlet pipe and oil return pipe to the oil outlet and oil return port of the oil injection machine respectively;

[0020] The step S4 comprises the following specific steps:

[0021] S4.1. Push the sealing cylinder toward one end of the steel strand to be replaced until the second sealing structure is inserted into the PE sleeve in the non-bonded rib, so that the second sealing structure clamps the PE sleeve to form a seal;

[0022] S4.2. Tighten the first sealing structure so that it clamps the new steel strand to form a seal.

[0023] Furthermore, the first sealing structure comprises a sealing cover and a sealing plug, and a conical hole is formed at one end of the sealing cylinder;

[0024] The step S2.1 includes the following specific steps:

[0025] S2.1.1. Put the sealing cover and sealing plug onto the new steel strand in sequence;

[0026] S2.1.2. Put the sealing tube onto the new steel strand;

[0027] The specific operation of step S4.2 is: connecting the sealing cover to the sealing cylinder, the sealing cover moves axially to squeeze the sealing plug, and the sealing plug is deformed under the squeezing of the tapered hole, so that the sealing plug clamps the new steel strand to form a seal.

[0028] Furthermore, the sealing plug is of a conical structure, and at least one protruding rib is provided on an end surface of the sealing plug close to the sealing cover and on a side surface of the sealing plug.

[0029] Furthermore, the inner wall of the sealing plug is provided with a spiral groove matching the spiral wire of the steel strand.

[0030] Furthermore, the second sealing structure comprises a sealing tube, the inner diameter of the sealing tube is smaller than the inner diameter of the sealing tube, and at least one sealing ring is provided on the inner wall of one end of the sealing tube;

[0031] The step S2.1 further comprises the following steps:

[0032] S2.1.3. Put the sealing tube into the new steel strand and connect and fix the sealing tube to the sealing cylinder;

[0033] In the step S4.1, when the second sealing structure is inserted into the PE sleeve in the non-bonded rib, the sealing ring and the PE sleeve are interference-fitted to form a seal.

[0034] Furthermore, the step S3 includes the following specific steps:

[0035] S3.1. Strip a certain length of the outer ring steel wire of the new steel strand and pierce the center wire. Use the same method to handle the steel strand to be replaced and the traction steel strand;

[0036] S3.2. Firmly connect the new steel strand to the steel strand to be replaced, and the traction steel strand to the steel strand to be replaced through connectors;

[0037] Wherein, the outer diameter of the connector is not greater than the outer diameter of the steel strand to be replaced.

[0038] Furthermore, the connector comprises a two-half cylinder, a pier groove is provided in the cylinder, and both ends of the cylinder are threadedly connected with tightening nuts.

[0039] Furthermore, a rubber ring is provided on the connector, and the outer diameter of the rubber ring is larger than the inner diameter of the PE sleeve in the non-bonded rib.

[0040] Beneficial Effects

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] 1. The construction method for replacing the unbonded steel strand of the present invention solves the problem that the unbonded steel strand in the prestressed anchor system cannot be replaced or is difficult to replace, and effectively extends the life cycle of the prestressed system.

[0043] 2. The construction method for replacing the bondless steel strand of the present invention injects grease into the sealing device through an oiling machine, so that the surface of the new steel strand and the gaps between the steel wires can be filled with grease, thereby ensuring the grease content of the bondless reinforcement after replacement and improving the anti-corrosion performance; at the same time, it makes it smoother for the new steel strand to be pulled into the PE sleeve, further improving the construction efficiency and reducing the damage of the steel strand to the PE sleeve.

[0044] 3. The construction method for replacing the unbonded steel strand of the present invention adopts a sealing cover to axially extrude the sealing plug, and cooperates with the tapered hole of the sealing cylinder to extrude, so that the sealing plug is deformed to clamp the new steel strand to achieve sealing. This can greatly improve the sealing effect and is more convenient for construction.

[0045] 4. The construction method for replacing bonded steel strands of the present invention adopts a conical structure for the sealing plug. The conical end of the sealing plug extends into the cavity of the sealing cylinder. The grease in the cavity can provide a certain pressure to deform the conical end of the sealing plug toward the steel strand, thereby achieving a better sealing effect. At the same time, the sealing plug adopts a spiral groove inner hole structure, which can fit the cross-sectional shape of the steel strand well. The sealing plug can seal the steel strand well, thereby achieving a better sealing effect.

[0046] 5. The construction method for replacing unbonded steel strands of the present invention provides a plurality of sealing ring grooves at the front end of the sealing tube to install the sealing ring. As the sealing tube is inserted, the sealing ring is compressed, and the sealing tube is used to squeeze the sealing ring forward to achieve sealing. The inner diameter of the sealing ring groove becomes smaller as it goes inward, and can adapt to PE sleeves of different diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of the present invention when applied;

[0048] Figure 2 for Figure 1 A schematic diagram of the enlarged structure at point A in the middle.

[0049] Figure 3 for Figure 2 A schematic diagram of the structure enlarged at B in the middle;

[0050] Figure 4 It is an enlarged schematic diagram of the structure of the sealing cylinder in the present invention;

[0051] Figure 5 It is an enlarged schematic diagram of the main structure of the sealing plug in the present invention;

[0052] Figure 6 It is an enlarged schematic diagram of the side view structure of the sealing plug in the present invention;

[0053] Figure 7 It is an enlarged schematic diagram of the structure of the sealing tube in the present invention;

[0054] Figure 8 It is an enlarged schematic diagram of the structure of the connector in the present invention.

[0055] Among them: 1-traction machine, 2-oil injection machine, 3-traction steel strand, 4-connector, 5-steel strand to be replaced, 6-new steel strand, 7-sealing device, 8-PE sleeve, 9-rubber ring, 41-cylinder, 42-pier groove, 43-tightening nut, 71-sealing cylinder, 72-oil inlet pipe, 73-oil return pipe, 74-sealing cover, 75-sealing plug, 76-sealing tube, 77-sealing ring, 711-conical hole, 751-raised rib, 752-spiral groove, 761-sealing ring groove. DETAILED DESCRIPTION

[0056] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0057] See also Figure 1-8 The present invention provides a construction method for replacing unbonded steel strands with pressure oil injection, which includes connecting a new steel strand 6 to one end of a steel strand 5 to be replaced in the unbonded reinforcement, pulling the other end of the steel strand 5 to be replaced, and injecting oil into the new steel strand 6 at the same time, until the new steel strand 6 is fully pulled into place and tensioning is completed.

[0058] The construction method for replacing the unbonded steel strand of the present invention solves the problem that the unbonded steel strand in the prestressed anchoring system cannot be replaced or is difficult to replace, and effectively prolongs the life cycle of the prestressed system.

[0059] The method comprises the following steps:

[0060] S1. Release the unbonded prestressed tendons and remove the anchor plates and clips at both ends of the prestressed tendons;

[0061] S2, insert the sealing device 7 onto the new steel strand 6, and connect the sealing device 7 with the oil injection machine 2;

[0062] S3, firmly connect the new steel strand 6 with the steel strand 5 to be replaced, and the traction steel strand 3 of the traction machine 1 with the steel strand 5 to be replaced;

[0063] S4, sealingly connecting the other end of the sealing device 7 to the PE sleeve 8 in the non-bonded rib, and sealingly connecting one end of the sealing device 7 to the new steel strand 6;

[0064] S5, start the oil injection machine 2 until the sealing device 7 is filled with grease, and maintain the oil injection pressure of 0.1-20 bar. The pressure oil injection method can not only make the grease enter the PE sleeve 8 better, but also squeeze the subsequent sealing plug, thereby improving the sealing effect;

[0065] S6, start the traction machine 1, pull out the steel strand 5 to be replaced, until the new steel strand 6 completely replaces the steel strand 5 to be replaced, remove the sealing device 7, disconnect the new steel strand 6 from the steel strand 5 to be replaced, disconnect the traction steel strand 3 from the steel strand 5 to be replaced, and cut off the new steel strand 6;

[0066] S7, repeating steps S3-S6 until all the steel strands 5 to be replaced in the prestressed channel are replaced;

[0067] S8. Install anchors at both ends and tension and anchor the replaced new steel strand 6 to complete the replacement of the unbonded steel strand.

[0068] The construction method for replacing the bondless steel strand of the present invention injects grease into the sealing device 7 through the oiling machine 2, so that the surface of the new steel strand and the gaps between the steel wires can be filled with grease, thereby ensuring the grease content of the bondless reinforcement after replacement and improving the anti-corrosion performance; at the same time, it makes it smoother for the new steel strand 6 to be pulled into the PE sleeve 8, further improving the construction efficiency and reducing the damage of the steel strand to the PE sleeve.

[0069] Preferably, the sealing device 7 in this embodiment includes a sealing cylinder 71, which is a hollow structure. The inner diameter of the sealing cylinder 71 is larger than the outer diameter of the new steel strand 6, so that a certain amount of grease can be temporarily stored in the sealing cylinder 71. A first sealing structure is provided at one end of the sealing cylinder 71 for clamping and sealing the new steel strand 6. A second sealing structure is provided at the other end of the sealing cylinder 71 for clamping and sealing the end of the PE sleeve 8, so that a closed cavity is formed in the sealing cylinder 71. During the oil filling process, a stable pressure can be maintained so that the grease can better enter the PE sleeve 8. An oil inlet pipe 72 and an oil return pipe 73 are respectively provided on the sealing cylinder 71, and a pressure valve (not shown in the figure) is provided on the oil inlet pipe 72 or the oil return pipe 73 to ensure that the grease in the sealing device 7 can maintain a certain pressure.

[0070] The above step S2 includes the following specific steps:

[0071] S2.1. Put the sealing tube 71 onto the new steel strand 6;

[0072] S2.2, connect the oil inlet pipe 72 and the oil return pipe 73 to the oil outlet and the oil return port of the oil injection machine 2 respectively;

[0073] The above step S4 includes the following specific steps:

[0074] S4.1, push the sealing cylinder 71 to move toward one end of the steel strand 5 to be replaced, until the second sealing structure is sleeved onto the PE sleeve 8 in the unbonded tendon, so that the second sealing structure clamps the PE sleeve 8 to form a seal;

[0075] S4.2. Tighten the first sealing structure so that the first sealing structure clamps the new steel strand 6 to form a seal.

[0076] Preferably, the first sealing structure in this embodiment includes a sealing cover 74 and a sealing plug 75, wherein the sealing plug 75 is a hollow structure, and a tapered hole 711 is opened at one end of the sealing cylinder 71, and the largest end of the tapered hole 711 faces the outside of the sealing cylinder 71;

[0077] The above step S2.1 includes the following specific steps:

[0078] S2.1.1. Put the sealing cover 74 and the sealing plug 75 onto the new steel strand 6 in sequence;

[0079] S2.1.2, put the sealing tube 71 onto the new steel strand 6;

[0080] The specific operation of the above step S4.2 is: connecting the sealing cover 74 to the sealing tube 71. Specifically, the sealing cover 74 can be connected to the sealing tube 71 by threads or screws. In this embodiment, threaded connection is preferred, which is more convenient to operate. The sealing cover 74 moves axially to extrude the sealing plug 75, and the sealing plug 75 is deformed under the extrusion of the tapered hole 711, so that the sealing plug 75 clamps the new steel strand 6 to form a seal.

[0081] In this embodiment, the sealing cover 74 is used to axially extrude the sealing plug 75, and cooperates with the conical hole 711 of the sealing cylinder 71 to extrude, so that the sealing plug 75 is deformed and clamps the new steel strand 6 to achieve sealing. This can greatly improve the sealing effect and is more convenient for construction.

[0082] Preferably, the sealing plug 75 is a conical structure, and the end surface of the sealing plug 75 close to the sealing cover 74 and the side of the sealing plug 75 are provided with at least one raised rib 751, so as to reduce the contact area and reduce the friction so that the sealing plug 75 can rotate more smoothly along the steel strand.

[0083] Preferably, since the steel strand is formed by spirally winding multiple steel wires, a spiral groove 752 matching the spiral wire of the steel strand is provided on the inner wall of the sealing plug 75. When the sealing plug 75 clamps the steel strand, the steel wire on the surface of the steel strand is embedded in the spiral groove 752, so that the steel strand fits tightly with the inner hole of the sealing plug 75 to reduce the gap, and when the steel strand and the sealing plug 75 move relative to each other, the sealing plug 75 can rotate freely to always achieve sealing, thereby further improving the sealing effect.

[0084] In this embodiment, the sealing plug 75 adopts a conical structure. The conical end of the sealing plug 75 extends into the cavity of the sealing tube 71. The grease in the cavity can provide a certain pressure, so that the conical end of the sealing plug 71 is deformed toward the steel strand, and the sealing effect is better. At the same time, the sealing plug adopts a spiral groove inner hole structure, which can fit the cross-sectional shape of the steel strand well. The sealing plug can seal the steel strand well and the sealing effect is better.

[0085] Preferably, the second sealing structure includes a sealing tube 76, the inner diameter of which is smaller than the inner diameter of the sealing tube 71. In this embodiment, the sealing tube 71 is connected to the PE sleeve 8 of the non-bonded rib 6 through the sealing tube 76, so that the sealing tube 71 is away from the steel strand 5 to be replaced, avoiding interference problems and being more conducive to construction. At least one sealing ring 77 is provided on the inner wall of one end of the sealing tube 76 to ensure sealing performance;

[0086] The above step S2.1 also includes the following steps:

[0087] S2.1.3, insert the sealing tube 76 onto the new steel strand 6, and connect and fix the sealing tube 76 to the sealing cylinder 71. Specifically, the sealing tube 76 and the sealing cylinder 71 can be connected by threads or screws. In this embodiment, threaded connection is preferred, which is more convenient to operate;

[0088] In the above step S4.1, when the second sealing structure is inserted into the PE sleeve 8 in the non-bonded rib, the sealing ring 77 and the PE sleeve 8 are interference-fitted to form a seal.

[0089] Preferably, there are multiple sealing rings 77 , which are installed in parallel in sealing ring grooves 761 provided on the inner wall of the sealing tube 76 , and the diameters of the sealing ring grooves 761 corresponding to the multiple sealing rings 77 gradually decrease along one end of the sealing tube 71 .

[0090] In this embodiment, a plurality of sealing ring grooves 761 are provided at the front end of the sealing tube 76 to install the sealing ring 77. As the sealing tube 76 is inserted, the sealing ring 77 is compressed, and the sealing tube 76 is used to squeeze the sealing ring 77 forward to achieve sealing. The inner diameter of the sealing ring groove 761 becomes smaller as it goes inward, and can adapt to PE sleeves of different diameters.

[0091] In other embodiments, the first sealing structure and the second sealing structure can also be independent sealing rings, and when the sealing tube 71 is inserted into the new steel strand 6, the sealing ring can be directly used to seal the new steel strand 6 and the PE sleeve by interference fit. Obviously, the sealing cover, sealing plug, and sealing tube structure in this embodiment have a better sealing effect.

[0092] Preferably, one end of the sealing tube 76 away from the sealing cylinder 71 is a bell mouth to facilitate the insertion of the steel strand.

[0093] Preferably, step S3 includes the following specific steps:

[0094] S3.1. Strip a certain length of the outer ring steel wire of the new steel strand 6 and pierce the center wire. Use the same method to process the steel strand 5 to be replaced and the traction steel strand 3.

[0095] S3.2, firmly connect the new steel strand 6 with the steel strand 5 to be replaced, and the traction steel strand 3 with the steel strand 5 to be replaced through the connector 4;

[0096] Among them, Figure 8 As shown, the connector 4 includes a two-half cylinder 41, a pier groove 42 is provided in the cylinder 41, the pier groove 42 is a through hole or a blind hole, and both ends of the cylinder 41 are threadedly connected with a tightening nut 43. After the center wire of the steel strand is pierced, the two-half cylinder 41 is covered on the center wire, so that the pier falls into the pier groove 42, and then the tightening nut 43 is tightened to achieve a quick connection of the steel strand. Further, a rubber ring 9 is provided on the connector 4, and there is at least one rubber ring 9, and the outer diameter of the rubber ring 9 is larger than the inner diameter of the PE sleeve 8 in the unbonded rib. Specifically, the outer diameter of the rubber ring 9 is 1-3 mm larger than the inner diameter of the PE sleeve 8.

[0097] The connector 4 of this embodiment can realize the connection of two sections of steel strands. At the same time, by adding a rubber ring 9 whose outer diameter is slightly larger than the inner diameter of the PE sleeve 8 to the connector 4, as much old grease as possible can be removed from the steel strands during replacement, and replacement with new grease can provide better long-term protection for the steel strands.

[0098] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A construction method for replacing unbonded steel strands with pressure oil injection, characterized in that: The method comprises the following steps: after disassembling the original prestressed anchor, connecting a new steel strand (6) to one end of the steel strand (5) to be replaced in the unbonded reinforcement, pulling the other end of the steel strand (5) to be replaced, and injecting oil into the new steel strand (6) at the same time, until the new steel strand (6) is completely pulled into place and tensioning is completed.

2. A construction method for replacing unbonded steel strands with pressure oil injection according to claim 1, characterized in that: The method comprises the following steps: S1. Release the unbonded prestressed tendons and remove the anchor plates and clips at both ends of the prestressed tendons; S2, inserting the sealing device (7) onto the new steel strand (6), and connecting the sealing device (7) with the oil injection machine (2); S3, firmly connecting the new steel strand (6) and the steel strand to be replaced (5), and the traction steel strand (3) of the traction machine (1) and the steel strand to be replaced (5); S4, sealingly connecting the other end of the sealing device (7) to the PE sleeve (8) in the non-bonded reinforcement, and sealingly connecting one end of the sealing device (7) to the new steel strand (6); S5, start the oil injection machine (2) until the sealing device (7) is filled with grease and the oil injection pressure is maintained at 0.1 to 20 bar; S6, starting the traction machine (1), pulling out the steel strand (5) to be replaced, until the new steel strand (6) completely replaces the steel strand (5) to be replaced, removing the sealing device (7), disconnecting the new steel strand (6) from the steel strand (5) to be replaced, disconnecting the traction steel strand (3) from the steel strand (5) to be replaced, and cutting off the new steel strand (6); S7, repeating steps S3-S6 until all the steel strands (5) to be replaced in the prestressed channel are replaced; S8. Install anchors at both ends and tension and anchor the replaced new steel strand (6) to complete the replacement of the unbonded steel strand.

3. A construction method for replacing unbonded steel strands with pressure oil injection according to claim 2, characterized in that: The sealing device (7) comprises a sealing cylinder (71), the inner diameter of the sealing cylinder (71) is larger than the outer diameter of the new steel strand (6), one end of the sealing cylinder (71) is provided with a first sealing structure, and the other end is provided with a second sealing structure, the sealing cylinder (71) is provided with an oil inlet pipe (72) and an oil return pipe (73), respectively, and the oil inlet pipe (72) or the oil return pipe (73) is provided with a pressure valve; The step S2 comprises the following specific steps: S2.

1. Put the sealing tube (71) onto the new steel strand (6); S2.2, connect the oil inlet pipe (72) and the oil return pipe (73) to the oil outlet and the oil return port of the oil injection machine (2) respectively; The step S4 comprises the following specific steps: S4.

1. Push the sealing cylinder (71) toward one end of the steel strand (5) to be replaced until the second sealing structure is inserted into the PE sleeve (8) in the non-bonded rib, so that the second sealing structure clamps the PE sleeve (8) to form a seal; S4.

2. Tighten the first sealing structure so that the first sealing structure clamps the new steel strand (6) to form a seal.

4. A construction method for replacing unbonded steel strands with pressure oil injection according to claim 3, characterized in that: The first sealing structure comprises a sealing cover (74) and a sealing plug (75), and a conical hole (711) is formed at one end of the sealing cylinder (71); The step S2.1 includes the following specific steps: S2.1.

1. Sequentially insert the sealing cover (74) and the sealing plug (75) onto the new steel strand (6); S2.1.

2. Put the sealing tube (71) onto the new steel strand (6); The specific operation of step S4.2 is: connecting the sealing cover (74) with the sealing cylinder (71), the sealing cover (74) moves axially to squeeze the sealing plug (75), and the sealing plug (75) is deformed under the squeezing of the tapered hole (711), so that the sealing plug (75) clamps the new steel strand (6) to form a seal.

5. A construction method for replacing unbonded steel strands with pressure oil injection according to claim 4, characterized in that: The sealing plug (75) is of a conical structure, and at least one protruding rib (751) is provided on an end surface of the sealing plug (75) close to the sealing cover (74) and on a side surface of the sealing plug (75). 。 6. A construction method for replacing unbonded steel strands with pressure oil injection according to claim 4, characterized in that: The inner wall of the sealing plug (75) is provided with a spiral groove (752) matching the spiral line of the steel strand.

7. A construction method for replacing unbonded steel strands with pressure oil injection according to claim 4, 5 or 6, characterized in that: The second sealing structure comprises a sealing tube (76), the inner diameter of the sealing tube (76) is smaller than the inner diameter of the sealing cylinder (71), and at least one sealing ring (77) is provided on the inner wall of one end of the sealing tube (76); The step S2.1 further comprises the following steps: S2.1.

3. Put the sealing tube (76) onto the new steel strand (6), and connect and fix the sealing tube (76) to the sealing cylinder (71); In the step S4.1, when the second sealing structure is inserted into the PE sleeve (8) in the non-bonded rib, the sealing ring (77) and the PE sleeve (8) are interference-fitted to form a seal.

8. The construction method for replacing unbonded steel strands with pressure oil injection according to claim 2, characterized in that: The step S3 comprises the following specific steps: S3.

1. Strip a certain length of the outer ring steel wire of the new steel strand (6) and pierce the center wire. The steel strand to be replaced (5) and the traction steel strand (3) are processed in the same way. S3.2, firmly connect the new steel strand (6) and the steel strand to be replaced (5), and the traction steel strand (3) and the steel strand to be replaced (5) through the connector (4); Wherein, the outer diameter of the connector (4) is not greater than the outer diameter of the steel strand (5) to be replaced.

9. A construction method for replacing unbonded steel strands with pressure oil injection according to claim 8, characterized in that: The connector (4) comprises a two-half cylinder (41), a pier groove (42) is provided in the cylinder (41), and both ends of the cylinder (41) are threadedly connected with tightening nuts (43).

10. The construction method for replacing unbonded steel strands with pressure oil injection according to claim 8, characterized in that: The connector (4) is provided with a rubber ring (9), and the outer diameter of the rubber ring (9) is larger than the inner diameter of the PE sleeve (8) in the non-bonded rib.

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