Pccp pipe with longitudinal steel wire controlling filament breakage influence range and manufacturing method thereof

Abstract

The application provides a PCCP pipeline adopting longitudinal steel wires to control the influence range of broken wires and a manufacturing method thereof, and belongs to the technical field of pipeline structures. In the production process of the PCCP pipeline, after the operation of winding the hoop prestressed steel wires is completed, the longitudinal steel wires are laid along the axial direction of the pipeline through a stress generating device. Then, the lap joint points of the longitudinal steel wires and the hoop prestressed steel wires are bonded by using high-performance bonding materials, and after the bonding materials are fully dried, the roller radiation mortar and asphalt anticorrosive layer operation is carried out. The application has the following characteristics: the longitudinal-hoop steel wire system has better cooperative working performance, when the hoop prestressed steel wire is broken, the prestress loss of the hoop prestressed steel wire can be effectively controlled within the range of the longitudinal steel wire arrangement under the dragging of the longitudinal steel wire, so that the pipeline still has certain bearing capacity near the broken wire. The application is suitable for the lining type or buried type PCCP pipeline, and has the advantages of simple construction and low cost.

Description

Technical Field

[0001] This invention belongs to the field of PCCP pipe structure technology, specifically relating to a PCCP pipe manufacturing method that effectively limits the impact range after the fracture of the circumferential prestressed steel wire by using the dragging effect of the longitudinal steel wire, and also relating to a novel PCCP pipe. Background Technology

[0002] Prestressed concrete cylinder pipe (PCCP) is a new type of composite multi-purpose pipe material, widely used in various long-distance water diversion projects. Traditional PCCP structures can be divided into lined and embedded types. Lined PCCP consists of a steel cylinder and a concrete lining forming the core, with circumferential prestressed steel wires wound around the outside of the steel cylinder, followed by a cement mortar protective layer. Embedded PCCP consists of a steel cylinder and concrete layers on both the inner and outer sides forming the core, with circumferential prestressed steel wires wound around the outside of the concrete core, followed by a cement mortar protective layer. The circumferential prestressed steel wires generate uniform pressure on the concrete core, enabling the pipe to resist tensile stresses generated by internal and external water pressure.

[0003] During operation, prestressed concrete pipe systems (PCCPs) may experience breakage of the circumferential prestressed steel wires due to factors such as design, manufacturing, construction, and environmental corrosion. This can cause cracks in the mortar protective layer and concrete core near the broken wire. As the stress conditions near the broken wire continue to deteriorate, multiple circumferential prestressed steel wires may break in the same area, further reducing the pipeline's load-bearing capacity and greatly increasing the risk of pipe bursts and other catastrophic accidents. Besides causing water supply interruptions, PCCP bursts can also lead to floods and public safety incidents, resulting in significant economic losses.

[0004] Currently, the engineering community has conducted extensive research on the repair and reinforcement technology of PCCP pipelines after wire breakage, and has proposed reinforcement measures such as external concrete encasing, pipe replacement, and external fiber-reinforced composite material application. However, these methods usually require excavation of the soil covering the broken PCCP section before reinforcement treatment. Traditional methods are characterized by cumbersome construction steps, large workload, and high repair costs. Chinese Patent CN208519336U, "A Novel PCCP Structure," discloses a novel PCCP structure in which a layer of longitudinal reinforcing steel is arranged on the inner and outer walls of the circumferential concrete core. This invention controls the impact range of circumferential prestressed steel wire breakage by adding longitudinal steel wires, thereby ensuring that the pipeline still has a certain load-bearing capacity after wire breakage, providing a method for early intervention to prevent and control wire breakage.

[0005] However, the following major problems still exist in this scheme: (1) The longitudinal steel wire and the circumferential prestressed steel wire do not form an integrated force system. The circumferential steel wire and the longitudinal steel wire cannot deform and bear force together to resist the load. (2) The material properties of the longitudinal steel wire are not fully utilized, and the effect of curbing the influence range of wire breakage is not significant. (3) The number of longitudinal steel wires is relatively large. However, this structural form only increases the stiffness of the pipe in the axial direction and contributes little to the stiffness in the tangential and circumferential directions. (4) The addition of more longitudinal steel wires will restrict the deformation of the circumferential prestressed steel wire under internal and external pressure and the performance of its load-bearing function, which will have an adverse effect on the overall flexibility of the pipe. (5) The arrangement of a large number of longitudinal steel wires leads to a relatively high manufacturing cost of the pipe and an increase in the overall weight, which is not conducive to large-scale production, promotion and application.

[0006] Therefore, it is urgent to consider further optimization of the PCCP structure to achieve better collaborative performance of the longitudinal-circular steel wire system. This would allow the longitudinal steel wire to fully utilize its material properties, enabling it to bear part of the load after the circumferential prestressed steel wire breaks, further curbing the impact of wire breakage and reducing the cost of the new PCCP structure. Summary of the Invention

[0007] One of the objectives of this invention is to provide a novel PCCP pipe manufacturing method that optimizes the synergistic working performance of longitudinal and circumferential steel wires and enables the longitudinal steel wires to bear part of the load after the circumferential prestressed steel wires break, thereby effectively curbing the impact range of wire breakage.

[0008] The second objective of this invention is to provide a novel PCCP pipe that can effectively control the impact range after the fracture of the circumferential prestressed steel wire and reduce the cost.

[0009] One of the technical solutions adopted by this invention to achieve its objective is: to provide a manufacturing method for a PCCP pipe that uses longitudinal steel wires to control the range of influence of broken wires, comprising the following steps:

[0010] S1. Fix the socket steel ring to both ends of the steel cylinder and set anchor points; pour concrete and cure it to the specified strength;

[0011] S2. Wrap circumferential prestressed steel wire around the outside of the cured outer concrete or steel cylinder;

[0012] S3. Anchor one end of the longitudinal steel wire to the anchor point on one side of the pipe, lay it out along the axial direction of the pipe, and anchor the other end to the anchor point on the other side of the pipe; the number of longitudinal steel wires is 4 to 8, and they are evenly distributed along the circumference of the steel cylinder.

[0013] S4. A high-performance adhesive is used to bond the overlap points of the circumferential prestressed steel wire and the longitudinal steel wire; the high-performance adhesive has a compressive strength ≥65MPa, a steel-to-steel tensile bond strength ≥30MPa, and a shear strength ≥18MPa.

[0014] S5. After the high-performance adhesive has dried sufficiently, roll-apply the outer mortar protective layer and the asphalt anti-corrosion layer.

[0015] The overall concept of the PCCP pipe manufacturing method provided by this invention, which uses longitudinal steel wires to control the influence range of wire breakage, is as follows:

[0016] In the structure of lined or buried PCCP pipelines, longitudinal steel wires are introduced. These longitudinal steel wires are laid after the circumferential prestressed steel wires are wound around them. A high-performance adhesive is used to bond the overlaps between the longitudinal and circumferential spiral steel wires. Under the bonding effect of the high-performance adhesive, the longitudinal steel wires and the circumferential prestressed steel wires are connected into a single load-bearing unit. Through the combined action and coordinated work of the longitudinal and circumferential prestressed steel wires, they jointly bear the load. When the circumferential prestressed steel wire breaks, the longitudinal steel wire can bear part of the load. Under the drag of the longitudinal steel wire, the prestress loss range can be effectively limited to the area where the longitudinal steel wire is arranged, thus effectively curbing the impact of wire breakage.

[0017] In this invention, the number of longitudinal steel wires needs to consider the following two points simultaneously: First, from the perspective of structural stress, the circumferential prestressed steel wires still play a major role in bearing the circumferential tensile stress load. In order to enable the circumferential prestressed steel wires to fully deform and perform their load-bearing function under internal and external pressure, the number of longitudinal steel wires needs to be minimized to ensure that the entire PCCP structure has a certain degree of flexibility. Second, to meet the design requirements of "lightweighting," it is necessary to avoid introducing too many longitudinal steel wires, which would increase the self-weight of the pipeline, minimize the cost of longitudinal steel wires and adhesives, and control the overall cost of the new PCCP pipeline. Taking all factors into consideration, this invention sets the number of longitudinal steel wires to 4 to 8, and distributes them evenly along the circumference of the steel cylinder.

[0018] Furthermore, to ensure that the longitudinal steel wires can effectively limit the prestress loss range after the circumferential prestressed steel wires break, the longitudinal steel wires should preferably be laid at locations where the pipeline is under greater stress or at weak points in the structure. Preferably, there are four longitudinal steel wires, laid at the top, bottom, and both sides of the pipe, or eight longitudinal steel wires can be used, evenly laid at 45° intervals along the circumference of the pipeline.

[0019] Furthermore, to ensure an effective and reliable connection at the overlap points of the longitudinal and circumferential prestressed wires, this invention employs a high-performance adhesive to bond the overlap points. This high-performance adhesive possesses a compressive strength ≥65 MPa, a steel-to-steel tensile bond strength ≥30 MPa, and a shear strength ≥18 MPa. The use of this high-performance adhesive ensures a reliable connection between the longitudinal and circumferential prestressed wires, forming a structural whole. This not only allows them to jointly bear loads but also, in the event of a fracture in the circumferential prestressed wire, enables the longitudinal wire to provide a dragging effect, more effectively limiting the impact range of prestress loss.

[0020] In the PCCP pipe manufacturing method provided by the present invention, the PCCP pipe can be an internally lined PCCP pipe or an embedded PCCP pipe.

[0021] In step S1, firstly, the socket steel rings of the PCCP joint are fabricated; then, the steel plate is rolled into a steel cylinder, and the socket steel rings are welded to both ends of the steel cylinder. The steel cylinder with the sockets is then hoisted into the formwork for accurate positioning. Before concrete pouring, metal anchor blocks are embedded or welded into the concrete pouring area on both sides of the pipe or into the socket steel rings (for lined PCCP pipes, the anchor blocks are welded to the socket steel rings; for embedded PCCP pipes, the anchor blocks are embedded in the concrete surface). The anchor blocks provide anchor points for subsequent wire wrapping and laying of longitudinal steel wires. Then, concrete is poured and cured. When the concrete strength reaches 70%–85% of the design strength, the next step of wire wrapping begins.

[0022] Furthermore, in step S1, when the PCCP pipeline is an internally lined PCCP pipeline, the concrete is placed inside the steel cylinder; when the PCCP pipeline is an embedded PCCP pipeline, the concrete includes an inner layer of concrete inside the steel cylinder and an outer layer of concrete outside the steel cylinder.

[0023] Furthermore, in step S2, when the PCCP pipe is an internally lined PCCP pipe, circumferential prestressed steel wire is wound around the outside of the steel cylinder; when the PCCP pipe is an embedded PCCP pipe, circumferential prestressed steel wire is wound around the outside of the cured outer layer of concrete.

[0024] Furthermore, in step S2, the cured core is placed on the prestressed winding platform. The core is rotated by the rotation of the winding platform, so that the high-strength steel wire is wound on the core with a certain prestress and pitch to form a circumferential prestressed steel wire.

[0025] Furthermore, in step S3, the longitudinal steel wires are anchored in the same way as the circumferential prestressed steel wires at both ends. That is, before the concrete pouring operation, metal anchor blocks are embedded or welded into the concrete areas to be poured on both sides of the pipe or into the socket steel rings. The anchor blocks are used to apply a fixed constraint to the longitudinal steel wires at both ends of the socket.

[0026] Furthermore, in step S3, the wire laying is carried out using a stress generating device that winds spiral steel wire, and the wire laying speed and forward speed of the stress generating device are controlled by the differential winding principle to achieve that the longitudinal steel wire has initial prestress or no initial prestress.

[0027] In this invention, the effective range of the "zero-stress zone" is essentially the same regardless of whether the longitudinal steel wire has initial prestress or not. However, further research has revealed that the longitudinal steel wire with initial prestress can also increase the stress of the circumferential steel wire near the "zero-stress zone" to a certain extent. Therefore, preferably, the longitudinal steel wire has initial prestress, which is 50% to 70% of the tensile strength of the longitudinal steel wire. By applying prestress to the longitudinal steel wire to enhance the limitation of the range of wire breakage, the material strength is fully utilized while the corresponding load-bearing capacity is also improved.

[0028] Preferably, the specifications, dimensions, and material parameters of the longitudinal steel wire are the same as those of the circumferential prestressed steel wire, which helps the longitudinal steel wire with initial prestress to achieve high-strength prestress.

[0029] Furthermore, in step S4, the high-performance adhesive includes one or more of epoxy structural adhesive, polyurethane structural adhesive, and acrylate structural adhesive. The high-performance adhesive has a compressive strength ≥65MPa, a steel-to-steel tensile bond strength ≥30MPa, and a shear strength ≥18MPa to ensure a reliable connection between the longitudinal steel wire and the circumferential prestressed steel wire, forming a structural whole. This not only allows them to jointly bear the load, but also, in the event of circumferential prestressed steel wire breakage, the longitudinal steel wire can provide a dragging effect on the circumferential steel wire, more effectively limiting the impact range of prestress loss. In addition, the aging resistance, fatigue resistance, and corrosion resistance of the high-performance adhesive must remain stable throughout its expected lifespan.

[0030] Furthermore, in step S4, side plates are used to fix and pressurize the adhesive at the overlap point of the circumferential prestressed steel wire and the longitudinal steel wire. The side plates include a first side plate and a second side plate located on both sides of the longitudinal steel wire. The two side plates and the socket anchor block enclose a construction area for the high-performance adhesive. The high-performance adhesive is then poured into this construction area, ensuring that the longitudinal steel wire is submerged. Subsequently, appropriate pressure is applied to the longitudinal steel wire using tools such as steel plates. After the high-performance adhesive has cured, the pressure fixing device is removed, thus completing the bonding operation at the overlap point of the circumferential prestressed steel wire and the longitudinal steel wire.

[0031] In step S5, after the high-performance adhesive has fully solidified and dried, the core is placed on the roller injection table and the cement mortar protective layer and the asphalt anti-corrosion layer are successively roller-injected by a high-speed roller injection machine.

[0032] The second technical solution adopted by the present invention to achieve the objective is to provide a PCCP pipe that uses longitudinal steel wires to control the range of influence of broken wires, which is manufactured by the manufacturing method described in the first objective of the present invention.

[0033] In some preferred embodiments, the PCCP pipe is an internally lined PCCP pipe, which, from the inside out, comprises: concrete, a steel cylinder, circumferential prestressed steel wires, longitudinal steel wires, and an outer protective mortar layer.

[0034] In some preferred embodiments, the PCCP pipeline is a buried PCCP pipeline, which, from the inside out, includes: an inner layer of concrete, a steel cylinder, an outer layer of concrete, circumferential prestressed steel wires, longitudinal steel wires, and an outer layer of protective mortar.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] (1) The present invention provides a manufacturing method for PCCP pipe that uses longitudinal steel wires to control the range of influence of broken wires. The combined action of longitudinal steel wires and circumferential prestressed steel wires is used to jointly bear the load. When the circumferential prestressed steel wire breaks, the prestress loss range can be effectively limited to the range of longitudinal steel wire arrangement under the drag of the longitudinal steel wire.

[0037] (2) The present invention provides a manufacturing method for PCCP pipes that uses longitudinal steel wires to control the range of wire breakage. The process is simple, requiring only the addition of longitudinal steel wire laying and overlap bonding steps to the traditional PCCP production line, without affecting the existing PCCP production line. The cost of the present invention is relatively low, requiring only the addition of longitudinal steel wires and high-performance adhesives in terms of materials. This manufacturing method has a wide range of applications and can be used for lined or buried PCCP pipes.

[0038] (3) In the PCCP pipe structure provided by this invention, which uses longitudinal steel wires to control the range of wire breakage, the material properties of the longitudinal steel wires are fully utilized. After the circumferential steel wires break, the longitudinal steel wires bear part of the load, that is, the longitudinal and circumferential steel wires form a more consistent stress-deformation system to jointly resist the load. At the same time, this invention achieves a more significant effect in curbing wire breakage with fewer longitudinal steel wires, further reducing the manufacturing cost of the new PCCP structure. Attached Figure Description

[0039] Figure 1A schematic flowchart of a manufacturing method for a PCCP pipe using longitudinal steel wire to control the range of influence of broken wires, provided by the present invention;

[0040] Figure 2 This is a schematic diagram illustrating the use of a stress generating device to lay longitudinal steel wires according to an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram illustrating the fixing and pressurization of the adhesive at the overlap point of the circumferential prestressed steel wire and the longitudinal steel wire using a side plate, as described in an embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram of the structure of an internally lined PCCP pipe provided in Embodiment 1 of the present invention;

[0043] Figure 5 This is a schematic diagram of the structure of an embedded PCCP pipeline provided in Embodiment 3 of the present invention;

[0044] Figure 6 This is a comparison diagram of the stress loss of the circumferential prestressed steel wire after wire breakage in Examples 3 and 4 of the present invention and Comparative Examples 1-3;

[0045] Figure 7 These are comparison diagrams of circumferential strain in concrete in Examples 3 and 4 of the present invention and Comparative Examples 2 and 3.

[0046] Figure 8 These are comparison diagrams of longitudinal-circumferential wire deformation in Embodiments 3 and 4 of the present invention and Comparative Examples 2 and 3;

[0047] Figure 9 The diagram shows a comparison of longitudinal wire stress in Examples 3 and 4 and Comparative Examples 2 and 3 of the present invention.

[0048] Among them, 1-concrete; 11-inner layer concrete; 12-outer layer concrete; 2-steel cylinder; 3-circumferential prestressed steel wire; 4-longitudinal steel wire; 5-outer protective mortar; 6-stress generating device; 7-metal anchor block; 8-core tube; 9-first side plate; 10-second side plate. Detailed Implementation

[0049] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0051] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0052] The high-performance adhesive used in Examples 1-4 of this invention is epoxy steel adhesive, and its performance indicators are shown in Table 1.

[0053] Table 1 Performance Indicators of Epoxy Steel Adhesive

[0054]

[0055] Example 1

[0056] This embodiment provides a novel lined PCCP pipe that uses eight longitudinal steel wires to control the impact range of broken wires. Its manufacturing method specifically includes the following steps:

[0057] Step (1): Make the socket and spigot steel rings of the PCCP connector.

[0058] Step (2): Making the steel cylinder. Roll the steel strip into a 1.5mm long strip and weld the joints of the steel strip. Then weld the socket steel ring and the spigot steel ring to both ends of the steel cylinder respectively.

[0059] Step (3): Pouring the core concrete. The core concrete is poured using a vertical vibration method. Before pouring, metal anchor blocks are welded to the socket and spigot steel rings to provide anchor points for subsequent wire wrapping and laying of longitudinal steel wires. The steel cylinder with socket and spigot steel rings at both ends is hoisted into the inner mold for core pouring and accurately positioned. The socket ring should match the working surface of the bottom mold. The concrete is mixed strictly according to the C55 concrete mix sheet, and poured along the inner wall of the steel mold, so that the steel cylinder is embedded in the outer wall of the concrete. The vibrator is turned on during pouring to ensure the concrete is compacted. The inner diameter of the concrete core is 2200mm, and the core thickness is 180mm. After pouring, the core concrete is steam cured. When the concrete strength reaches 70% of the design strength, the next step of wire wrapping begins.

[0060] Step (4): Winding the prestressed steel wire. Place the cured core tube on the prestressed wire winding table. Before winding, spray a layer of cement slurry onto the core tube surface. Rotate the winding table to rotate the core tube. Control the rotation speed of the table and the wire feeding speed to generate a prestress of 1110 MPa (70% of the wire's tensile strength) in the 5mm diameter high-strength steel wire (elastic modulus 205000 MPa, tensile strength 1570 MPa), and wind it onto the core tube with an 18mm pitch. The stress fluctuations must be monitored throughout the winding process.

[0061] Step (5): Laying the longitudinal steel wires. The specifications, dimensions, and material parameters of the longitudinal steel wires are the same as those of the circumferential prestressed steel wires. For example... Figure 2As shown, before formal laying, one end of the longitudinal steel wire 4 is anchored to the metal anchor block 7 at the socket end, and the other end is wound around the stress generating device 6. The stress generating device 6 translates along the axial direction of the core 8 while rotating around its own rotation axis to release the wire. By controlling the rotational linear velocity of the stress generating device 6 to be equal to the translational velocity, the longitudinal steel wire 4 is prevented from generating prestress. The other end of the longitudinal steel wire 4 is anchored to the metal anchor block at the spigot end.

[0062] Step (6): Use a high-performance adhesive to bond the overlap points of the circumferential prestressed circumferential steel wires and longitudinal steel wires. First, strictly follow the mixing ratio of the epoxy steel bonding adhesive to prepare the adhesive, pour it into a clean container, and stir thoroughly. Figure 3 As shown, a first side plate 9 and a second side plate 10 are erected on both sides of the longitudinal steel wire. The well-mixed epoxy steel bonding adhesive is poured into the area enclosed by the first side plate 9, the second side plate 10, and the socket anchor block. Pouring is stopped when the epoxy steel bonding adhesive is about to submerge the longitudinal steel wire. Then, appropriate pressure is immediately applied to the longitudinal steel wire using tools such as steel plates. The epoxy steel bonding adhesive cures in 24 hours at 25°C. The pressure fixing devices are removed. If the temperature is below 25°C, the curing time should be extended accordingly.

[0063] Step (7): Roller-cast outer mortar protective layer and asphalt anti-corrosion layer. Prepare mortar according to the strength of M45 mortar, and the net protective layer thickness (distance from the outer side of the longitudinal steel wire to the outer side of the mortar protective layer) shall not be less than 25mm.

[0064] The novel internally lined PCCP pipe structure manufactured in this embodiment is as follows: Figure 4 As shown. From the inside to the outside of the pipe, it consists of concrete 1, steel cylinder 2, circumferential prestressed steel wire 3, longitudinal steel wire 4, and outer protective mortar 5. Among them, there are 8 longitudinal steel wires, which are laid at 45° intervals along the circumference of the pipe.

[0065] Example 2

[0066] This embodiment provides a novel lined PCCP pipe that uses six longitudinal steel wires to control the range of influence of broken wires. Four of the longitudinal steel wires are respectively positioned at the top, bottom, and sides of the pipe, while the other two are positioned between the bottom and the sides of the pipe. All other steps of the manufacturing method are the same as in Embodiment 1.

[0067] Example 3

[0068] This embodiment provides a novel buried PCCP pipe that uses four longitudinal steel wires to control the impact range of broken wires. Its manufacturing method specifically includes the following steps:

[0069] Step (1): Make the socket and spigot steel rings of the PCCP connector.

[0070] Step (2): Making the steel cylinder. Roll the steel strip into a 1.5mm long strip and weld the joints of the steel strip. Then weld the socket steel ring and the spigot steel ring to both ends of the steel cylinder respectively.

[0071] Step (3): Pouring the core concrete. The core concrete is poured using a vertical vibration method. Before pouring, metal anchor blocks are embedded in the concrete areas on both sides of the pipe to provide anchor points for subsequent wire wrapping and laying of longitudinal steel wires. The steel cylinder with socket and spigot steel rings at both ends is hoisted into the inner mold for core pouring and accurately positioned. The socket ring should match the working surface of the bottom mold. Concrete is mixed strictly according to the C55 concrete mix sheet, and poured along the inner and outer walls of the steel mold, embedding the steel cylinder in the concrete. The vibrator is turned on during pouring to ensure the concrete is compacted. The inner diameter of the concrete core is 1600mm, the outer diameter of the steel cylinder is 1703mm, and the core thickness is 130mm. After pouring, the core concrete is steam-cured. When the concrete strength reaches 70% of the design strength, the next step, wire wrapping, begins.

[0072] Step (4): Winding the prestressed steel wire. Place the cured core tube on the prestressed wire winding table. Before winding, spray a layer of cement slurry onto the core tube surface. Rotate the winding table to rotate the core tube. Control the rotation speed of the table and the wire feeding speed to generate a prestress of 1110 MPa (70% of the wire's tensile strength) in the 5mm diameter high-strength steel wire (elastic modulus 205000 MPa, tensile strength 1570 MPa), and wind it onto the core tube with a pitch of 17mm. The stress fluctuations must be monitored throughout the winding process.

[0073] Step (5): Laying the longitudinal steel wires. The specifications, dimensions, and material parameters of the longitudinal steel wires are the same as those of the circumferential prestressed steel wires. For example... Figure 2 As shown, before formal laying, one end of the longitudinal steel wire 4 is anchored to the metal anchor block 7 at the socket end, and the other end is wound around the stress generating device 6. The stress generating device 6 translates along the axial direction of the core 8 while rotating around its own rotation axis to release the wire. By controlling the rotational linear velocity of the stress generating device 6 to be equal to the translational velocity, the longitudinal steel wire 4 is prevented from generating prestress. The other end of the longitudinal steel wire 4 is anchored to the metal anchor block at the spigot end.

[0074] Step (6): Use a high-performance adhesive to bond the overlap points of the circumferential prestressed circumferential steel wires and longitudinal steel wires. First, strictly follow the mixing ratio of the epoxy steel bonding adhesive to prepare the adhesive, pour it into a clean container, and stir thoroughly. Figure 3As shown, a first side plate 9 and a second side plate 10 are erected on both sides of the longitudinal steel wire. The well-mixed epoxy steel bonding adhesive is poured into the area enclosed by the first side plate 9, the second side plate 10, and the socket anchor block. Pouring is stopped when the epoxy steel bonding adhesive is about to submerge the longitudinal steel wire. Then, appropriate pressure is immediately applied to the longitudinal steel wire using tools such as steel plates. The epoxy steel bonding adhesive cures in 24 hours at 25°C. The pressure fixing devices are removed. If the temperature is below 25°C, the curing time should be extended accordingly.

[0075] Step (7): Roller-cast outer mortar protective layer and asphalt anti-corrosion layer. Prepare mortar according to the strength of M45 mortar, and the net protective layer thickness (distance from the outer side of the longitudinal steel wire to the outer side of the mortar protective layer) shall not be less than 25mm.

[0076] The novel embedded PCCP pipe structure manufactured in this embodiment is as follows: Figure 5 As shown. From the inside to the outside of the pipe, it consists of an inner layer of concrete 11, a steel cylinder 2, an outer layer of concrete 12, circumferential prestressed steel wires 3, longitudinal steel wires 4, and an outer layer of protective mortar 5. Among them, there are 4 longitudinal steel wires, which are distributed at the top, bottom and sides of the pipe.

[0077] Example 4

[0078] This embodiment provides a novel buried PCCP pipe that uses four longitudinal prestressed steel wires to control the range of influence of broken wires.

[0079] The difference between this embodiment and embodiment 3 is that the specific operation of laying the longitudinal steel wire in step (5) is as follows: the specifications, dimensions, and material parameters of the longitudinal steel wire are the same as those of the circumferential prestressed steel wire. For example Figure 2 As shown, before formal laying, one end of the longitudinal steel wire 4 is anchored to the metal anchor block 7 at the socket end, and the other end is wound around the stress generating device 6. The stress generating device 6 translates along the axial direction of the core 8 while rotating around its own axis to release the wire. By controlling the rotational linear velocity of the stress generating device 6 to be less than the translational velocity, an initial prestress of 1100 MPa (70% of the wire's tensile strength) is generated in the longitudinal steel wire 4. The other end of the longitudinal steel wire 4 is anchored to the metal anchor block at the spigot end. The remaining steps of the manufacturing method are the same as in Example 3.

[0080] Comparative Example 1

[0081] The embedded PCCP pipe without longitudinal steel wires is composed of an inner layer of concrete, a steel cylinder, an outer layer of concrete, circumferential prestressed steel wires, and an outer layer of protective mortar, arranged sequentially from the inside to the outside. The structure and parameters of the steel cylinder, concrete, and circumferential prestressed steel wires are the same as in Example 3. Since this comparative example has no longitudinal steel wires, steps (5) and (6) are removed from the steps in Example 3, while the remaining steps are the same as in Example 3.

[0082] Comparative Example 2

[0083] An embedded PCCP pipe with four longitudinal steel wires was manufactured, wherein the four longitudinal steel wires were located inside the steel cylinder. The difference between this embodiment and Comparative Example 1 is that, before pouring the core concrete in step (3), the four longitudinal steel wires were fixed to the bottom, top, and sides of the pipe inside the steel cylinder, respectively. Anchors were used to pre-tighten both ends of the longitudinal steel wires, controlling the tension displacement so that the longitudinal steel wires did not generate prestress, and the longitudinal steel wires did not contact the steel cylinder. The anchors were removed after the concrete was poured. The remaining construction steps were the same as in Comparative Example 1.

[0084] Comparative Example 3

[0085] An embedded PCCP pipe with four longitudinal steel wires was manufactured, wherein the four longitudinal steel wires were placed inside the outer layer of concrete. The difference between this embodiment and Comparative Example 1 is that, before pouring the core concrete in step (3), the four longitudinal steel wires were fixed to the bottom, top, and sides of the pipe inside the outer layer of concrete. Anchors were used to pre-tighten both ends of the longitudinal steel wires, controlling the tension displacement so that the longitudinal steel wires did not generate prestress, and the longitudinal steel wires did not contact the steel cylinder. The anchors were removed after the concrete was poured. The remaining construction steps were the same as in Comparative Example 1.

[0086] Application performance simulation test

[0087] The PCCP pipelines of Examples 3 and 4 and Comparative Examples 1-3 were modeled using the general-purpose commercial software ABAQUS. Solid elements were used for concrete and mortar, rod elements for circumferential and longitudinal steel wires, and shell elements for the steel cylinder. The bond-slip effect between the steel wires and mortar was simulated by creating a nonlinear connector spring and meshing the circumferential steel wires and mortar with overlapping nodes. All materials were modeled using elastoplastic constitutive models. The simulation addressed the possibility of wire breakage under internal water pressure testing conditions. The PCCP was placed vertically with the spigot facing upwards, and the vertical degrees of freedom were constrained at the bottom of the pipe, with the spigot end considered fixed. Loading was performed in four steps:

[0088] The first step is to apply circumferential steel wire prestress and use the unit birth and death method to suppress the outer mortar unit;

[0089] The second step is to activate the outer mortar unit using the unit birth and death method and apply structural gravity.

[0090] The third step is to apply internal water pressure to the inner wall of the pipe to 0.5 MPa;

[0091] The fourth step is to use the unit birth and death method to suppress the steel wire units in the middle of the pipe and simulate the wire breakage effect.

[0092] (I) Comparison of Circumferential Steel Wire Prestressing

[0093] Extracting the path of the circumferential steel wire and plotting the wire stress are as follows: Figure 6 As shown, a certain range of "zero stress zone" appears after the circumferential prestressed steel wire breaks, accompanied by a large stress drop gradient in the vicinity. Comparative Example 1, which did not apply any longitudinal steel wire, has the largest stress loss range near the broken wire. Comparative Examples 2 and 3, which have longitudinal steel wires on the inner side of the steel cylinder and the inner side of the outer concrete layer, have the next largest stress loss range. In contrast, Examples 3 and 4 of the present invention have the smallest stress loss range near the broken wire.

[0094] (II) Comparison of Circumferential Strain of Pipe Core Concrete

[0095] Extract a 360° circumferential path of the core concrete near the break point, and plot the circumferential strain of the concrete as shown. Figure 7 As shown in the figure, in Examples 3 and 4 of the present invention, the circumferential strain of the concrete is less than that in Comparative Examples 2 and 3. This indicates that the manufacturing method of the present invention, which lays the longitudinal steel wire after winding the circumferential prestressed steel wire and uses a high-performance adhesive to bond the overlap of the longitudinal steel wire and the circumferential spiral steel wire, can result in a smaller prestress loss value of the circumferential steel wire and a better restraining effect on the core concrete than in Comparative Examples 2 and 3.

[0096] Based on the calculation results comparing the prestress of the circumferential steel wire and the circumferential stress of the core concrete, under the condition of arranging the same number of longitudinal steel wires, the present invention has a more obvious and effective effect in curbing the range of wire breakage.

[0097] (III) Deformation diagram of longitudinal-circumferential steel wire

[0098] With a deformation amplification factor of 5, the longitudinal and circumferential wire deformation diagrams after wire breakage are shown below. Figure 8 As shown.

[0099] As can be seen from the figures, in Comparative Examples 2 and 3, the longitudinal and circumferential steel wires are not tightly attached and are not connected by an effective bonding method, making it difficult for the longitudinal and circumferential steel wires to form a unified whole to resist the load. However, in Embodiments 3 and 4 of the present invention, the overlap points of the longitudinal and circumferential steel wires are bonded, allowing the longitudinal and circumferential steel wires to deform and bear force collaboratively, jointly resisting the load. After the circumferential prestressed steel wire breaks, the longitudinal steel wire exerts a significant dragging effect on the circumferential steel wire.

[0100] (iv) Longitudinal steel wire stress cloud diagram

[0101] Figure 9 This displays a stress cloud diagram of the longitudinal steel wire after breakage. Figure 9It can be seen that in Comparative Examples 2 and 3, the longitudinal steel wire failed to form an effective whole with the circumferential steel wire to share the load, and the maximum stress of the longitudinal steel wire after the wire broke was only about 7 MPa. However, in the working conditions corresponding to Examples 3 and 4 of the present invention, the longitudinal steel wire had a significant dragging effect on the circumferential steel wire after the prestressed steel wire broke, so the stress near the broken wire was greater, and the material properties of the longitudinal steel wire were fully utilized (the maximum stress of the longitudinal steel wire in Example 3 was 1260 MPa, and the maximum stress of the longitudinal steel wire in Example 4 was 1541 MPa). The longitudinal and circumferential steel wires deformed and shared the load together.

[0102] In summary, the manufacturing method of PCCP pipe with longitudinal steel wire controlling the influence range of broken wire provided by the present invention has achieved the following effects: (1) The material properties of the longitudinal steel wire are fully utilized. After the circumferential steel wire breaks, the longitudinal steel wire bears part of the load, that is, the longitudinal and circumferential steel wires form a more consistent stress-deformation system to jointly resist the load; (2) The longitudinal steel wire further curbs the influence range of broken wire; (3) Under the condition of laying the same number of longitudinal steel wires, the effect of the present invention in curbing broken wire is more significant. Therefore, each pipe section can be laid with fewer longitudinal steel wires, thereby reducing the manufacturing cost of the new PCCP structure.

[0103] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a PCCP pipe using longitudinal steel wires to control the range of influence of broken wires, characterized in that, Includes the following steps: S1. Fix the socket steel ring to both ends of the steel cylinder and set anchor points; pour concrete and cure it to the specified strength; S2. Wrap circumferential prestressed steel wire around the outside of the cured outer concrete or steel cylinder; S3. Anchor one end of the longitudinal steel wire to an anchor point on one side of the pipe, lay it out along the axial direction of the pipe, and anchor the other end to an anchor point on the other side of the pipe; the number of longitudinal steel wires is 4 to 8, evenly distributed along the circumference of the steel cylinder; the longitudinal steel wires have initial prestress, the magnitude of which is 50% to 70% of the tensile strength of the longitudinal steel wire; the specifications, dimensions and material parameters of the longitudinal steel wires are the same as those of the circumferential prestressed steel wires; S4. A high-performance adhesive is used to bond the overlap points of the circumferential prestressed steel wire and the longitudinal steel wire; the high-performance adhesive has a compressive strength ≥65MPa, a steel-to-steel tensile bond strength ≥30MPa, and a shear strength ≥18MPa. S5. After the high-performance adhesive has dried sufficiently, roll-apply the outer mortar protective layer and the asphalt anti-corrosion layer.

2. The manufacturing method according to claim 1, characterized in that, In step S1, when the PCCP pipeline is an internally lined PCCP pipeline, the concrete is placed inside the steel cylinder; when the PCCP pipeline is an embedded PCCP pipeline, the concrete includes an inner layer of concrete inside the steel cylinder and an outer layer of concrete outside the steel cylinder.

3. The manufacturing method according to claim 2, characterized in that, In step S2, when the PCCP pipe is an internally lined PCCP pipe, circumferential prestressed steel wire is wound around the outside of the steel cylinder; when the PCCP pipe is an embedded PCCP pipe, circumferential prestressed steel wire is wound around the outside of the cured outer concrete layer.

4. The manufacturing method according to claim 1, characterized in that, In step S3, the wire laying is carried out using a stress generating device that winds spiral steel wire, and the wire laying speed and forward speed of the stress generating device are controlled by the differential winding principle to achieve that the longitudinal steel wire has initial prestress or no initial prestress.

5. The manufacturing method according to claim 1, characterized in that, In step S4, the high-performance adhesive includes one or more of epoxy structural adhesive, polyurethane structural adhesive, and acrylate structural adhesive.

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