A pccp pipe structure and a production method thereof

Abstract

The present application relates to prestressed concrete cylinder pipe technical field, disclose a kind of PCCP pipe structure and production method, including from inside to outside concrete inner layer, steel cylinder body, first mortar protective layer, concrete outer layer, second mortar protective layer and coating;First prestressed structure, including a plurality of first prestressed members, a plurality of the first prestressed members are arranged on the concrete outer layer along the axial direction, and located in the second mortar protective layer;Second prestressed structure, including a plurality of second prestressed members, a plurality of the second prestressed members are distributed on the steel cylinder body along the axial direction, and extend into the concrete inner layer;The first prestressed member and the second prestressed member cooperatively form the prestressed force of the steel cylinder body. The present application solves the problem that the overall stress distribution of the pipe body is greatly affected by the broken wire under the overall arrangement of the prestressed steel wire, and the pipe body is prone to cracks due to excessive prestress during winding.

Description

Technical Field

[0001] This invention relates to the field of prestressed concrete cylinder pipe technology, and in particular to a PCCP pipe structure and manufacturing method. Background Technology

[0002] Prestressed steel cylinder concrete pipe is mainly composed of a concrete core, a steel cylinder, prestressed steel wires, and a mortar protective layer. Due to its high strength, high sealing performance, and high impermeability, it is widely used in large-scale water transfer projects between water sources in different regions, such as the South-to-North Water Diversion Project and the Liaoning Northwest Water Supply Project.

[0003] The high strength of prestressed concrete cylinder pipes is mainly attributed to the prestressing wires, the steel cylinder, and the concrete layer. Prestressed concrete cylinder pipes are typically laid underground, and their service environment is relatively complex. During long-term service, the prestressing wires inside are prone to breakage due to soil erosion and internal loads. To improve the performance of the prestressing wires during long-term service, researchers have proposed many methods.

[0004] For example, invention patent CN107599273B proposes a polymer-reinforced prestressed steel cylinder concrete pipe forming process, which can effectively improve the corrosion resistance of prestressed steel wires. However, this method still has the following problems: In the existing prestressed steel cylinder concrete pipe manufacturing process, the prestressed steel wire is generally wound as a whole around the outside of the steel cylinder and subjected to strong prestress. The steel wire subjected to strong prestress is prone to breakage under complex environmental conditions. If there is even one break in the prestressed steel wire, it will cause a change in the stress of the entire pipe body, which will lead to a decrease in the strength of the pipe body and may eventually induce a pipeline explosion, threatening people's lives and property.

[0005] Furthermore, in the existing manufacturing process, the prestressed steel wire is wound from one end of the tube to the other. Due to the sudden change in stress, a stress gradient is formed at the interface between the wound and unwound parts of the tube, which will cause the tube to continuously develop cracks.

[0006] Therefore, it is necessary to improve the winding process of prestressed steel wire in the existing technology and optimize the prestressed steel cylinder concrete pipe structure to effectively improve the toughness level of the prestressed steel cylinder concrete pipe. Summary of the Invention

[0007] The purpose of this invention is to provide a PCCP pipe structure and manufacturing method to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides the following solution: The present invention provides a PCCP pipe structure, comprising:

[0009] The layers arranged from the inside out are: an inner concrete layer, a steel cylinder body, a first mortar protective layer, an outer concrete layer, a second mortar protective layer, and a coating layer.

[0010] The first prestressed structure includes a plurality of first prestressed members, which are axially wound around the outer layer of concrete and located within the second mortar protective layer.

[0011] The second prestressed structure includes a plurality of second prestressed members, which are distributed axially on the steel cylinder body and extend into the inner layer of concrete.

[0012] The first prestressed member and the second prestressed member work together to form a prestressing resultant force on the steel cylinder body.

[0013] Preferably, the first prestressed member includes a first steel wire, and a plurality of the first steel wires are axially wound on the outer layer of concrete and located within the second mortar protective layer. The first steel wires apply prestress to the outer layer of concrete from the outside to the inside.

[0014] Preferably, the second prestressed member includes a sleeve, which is fitted onto the outer wall of the steel cylinder body. One end of a plurality of tower columns is fixedly connected to the inner wall of the steel cylinder body at equal intervals along the circumference. The other end of the tower columns extends into the inner layer of concrete. The sleeve and the tower columns are located on the same vertical plane. A plurality of second steel wires are provided on the steel cylinder body, and the second steel wires are in contact with the tower columns.

[0015] Preferably, a plurality of connectors are provided at equal intervals along the circumference on both sides of the steel cylinder body. The connectors include a plurality of buckles distributed along the circumference of the steel cylinder body. The tower column is located in the middle of the steel cylinder body. Two buckles located symmetrically on both sides of the steel cylinder body are fixedly connected to both ends of the second steel wire. One end of the tower column is in contact with the middle of the second steel wire.

[0016] Preferably, a groove is provided on the outer wall of the steel cylinder body, the sleeve is located in the groove, and the first mortar protective layer is laid in the groove.

[0017] A method for producing a PCCP pipe structure includes the following steps:

[0018] S1. Install the second prestressed member on the steel cylinder body and pour the inner concrete layer and the first mortar protective layer.

[0019] S2. Pour the outer layer of concrete and wrap the first prestressed member around the outer layer of concrete.

[0020] S3. Pour the second mortar protective layer, and apply a coating after pouring.

[0021] Preferably, the prestress applied by the first prestressing members decreases gradually from the middle of the steel cylinder body towards both ends.

[0022] Preferably, the coating is an epoxy coal tar coating.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] 1. The present invention provides a PCCP pipe structure and production method, wherein a first prestressing member is set on the outside of the steel cylinder body, and prestress is applied to the steel cylinder body in sections, thereby avoiding the loss of prestress of the entire cylinder body due to a break in one part of the steel wire.

[0025] 2. The present invention provides a PCCP pipe structure and production method, wherein a second prestressing member is set inside the steel cylinder body, and an inward tensile force is added inside the steel cylinder to apply a part of the prestress to the steel cylinder, thereby achieving a synergistic effect with the first prestressing member outside the steel cylinder to form the prestress resultant force of the steel cylinder.

[0026] 3. The PCCP pipe structure and production method provided by the present invention use two sets of prestressed components superimposed to apply prestress to the pipe body, which avoids the problem of continuous cracking caused by the sudden increase of prestress in the pipe body due to the winding of steel wire during the original pipe body manufacturing process. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the first prestressed member of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the second prestressed member of the present invention;

[0031] Figure 4 This is a schematic diagram of the hoop structure of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the first prestressed member and the second prestressed member of the present invention;

[0033] Figure 6 This is a schematic diagram of the stress on the first prestressed member of the present invention and the resulting stress gradient;

[0034] Figure 7 This is a schematic diagram of the stress on the second prestressed member of the present invention and the resulting stress gradient;

[0035] Figure 8 This is a schematic diagram of the stress gradient combination of the first prestressed member and the second prestressed member of the present invention;

[0036] Among them, 1. Concrete inner layer; 2. Steel cylinder body; 3. First mortar protective layer; 4. Concrete outer layer; 5. Second mortar protective layer; 6. Coating; 7. First prestressed component; 71. First steel wire; 8. Second prestressed component; 81. Hoop; 82. Tower column; 83. Second steel wire; 84. Buckle. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1:

[0040] Reference Figures 1-8 This invention provides a PCCP pipe structure, comprising:

[0041] The layers arranged from the inside out are: inner concrete layer 1, steel cylinder body 2, first mortar protective layer 3, outer concrete layer 4, second mortar protective layer 5, and coating layer 6.

[0042] The first prestressed structure includes a plurality of first prestressed members 7, which are axially wound around the outer concrete layer 4 and located within the second mortar protective layer 5.

[0043] The second prestressed structure includes a number of second prestressed members 8, which are distributed axially on the steel cylinder body 2 and extend into the inner concrete layer 1.

[0044] The first prestressing member 7 and the second prestressing member 8 work together to form a prestressing resultant force on the steel cylinder body 2.

[0045] In a further optimized scheme, the first prestressed member 7 includes a first steel wire 71, and a plurality of first steel wires 71 are wound axially on the outer concrete layer 4 and located within the second mortar protective layer 5. The first steel wires 71 apply prestress to the outer concrete layer 4 from the outside to the inside.

[0046] Reference Figure 6 Several first steel wires 71 apply prestress to the steel cylinder body 2 respectively.

[0047] In a further optimized design, the second prestressed member 8 includes a sleeve 81, which is fitted onto the outer wall of the steel cylinder body 2. Several tower columns 82 are fixedly connected at equal intervals along the circumference on the inner wall of the steel cylinder body 2. The other end of the tower columns 82 extends into the inner concrete layer 1. The sleeve 81 and the tower columns 82 are located on the same vertical plane. Several second steel wires 83 are provided on the steel cylinder body 2, and the second steel wires 83 are in contact with the tower columns 82.

[0048] The sleeve 81 is fitted onto the steel cylinder body 2, and the tower column 82 extends into the steel cylinder body 2 and is connected to the second steel wire 83. By tightening the sleeve 81, support is provided for the tower column 82, and the force on the tower column 82 is offset.

[0049] The scheme is further optimized by providing several connectors at equal intervals along the circumference on both sides of the steel cylinder body 2. The connectors include several buckles 84 distributed along the circumference of the steel cylinder body 2. The tower column 82 is located in the middle of the steel cylinder body 2. Two buckles 84 located symmetrically on both sides of the steel cylinder body 2 are fixedly connected to both ends of the second steel wire 83. One end of the tower column 82 is in contact with the middle of the second steel wire 83.

[0050] Reference Figure 3 The buckles 84 are distributed in several locations on the inner wall of the steel cylinder body 2. Each tower column 82 has the same number of buckles 84 on both sides. The buckles 84 are used to connect the two ends of the second steel wire 83, and simultaneously apply force to the second steel wire 83 through the tower column 82. (Refer to...) Figure 6 This is the force diagram of the second prestressed member 8. The resultant force in the horizontal direction is zero, and prestress is applied in the vertical direction, which is counteracted by the force applied by the external sleeve 81. AB And it provides an inward force.

[0051] The scheme is further optimized by creating a groove on the outer wall of the steel cylinder body 2, with the sleeve 81 located inside the groove, and the first mortar protective layer 3 laid inside the groove.

[0052] The sleeve 81 is located in the groove. After the sleeve 81 is installed, the first mortar protective layer 3 is laid to cover the sleeve 81.

[0053] A method for producing a PCCP pipe structure includes the following steps:

[0054] S1. Install the second prestressed member 8 on the steel cylinder body 2, and pour the inner concrete layer 1 and the first mortar protective layer 3.

[0055] The sleeve 81 is a ring structure. Several ring-shaped sleeves 81 are axially spaced and fixedly connected to the steel cylinder body 2. The sleeve 81 applies a force to one end of the tower column 82, and the other end of the tower column 82 extends into the steel cylinder body 2. Several buckles 84 are provided on the inner wall of the steel cylinder body 2. The two ends of the second steel wire 83 are fixedly connected to the buckles 84 on both sides. A cable-like structure is used to add an inward tension inside the steel cylinder body 2, applying a part of the prestress to the steel cylinder body 2. A concrete inner layer 1 is poured inside the steel cylinder body 2, and a first mortar protective layer 3 is poured on the outside, covering the sleeve 81. The magnitude of the prestress applied by the second steel wire 83 decreases from the two ends to the middle, that is, FA1=FB1>FA2=FB2>FA3=FB3, forming a stress gradient that is large at both ends and small in the middle.

[0056] S2. Pour the outer concrete layer 4 and wrap the first prestressed member 7 around the outer concrete layer 4.

[0057] Pour the outer concrete layer 4 in step S1, referring to... Figure 2 Several first steel wires 71 are wound axially on the outer layer of concrete 4. By dividing a single steel wire into multiple segments for winding, prestress is applied to the steel cylinder body 2 in segments to avoid the entire steel cylinder body 2 losing prestress due to a single point of the steel wire rope.

[0058] S3. Pour the second mortar protective layer 5, and apply the coating 6 after pouring.

[0059] On the basis of S2, a second mortar protective layer 5 is poured to cover the first steel wire 71, and a coating 6 is applied to cover the second mortar protective layer 5.

[0060] The scheme was further optimized so that the prestress applied by several first prestressed members 7 gradually decreased from the middle of the steel cylinder body 2 to both ends.

[0061] Reference Figure 2 , Figure 6 The force added to the first prestressed member 7 is the greatest in the middle and decreases towards both sides, further providing support for the tower column 82.

[0062] Specifically, the steel cylinder body 2 is symmetrically divided into segments, with points A and B on the left and right, and point C in the middle. The prestress applied to the first steel wire 71 decreases from the middle to both ends, i.e., FAC3 = FBC3 > FAC2 = FBC2 > FAC1 = FBC1, forming a stress gradient that is smaller at both ends and larger in the middle.

[0063] The scheme was further optimized, and coating 6 was an epoxy coal tar coating.

[0064] The epoxy coal tar coating further protects the pipe body.

[0065] Example 2:

[0066] Using the finite element method, the relevant pipe body parameters of PCCP under the traditional wire winding process (Comparative Example 1), the external winding segmented steel wire process (Comparative Example 2), the internal cable steel wire process (Comparative Example 3), and the external winding segmented steel wire process combined with the internal cable steel wire process (Example) were analyzed. The basic parameters of the pipeline set by the finite element analysis are shown in Table 1.

[0067] Table 1:

[0068]

[0069]

[0070] The relevant load indicators of the PCCP during long-term service were tested through finite element analysis, and the calculation results are shown in Table 2.

[0071] Table 2:

[0072]

[0073] The results show that the production process provided by this invention can effectively improve the load-bearing capacity of PCCP. The prestress loss of PCCP is evaluated by analyzing the finite element analysis results through prestress composite calculation.

[0074] 1. Prestress loss caused by wire stress relaxation

[0075] The prestress loss caused by wire stress relaxation is calculated using the following formula:

[0076] σ s2 =0.08σ con φ t φ (1)

[0077]

[0078] σ con =0.075f tpk (3)

[0079] In the formula:

[0080] σ s2 Prestress loss due to wire stress relaxation, N / mm 2 ;

[0081] σ con : Prestressed steel wire tension control value, N / mm 2 ;

[0082] Φ tThe influence coefficient of the core manufacturing process is 1.0 for vertical casting and 1.2 for centrifugal molding.

[0083] Φ: Reinforcement influence coefficient;

[0084] Φ1, Φ2: Influence coefficients of reinforcement in the first and second layers.

[0085] 2. Prestress loss σ caused by shrinkage and creep s3 (Values ​​are taken from Table 4.2.8 of CECS140 specification), and the difference is selected.

[0086] 3. Prestress loss caused by elastic compression of concrete

[0087] The prestress loss caused by elastic compression of concrete is calculated using the following formula:

[0088] σ s7 =0.5n1ρ y σ con (4)

[0089] In the formula:

[0090] n s The ratio of the elastic modulus of prestressed steel wire to the elastic modulus of concrete;

[0091] σ con : Prestressed steel wire tension control value, N / mm 2 ;

[0092] σ y Circumferential prestressed steel wire reinforcement ratio.

[0093] (4) Calculation of effective prestress

[0094] Effective prestress is calculated using the following formula:

[0095] σ p =σ p1 +σ p2 (5)

[0096]

[0097]

[0098] A cy =1000(ht) y +t y n y (8)

[0099] A cy =1000[h c -t y +t y n y +Ap1 (n s -n m )+(d+t d )n m (9)

[0100] In the formula:

[0101] n s The ratio of the elastic modulus of prestressed steel wire to the elastic modulus of concrete;

[0102] E c Elastic modulus of the core concrete (N / mm²) 2 );

[0103] σ p Normal preload stress on the circumferential section of the pipe wall (N / mm) 2 );

[0104] σ pl Prestress (N / mm) of a single layer of reinforcing bar or the first layer of prestressed steel wire on the circumferential section of the pipe wall. 2 );

[0105] σ p2 Normal prestress of the second layer of prestressed steel wire on the circumferential section of the pipe wall (N / mm) 2 );

[0106] A cy Calculated area (mm²) of the core and cylinder when using single-layer wire winding 2 );

[0107] A cy’ Calculated area (mm²) of the core and cylinder when double-layered wire winding 2 ).

[0108] The calculation results of prestress loss are shown in Table 3.

[0109] Table 3:

[0110] tubular Comparative Example 1 Comparative Example 2 Comparative Example 3 Example <![CDATA[σ s2 (N / mm 2 )]]> 94.2 102.37 113.28 62.31 <![CDATA[σ s3 (N / mm 2 )]]> 38.65 47.98 52.37 21.35 <![CDATA[σ s7 (N / mm 2 )]]> 35.04 49.21 47.25 13.22 <![CDATA[σ s (N / mm 2 )]]> 167.89 199.56 212.9 96.88

[0111] in:

[0112] σ s2 Prestress loss due to wire stress relaxation, N / mm 2 ;

[0113] σ s3 Prestress loss due to shrinkage and creep, N / mm 2 ;

[0114] σ s7 Prestress loss due to elastic compression of concrete, N / mm 2 ;

[0115] σ s Total prestress loss, N / mm 2 ;

[0116] Upon review, the production process provided by this invention can effectively reduce the prestress loss of PCCP during long-term service.

[0117] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0118] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A PCCP pipe structure, characterized in that, include: The layers arranged from the inside out are: inner concrete layer (1), steel cylinder body (2), first mortar protective layer (3), outer concrete layer (4), second mortar protective layer (5), and coating layer (6); The first prestressed structure includes a plurality of first prestressed members (7), which are axially wound around the outer concrete layer (4) and located within the second mortar protective layer (5). The second prestressed structure includes a plurality of second prestressed members (8), which are distributed axially on the steel cylinder body (2) and extend into the inner concrete layer (1). The first prestressed member (7) and the second prestressed member (8) work together to form a prestressing resultant force on the steel cylinder body (2); The first prestressed member (7) includes a first steel wire (71), and several first steel wires (71) are axially wound around the outer concrete layer (4) and located inside the second mortar protective layer (5). The first steel wires (71) apply prestress to the outer concrete layer (4) from the outside to the inside. The second prestressed member (8) includes a sleeve (81), which is sleeved on the outer wall of the steel cylinder body (2). One end of several tower columns (82) is fixedly connected to the inner wall of the steel cylinder body (2) at equal intervals along the circumference. The other end of the tower columns (82) extends into the inner concrete layer (1). The sleeve (81) and the tower columns (82) are located on the same vertical plane. A plurality of second steel wires (83) are provided on the cylinder body (2), and the second steel wires (83) are in contact with the tower column (82); a plurality of connectors are provided at equal intervals along the circumference on both sides of the steel cylinder body (2), and the connectors include a plurality of buckles (84) distributed along the circumference of the steel cylinder body (2); the tower column (82) is located in the middle of the steel cylinder body (2), and two buckles (84) located symmetrically on both sides of the steel cylinder body (2) are fixedly connected to the two ends of the second steel wires (83) respectively; one end of the tower column (82) is in contact with the middle of the second steel wires (83); the prestress applied by the first prestressing member (7) decreases gradually from the middle of the steel cylinder body (2) to both ends.

2. The PCCP pipe structure according to claim 1, characterized in that: The outer wall of the steel cylinder body (2) is provided with a groove, the sleeve (81) is located in the groove, and the first mortar protective layer (3) is laid in the groove.

3. A method for producing a PCCP pipe structure, applicable to the PCCP pipe structure described in claim 1, characterized in that, Includes the following steps: S1. Install the second prestressed member (8) on the steel cylinder body (2) and pour the inner concrete layer (1) and the first mortar protective layer (3); S2. Pour the outer layer of concrete (4) and wrap the first prestressed member (7) around the outer layer of concrete (4); S3. Pour the second mortar protective layer (5), and apply the coating after pouring (6).

4. The method for producing a PCCP pipe structure according to claim 3, characterized in that: The coating (6) is an epoxy coal tar coating.

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