Leakage prevention method for prestressed steel cylinder concrete pipeline and steel pipeline

Abstract

The invention discloses an anti-leakage method for a prestressed steel cylinder concrete pipeline and a steel pipeline, and relates to the technical field of pipeline construction, and the anti-leakage method comprises the following steps: S1, pipeline pretreatment: adopting endoscopic detection or manual probing to record structural defects, mainly including cracks, deformation, corrosion and deposition and leakage of functional defects, then sundries, oil stains and sharp protrusions on the inner wall of the pipeline are removed, the local damaged position is repaired and leveled, meanwhile, accumulated water in the pipeline is drained, and it is guaranteed that the construction face is dry; an HDPE-U-shaped folding lining method or a stainless steel lining method can be selected, and the HDPE-U-shaped folding lining method specifically comprises the steps that an HDPE pipe is subjected to U-shaped folding through special equipment, a winding belt is synchronously adopted for bundling and fixing, the folding pipe is pulled to penetrate into an old pipeline along the axis of the pipeline, a guide sliding opening and a roller frame are arranged to reduce friction resistance, and the lining is formed; and releasing the stress of the pipeline to enable the pipeline to recover to be round and closely fit with the inner wall of the original pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline construction, in particular to a leakage prevention method for a prestressed steel cylinder concrete pipeline and a steel pipeline. Background Art

[0002] Prestressed concrete cylinder pipe (PCCP) and steel pipelines are widely used in long-distance water transmission and urban pipe network projects. However, due to factors such as external environmental erosion, internal medium corrosion, and foundation settlement, pipelines are prone to defects such as cracks, joint leakage, and corrosion perforation, leading to medium leakage, resource waste, environmental pollution, and even safety accidents.

[0003] Traditional pipeline repair methods, including excavation and pipe replacement, patch repairs, and others, are subject to long construction periods, significant environmental impacts, and high repair costs. In recent years, trenchless repair technologies, such as lining and spraying, have gradually developed, but their adaptability to different pipe materials and their effectiveness still need to be improved. For example, HDPE lining is prone to wrinkling at elbows, while stainless steel lining presents challenges in welding quality control and ensuring proper fit with the original pipe. Therefore, a reliable leak prevention method applicable to a variety of pipe materials is urgently needed. Summary of the Invention

[0004] The purpose of the present invention is to provide a leakage prevention method for prestressed concrete cylinder pipes and steel pipes. Through comprehensive pretreatment, lining construction, end treatment and quality inspection, the problem of pipeline leakage is effectively solved, the service life of the pipeline is extended, and the construction cost and the impact on the surrounding environment are reduced.

[0005] In view of the above problems, the technical solution proposed by the present invention is:

[0006] A method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe comprises the following steps:

[0007] Step S1, pipeline pretreatment: Use endoscopic inspection or manual exploration to record structural defects, which mainly include cracks, deformation, corrosion, and functional defects such as deposition and leakage. Then remove debris, oil stains and sharp protrusions on the inner wall of the pipeline, repair and level the local damaged areas, and at the same time, remove water from the pipe to ensure that the construction surface is dry.

[0008] Step S2, lining construction: either the HDPE-U-shaped folding lining method or the stainless steel lining method can be selected. The HDPE-U-shaped folding lining method is specifically as follows: the HDPE pipe is folded into a U shape by special equipment, and is simultaneously tied and fixed with a wrapping belt. The folded pipe is pulled along the pipeline axis and inserted into the old pipeline. A guide sliding port and a roller rack are set to reduce friction resistance, release the pipeline stress to restore the circular shape, and fit closely with the original pipeline inner wall. The restored lining pipe is fixed with pipe clamps or anchors. The stainless steel lining method is specifically as follows: the stainless steel plate is rolled into a pipe blank, the weld area is pre-treated by degreasing and rust removal, and the pipe blank is expanded to the designed size by mechanical or hydraulic expansion in the original pipeline. The longitudinal seam and circumferential seam are welded by argon arc welding. Ventilation is maintained during the welding process. The elbow is welded on-site with segmented prefabricated arc plates to ensure a smooth transition.

[0009] Step S3, end treatment: A socket-type steel flange is installed at the end of the concrete pipe, and a sealing material is filled to form a flexible connection. The flange is fixed to the fracture of the steel pipe by welding, and the weld is inspected. The end of the PE lined pipe is formed into a flange connection surface through a hot pressing and flanging process, and is sealed with the metal flange. Secondly, the exposed metal parts are coated with anti-corrosion paint and covered with glass cloth for enhanced protection;

[0010] Step S4, quality inspection: Use CCTV endoscopy system to check the integrity and fit of the liner pipe, perform pressure test on the port connection part to verify the sealing performance, perform water pressure test according to the standard, monitor the pressure drop and water seepage, and conduct pipe inspection on the repaired pipeline to ensure that there is no foreign matter left.

[0011] As a preferred technical solution of the present invention, in step S2, the HDPE pipe is made of high-density polyethylene and undergoes a trial penetration test before insertion to ensure that there are no scratches on the surface exceeding a specified depth.

[0012] As a preferred technical solution of the present invention, in step S2, the material of the stainless steel plate meets the austenitic stainless steel standard, the welding process adopts DC argon arc welding, and the weld surface is passivated.

[0013] As a preferred technical solution of the present invention, in step S3, the joints of the composite pipe sections are pretreated during construction. When the gap exceeds the specified range, epoxy resin-based filling materials are used for sealing and filling, and the misaligned or stepped parts are mechanically corrected or polished.

[0014] As a preferred technical solution of the present invention, in step S3, the anti-corrosion coating adopts a chlorosulfonated polyethylene coating system. Before construction, the base layer is sandblasted to remove rust, and primer, intermediate paint and topcoat are applied in sequence to form a multi-layer protective structure.

[0015] As a preferred technical solution of the present invention, in step S4, the water pressure test is carried out in stages, including a preliminary test to remove air, a main test to check strength and tightness, and a pressure change curve is recorded during the test.

[0016] As a preferred technical solution of the present invention, the annular gap between the HDPE liner pipe and the original pipeline is filled with a curable filling material and is densely filled by a pressure grouting process.

[0017] As an optimal technical solution of the present invention, a supporting and positioning device is set between the stainless steel liner pipe and the original pipe, including an annular support and an axial guide strip. The stainless steel liner pipe is centered and maintains a uniform gap with the inner wall of the original pipe.

[0018] As a preferred technical solution of the present invention, in step S4, a distributed leakage monitoring system is set up after the pipeline is repaired, including a pressure sensor, an optical fiber sensor and a data analysis module to collect and analyze pipeline operation status data in real time.

[0019] As a preferred technical solution of the present invention, in step S4, the working pit during construction is supported by steel sheet piles or concrete wall, a drainage system is set up at the bottom of the pit, and groundwater control adopts light well point or deep well dewatering technology to ensure a dry working environment.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention adopts a comprehensive HDPE-U-type folding lining method and a stainless steel lining method, which can be flexibly selected according to the pipe material, structural characteristics and on-site construction conditions. It is suitable for different types of prestressed steel cylinder concrete pipes and steel pipes, and the defects on the inner wall of the pipe are removed through pretreatment. The lining material fits tightly with the original pipe to form a composite structure, which effectively improves the pipe's impermeability and pressure bearing capacity. The end treatment adopts a variety of sealing and anti-corrosion measures to ensure the long-term sealing of the interface. At the same time, the trenchless construction method reduces the impact on ground traffic and the surrounding environment, and shortens the construction period. Both the HDPE-U-type folding lining method and the stainless steel lining method can be carried out while the pipeline is in non-stop operation, minimizing the impact on users.

[0022] Secondly, compared to traditional excavation and pipe replacement methods, this method significantly reduces material consumption and construction costs, while also extending the service life of the pipes, resulting in excellent economic benefits. It also reduces earthwork excavation and construction waste, aligning with the concept of green construction. The repaired pipes also significantly reduce leakage, saving water and energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application.

[0024] Figure 1 This is a flow chart of a method for preventing leakage of prestressed steel cylinder concrete pipes and steel pipes provided by the present invention. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features indicated. Thus, features specified as "first" or "second" may explicitly or implicitly include one or more of such features; and in the description of this application, unless otherwise specified, "plurality" means two or more.

[0027] See also Figure 1 The present invention provides a technical solution: a method for preventing leakage of prestressed concrete cylinder pipes and steel pipes, comprising the following steps:

[0028] Step S1, pipeline pretreatment: Use endoscopic inspection or manual exploration to record structural defects, which mainly include cracks, deformation, corrosion, and functional defects such as deposition and leakage. Then remove debris, oil stains and sharp protrusions on the inner wall of the pipeline, repair and level the local damaged areas, and at the same time, remove water from the pipe to ensure that the construction surface is dry.

[0029] Step S2, lining construction: either the HDPE-U-shaped folding lining method or the stainless steel lining method can be selected. The HDPE-U-shaped folding lining method is specifically as follows: the HDPE pipe is folded into a U shape by special equipment, and is simultaneously tied and fixed with a wrapping belt. The folded pipe is pulled along the pipeline axis and inserted into the old pipeline. A guide sliding port and a roller rack are set to reduce friction resistance, release the pipeline stress to restore the circular shape, and fit closely with the original pipeline inner wall. The restored lining pipe is fixed with pipe clamps or anchors. The stainless steel lining method is specifically as follows: the stainless steel plate is rolled into a pipe blank, the weld area is pre-treated by degreasing and rust removal, and the pipe blank is expanded to the designed size by mechanical or hydraulic expansion in the original pipeline. The longitudinal seam and circumferential seam are welded by argon arc welding. Ventilation is maintained during the welding process. The elbow is welded on-site with segmented prefabricated arc plates to ensure a smooth transition.

[0030] Step S3, end treatment: A socket-type steel flange is installed at the end of the concrete pipe, and a sealing material is filled to form a flexible connection. The flange is fixed to the fracture of the steel pipe by welding, and the weld is inspected. The end of the PE lined pipe is formed into a flange connection surface through a hot pressing and flanging process, and is sealed with the metal flange. Secondly, the exposed metal parts are coated with anti-corrosion paint and covered with glass cloth for enhanced protection;

[0031] Step S4, quality inspection: Use CCTV endoscopy system to check the integrity and fit of the liner pipe, perform pressure test on the port connection part to verify the sealing performance, perform water pressure test according to the standard, monitor the pressure drop and water seepage, and conduct pipe inspection on the repaired pipeline to ensure that there is no foreign matter left.

[0032] 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.

[0033] Among them, in step S2, the HDPE pipe is made of high-density polyethylene material, and a trial penetration test is performed before insertion to ensure that there are no scratches on the surface exceeding the specified depth; the stainless steel plate material meets the austenitic stainless steel standard, the welding process adopts DC argon arc welding, and the weld surface is passivated.

[0034] Among them, in step S3, the joints of the composite pipe sections are pretreated during construction. When the gap exceeds the specified range, epoxy resin-based filling materials are used for sealing and filling, and the misaligned or stepped parts are mechanically corrected or polished; the anti-corrosion coating adopts a chlorosulfonated polyethylene coating system, and the base layer is sandblasted and derusted before construction, and primer, intermediate paint and topcoat are applied in sequence to form a multi-layer protective structure.

[0035] Among them, in step S4, the water pressure test is carried out in stages, including a preliminary test to remove air and a main test to check strength and tightness, and the pressure change curve is recorded during the test.

[0036] Among them, the annular gap between the HDPE liner pipe and the original pipeline is injected with curable filling material and filled densely through a pressure grouting process. A supporting positioning device is set between the stainless steel liner pipe and the original pipeline, including an annular support and an axial guide strip. The stainless steel liner pipe is centered and maintains a uniform gap with the inner wall of the original pipeline.

[0037] Among them, in step S4, a distributed leakage monitoring system is set up after the pipeline is repaired, including a pressure sensor, a fiber optic sensor and a data analysis module to collect and analyze the pipeline operation status data in real time; during construction, the working pit is supported by steel sheet piles or concrete wall, a drainage system is set up at the bottom of the pit, and groundwater control adopts light well points or deep well dewatering technology to ensure a dry working environment.

[0038] Example 1: Prestressed concrete cylinder pipe repair

[0039] Construction steps:

[0040] Pipeline pretreatment: Endoscopic inspection to locate cracks, misaligned interfaces and other defects. Remove debris from the inner wall, repair damaged areas, and remove accumulated water.

[0041] Lining construction (HDPE-U folding method): Fold the HDPE pipe and bundle it, then pull it into the original pipeline. Release the stress to restore the inner lining pipe to a round shape and fix it to the original pipeline.

[0042] End treatment: The concrete end is equipped with a socket steel flange and filled with sealing material. The PE lined end is flanged to connect the metal flange, and the metal parts are coated with anti-corrosion paint.

[0043] Quality inspection: CCTV checks the fit of the lining, pressure test verifies the sealing, water pressure test verifies the strength, and pipe cleaning confirms that there are no foreign objects.

[0044] Example 2: Steel gas pipeline repair

[0045] Construction steps: Pre-treat the pipeline, detect and locate corrosion perforations and areas of wall thinning. Remove rust and oil stains on the inner wall and temporarily seal the perforations.

[0046] Lining construction (stainless steel lining method): stainless steel sheets are rolled into tube blanks, which are then expanded to fit the original pipe. Argon arc welding of longitudinal circumferential seams and prefabrication and welding of elbows are performed.

[0047] End treatment: Steel fracture welding flange, liner end flange sealing connection. Flange and weld anti-corrosion treatment for enhanced protection;

[0048] Quality Inspection: Endoscopic inspection of weld quality and tightness test to verify seal. Leakage detection system monitors operating status in real time.

[0049] Among them, the assessment and inspection of welding quality shall be carried out according to the following table:

[0050] Butt fusion welding procedure qualification inspection and test requirements

[0051]

[0052] Relationship between temperature and bulk modulus

[0053] Temperature (℃) Bulk modulus (MPa) Temperature (℃) Bulk modulus (MPa) Temperature (℃) Bulk modulus (MPa) 5 2080 15 2140 25 2210 10 2110 20 2170 30 2230

[0054] Specifically, this leak prevention method for prestressed concrete-cylinder pipes and steel pipes works as follows: During use, a systematic four-step repair process is implemented to enhance the pipe structure and improve sealing performance. First, during the pretreatment phase, endoscopic or manual inspection is used to identify structural defects such as cracks and deformation, as well as functional defects such as deposits and leaks. Debris is removed from the inner wall and damage is repaired, creating conditions for subsequent construction. During the lining construction phase, either an HDPE U-shaped folded lining or a stainless steel lining method is selected based on the pipeline's operating conditions. The former uses a folding-pull-and-restore circular process to form a tightly fitting flexible protective layer, while the latter uses a rolling-expansion-and-welding process to create a rigid, corrosion-resistant lining. Both processes utilize special treatment at the elbows to ensure a smooth transition. During the end treatment phase, socket-type steel flanges and welded flanges are used for different pipe fractures. Heat-pressed flanging and sealing material filling are used to achieve a sealed connection between the lining and the existing pipe. An anti-corrosion coating is applied to enhance durability. During the quality inspection phase, CCTV endoscopy is used to check the integrity of the lining, pressure testing is used to verify the sealing of the ports, and water pressure testing is used to test the strength and tightness of the pipeline in stages. This is combined with pipe penetration testing to ensure that no foreign matter remains. Finally, a distributed leakage monitoring system is used to monitor the pipeline operation status in real time, forming a complete leakage prevention system from defect repair to long-term monitoring.

[0055] In the several embodiments provided in this application, it should be understood that the disclosed systems, modules and methods can be implemented in other ways. For example, the module embodiments described above are merely illustrative. For example, the division of units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of modules or units, which can be electrical, mechanical or other forms.

[0056] The above embodiments are intended only to illustrate the technical solutions of the present application and are not intended to limit them. The present application is not limited to the precise structures described above and illustrated in the accompanying drawings, and it cannot be assumed that the specific implementation of the present application is limited to these descriptions. For those skilled in the art of the present application, any changes and modifications made without departing from the concept of the present application should be deemed to fall within the scope of protection of the present application.

Claims

1. A method for preventing leakage of prestressed concrete cylinder pipes and steel pipes, characterized in that: The following steps are involved: Step S1, pipeline pretreatment: Use endoscopic inspection or manual exploration to record structural defects, which mainly include cracks, deformation, corrosion, and functional defects such as deposition and leakage. Then remove debris, oil stains and sharp protrusions on the inner wall of the pipeline, repair and level the local damaged areas, and at the same time, remove water from the pipe to ensure that the construction surface is dry. Step S2, lining construction: either the HDPE-U-shaped folding lining method or the stainless steel lining method can be selected. The HDPE-U-shaped folding lining method is specifically as follows: the HDPE pipe is folded into a U shape by special equipment, and is simultaneously tied and fixed with a wrapping belt. The folded pipe is pulled along the pipeline axis and inserted into the old pipeline. A guide sliding port and a roller rack are set to reduce friction resistance, release the pipeline stress to restore the circular shape, and fit closely with the original pipeline inner wall. The restored lining pipe is fixed with pipe clamps or anchors. The stainless steel lining method is specifically as follows: the stainless steel plate is rolled into a pipe blank, the weld area is pre-treated by degreasing and rust removal, and the pipe blank is expanded to the designed size by mechanical or hydraulic expansion in the original pipeline. The longitudinal seam and circumferential seam are welded by argon arc welding. Ventilation is maintained during the welding process. The elbow is welded on-site with segmented prefabricated arc plates to ensure a smooth transition. Step S3, end treatment: A socket-type steel flange is installed at the end of the concrete pipe, and a sealing material is filled to form a flexible connection. The flange is fixed to the fracture of the steel pipe by welding, and the weld is inspected. The end of the PE lined pipe is formed into a flange connection surface through a hot pressing and flanging process, and is sealed with the metal flange. Secondly, the exposed metal parts are coated with anti-corrosion paint and covered with glass cloth for enhanced protection; Step S4, quality inspection: Use CCTV endoscopy system to check the integrity and fit of the liner pipe, perform pressure test on the port connection part to verify the sealing performance, perform water pressure test according to the standard, monitor the pressure drop and water seepage, and conduct pipe inspection on the repaired pipeline to ensure that there is no foreign matter left.

2. A method for preventing leakage of a prestressed concrete cylinder pipe or steel pipe according to claim 1, characterized in that: In step S2, the HDPE pipe is made of high-density polyethylene and undergoes a trial penetration test before insertion to ensure that there are no scratches on the surface exceeding a specified depth.

3. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: In step S2, the material of the stainless steel plate complies with the austenitic stainless steel standard, the welding process adopts DC argon arc welding, and the weld surface is passivated.

4. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: In step S3, the joints of the composite pipe sections are pre-treated during construction. When the gap exceeds the specified range, epoxy resin-based filling materials are used for sealing and filling, and the misaligned or stepped parts are mechanically corrected or polished.

5. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: In step S3, the anti-corrosion coating adopts a chlorosulfonated polyethylene coating system. Before construction, the base layer is sandblasted to remove rust, and primer, intermediate paint and topcoat are applied in sequence to form a multi-layer protective structure.

6. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: In step S4, the water pressure test is carried out in stages, including a preliminary test to remove air and a main test to check strength and tightness. The pressure change curve is recorded during the test.

7. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: The annular gap between the HDPE liner pipe and the original pipeline is filled with a curable filling material and is densely filled through a pressure grouting process.

8. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: A supporting and positioning device is provided between the stainless steel lining pipe and the original pipe, including an annular support and an axial guide strip. The stainless steel lining pipe is centered and maintains a uniform gap with the inner wall of the original pipe.

9. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: In step S4, after the pipeline is repaired, a distributed leakage monitoring system is set up, including a pressure sensor, an optical fiber sensor and a data analysis module, to collect and analyze pipeline operation status data in real time.

10. The method for preventing leakage of a prestressed concrete cylinder pipe or a steel pipe according to claim 1, characterized in that: In step S4, the working pit during construction is supported by steel sheet piles or concrete retaining walls, a drainage system is set up at the bottom of the pit, and groundwater control adopts light well point or deep well dewatering technology to ensure a dry working environment.

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