A lightweight, corrosion-resistant prestressed steel cylinder concrete pipe and its preparation method

Abstract

The present invention discloses a lightweight, corrosion-resistant prestressed concrete-cement tube pipe, comprising a steel tube, a UHPC core, a BFRP prestressed tendon layer, and a mortar protective layer. The UHPC core comprises two layers, one on each side of the steel tube. The BFRP prestressed tendon layer is secured by a split basalt anchoring device comprising an inner BFRP-RPM nesting element and an outer epoxy resin grouting layer. The UHPC core is designed with a variable cross-sectional thickness distribution along the axial direction, with a thickness of 60-80 mm at the socket end and 40-50 mm at the middle. BFRP prestressed tendons are used to replace traditional high-strength prestressed steel wire. BFRP material has excellent corrosion resistance and can maintain stable performance in chloride ion corrosive environments, thus avoiding wire breakage caused by corrosion, significantly improving the corrosion resistance of the pipe and extending its service life.

Description

Technical Field

[0001] The present invention relates to a concrete pipe, in particular to a lightweight, corrosion-resistant prestressed steel cylinder concrete pipe and a preparation method thereof. Background Art

[0002] Traditional prestressed concrete cylinder pipe (PCCP), as an important pipeline structure, is widely used in water and gas transmission projects in water conservancy, municipal administration, and industry. It combines the advantages of steel and concrete, enhancing the pipe's load-bearing capacity and durability through prestressing technology. However, with the increasing complexity of engineering applications and the continuous improvement of project requirements, traditional PCCP pipes have gradually exposed certain issues in terms of corrosion resistance, lightweighting, and long-term performance stability, limiting their wider application.

[0003] In harsh environments such as chloride ion corrosion, the high-strength prestressed steel wires in traditional PCCP pipes are prone to corrosion, resulting in a decrease in the structural strength of the pipeline and even causing wire breakage accidents, seriously affecting the safe operation and service life of the pipeline.

[0004] Furthermore, traditional PCCP pipes, due to their thick-walled concrete structure, are heavy, increasing energy consumption during production, transportation, and installation. This also limits their application in certain specialized projects, such as high-altitude installations and deep-sea installations. Furthermore, over long-term use, traditional PCCP pipes experience a gradual decline in structural performance due to factors such as material aging and environmental corrosion, making them difficult to meet the long-term safety and reliability requirements of projects.

[0005] Therefore, there is an urgent need for a lightweight, corrosion-resistant prestressed steel cylinder concrete pipe and a preparation method thereof to solve the technical problems existing in the above-mentioned prior art. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the prior art and provides a lightweight, corrosion-resistant prestressed steel cylinder concrete pipe and a preparation method thereof.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a lightweight, corrosion-resistant prestressed concrete cylinder pipe, comprising: a steel cylinder, a UHPC pipe core, a BFRP prestressed tendon layer, and a mortar protective layer; the BFRP prestressed tendons are evenly wound around the outer surface of the steel cylinder, and the UHPC pipe core has two layers, one cast on each side of the steel cylinder;

[0008] The BFRP prestressed tendon layer is fixed by a split basalt anchoring device, which includes an inner BFRP-RPM nesting member and an outer epoxy resin grouting layer;

[0009] The UHPC core is designed with variable cross-section thickness distribution along the axial direction, and the thickness of the socket end is =60~80mm, middle thickness =40~50mm.

[0010] The surface of the BFRP prestressed tendons is treated by plasma etching to form =3.5~5.0μm micro-nano rough structure, and coated with 0.5%-1.0% - Nano-SiO2 coating of aminopropyltriethoxysilane; the contact surface between the BFRP-RPM nesting part and the reinforcement of the split basalt anchoring device is provided with a 30° tapered self-locking structure, and the anchoring efficiency coefficient is ≥0.95.

[0011] In a preferred embodiment of the present invention, the mortar protective layer adopts a composite mortar added with polypropylene fiber and nano-titanium dioxide, wherein the volume content of the polypropylene fiber is 0.1% to 0.3%, and the mass content of the nano-titanium dioxide is 1% to 3%.

[0012] In a preferred embodiment of the present invention, a method for preparing a lightweight, corrosion-resistant, prestressed concrete cylinder pipe is provided. The method comprises the following steps:

[0013] S1. Using a six-degree-of-freedom robot for intelligent winding, the BFRP prestressed tendons are evenly wound around the outer surface of the steel cylinder, and the tension, angle and spacing parameters are monitored in real time;

[0014] S2, implement gradient prestressing control through fiber Bragg grating sensors, loading in three stages;

[0015] S3. Cast the UHPC material and vibrate it to compact it. A variable-section formwork system is used for casting the UHPC core. The thickness transition curve is determined through finite element topology optimization. The thickness of the socket end is 70 mm and the thickness of the middle is 45 mm. The inner surface of the formwork is treated with superhydrophobic treatment, and the contact angle after treatment reaches 160°. A composite mortar with a thickness of 5 mm is applied to the outer surface of the UHPC core.

[0016] In a preferred embodiment of the present invention, the three-stage loading includes: a loading rate of 0.1 MPa / s in the 0-30% σ_con stage; a loading rate of 0.5 MPa / s in the 30-80% σ_con stage; and a stress relaxation compensation algorithm is enabled in the 80-100% σ_con stage.

[0017] In a preferred embodiment of the present invention, in step S1, an infrared thermal imaging broken wire detection module is integrated into the intelligent wire winding process, and the broken wire rate is ≤0.05%.

[0018] In a preferred embodiment of the present invention, the UHPC tube core has a 28d compressive strength of ≥150 MPa, a tensile strength of ≥12 MPa, and an electric flux of ≤500C.

[0019] In a preferred embodiment of the present invention, in step S3, the variable-section formwork system performs super-hydrophobic treatment on the inner surface of the formwork before casting the UHPC tube core, and the contact angle between the treated formwork and the UHPC tube core is ≥150°.

[0020] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0021] (1) Use BFRP prestressed tendons to replace traditional high-strength prestressed steel wires. BFRP materials have excellent corrosion resistance and can maintain stable performance in chloride ion corrosion environments, thereby avoiding wire breakage caused by corrosion, thereby significantly improving the corrosion resistance of the pipeline and extending the service life of the pipeline.

[0022] (2) Use UHPC to replace traditional pipe core concrete. UHPC has higher compressive strength and tensile strength. It can reduce the wall thickness of the pipe core concrete while ensuring the performance of the pipeline, thereby reducing the weight of the pipeline, thus achieving lightweight design of the pipeline and reducing energy consumption and costs during production, transportation and installation.

[0023] (3) By optimizing the structural design and preparation process of the pipeline, such as adopting intelligent wire winding technology, gradient prestressing tensioning control and variable cross-section template system, the pipeline can maintain stable performance during long-term use, thereby significantly improving the durability of the pipeline and meeting the needs of long-term stable operation.

[0024] (4) Using green and low-carbon materials such as UHPC to replace traditional high-energy consumption materials, and optimizing the preparation process to reduce energy consumption in the production process, thereby significantly reducing carbon emissions during the production and transportation of pipelines, which is in line with the development trend of green and low-carbon.

[0025] (5) The present invention effectively solves the technical problems of corrosion, weight, durability and carbon emissions encountered by traditional prestressed steel tube concrete pipes during their application by adopting new materials such as BFRP prestressed tendons and UHPC and optimizing the preparation process, thereby improving pipeline performance, extending service life, reducing energy consumption and costs, and complying with the green and low-carbon development trend. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts.

[0027] Figure 1This is a flow chart of a method for preparing a lightweight, corrosion-resistant prestressed steel cylinder concrete pipe according to a preferred embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of the lightweight corrosion-resistant prestressed steel cylinder concrete pipe structure of a preferred embodiment of the present invention.

[0029] In the figure, 1. Steel cylinder; 2. UHPC tube core; 3. BFRP prestressed tendon layer; 4. Mortar protective layer. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0032] like Figure 1 As shown, a method for preparing a lightweight, corrosion-resistant prestressed steel cylinder concrete pipe comprises the following steps:

[0033] S1: A six-degree-of-freedom robot is used for intelligent silk winding. The robot performs trajectory planning in joint space or Cartesian space to ensure precision and efficiency. Joint space planning determines the sequence of joint angle changes to plan the spatial trajectory of the end arm, while Cartesian space planning directly plans the position changes of the end arm to meet different silk winding requirements.

[0034] During the winding process, tension, angle, and spacing parameters are monitored in real time to ensure winding quality. Sensor data is processed using sensor data acquisition and processing algorithms such as weighted smoothing, mutation extraction, and simple moving average to ensure data accuracy and stability.

[0035] It's worth noting that the 6DOF robot achieves precise angle and trajectory control through dual-mode trajectory planning. In joint space mode, the controller calculates the rotational sequence of the J1-J6 axes, enabling the winding head to follow the spatial curve of the variable-section pipe. For example, in the socket area, by adjusting the linear displacement rate of the J4-J6 axes, the winding angle can be dynamically switched from 90° to 85° / 95° with an error of ≤±0.5°. Cartesian space mode is used for straight pipe sections. CAM software generates a helical trajectory, and the KEYENCE LK-G80 laser ranging sensor scans the pipe surface in real time, dynamically correcting trajectory deviations and maintaining a pitch error of ≤±1mm. The combination of these two modes ensures angular accuracy and trajectory smoothness in different sections.

[0036] The monitoring system integrates multiple sensors for multifunctional real-time monitoring. A strain gauge tension sensor measures rebar tension in real time with an accuracy of ±1% FS, and a Yaskawa Sigma-7 servo motor dynamically compensates for tension fluctuations. A linear laser displacement sensor measures the distance between adjacent rebars with an accuracy of ±0.2mm, and a PID algorithm adjusts the robot's movement speed. A FLIR A315 infrared thermal imaging module detects broken wires at a 50Hz frequency, triggering an alarm and locating the location within 0.1s when a temperature difference of 2°C or greater is detected, with an accuracy of ±5mm. Data is integrated and processed by a Siemens S7-1500 PLC, filtered using weighted smoothing and mutation extraction algorithms, and displayed and tracked in real time on the Weiluntong MT8102iE touchscreen.

[0037] The integrated infrared thermal imaging broken wire detection module uses infrared thermal imaging technology to detect broken wires. When a broken wire is detected, the module triggers an alarm mechanism to promptly address the problem, ensuring the continuity and quality of the winding. The broken wire rate is ≤ 0.05%.

[0038] S2: Prestress changes are monitored using fiber grating sensors. These sensors are mounted on the surface of the structure or on screws that secure it to the structure. This allows for monitoring structural deformation and the interaction between the surrounding rock and the structure. Finite element analysis can be used to analyze strain at various locations, enabling precise monitoring of prestress.

[0039] The loading method is divided into three stages, and the stress value is corrected by the stress relaxation compensation algorithm to ensure the accuracy of prestressing.

[0040] The first stage: 0~30%σ_con, loading rate 0.1MPa / s, slow loading to avoid impact on the structure.

[0041] The second stage: 30%~80%σ_con, loading rate 0.5MPa / s, gradually increase the prestress to 80% of the design value.

[0042] The third stage: 80%~100%σ_con, the stress relaxation compensation algorithm is enabled to precisely control the prestress and ensure the accuracy of prestressing.

[0043] S3: Utilizing a variable-section formwork system, finite element topology optimization was used to determine the thickness transition curve to optimize the formwork's structural design. Formwork design considered factors such as rigidity, strength, stability, as well as long-distance transportation and assembly accuracy to ensure formwork stability and accuracy during the pouring process. Furthermore, the demolding hydraulic cylinders were configured based on the desired demolding load to reduce the workload on workers.

[0044] Before casting the UHPC core, the inner surface of the formwork is treated with a superhydrophobic treatment. The contact angle between the treated formwork and the UHPC core is ≥150°, improving its anti-fouling and self-cleaning capabilities, facilitating demolding, and extending its service life. This superhydrophobic treatment is achieved through methods such as electrochemical etching, layer-by-layer self-assembly, sol-gel, or electrodeposition.

[0045] The 28d compressive strength of the UHPC tube core is ≥150MPa, the tensile strength is ≥12MPa, and the electric flux is ≤500C, ensuring the high performance and durability of the tube core and meeting the use requirements of lightweight and corrosion-resistant prestressed steel tube concrete pipes.

[0046] A lightweight, corrosion-resistant prestressed steel cylinder concrete pipe comprises: a steel cylinder 1, a UHPC pipe core 2, a BFRP prestressed tendon layer 3 and a mortar protective layer 4; the UHPC pipe core 2 has two layers, one located on each side of the steel cylinder 1.

[0047] The BFRP prestressed tendon layer 3 is secured using a split basalt anchor system consisting of an inner BFRP-RPM insert and an outer epoxy grouting layer. The BFRP-RPM insert features a 30° taper self-locking structure at the interface with the reinforcement, achieving an anchoring efficiency coefficient of ≥0.95, ensuring secure anchorage of the prestressed tendons.

[0048] The surface of the BFRP prestressed tendons is treated to enhance the bonding performance between the prestressed tendons and concrete. The surface of the BFRP prestressed tendons is treated with plasma etching to form a micro-nano rough structure of 3.5-5.0μm, and is coated with a nano-SiO2 coating containing 0.5%-1.0% aminopropyltriethoxysilane to improve the corrosion resistance and interfacial bonding strength of the tendons.

[0049] The UHPC tube core 2 features a variable cross-sectional thickness distribution along the axial direction, with a thickness of 60-80mm at the socket end and 40-50mm in the middle, achieving a lightweight design. Furthermore, the UHPC tube core has a 28d compressive strength of ≥150MPa, a tensile strength of ≥12MPa, and an electrical flux of ≤500C, ensuring high performance and durability.

[0050] The mortar protective layer 4 adopts a composite mortar added with polypropylene fiber and nano-titanium dioxide. The volume content of polypropylene fiber is 0.1%~0.3%, which improves the crack resistance of the mortar; the mass content of nano-titanium dioxide is 1%~3%, which gives the mortar self-cleaning ability and extends the service life of the pipeline.

[0051] Example 1

[0052] Raw material preparation

[0053] The steel cylinder is made of Q345B steel, with an outer diameter of 1000mm, a wall thickness of 10mm, and a length of 6000mm. The BFRP prestressed tendons are 8mm in diameter and have been plasma-etched to create a 4.0μm micro-nano roughness. They are then coated with a nano-SiO2 coating containing 0.8% aminopropyltriethoxysilane.

[0054] UHPC materials are cement, silica fume, quartz sand, high-efficiency water reducer and water. After mixing in proportion, the 28-day compressive strength reaches 180MPa, the tensile strength reaches 15MPa, and the electrical flux is 400C.

[0055] The mortar protective layer materials are ordinary Portland cement, polypropylene fiber, with a volume content of 0.2%, and nano titanium dioxide, with a mass content of 2%.

[0056] A six-degree-of-freedom robot equipped with tension, angle, and spacing sensors is used. Using Cartesian spatial planning, the robot precisely controls the winding trajectory, ensuring that the BFRP prestressed tendons are evenly wound around the outer surface of the steel cylinder. Real-time tension monitoring is maintained, controlling the tension to 500N ± 5%, the angle to 90°, and the spacing to 50mm ± 2%. A weighted smoothing algorithm processes sensor data to ensure winding quality. An integrated infrared thermal imaging wire breakage detection module keeps the wire breakage rate below 0.03%.

[0057] Fiber Bragg grating (FBG) sensors are placed on the surface of the BFRP prestressed tendons. Loading is performed in three stages: Stage 1: 0–30% σ_con, where σ_con is the design prestress value, at a loading rate of 0.1 MPa / s. Stage 2: 30–80% σ_con, at a loading rate of 0.5 MPa / s. Stage 3: 80–100% σ_con, with a stress relaxation compensation algorithm activated to ensure accurate prestress application. FBG sensors monitor prestress changes in real time to ensure controllable tensioning.

[0058] A variable-section formwork system was used, and the thickness transition curve was determined through finite element topology optimization. The socket end thickness was 70mm, and the center thickness was 45mm. The inner surface of the formwork was treated with a superhydrophobic treatment, achieving a contact angle of 160°. The UHPC material was poured, vibrated, and cured for 28 days to ensure that the UHPC core performance met the standards.

[0059] Apply composite mortar to the outer surface of the UHPC tube core with a thickness of 5mm. Curing for 7 days to ensure that the mortar protective layer is tightly bonded to the UHPC tube core.

[0060] In a preferred embodiment, the lightweight corrosion-resistant prestressed steel cylinder concrete pipe also includes: a graphene-nanosilica composite coating attached to the inner side of the UHPC pipe core by chemical vapor deposition, with a thickness of 0.1~0.5mm and a chloride ion diffusion coefficient.

[0061] The UHPC tube core is a basalt fiber-carbon nanotube hybrid UHPC tube core. The fiber volume fraction is distributed in a gradient of 8% to 5% from the inside to the outside, and is built with segmented variable diameter basalt composite reinforcement. The diameter of the two ends of the basalt composite reinforcement is 15% to 20% larger than that of the middle section. The tensile stress is sinusoidally distributed along the basalt fiber-carbon nanotube hybrid UHPC tube core.

[0062] It should be further noted that variable-diameter BFRP prestressed tendons are prefabricated through a customized pultrusion process. A segmented heating furnace with a temperature tolerance of ±2°C is used to control the mold temperature field, producing tapered transitional bars composed of standard and thickened segments, ensuring fiber continuity without breakage. The robotic winding system features a three-station reel support, each with independent tension control via a magnetic powder brake. A Panasonic MINAS A6 servo motor drives the synchronous belt, enabling rapid switching within 10 seconds, enabling continuous winding of rebars of varying diameters.

[0063] The variable diameter winding process uses a Raytek 3i2ML laser diameter gauge with an accuracy of ±0.02mm to identify the rebar diameter in real time and automatically adjust the corresponding process parameters: standard sections of small-diameter rebar are wound with a tension of 500-600N and an angle of 85°-95°; thickened sections of large-diameter rebar are wound with a tension of 700-800N and a spacing of 60-70mm to prevent overlap. A gradual change mode is activated 500mm before the diameter switching point. The robot's movement speed is linearly adjusted to 50-30mm / s and the pipe rotation speed is adjusted to 1-1.5rpm. A Basler vision sensor monitors the transition section quality to ensure a smooth transition of the helix angle. This increases the cross-sectional area of ​​the rebar at the socket end by 44% and the tensile stiffness by over 50%, effectively reducing stress concentration at the interface. Software parameters can be adapted to multiple production specifications without hardware modification.

[0064] Microbial mineralization repair mortar layer, containing Bacillus pasteurianus and calcium carbonate precursor, is used to repair cracks on the surface of the mortar protective layer.

[0065] Example 2

[0066] Raw material preparation

[0067] The steel cylinder is made of Q390B steel, with an outer diameter of 1200mm, a wall thickness of 12mm, and a length of 8000mm. The BFRP prestressed tendons are 10mm in diameter and have been plasma-etched to create a 4.5μm micro-nano roughness. They are then coated with a nano-SiO2 coating containing 1.0% aminopropyltriethoxysilane.

[0068] The optimized mix ratio of UHPC materials achieves a 28-day compressive strength of 200 MPa, a tensile strength of 18 MPa, and an electrical flux of 350°C. The mortar protective layer material is based on ordinary Portland cement, with 0.1% steel fiber added to improve crack resistance.

[0069] The robot uses a six-degree-of-freedom robot equipped with high-precision tension and angle sensors. The robot uses joint space planning combined with particle swarm optimization to find the optimal winding path.

[0070] Real-time monitoring controls tension at 600N ± 3%, angles between 85° and 95°, and spacing at 45mm ± 1%. Sensor data is processed using an extraction mutation algorithm to improve winding accuracy. An integrated infrared thermal imaging wire breakage detection module keeps the wire breakage rate below 0.02%.

[0071] Fiber Bragg grating sensors are placed at the junction of the BFRP prestressing tendons and the steel cylinder. Loading is performed in three stages, with an optimized loading rate: Stage 1: 0-30% σ_con, loading rate 0.15 MPa / s; Stage 2: 30-80% σ_con, loading rate 0.6 MPa / s; Stage 3: 80-100% σ_con. An improved stress relaxation compensation algorithm is used to improve prestress control accuracy. Using fiber Bragg grating sensors and finite element analysis, prestress distribution and structural deformation are monitored in real time.

[0072] A variable-section formwork system was adopted, and through topological optimization and 3D printing technology, a complex thickness transition curve was achieved. The thickness of the socket end is 80 mm, and the thickness in the middle is 40 mm. The inner surface of the formwork was treated with superhydrophobicity, and the contact angle after treatment reached 165°. The optimized UHPC material was cast using vacuum-assisted casting technology to improve the density and was cured for 28 days. A composite mortar with added steel fiber was applied to the outer surface of the UHPC core with a thickness of 6 mm. Curing was carried out for 14 days to ensure that the mortar protective layer has excellent crack resistance and durability. The following is a performance comparison and conclusion between Example 1 and Example 2.

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077] Table 3

[0078]

[0079] Conclusion: Example 2 is superior to Example 1 in many aspects of performance.

[0080] Example 2 selected higher-strength steel cylinders and BFRP prestressed tendons, optimized the mix ratio of UHPC and mortar protective layer, and improved the overall performance of the material.

[0081] Example 2 adopts a more advanced wire winding trajectory planning method, a faster prestressing loading rate and a more accurate stress control algorithm, while optimizing the UHPC pouring and mortar construction process.

[0082] Example 2 performs well in terms of lightweight effect, corrosion resistance and structural performance, especially the significant improvement in structural performance, which can meet engineering applications with higher requirements.

[0083] It should be emphasized that Example 1 has good performance and is suitable for general engineering needs:

[0084] The preparation method and material selection of Example 1 can already meet the application scenarios of most lightweight corrosion-resistant prestressed steel cylinder concrete pipes, and have the advantages of cost-effectiveness and process maturity.

[0085] Example 2 is more suitable for high-end or special engineering needs:

[0086] The optimized design and advanced technology of Example 2 make it more suitable for projects with extremely high requirements on pipeline performance, such as water and gas transmission projects in harsh environments such as high pressure, large flow, and strong corrosion.

[0087] The concrete pipes produced using the aforementioned preparation method are targeted at areas with medium-to-high corrosion environments. Basalt fiber, a pollution-free, reusable, green, and low-carbon industrial raw material, is used to produce basalt fiber composite rebar with excellent properties such as lightweight, high tensile strength, and corrosion resistance. Using it to replace high-strength prestressed steel wire in PCCP pipes effectively addresses the issue of corrosion and breakage of high-strength prestressed steel wire in chloride-corroded environments. Replacing traditional core concrete with ultra-high-performance concrete (UHPC) reduces wall thickness, significantly lowers concrete usage, and reduces weight, thereby reducing energy consumption during production, transportation, and installation. This lightweight, corrosion-resistant prestressed concrete cylinder pipe (PCCP) based on basalt composite rebar (BFRP) and ultra-high-performance concrete (UHPC) significantly extends its service life and reduces carbon emissions compared to traditional PCCP pipes.

[0088] The above description is based on the ideal embodiment of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the content of the specification and must be determined according to the scope of the claims.

Claims

1. A lightweight, corrosion-resistant prestressed concrete cylinder pipe, characterized in that: include: Steel cylinder, UHPC tube core, BFRP prestressed tendon layer and mortar protective layer; BFRP prestressed tendons are evenly wrapped around the outer surface of the steel cylinder, and the UHPC tube core has two layers, which are cast on both sides of the steel cylinder respectively; The BFRP prestressed tendon layer is fixed by a split basalt anchoring device, which includes an inner BFRP-RPM nesting member and an outer epoxy resin grouting layer; The UHPC core is designed with variable cross-section thickness distribution along the axial direction, and the thickness of the socket end is =60~80mm, middle thickness =40~50mm; The surface of the BFRP prestressed tendons is treated by plasma etching to form =3.5~5.0μm micro-nano rough structure, and coated with 0.5%-1.0% - Nano-SiO2 coating of aminopropyltriethoxysilane; the contact surface between the BFRP-RPM nesting part and the reinforcement of the split basalt anchoring device is provided with a 30° tapered self-locking structure, and the anchoring efficiency coefficient is ≥0.

95.

2. The lightweight, corrosion-resistant prestressed concrete cylinder pipe according to claim 1, characterized in that: The mortar protective layer adopts a composite mortar added with polypropylene fiber and nano titanium dioxide, wherein the volume content of the polypropylene fiber is 0.1% to 0.3%, and the mass content of the nano titanium dioxide is 1% to 3%.

3. A method for preparing a lightweight, corrosion-resistant prestressed concrete cylinder pipe, based on the lightweight, corrosion-resistant prestressed concrete cylinder pipe according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1. Using a six-degree-of-freedom robot for intelligent winding, the BFRP prestressed tendons are evenly wound around the outer surface of the steel cylinder, and the tension, angle and spacing parameters are monitored in real time; S2, implement gradient prestressing tension control through fiber grating sensors, loading in three stages; S3. Cast the UHPC material and vibrate it to compact it. A variable-section formwork system is used for casting the UHPC core. The thickness transition curve is determined through finite element topology optimization. The thickness of the socket end is 70 mm and the thickness of the middle is 45 mm. The inner surface of the formwork is treated with superhydrophobic treatment, and the contact angle after treatment reaches 160°. A composite mortar with a thickness of 5 mm is applied to the outer surface of the UHPC core.

4. The method for preparing a lightweight, corrosion-resistant prestressed concrete cylinder pipe according to claim 3, characterized in that: The three-stage loading includes: a loading rate of 0.1 MPa / s in the 0-30% σ_con stage; a loading rate of 0.5 MPa / s in the 30-80% σ_con stage; and a stress relaxation compensation algorithm is enabled in the 80-100% σ_con stage.

5. The method for preparing a lightweight, corrosion-resistant prestressed concrete cylinder pipe according to claim 3, characterized in that: In step S1, an infrared thermal imaging broken wire detection module is integrated into the intelligent wire winding process, and the broken wire rate is ≤0.05%.

6. The method for preparing a lightweight, corrosion-resistant prestressed concrete cylinder pipe according to claim 3, characterized in that: The UHPC tube core has a 28d compressive strength of ≥150 MPa, a tensile strength of ≥12 MPa, and an electric flux of ≤500C.

7. The lightweight, corrosion-resistant prestressed concrete cylinder pipe according to claim 3, characterized in that: In step S3, the variable-section formwork system performs super-hydrophobic treatment on the inner surface of the formwork before casting the UHPC tube core, and the contact angle between the treated formwork and the UHPC tube core is ≥150°.

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