Single-layer wire-wrapped PCCP suitable for high-load condition and manufacturing method of single-layer wire-wrapped PCCP

Abstract

The invention discloses a single-layer wire wrapping PCCP suitable for a high-load condition and a manufacturing method, and particularly relates to the technical field of PCCPs. The single-layer wire-wrapped PCCP suitable for the high-load condition comprises a steel cylinder, a bellmouth and an insertion opening are welded to the two ends of the steel cylinder respectively, the steel cylinder is internally lined with an inner concrete layer and externally lined with an outer concrete layer, the inner concrete layer, the outer concrete layer, the steel cylinder, the bellmouth and the insertion opening form a pipe core, and the inner concrete layer is mainly located in the steel cylinder and the insertion opening. Wherein the inserting opening of one PCCP is inserted into the bearing opening of the other PCCP, then butt joint of the two pipelines is achieved, and a plurality of circles of winding wires are wound on the outer ring of the concrete layer. The single-layer wire winding PCCP suitable for the high-load condition can meet the operation requirement of a high-working-pressure and high-soil-covering water conveying pipeline, the production process is simplified, the production efficiency is improved, the labor cost is reduced, the production noise is reduced, and the long-term durability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of PCCP, and in particular to a single-layer wire-wrapped PCCP suitable for high-load conditions and a manufacturing method thereof. Background Art

[0002] PCCP (prestressed steel cylinder concrete pipe) is widely used in the development and construction of water conservancy and municipal engineering in my country due to its wide application range, strong resistance to external loads, low economic cost, and easy installation. PCCP is a composite pipe composed of a concrete pipe core, a steel cylinder, prestressed steel wire, and a mortar protective layer. The prestressed steel wire is the key load-bearing structure, which generates uniform pre-compression stress on the pipe core to resist the tensile stress generated by internal and external loads of the pipeline.

[0003] The diameter of the prestressed steel wire currently used in China is 4-7mm cold-drawn steel wire. When the pipeline is under high load conditions (large soil cover depth and high working pressure), the circumferential prestressed steel wire reinforcement area of ​​the pipeline needs to be increased accordingly. In many cases, according to the minimum pitch specified by the standard, single-layer wire winding with 7mm steel wire can no longer meet the requirements. At this time, multi-layer wire winding is generally used to ensure the circumferential prestressed steel wire area, that is, 2-3 layers of prestressed steel wire need to be wound. When making multi-layer wire-wrapped pipelines, firstly, wire winding is carried out according to the conventional process and a cement mortar protective layer is made. Then, the surface of the first layer of mortar protective layer is scraped flat. After the strength of the scraped mortar protective layer meets the wire winding requirements, the second layer of wire winding is carried out, and this cycle is repeated until the designed number of wire winding layers is reached. Although multi-layer wire-wrapped pipes can meet the needs of engineering use, there are the following problems in the manufacturing process: ① The existing mortar protective layer scraping technology cannot guarantee that the mortar surface after scraping is 100% flat, and there will always be unevenness, which will cause the prestressed steel wire of the second layer of wire wrapping to not fit tightly with the mortar surface, resulting in uneven force on the steel wire, affecting the safe operation of the pipeline; ② Multiple wire wrapping will greatly reduce the production efficiency of the pipeline and increase labor costs. The efficiency is reduced by 32% and the labor cost is increased by 43%.

[0004] Therefore, it is necessary to provide a single-layer wire-wrapped PCCP suitable for high load conditions and a manufacturing method to solve the above technical problems. Summary of the invention

[0005] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a single-layer wire-wrapped PCCP suitable for high load conditions and a production method that can meet the operation requirements of high working pressure and high cover water pipelines, and simplifies the production process, improves production efficiency, reduces labor costs, reduces production noise, and improves long-term durability.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A single-layer wire-wrapped PCCP suitable for high-load conditions comprises: a steel cylinder, wherein a socket and a spigot are welded at both ends of the steel cylinder respectively, the steel cylinder is lined with an inner concrete layer and lined with an outer concrete layer, the inner concrete layer, the outer concrete layer, the steel cylinder, the socket and the spigot constitute a pipe core, the inner concrete layer is mainly located inside the steel cylinder and the spigot, when two PCCPs are butt-jointed, the spigot of one PCCP is inserted into the socket of the other PCCP, thereby realizing the butt-jointing of the two pipes, a plurality of turns of winding wire are wound around the outer circle of the concrete layer, the winding wire is a large-diameter prestressed steel wire or a prestressed steel strand, the large-diameter prestressed steel wire has a diameter of 10 mm, and the prestressed steel strand has a diameter of 9.53 mm, the outer concrete layer and the outer side of the winding wire are wrapped with an outer protective layer, one end of the outer protective layer is flush with the socket port, and the other end is flush with an end of the spigot close to the steel cylinder.

[0008] Preferably, both the inner and outer layers of the steel cylinder have smooth surface structures and are directly bonded to the inner concrete layer and the outer concrete layer.

[0009] Preferably, a plurality of protrusions are welded on the outer side of the steel cylinder, and the height of the protrusions is 1 / 10 of the thickness of the outer concrete layer.

[0010] Preferably, a plurality of metal plates distributed in a circular array are welded on the outer ring of the steel cylinder, the length of the metal plate is consistent with the length of the steel cylinder, and the thickness of the outer concrete layer is equal to the thickness of the metal plate, that is, after the outer concrete layer is formed, the outer surface of the metal plate and the outer concrete layer are on the same arc surface, and the side of the metal plate away from the steel cylinder is arc-shaped, and when the winding wire is wound on the outer concrete layer, the winding wire contacts the outer side of the metal plate.

[0011] Preferably, a through groove is provided on one side of the metal plate close to the steel cylinder, so that the outer concrete layer can penetrate the through groove to form a whole without destroying the continuity of the outer concrete layer.

[0012] Preferably, a plurality of threaded seats are welded on one of the metal plates, a fixing plate is mounted on the threaded seat by bolts, and an arc-shaped slot is provided on one side of the fixing plate.

[0013] Preferably, a first lock is installed on the socket, and a locking structure is installed on the plug, and the locking structure is used to fix the winding wire. The socket and the plug are both provided with mounting seats, and the locking structure includes a fixing seat that can be plugged into the mounting seat, and a pressure plate is provided on the fixing seat, and the pressure plate is fixed to the fixing seat by multiple bolts, and the same second lock is fixedly installed on the fixing seat and the pressure plate, and the second lock is a clip-type lock. After the clip is removed from the lock, the remaining part is equally cut into parts along the lock hole, and the two parts are respectively welded to the fixing seat and the pressure plate.

[0014] Preferably, the inner concrete layer and the outer concrete layer are made of high-performance self-compacting concrete with a concrete strength of C60-C80, which is composed of cement, water, sand, stone, admixtures, fly ash and silica fume.

[0015] Preferably, the cement in the inner concrete layer and the outer concrete layer is PO52.5 type cement, the sand is natural medium sand, the stone is made by an impact crusher and is in the form of cubic particles, free of tension and cracks, and uniform in shape, the admixture is polycarboxylic acid, the fly ash is Grade I, and the silica fume is SF90 type.

[0016] Preferably, the outer protective layer is a high ductility concrete (HDC) protective layer, which is composed of cement, fly ash, mineral powder, sand, fiber, admixture and water.

[0017] Preferably, the cement in the outer protective layer is PO42.5 type cement, the fly ash is grade I, the mineral powder is S95 type, the fiber is PP fiber, and the admixture is polycarboxylic acid.

[0018] A method for preparing a single-layer wire-wrapped PCCP suitable for high-load conditions comprises the following steps:

[0019] S1: Steel cylinder production: The finished steel cylinder consists of a socket, a spigot, a cylinder body, a convex block on the surface of the cylinder body, and a metal plate on the surface of the cylinder body. The socket and the spigot are rolled into a circle by a rolling device, and then welded by manual arc welding. The size is fixed by the expansion and plate edge process. The cylinder body is made of thin steel plates automatically rolled and welded by a spiral welding machine. The socket and the cylinder body are welded and fixed together on the spiral welding machine. The convex block on the surface of the cylinder body and the metal plate are fixed by manual welding after the steel cylinder is made.

[0020] S2: Pipe core casting: The pipe core uses high-performance (C60-C80) self-compacting concrete, and the "centralized feeding" method is used during casting, that is, the dividing cone is separated by a baffle to form 3 to 5 small feeding ports of 200 mm, and the concrete is poured into the pipe core mold through the small feeding ports. This method can significantly control quality problems such as concrete segregation and many cavitations on the surface of the pipe after demoulding. After casting, steam curing is used in winter, with a curing temperature of 35 to 40°C and a curing time of 6 hours. In summer, it can be naturally cured by covering with a protective cover for 6 to 8 hours;

[0021] S3: Wire wrapping: When using 10mm prestressed steel wire or 9.53mm steel strand for wire wrapping, it is necessary to use 1 / 3 of the designed wire wrapping stress for dense wrapping at the socket part, and then use full stress and normal pitch for wire wrapping after exceeding the socket part; the main reason is that the wire wrapping stress of 10mm prestressed steel wire or 9.53mm steel strand is large, and the full stress wire wrapping at the socket part will exceed the socket stiffness limit, resulting in excessive deformation of the socket. The excessive deformation of the socket will spread to the surroundings in the form of stress concentration, which will cause cracks in the pipe core concrete and wire wrapping failure.

[0022] After winding to the socket, start to reduce the stress to 1 / 3 of the designed winding stress when there are 2-5 turns left for dense winding. The main reason is to protect the anchor block by reducing the winding stress at the end, and prevent the anchor block from being deformed or pulled apart due to excessive fixing tension at the end.

[0023] S4: Production of protective layer: The protective layer is cast with high ductility concrete (HDC). It should be noted that when adding fibers during concrete mixing, they need to be added in batches and in certain amounts, and cannot be added all at once, to ensure that the fibers are well dispersed in the concrete. When pouring, they need to be vibrated and poured in certain amounts and at different times to ensure the uniformity of the quality of the protective layer. After pouring, cover with a protective cover and steam cure for 6 hours at a curing temperature of 45-50°C.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The use of high-performance concrete (C60-C80) to cast the PCCP pipe core significantly improves the long-term durability of the PCCP pipe core.

[0026] (2) The use of high-performance self-compacting concrete eliminates the need for vibration and compaction, significantly reduces production noise, and improves the working environment for workers.

[0027] (3) After using high-performance self-compacting concrete that does not require vibration, the maintenance of PCCP molds is greatly reduced and the service life of the mold is extended.

[0028] (4) The use of high-performance self-compacting concrete does not require vibration, which reduces the amount of compressed air required for mold vibration and reduces energy consumption.

[0029] (5) By setting a protrusion on the outside of the steel cylinder, it is ensured that the relative position of the steel cylinder and the inner concrete layer and the outer concrete layer will not be offset due to excessive winding stress during the winding process, thereby ensuring that the tube core will not have quality defects during the winding process.

[0030] (6) The winding wire will be fixed by multiple fixing plates, which can provide a more comprehensive fixing effect on the winding wire. In special cases, when a section of the steel wire is broken due to the external environment, the other sections of the steel wire will not slip due to the fixation of the metal plates, thereby improving the stability and safety of PCCP, especially for applications under high load conditions.

[0031] (7) By changing the material and structure of the winding wire (from multiple layers of 7 mm prestressed steel wire to single layers of 9.53 mm prestressed steel strands and 10 mm prestressed steel wire), it not only meets the needs under high working pressure and high soil cover conditions, but also simplifies the production process, improves production efficiency, and reduces labor costs.

[0032] (8) The 10 mm prestressed steel wire and 9.53 mm prestressed steel strand are fixed with clip-type locks, which have better stability and safety than the traditional PCCP groove anchoring.

[0033] (9) The use of high ductility concrete (HDC) as the outer protective layer enhances the deformation resistance of the pipeline protective layer, reduces the risk of cracking of the protective layer caused by external factors such as foundation settlement, and greatly improves the long-term durability of the PCCP protective layer, ensuring the safe operation of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a single-layer wire-wrapped PCCP suitable for high-load conditions provided by the present invention;

[0035] Figure 2 A schematic diagram of a decomposed single-layer wire-wrapped PCCP suitable for high-load conditions provided by the present invention;

[0036] Figure 3 A schematic diagram of the structure of a single-layer wire-wrapped PCCP tube core suitable for high-load conditions provided by the present invention after being wound with winding wire;

[0037] Figure 4 Schematic diagram of the structures of three steel cylinders of single-layer wire-wrapped PCCP embodiments 2-4 suitable for high load conditions provided by the present invention;

[0038] Figure 5 A schematic diagram of the structure of a metal plate in a single-layer wire-wrapped PCCP suitable for high-load conditions provided by the present invention;

[0039] Figure 6 A schematic diagram of an embodiment of a single-layer wire-wrapped PCCP tube core suitable for high-load conditions provided by the present invention;

[0040] Figure 7 for Figure 4 A magnified view of part A;

[0041] Figure 8 A schematic diagram of the structure of the locking structure in the single-layer wire-wrapped PCCP suitable for high-load conditions provided by the present invention;

[0042] Fig. 9 An exploded schematic diagram of a second lock in a single-layer wire-wrapped PCCP suitable for high-load conditions provided by the present invention;

[0043] Fig.10 An exploded schematic diagram of a metal plate, a threaded seat and a fixing plate in a single-layer wire-wrapped PCCP suitable for high-load conditions provided by the present invention;

[0044] Fig.11A schematic cross-sectional view of the outer protective layer of a single-layer wire-wrapped PCCP suitable for high load conditions provided by the present invention.

[0045] Among them, the names corresponding to the figure marks are: 1-inner concrete layer, 2-steel cylinder, 201-bump, 21-metal plate, 22-threaded seat, 23-fixing plate, 3-socket, 31-first lock, 4-socket, 41-locking structure, 411-fixing seat, 412-pressure plate, 413-second lock, 5-outer concrete layer, 6-winding wire, 7-outer protective layer, 8-mounting seat. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The embodiments of the present invention include but are not limited to the following embodiments.

[0047] The high load condition in the single-layer wire-wrapped PCCP suitable for high load conditions provided by the present invention is that the working pressure is ≥1.0Mpa or the covering soil is ≥6mm.

[0048] Example 1

[0049] like Figure 1-11 As shown, the single-layer wire-wrapped PCCP suitable for high-load conditions provided by the present invention comprises: a steel cylinder 2, wherein the two ends of the steel cylinder 2 are respectively welded with a socket 3 and a spigot 4, the steel cylinder 2 is lined with an inner concrete layer 1, and is lined with an outer concrete layer 5, wherein the inner concrete layer 1, the outer concrete layer 5, the steel cylinder 2, the socket 3 and the spigot 4 constitute a pipe core, wherein the inner concrete layer 1 is mainly located inside the steel cylinder 2 and the spigot 4, and the outer concrete layer 5 is mainly located outside the steel cylinder 2 and the socket 3, and when two PCCPs are butt-jointed, the spigot 4 of one PCCP is inserted into the other PCCP. In the socket 3 of CCP, the two pipes are connected to each other. Multiple circles of winding wire 6 are wound on the outer circle of the concrete layer 5. The winding wire 6 is a large-diameter prestressed steel wire or a prestressed steel strand. The large-diameter prestressed steel wire has a diameter of 10 mm, and the prestressed steel strand has a diameter of 9.53 mm. The outer concrete layer 5 is lined with an outer protective layer 7. The outer protective layer 7 covers the winding wire 6. The outer protective layer 7 has a protective effect on the winding wire 6. One end of the outer protective layer 7 is flush with the port of the socket 3, and the other end is flush with the end of the socket 4 close to the steel cylinder 2.

[0050] Example 2

[0051] like Figure 4As shown in (a), the inner and outer layers of the steel cylinder 2 are both smooth structures, which are directly bonded to the inner concrete layer 1 and the outer concrete layer 5. This embodiment is suitable for large-diameter PCCP because the contact area between the outer concrete layer 5 and the inner concrete layer 1 of the large-diameter PCCP and the steel cylinder 2 is large, so the friction force is large. During the wire winding process, the friction force can withstand the pulling force of the wire winding, so that the outer concrete layer 5 and the inner concrete layer 1 will not be relatively offset from the steel cylinder 2.

[0052] Example 3

[0053] like Figure 4 As shown in (b), a plurality of protrusions 201 are welded on the outside of the steel cylinder 2, and the height of the protrusions 201 is 1 / 10 of the thickness of the outer concrete layer 5. This embodiment is suitable for small-diameter PCCP. In the small-diameter PCCP, the contact area between the outer concrete layer 5 and the inner concrete layer 1 and the steel cylinder 2 is small, resulting in small friction. During the wire winding process, the friction is difficult to withstand the tensile force of the wire winding, which easily causes the outer concrete layer 5 and the inner concrete layer 1 to be relatively offset from the steel cylinder 2. Based on this situation, the main function of the protrusions 201 in this embodiment is that the tensile force is large after the large-diameter prestressed steel wire or prestressed steel strand is used during the wire winding process. After the tube core is fixed by the wire winding machine pressure cover, the friction between the inner concrete layer 1 and the outer concrete layer 5 of the tube core and the steel cylinder 2 is greater than the tensile force, thereby ensuring that the relative position of the steel cylinder and the inner concrete layer 1 and the outer concrete layer 5 of the tube core will not be offset due to excessive wire winding stress during the wire winding process, thereby ensuring that the tube core will not have quality defects during the wire winding process. The height of the protrusion 201 is 1 / 10 of the thickness of the outer concrete layer 5, which helps to improve the convenience of construction.

[0054] Example 4

[0055] like Figure 4 As shown in (c), a plurality of metal plates 21 distributed in a circular array are welded on the outer ring of the steel cylinder 2, the length of the metal plate 21 is consistent with the length of the steel cylinder 2, and the thickness of the outer concrete layer 5 is equal to the thickness of the metal plate 21, that is, after the outer concrete layer 5 is formed, the outer surface of the metal plate 21 and the outer concrete layer 5 are on the same arc surface, and the side of the metal plate 21 away from the steel cylinder 2 is arc-shaped. When the winding wire 6 is wound on the outer concrete layer 5, the winding wire 6 contacts the outer side of the metal plate 21. Under the action of the metal plate 21, the stress of the winding wire 6 can be distributed more evenly, which is more conducive to the stable use of PCCP. It should be emphasized that since the diameter of the winding wire 6 is relatively thick, compared with the traditional multi-layer filaments, the stress of the winding wire 6 will be greater and more concentrated, so the stress needs to be evenly distributed, so as to be conducive to the long-term and stable use of PCCP.

[0056] Example 5

[0057] like Figure 5As shown, this embodiment is further implemented based on the embodiment 4, and a through groove is opened on the side of the metal plate 21 close to the steel cylinder 2, so that the outer concrete layer 5 can penetrate the through groove to form a whole without destroying the continuity of the outer concrete layer 5.

[0058] Example 6

[0059] like Figure 6-7 As shown, a plurality of threaded seats 22 are welded on one of the metal plates 21, and a fixing plate 23 is installed on the threaded seat 22 by bolts. An arc-shaped groove is provided on one side of the fixing plate 23. When all the winding wires 6 are wound, the plurality of fixing plates 23 are respectively fixed on the corresponding threaded seats 22. The arc-shaped groove clamps the winding wire 6 and fixes the winding wire 6. After the winding work of a PCCP is completed, the winding wire 6 will be fixed by the plurality of fixing plates 23. In this case, the winding wire 6 is like being divided into a plurality of parts, and the plurality of parts are continuous, which does not affect the distribution of stress. This can achieve a more comprehensive fixing effect on the winding wire 6. In the later use process, even if the winding wire 6 is broken at a certain place, it will not affect other parts.

[0060] Example 7

[0061] like Figure 6 , 8 -9, a first lock 31 is installed on the socket 3, and the first lock 31 is a clip-type lock that can provide a strong anchoring force. Because the single-layer winding wire 6 has a greater stress, a first lock 31 with a greater anchoring force is required for use in conjunction with it. A locking structure 41 is installed on the socket 4, and the locking structure 41 is used to fix the winding wire 6. Both the socket 3 and the socket 4 are provided with a mounting seat 8, and the locking structure 41 includes a fixing seat 411 that can be plugged into the mounting seat 8, and a pressure plate 412 is provided on the fixing seat 411, and the pressure plate 412 is fixed to the fixing seat 411 by multiple bolts. The same second lock 413 is fixedly installed on the fixing seat 411 and the pressure plate 412, and the second lock 413 is a clip-type lock. After the clip is removed from the lock, the remaining part is equally divided into parts along the lock hole, and the two parts are respectively welded to the fixing seat 411 and the pressure plate 412. The winding wire 6 cannot be broken during the winding process of the winding machine. If it is broken, it needs to be rewound. Therefore, when the winding wire 6 is located in the locking structure 41, the pressure plate 412 is fixed on the fixing seat 411, and at the same time, it is ensured that the winding wire 6 is located in the locking hole, and then the clip is installed to fix the winding wire 6. Then, the winding wire 6 is cut off, and the winding process is completed.

[0062] A method for preparing a single-layer wire-wrapped PCCP suitable for high-load conditions comprises the following steps:

[0063] S1: Steel cylinder production: The finished steel cylinder consists of a socket, a spigot, a cylinder body, a convex block on the surface of the cylinder body, and a metal plate on the surface of the cylinder body. The socket and the spigot are rolled into a circle by a rolling device, and then welded by manual arc welding. The size is fixed by the expansion and plate edge process. The cylinder body is made of thin steel plates automatically rolled and welded by a spiral welding machine. The socket and the cylinder body are welded and fixed together on the spiral welding machine. The convex block on the surface of the cylinder body and the metal plate are fixed by manual welding after the steel cylinder is made.

[0064] S2: Pipe core casting: The pipe core uses high-performance (C60-C80) self-compacting concrete, and the "centralized feeding" method is used during casting, that is, the dividing cone is separated by a baffle to form 3 to 5 small feeding ports of 200 mm, and the concrete is poured into the pipe core mold through the small feeding ports. This method can significantly control quality problems such as concrete segregation and many cavitations on the surface of the pipe after demoulding. After casting, steam curing is used in winter, with a curing temperature of 35 to 40°C and a curing time of 6 hours. In summer, it can be naturally cured by covering with a protective cover for 6 to 8 hours;

[0065] S3: Wire wrapping: When using 10mm prestressed steel wire or 9.53mm steel strand for wire wrapping, it is necessary to use 1 / 3 of the designed wire wrapping stress for dense wrapping at the socket part, and then use full stress and normal pitch for wire wrapping after exceeding the socket part; the main reason is that the wire wrapping stress of 10mm prestressed steel wire or 9.53mm steel strand is large, and the full stress wire wrapping at the socket part will exceed the socket stiffness limit, resulting in excessive deformation of the socket. The excessive deformation of the socket will spread to the surroundings in the form of stress concentration, which will cause cracks in the pipe core concrete and wire wrapping failure.

[0066] After winding to the socket, start to reduce the stress to 1 / 3 of the designed winding stress when there are 2-5 turns left for dense winding. The main reason is to protect the anchor block by reducing the winding stress at the end, and prevent the anchor block from being deformed or pulled apart due to excessive fixing tension at the end.

[0067] S4: Production of protective layer: The protective layer is cast with high ductility concrete (HDC). It should be noted that when adding fibers during concrete mixing, they need to be added in batches and in certain amounts, and cannot be added all at once, to ensure that the fibers are well dispersed in the concrete. When pouring, they need to be vibrated and poured in certain amounts and at different times to ensure the uniformity of the quality of the protective layer. After pouring, cover with a protective cover and steam cure for 6 hours at a curing temperature of 45-50°C.

[0068] The core concrete of the present invention adopts high-performance self-compacting concrete with a concrete strength of C60-C80. The application of this material can improve the durability of the pipeline, improve the working environment of workers, reduce energy consumption, and extend the service life of the mold. Field tests show that after the core of the pipe is cast with high-performance self-compacting concrete, the durability index of the pipeline is improved by 30%; the vibration noise at the production site is reduced from 110 decibels to 65 decibels; the amount of compressed air used for casting is reduced by 75%; and the mold maintenance amount is reduced by 80% after vibration is no longer required.

[0069] The control indexes of the mixture performance in the current self-compacting concrete standard cannot meet the requirements of the performance indexes of high-performance self-compacting concrete for PCCP. In order to obtain high-performance self-compacting concrete that meets the casting requirements of PCCP, we have conducted a large number of experiments. The most determined control indexes of the mixture working performance are:

[0070]

[0071] The final mix ratio is:

[0072]

[0073] The protective layer 7 of the present invention is cast and formed by high ductility concrete (HDC) protective layer. This material not only retains the strength characteristics of concrete, but also has strong deformation resistance. Its crack resistance strain is increased by 32.6% to 147% compared with roller-sprayed mortar under different proportions, which can ensure that the protective layer of the pipeline is not easily cracked due to external factors such as foundation settlement during operation.

[0074] In order to obtain HDC that meets the production requirements of PCCP, we conducted a large number of experiments. Finally, based on the basic requirements of localization of materials and domestication of fibers, we obtained a reliable mix ratio that meets the production requirements of PCCP by reducing cement, increasing mineral admixtures, and controlling the sand-cement ratio:

[0075]

[0076] The winding wire 6 of the present invention is changed from the original multi-layer 7mm prestressed steel wire to a single-layer 9.53mm prestressed steel strand and a 10mm prestressed steel wire. The main consideration is that under high working pressure, high soil cover and high load conditions, the circumferential prestressed steel wire reinforcement area of ​​the pipeline needs to be greatly increased. When using 7mm prestressed steel wire, single-layer winding according to the minimum pitch specified in the standard can no longer meet the requirements, and multi-layer winding is required. For example, if a PCCP with a working pressure of 1.2 and a soil cover of 11m uses 7mm steel wire, multi-layer winding is required, while a single-layer winding of 10mm prestressed steel wire or 9.53mm prestressed steel strand can meet the requirements.

[0077] In addition, although multi-layer wire-wrapped pipes can meet the needs of engineering use, they have the following problems in the manufacturing process: ① The existing mortar protective layer scraping technology cannot guarantee that the mortar surface after scraping is 100% flat, and there will always be unevenness, which will cause the prestressed steel wire of the second layer of wire wrapping to not fit tightly with the mortar surface, resulting in uneven force on the steel wire, affecting the safe operation of the pipeline; ② Multiple wire wrapping will greatly reduce the production efficiency of the pipeline and increase labor costs. The efficiency is reduced by 32% and the labor cost is increased by 43%.

[0078] In addition, the bond strength between 9.53mm prestressed steel strand and 10mm prestressed steel wire and the concrete protective layer is significantly better than that of 7mm prestressed steel wire, which can significantly improve the quality of the pipeline protective layer and the overall quality of the pipeline. The specific experimental data are as follows:

[0079]

Claims

1. A single-layer wire-wrapped PCCP suitable for high load conditions, characterized in that: include: A steel cylinder (2), wherein both ends of the steel cylinder (2) are respectively welded with a socket (3) and a spigot (4), wherein the steel cylinder (2) is lined with an inner concrete layer (1) and lined with an outer concrete layer (5), wherein both the inner and outer layers of the steel cylinder (2) have smooth surface structures, wherein the inner concrete layer (1), the outer concrete layer (5), the steel cylinder (2), the socket (3) and the spigot (4) form a pipe core, wherein the inner concrete layer (1) is mainly located inside the steel cylinder (2) and the spigot (4), and the outer concrete layer (5) is mainly located outside the steel cylinder (2) and the socket (3), and when two PCCPs are butt-jointed, one of the PCCPs The socket (4) of the PCCP is inserted into the socket (3) of another PCCP, thereby achieving the docking of the two pipes. A plurality of winding wires (6) are wound around the outer ring of the concrete layer (5). The winding wires (6) are large-diameter prestressed steel wires or prestressed steel strands. The diameter of the large-diameter prestressed steel wires is 10 mm, and the diameter of the prestressed steel strands is 9.53 mm. The outer concrete layer (5) and the winding wires (6) are wrapped around an outer protective layer (7). One end of the outer protective layer (7) is flush with the end of the socket (3), and the other end is flush with the end of the socket (4) close to the steel cylinder (2).

2. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 1, characterized in that: A plurality of protrusions (201) are welded on the outside of the steel cylinder (2), and the height of the protrusions (201) is 1 / 10 of the thickness of the outer concrete layer (5).

3. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 1, characterized in that: A plurality of metal plates (21) distributed in a ring array are welded on the outer ring of the steel cylinder (2); a through groove is provided on the side of the metal plate (21) close to the steel cylinder (2); the outer concrete layer (5) penetrates the through groove to form a whole; the length of the metal plate (21) is consistent with the length of the steel cylinder (2); the thickness of the outer concrete layer (5) is equal to the thickness of the metal plate (21); after the outer concrete layer (5) is formed, the outer surface of the metal plate (21) and the outer concrete layer (5) are on the same arc surface; the side of the metal plate (21) away from the steel cylinder (2) is arc-shaped; when the winding wire (6) is wound on the outer concrete layer (5), the winding wire (6) contacts the outer side of the metal plate (21).

4. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 3, characterized in that: A plurality of threaded seats (22) are welded on one of the metal plates (21), a fixing plate (23) is mounted on the threaded seat (22) via bolts, and an arc-shaped slot is provided on one side of the fixing plate (23).

5. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 1, 2 or 3, characterized in that: A first lock (31) is welded onto the socket (3), and a locking structure (41) is installed onto the socket (4). The locking structure (41) is used to fix the winding wire (6). Both the socket (3) and the socket (4) are provided with a mounting seat (8). The locking structure (41) comprises a fixing seat (411) which can be plugged into the mounting seat (8). A pressing plate (412) is provided on the fixing seat (411). The pressing plate (412) is fixed to the fixing seat (411) by a plurality of bolts. The fixing seat (411) and the pressing plate (412) are fixedly provided with the same second lock (413). The second lock (413) is a clip-type lock. After the clip is removed from the second lock (413), the remaining part is equally divided into parts along the lock hole. The two parts are respectively welded to the fixing seat (411) and the pressing plate (412).

6. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 1, 2 or 3, characterized in that: The inner concrete layer (1) and the outer concrete layer (5) are made of high-performance self-compacting concrete with a concrete strength of C60-C80, which is composed of cement, water, sand, stone, admixtures, fly ash and silica fume.

7. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 6, characterized in that: The cement in the inner concrete layer (1) and the outer concrete layer (5) is PO52.5 type cement, the sand is natural medium sand, the stone is produced by an impact crusher and is in the form of cubic particles, free of tension and cracks, and uniform in shape, the admixture is polycarboxylic acid, the fly ash is Grade I, and the silica fume is SF90 type.

8. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 1, 2 or 3, characterized in that: The outer protective layer (7) is a high ductility concrete (HDC) protective layer, which is composed of cement, fly ash, mineral powder, sand, fiber, admixture and water.

9. A single-layer wire-wrapped PCCP suitable for high load conditions according to claim 8, characterized in that: The cement in the outer protective layer (7) is PO42.5 type cement, the fly ash is Grade I, the mineral powder is S95 type, the fiber is PP fiber, and the admixture is polycarboxylic acid.

10. A method for preparing a single-layer wire-wrapped PCCP suitable for high-load conditions, which is suitable for the single-layer wire-wrapped PCCP suitable for high-load conditions as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1: Steel cylinder production: The finished steel cylinder consists of a socket, a spigot, a cylinder body, a convex block on the surface of the cylinder body, and a metal plate on the surface of the cylinder body. The socket and the spigot are rolled into a circle by a rolling device, and then welded by manual arc welding. The size is fixed by the expansion and plate edge process. The cylinder body is made of thin steel plates automatically rolled and welded by a spiral welding machine. The socket and the cylinder body are welded and fixed together on the spiral welding machine. The convex block on the surface of the cylinder body and the metal plate are fixed by manual welding after the steel cylinder is made. S2: Pipe core casting: The pipe core adopts high-performance (C60-C80) self-compacting concrete, and the "centralized feeding" method is adopted during casting, that is, the dividing cone is separated by a baffle to form 3 to 5 small feeding ports of 200 mm, and the concrete is poured into the pipe core mold through the small feeding ports. After casting, steam curing is adopted in winter, the curing temperature is 35 to 40 ° C, and the curing time is 6 hours. In summer, it can be covered with a protective cover and naturally cured for 6 to 8 hours; S3: Wire winding: When using 10mm prestressed steel wire or 9.53mm steel strand for wire winding, it is necessary to use 1 / 3 of the designed wire winding stress for dense winding at the socket part, and then use full stress and normal pitch for wire winding after exceeding the socket part; After winding to the socket, start to reduce the stress to 1 / 3 of the designed winding stress when there are 2-5 turns left and then perform dense winding; S4: Production of protective layer: The protective layer is cast with high ductility concrete (HDC). It should be noted that when adding fibers during concrete mixing, they need to be added in batches and in certain amounts, and cannot be added all at once, to ensure that the fibers are well dispersed in the concrete. When pouring, they need to be vibrated and poured in certain amounts and at different times to ensure the uniformity of the quality of the protective layer. After pouring, cover with a protective cover and steam cure for 6 hours at a curing temperature of 45-50°C.

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