Underground pipeline in-situ repairing method and composite lining

Abstract

The invention provides an underground pipeline in-situ repairing method and a composite lining. The method specifically comprises the following steps that the inner wall of a to-be-repaired pipeline is coated with a polyurea material in a blade coating mode to construct a first polyurea lining layer; then one side of a toughening material sheet infiltrated with the same polyurea material is attached to the first polyurea lining layer to form a toughening layer; then continuously blade-coating the same polyurea material on the other surface of the toughening material sheet to construct a second polyurea lining layer; and finally, after curing, a three-layer composite lining of a first polyurea lining layer, a toughening layer and a second polyurea lining layer from the inner wall of the pipeline to the center of the pipeline is formed in the to-be-repaired pipeline. On the premise of ensuring that the new lining layer can be tightly attached to the old pipeline and not obviously reducing the overflowing section of the pipeline, the bearing capacity, the impermeability, the corrosion resistance and the water flow scouring resistance of the old pipeline are obviously improved, and the service life is effectively prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of in-situ repair of underground pipelines, and in particular to an in-situ repair method and a composite lining for underground pipelines. Background Art

[0002] my country's underground drainage pipes and water conservancy culverts are mainly made of concrete or reinforced concrete. During their long service, a large number of large-diameter underground pipes have become "aged", with various diseases such as leakage, cracking, corrosion and thinning. If they are not reinforced and repaired in time, they will lead to a series of safety problems such as road collapse and soil settlement and deformation. For pipelines (culverts) with diseases, there are currently two effective non-excavation repair methods: (1) directly inserting a new complete liner pipe inside; (2) constructing a new complete liner layer on its inner wall by spraying cement mortar. Both types of repair methods can achieve the purpose of restoring the water transmission function.

[0003] However, the construction process of method (1) is complicated, and it is very easy for the new lining pipe and the old pipe to not fit tightly, resulting in the inability of the new and old pipes to simultaneously perform load-bearing functions after repair. The disadvantage of method (2) is that the cement mortar is prone to shrinkage during the curing process, and after curing, the porosity is large, and the durability and water erosion resistance are poor. It is easy to suffer secondary damage under the scouring or erosion of the fluid in the pipe, and the long-term repair effect is difficult to guarantee. In addition, the cement mortar lining layer is usually thick, which can easily cause a significant reduction in the flow section of the old pipe, resulting in a decrease in the flow capacity of the pipe after repair.

[0004] Existing Chinese patent document CN102359696A discloses a lining hose used for repairing old pipelines by the flipping method. This hose is added with fiber materials with high mechanical performance indexes in different proportions as needed, so that the lining hose not only plays the role of resin carrying substrate, but also improves the mechanical performance index of the lining layer. Compared with the commonly used lining hose, the wall thickness of the lining hose can be reduced, and the flow volume of the old pipeline after repair can be increased. However, the fit between this lining hose and the old pipeline is still not tight enough, and its bearing capacity, impermeability, corrosion resistance and other properties need to be further improved.

[0005] The present invention intends to develop a composite lining for in-situ repair of underground pipelines that can significantly improve the bearing capacity, impermeability, corrosion resistance and water scouring resistance of the old pipeline, and effectively extend the service life, under the premise of ensuring that the new lining layer and the old pipeline can fit tightly and without significantly reducing the flow cross-section of the pipeline. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for in-situ repair of underground pipelines and a composite lining. The present invention can significantly improve the bearing capacity and impermeability, corrosion resistance and water erosion resistance of the old pipeline, while ensuring that the new lining layer and the old pipeline can fit tightly and without significantly reducing the flow cross-section of the pipeline, thereby effectively extending the service life.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for in-situ repair of an underground pipeline, which specifically comprises the following steps:

[0009] S1. Scrape polyurea material on the inner wall of the pipeline to be repaired to construct a first polyurea lining layer;

[0010] S2, laminating one side of the toughening material sheet soaked with the same polyurea material on the first polyurea lining layer to form a toughening layer;

[0011] S3, then continue to scrape the same polyurea material on the other side of the toughening material sheet to construct a second polyurea lining layer;

[0012] S4. After final solidification, a three-layer composite lining of the first polyurea lining layer-the toughening layer-the second polyurea lining layer is formed in the pipeline to be repaired from the inner wall of the pipeline to the center of the pipeline.

[0013] Further,

[0014] Before step S1, step S0 is also included:

[0015] Deeply clean the inner wall of the pipe to be repaired, remove the attachments, debris, convex spots, etc. on the inner wall of the old pipe, so that the inner wall of the old pipe remains flat and smooth;

[0016] Pre-treat the cleaned inner wall of the old pipe and use quick-hardening cement to fill the large depressions or cracks in the old pipe;

[0017] A layer of water-based epoxy resin primer is applied along the entire section of the inner wall of the pipeline. The water-based epoxy resin coating is uniform and complete, covers the entire inner wall surface, and has no sagging, convex spots, etc.; after the water-based epoxy resin primer is cured, the polyurea material is applied.

[0018] Further,

[0019] In steps S1 and S3, the single coating thickness of the polyurea material is 0.5-1 mm, the single coating distance along the axial direction of the pipeline is 25-30 cm, the coating interval between two adjacent layers does not exceed 3 minutes, and there is at least 1 cm coverage at the connection, generally 1-2 cm.

[0020] Specifically, in steps S1 and S3, the scraping operation is to paint the entire repair section and the polyurea material is completely cured before returning to the starting point for the next scraping operation, and the cycle is repeated multiple times until the first polyurea lining layer or the second polyurea lining layer is completed.

[0021] Further,

[0022] The thickness of the first polyurea lining is half of the total design thickness of the composite lining layer.

[0023] Further,

[0024] The specific process of step S2 is as follows: the pre-prepared toughening material sheet is evenly soaked in the polyurea material, and one side of the toughening material sheet is attached to the first polyurea lining layer in the pipeline. When attaching the toughening material sheets, the first toughening material sheet of the upper half is attached first, and then the second toughening material sheet of the lower half is attached; the overlap of the first toughening material sheet and the second toughening material sheet is located at the sides of the pipeline, and the overlap length is 1 to 2 cm; the axial size of the toughening material sheet is 50 to 80 cm, the overlap length of adjacent toughening material sheets is 1 to 2 cm, and the overlap of adjacent toughening material sheets cannot be located at the socket.

[0025] Furthermore, the wrinkles on the toughening material sheet after lamination are smoothed, so that the polyurea on the toughening material sheet can be integrally laminated on the first polyurea lining layer to form a toughening layer after curing.

[0026] Further,

[0027] The toughening material sheet in step S2 includes, but is not limited to, sheet-shaped toughening materials of other materials such as glass fiber cloth, metal mesh, glass fiber reinforced plastic fiber cloth, and carbon fiber cloth.

[0028] Furthermore, the glass fiber cloth is a single-layer mesh cloth woven from alkali-free glass fibers, with a thickness of 1 mm and a mesh size of 4 to 5 mm.

[0029] Furthermore, the polyurea material includes component A and component B, wherein component A includes the following raw materials in parts by weight: 31 to 55 parts of isocyanate, 45 to 69 parts of polyol, and 2 to 10 parts of silane coupling agent; component B includes the following raw materials in parts by weight: 40 to 80 parts of polyaspartic acid ester resin, 2 to 5 parts of defoamer, 1 to 6 parts of leveling agent, 1 to 5 parts of antioxidant, and 40 to 65 parts of color filler; when used, the mass ratio of component A to component B is 2:1 to 1:1.

[0030] Preferably, the isocyanate is at least one of toluene diisocyanate trimer and hexamethylene diisocyanate trimer.

[0031] Preferably, the polyol is at least one of polyoxypropylene ether diol and polyoxypropylene ether triol having molecular weights of 1000, 2000 and 3000 respectively.

[0032] Preferably, the silane coupling agent is at least one of γ-aminopropyltriethoxysilane (KH-550), γ-glycidyloxypropyltrimethoxysilane (KH-560), N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and bis(3-trimethoxysilylpropyl)amine.

[0033] Preferably, the polyaspartic acid ester resin is selected from at least one of polyaspartic acid ester resin Desmophen NH1420, polyaspartic acid ester resin Desmophen NH 1520, polyaspartic acid ester resin Desmophen NH 1220, polyaspartic acid ester resin F420, polyaspartic acid ester resin F520 and polyaspartic acid ester resin F220.

[0034] The above-mentioned polyaspartic acid ester resins are all selected from the commercially available products of the corresponding models of Covestro.

[0035] Preferably, the defoaming agent is at least one of BYK-065 (BASF Chemical Co., Ltd.), BYK-A535 (BASF Chemical Co., Ltd.), Deqian-6800 (Deqian (Shanghai) Chemical Co., Ltd.), FoamStar ST2410AC (BASF Chemical Co., Ltd.), etc.

[0036] The above defoamers are all known commercial products of the corresponding manufacturers, among which: BYK-065 and BYK-A535 are chemically composed of foam-breaking polysiloxane solutions, the main component of Deqian-6800 is a polysiloxane mixture containing hydrophobic particles, and FomaStartST2410AC is a new mineral oil-based compound.

[0037] Preferably, the leveling agent is at least one of BYK-350 (BYK Chemical Company, Germany), BYK-356 (BYK Chemical Company, Germany), BYK-361 (BYK Chemical Company, Germany), etc.

[0038] The above-mentioned leveling agents are all commercially available products of corresponding manufacturers, and their main chemical components are polyacrylates.

[0039] Preferably, the antioxidant is at least one of commercially available antioxidant 1076 (BASF Chemical Co., Ltd.), antioxidant 1098 (BASF Chemical Co., Ltd.), antioxidant 1330 (BASF Chemical Co., Ltd.), etc.

[0040] The above antioxidants are all commercially available products from corresponding manufacturers.

[0041] Preferably, the pigment filler is at least one of rutile titanium dioxide, carbon black, 400 mesh talc powder, 1250 mesh heavy calcium powder, and 1250 mesh wollastonite powder.

[0042] Furthermore, the pipe to be repaired is a large-diameter underground drainage pipe with an inner diameter of more than 800 mm.

[0043] Further,

[0044] The step S4 also includes: curing the completed composite lining under natural conditions for 4 hours before returning to normal use, and achieving the best repair effect after 72 hours.

[0045] Further,

[0046] In combination with actual needs, the same method can be used to construct an inner lining repair layer composed of alternating multiple layers of polyurea and multiple layers of toughening material sheets inside the pipeline.

[0047] Furthermore, the polyurea material can be applied by manual brushing or mechanical brushing (such as high-pressure airless spraying).

[0048] In a second aspect, the present invention also provides a composite lining obtained by the above method, wherein the composite lining includes a first polyurea lining layer, a toughening layer and a second polyurea lining layer formed in the pipe to be repaired from the inner wall of the pipe to the center of the pipe.

[0049] Furthermore, the composite lining is a multi-layer structure in which multiple toughening layers and second polyurea lining layers are alternately combined.

[0050] Beneficial effects of the present invention:

[0051] 1. The in-situ trenchless repair method provided by the present invention can be used for the reinforcement and repair of large-diameter pipelines. The composite lining constructed by the present invention has good mechanical properties and excellent anti-seepage, anti-corrosion and water flow erosion resistance properties, which can improve the durability and bearing capacity of the repaired pipeline and extend the service life of the pipeline.

[0052] In particular, the polyurea material used in the first and second polyurea lining layers of the present invention is a two-component system. The A and B components can be used after being accurately weighed and stirred evenly, and the operation is simple and convenient. The interface bonding strength between the polyurea material layer and the concrete is not less than 3.0MPa. The adhesion retention rate in a long-term immersion environment is greater than 80%. The gel time of the polyurea material is 20 to 40 minutes, and the surface is dry in 1 to 2 hours. It is less affected by the environmental humidity, and the coating is dense and smooth, which can reduce the resistance to liquid circulation. The tensile strength is not less than 30MPa, it is impermeable under a water pressure of 0.4MPa, and it does not deteriorate in an acid corrosion environment.

[0053] 2. The composite lining constructed by the present invention has excellent mechanical properties and fits tightly with the inner wall of the old pipeline to form a composite bearing structure with a smooth surface, which greatly improves the bearing capacity of the old pipeline.

[0054] 3. The composite lining constructed by the present invention has a small design thickness, has little impact on the cross-sectional shrinkage rate of the old pipeline, and will not significantly reduce the flow capacity of the old pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments or technical points of the present invention, the drawings required for use in the embodiments or prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For other technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0056] Figure 1 A schematic flow chart of the in-situ trenchless repair method provided by the present invention.

[0057] Figure 2 This is a schematic diagram of the radial cross-sectional structure of the composite repair liner provided by the present invention.

[0058] Figure 3 A schematic diagram of a radial cross section of a pipeline showing a method for laminating a toughening material sheet (glass fiber cloth) provided by the present invention.

[0059] Figure 4 A schematic diagram of the method for fitting adjacent axial sections of a pipeline provided by the present invention.

[0060] Figure 5 This is a comparison chart of the bearing capacity test results of the concrete pipe before and after repair according to the embodiment of the present invention.

[0061] Explanation of the reference numerals: 1 - water-based epoxy resin coating; 2 - first polyurea lining layer; 3 - toughening layer; 301 - first toughening material sheet; 302 - second toughening material sheet; 303 - overlapping portion; 4 - second polyurea lining layer; 5 - pipeline to be repaired. DETAILED DESCRIPTION

[0062] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical points and solutions in the embodiments of the present invention. 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 work are within the scope of protection of the present invention.

[0064] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, front, back, left, right, inside, outside, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the characteristic posture changes, the directional indication will also change accordingly.

[0065] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0066] In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are all conventional products that can be purchased commercially.

[0067] Example 1

[0068] like Figure 1-4 As shown, the present invention provides a method for in-situ repair of underground pipelines, which specifically includes the following steps:

[0069] S0. Deeply clean the inner wall of the pipe (culvert) to be repaired, remove the attachments, debris, convex points, etc. on the inner wall of the old pipe, so that the inner wall of the old pipe remains flat and smooth;

[0070] Pre-treat the cleaned inner wall of the old pipe and use quick-hardening cement to fill the large depressions or cracks in the old pipe;

[0071] A layer of waterborne epoxy resin primer is applied along the entire section of the inner wall of the pipeline to form a waterborne epoxy resin coating 1, which is uniform and complete, covers the entire inner wall surface, and has no sagging, convex spots, etc.; after the waterborne epoxy resin primer is cured, the polyurea material is applied.

[0072] S1. Smearing polyurea material on the inner wall of the pipeline to be repaired to construct a first polyurea lining layer 2.

[0073] S2, and then attaching one side of the toughening material sheet soaked with the same polyurea material to the first polyurea lining layer 2 to form a toughening layer 3. As a preferred embodiment, the specific process is as follows:

[0074] The pre-prepared toughening material sheet is evenly soaked in the polyurea material, and one side of the toughening material sheet is attached to the first polyurea lining layer 1 in the pipeline. When attaching the toughening material sheets, the first toughening material sheet 301 (upper semicircular part) is attached first, and then the second toughening material sheet 302 (lower semicircular part) is attached; the overlapping parts 303 of the first toughening material sheet 301 (upper semicircular part) and the second toughening material sheet 302 (lower semicircular part) are located at the sides of the pipeline (culvert), and the overlapping length is generally controlled at 1 to 2 cm. In this embodiment, the overlapping length of the upper and lower semicircular toughening material sheets is 1 cm; the axial size of the toughening material sheet is generally controlled at 50 to 80 cm, and the axial size of this embodiment is 50 cm; the overlapping length of adjacent toughening material sheets is generally controlled at 1 to 2 cm, and the overlapping length of adjacent toughening sheets in this embodiment is 1 cm, and the overlapping parts 303 of adjacent toughening material sheets are not located at the socket.

[0075] The wrinkles on the toughening material sheet after bonding are smoothed, so that the polyurea on the toughening material sheet can be bonded as a whole on the first polyurea lining layer 1 to form a toughening layer 3 after curing.

[0076] like Figure 4 As shown, if multiple sections are involved, multiple first toughening material sheets 301 (upper semicircle part) and second toughening material sheets 302 (lower semicircle part) are overlapped in the axial direction of the pipeline at multiple sections in the axial direction of the pipeline. Similarly, the overlap length is generally 1-2 cm, and in this embodiment, it is controlled at 1 cm.

[0077] The toughening material sheet of the present invention includes but is not limited to sheet-shaped toughening materials of other materials such as glass fiber cloth, metal mesh, glass fiber reinforced plastic fiber cloth, carbon fiber cloth, etc. This embodiment is described by taking glass fiber cloth as an example, wherein the glass fiber cloth is a single-layer mesh cloth woven from alkali-free glass fiber, with a thickness of 1 mm and a mesh size of 5 mm.

[0078] S3, then continue to scrape the same polyurea material on the other side of the toughening material sheet to construct a second polyurea lining layer 4;

[0079] S4. After final solidification, a three-layer composite lining of the first polyurea lining layer 2, the toughening layer 3 and the second polyurea lining layer 4 is formed in the pipeline to be repaired from the inner wall of the pipeline to the center of the pipeline.

[0080] As a preferred embodiment, in steps S1 and S3 of this embodiment, the single coating thickness of the polyurea material is about 0.5 mm, the single coating distance along the axial direction of the pipeline is 25 to 30 cm, the coating interval between two adjacent layers does not exceed 3 minutes, and there is at least 1 cm coverage at the connection. The total thickness of the composite lining is about 3 mm.

[0081] Specifically, in steps S1 and S3, the scraping operation is to paint the entire repair section and the polyurea material is completely cured before returning to the starting point for the next scraping, and the cycle is repeated multiple times until the first polyurea lining layer or the second polyurea lining layer is completed. The polyurea material can be applied by manual brushing or mechanical brushing (such as high-pressure airless spraying).

[0082] The thickness of the first polyurea lining is half of the total design thickness of the composite lining layer.

[0083] As a preferred embodiment, the polyurea material used in this embodiment includes component A and component B, wherein component A includes the following raw materials in parts by weight: 31 to 55 parts of isocyanate, 45 to 69 parts of polyol, and 2 to 10 parts of silane coupling agent; component B includes the following raw materials in parts by weight: 40 to 80 parts of polyaspartic acid ester resin, 2 to 5 parts of defoaming agent, 1 to 6 parts of leveling agent, 1 to 5 parts of antioxidant, and 40 to 65 parts of color filler; when used, the mass ratio of component A to component B is 2:1 to 1:1.

[0084] This embodiment more specifically provides a polyurea material for forming a polyurea lining layer 2 and a polyurea protective layer 4 and a preparation method thereof, wherein the polyurea material comprises component A and component B.

[0085] Component A includes the following raw materials in parts by weight: 36 parts of hexamethylene diisocyanate trimer, 62 parts of polyoxypropylene ether diol with a molecular weight of 2000, and 2 parts of γ-glycidyloxypropyl trimethoxysilane. The preparation method of component A is as follows: weigh the above-mentioned weight portion of polyoxypropylene ether diol and add it to the reactor, stir and heat it to 110°C; vacuum pump evacuates to -0.1MPa to dehydrate and remove the water in the raw material until the water content of the raw material drops to less than 5 parts per thousand; cool the liquid material to 55°C; weigh the above-mentioned weight portion of hexamethylene diisocyanate trimer and add it to the reactor, stir and disperse for 0.5 hours, slowly heat to 85°C and react for 2 hours, and use di-n-butylamine titration method to detect the NCO value; when the NCO value reaches the design value of 100%, weigh the above-mentioned weight portion of γ-glycidyl ether oxypropyl trimethoxy silane and add it to the reactor, keep it warm for 0.5 hours; cool the liquid material to 55°C, discharge it, and obtain component A material. The NCO design value in the scheme is the theoretical NCO value calculated by formula design.

[0086] Component B includes the following raw materials in parts by weight: 62 parts of polyaspartic acid ester resin F420, 1 part of antioxidant 1076 (BASF Chemical Co., Ltd.), 1 part of defoamer 6800 (Deqian (Shanghai) Chemical Co., Ltd.), 1 part of leveling agent BYK-356 (BYK Chemical Company, Germany), and 35 parts of pigments and fillers; the pigments and fillers are composed of 1 part of white slurry (rutile titanium dioxide), 0.2 parts of black slurry (carbon black), 20 parts of 400 mesh talc, 7 parts of 1250 mesh heavy calcium, and 6.8 parts of 1250 mesh wollastonite powder. The preparation method of component B is as follows: weigh the above-mentioned polyaspartic acid ester resin F420 and antioxidant 1076 in parts by weight, add them into a vacuum stirring kettle, start stirring, and heat the liquid to 110°C; add pigments and fillers into the vacuum stirring kettle, stir for 0.5 hours, and maintain 110°C; use a vacuum pump to evacuate to -0.1MPa to dehydrate and remove moisture from the raw materials until the moisture content of the raw materials drops to less than 0.5 parts per million; add the above-mentioned defoamer 6800 and leveling agent BYK-356 and stir for 0.5 hours; cool to 55°C, discharge the material, and obtain component B material.

[0087] When this embodiment is used, the mass ratio of component A to component B is 2:1.

[0088] The repair method of this embodiment also includes curing the completed composite lining at room temperature for at least 4 hours, and the repair effect is optimal after 72 hours.

[0089] The repair method provided in this embodiment can also be combined with actual needs, and the same method can be used to construct an inner lining repair layer composed of multiple layers of polyurea and multiple layers of glass fiber cloth alternately combined inside the pipeline.

[0090] like Figure 2 As shown, a composite lining for trenchless in-situ repair of underground pipelines can be obtained by the above-mentioned repair method, and the composite lining includes a first polyurea lining layer, a toughening layer and a second polyurea lining layer formed in the pipeline to be repaired from the inner wall of the pipeline to the center of the pipeline. Similarly, according to actual needs, a composite lining with a multi-layer structure in which multiple toughening layers and second polyurea lining layers are alternately combined can be obtained.

[0091] The performance of the pipe before and after the repair of the polyurea-glass fiber cloth composite lining obtained in the embodiment of the present invention was tested and the results were recorded. The bearing capacity test results of the concrete pipe before and after the repair are as follows: Figure 5 The surface of the prepared lining layer is smooth and dense, closely fits the inner wall of the pipeline, is impermeable after 2 hours under 0.4MPa water pressure, and the maximum bearing capacity of the pipeline is increased by 78%.

[0092] This is due to the fact that the polyurea material used in the present invention is a two-component system. The active group of component A is an isocyanate group, and the active group of component B is an amine group. After the two are mixed and reacted, a urea group is generated. This molecular segment has high cohesive energy, which can give the material excellent mechanical properties; in addition, the system contains a large number of flexible segments, which can give the material excellent flexibility; finally, the isocyanate and amine groups have strong reaction selectivity and are not affected by moisture. The spraying process is adopted to make the formed coating more dense. In addition, components A and B can be used after being accurately weighed and stirred evenly, which is simple and convenient to operate. After testing and verification, the interfacial bonding strength between the polyurea layer formed by the polyurea material of the present invention and concrete is not less than 3.0MPa; the adhesion retention rate in a long-term immersion environment is greater than 80%; the gel time of the polyurea material is 20 to 40 minutes, and the surface is dry in 1 to 2 hours. It is less affected by environmental humidity, and the coating is dense, smooth, and has no cracks when bent, which can reduce the resistance to liquid circulation; the tensile strength is not less than 40MPa, it is impermeable under a water pressure of 0.4MPa, and it does not deteriorate in an acid corrosion environment. The performance parameters are measured by conventional methods. Therefore, in practical applications, the polyurea layer can better resist the leakage or corrosion of rainwater and sewage, so that the formed polyurea layer is smooth and flat, has good hydrophobicity, is conducive to the flow of water in the pipe, and prolongs the service life of the pipe while also improving the water delivery capacity.

[0093] The polyurea-glass fiber cloth composite lining and in-situ brushing repair method of the present invention can overcome the problems of water seepage, corrosion, scouring resistance, poor bearing capacity, etc. existing in existing large-diameter drainage pipes (culverts), thereby extending the normal working life of large-diameter drainage pipes (culverts).

[0094] The above descriptions are only some preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for in-situ repair of underground pipelines, characterized in that: The specific steps include: S1. Scrape polyurea material on the inner wall of the pipeline to be repaired to construct a first polyurea lining layer; S2, laminating one side of the toughening material sheet soaked with the same polyurea material on the first polyurea lining layer to form a toughening layer; S3, then continue to scrape the same polyurea material on the other side of the toughening material sheet to construct a second polyurea lining layer; S4. After final solidification, a three-layer composite lining of the first polyurea lining layer-the toughening layer-the second polyurea lining layer is formed in the pipeline to be repaired from the inner wall of the pipeline to the center of the pipeline.

2. The method for in-situ repair of underground pipelines according to claim 1, characterized in that: Before step S1, step S0 is also included: Deeply clean the inner wall of the pipe to be repaired, remove the attachments, debris, and bumps on the inner wall of the old pipe, and keep the inner wall of the old pipe flat and smooth; Pre-treat the cleaned inner wall of the old pipe and use quick-hardening cement to fill the large depressions or cracks in the old pipe; A layer of water-based epoxy resin primer is applied along the entire section of the inner wall of the pipeline. The water-based epoxy resin coating is uniform and complete, covers the entire inner wall surface, and has no sagging or convex spots. After the water-based epoxy resin primer is cured, the polyurea material is applied.

3. The method for in-situ repair of underground pipelines according to claim 1, characterized in that: In steps S1 and S3, the single coating thickness of the polyurea material is 0.5-1 mm, the single coating distance along the axial direction of the pipeline is 25-30 cm, the coating interval between two adjacent layers does not exceed 3 minutes, and there is a 1-2 cm coverage at the connection; In steps S1 and S3, the scraping operation is to paint the entire repair section and the polyurea material is completely cured before returning to the starting point for the next scraping operation, and the cycle is repeated until the first polyurea lining layer or the second polyurea lining layer is completed.

4. The method for in-situ repair of underground pipelines according to claim 3, characterized in that: The thickness of the first polyurea lining layer is half of the total designed thickness of the composite lining layer.

5. The method for in-situ repair of underground pipelines according to claim 1, characterized in that: The specific process of step S2 is as follows: The pre-prepared toughening material sheet is evenly soaked in polyurea material, and one side of the toughening material sheet is attached to the first polyurea lining layer in the pipeline. When attaching the toughening material sheet, the first toughening material sheet of the upper half is attached first, and then the second toughening material sheet of the lower half is attached; the overlap of the first toughening material sheet and the second toughening material sheet is located at the sides of the pipeline, and the overlap length is 1 to 2 cm; the axial size of the toughening material sheet is 50 to 80 cm, the overlap length of adjacent toughening material sheets is 1 to 2 cm, and the overlap of adjacent toughening material sheets cannot be located at the socket; The wrinkles on the toughening material sheet after bonding are smoothed, so that the polyurea on the toughening material sheet can be bonded as a whole on the first polyurea lining layer to form a toughening layer after curing.

6. The method for in-situ repair of underground pipelines according to claim 1, characterized in that: The toughening material sheet in step S2 includes but is not limited to glass fiber cloth, metal mesh, glass fiber reinforced plastic fiber cloth, and carbon fiber cloth.

7. The method for in-situ repair of underground pipelines according to claim 6, characterized in that: The glass fiber cloth is a single-layer mesh cloth woven from alkali-free glass fibers, with a thickness of 1 mm and a mesh size of 4 to 5 mm.

8. The method for in-situ repair of underground pipelines according to claim 1, characterized in that: The polyurea material comprises component A and component B, wherein component A comprises the following raw materials in parts by weight: 31 to 55 parts of isocyanate, 45 to 69 parts of polyol, and 2 to 10 parts of silane coupling agent; component B comprises the following raw materials in parts by weight: 40 to 80 parts of polyaspartic acid ester resin, 2 to 5 parts of defoamer, 1 to 6 parts of leveling agent, 1 to 5 parts of antioxidant, and 40 to 65 parts of color filler; when in use, the mass ratio of component A to component B is 2:1 to 1:

1.

9. A composite lining obtained by the method according to any one of claims 1 to 8, characterized in that: The composite lining comprises a first polyurea lining layer, a toughening layer and a second polyurea lining layer which are formed in the pipeline to be repaired from the inner wall of the pipeline to the center of the pipeline.

10. The composite liner according to claim 9, characterized in that: The composite lining is a multi-layer structure in which multiple toughening layers and second polyurea lining layers are alternately combined.

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