Aqueduct expansion joint double-water-stop structure and construction method

Abstract

The invention relates to the field of aqueduct expansion joints, and discloses an aqueduct expansion joint double-water-stop structure and a construction method.The aqueduct expansion joint double-water-stop structure comprises an aqueduct body, an embedded groove is formed in the aqueduct body, a rubber water-stop belt is arranged on the inner wall of the aqueduct body, and a U-shaped protruding structure is arranged in the middle of the rubber water-stop belt and located in the middle of the expansion joint; the lower surface of the rubber waterstop is arranged on the inner wall of the pre-buried groove, a polyurea waterproof coating is arranged on the outer wall of the rubber waterstop, the outer wall of the polyurea waterproof coating is arranged on the inner wall of the pre-buried groove, and shrinkage concrete is arranged on the inner wall of the pre-buried groove. The exposed part of the rubber waterstop and the areas on the two sides of the joint are covered with the epoxy prime coat, the bonding force between the polyurea waterproof coating and the base layer and the rubber waterstop is enhanced, base layer holes are sealed, water permeation is prevented, the polyurea waterproof coating material is sprayed in a layered mode to form a U-shaped wrapping structure, the exposed part of the waterstop and the concrete joint are covered, and the waterproof effect is achieved. And the sealing performance of the joint is improved.

Description

Technical Field

[0001] The invention relates to the technical field of aqueduct expansion joints, and in particular to a double water-stopping structure for an aqueduct expansion joint and a construction method. Background Art

[0002] As my country's water conservancy projects develop towards large-scale, long-distance water delivery, aqueducts, as related water delivery buildings, have a direct impact on project benefits and ecological safety due to their structural safety and anti-seepage performance. Expansion joints, as the weak link in the aqueduct structure, are prone to deformation and leakage under the action of temperature stress, foundation settlement and hydraulic loads, and have become a prominent problem restricting the durability of the project. In recent years, although materials such as polyurethane sealants and metal waterstops have partially improved the anti-seepage effect, they still face problems such as complex construction and high maintenance costs. How to construct a composite waterproof system that takes into account both elastic deformation capacity and long-term anti-seepage performance has become a technical bottleneck that needs to be broken through in the field of water conservancy projects. In current technology, expansion joints are mostly sealed with asphalt or with a single rubber waterstop. The former has the defects of poor weather resistance and easy aging and cracking, while the latter is difficult to adapt to high water pressure (>0.6MPa) and large displacement (>±30%) working conditions due to its poor joint sealing and insufficient scouring resistance. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a double water-stopping structure and construction method for aqueduct expansion joints to solve the problems of poor weather resistance, easy aging and cracking, loose joint closure, insufficient scour resistance, and difficulty in adapting to high water pressure and large displacement. This application improves the closure of the joints through the coordinated construction process of "polyurea waterproof coating and rubber waterstop" through the complementary material properties and structural design optimization.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solutions: a double water-stop structure for an aqueduct expansion joint, comprising an aqueduct main body, an embedded groove is opened inside the aqueduct main body, a rubber waterstop is arranged on the inner wall of the aqueduct main body, a U-shaped protrusion structure is arranged in the middle of the rubber waterstop, which is located in the middle of the expansion joint, the lower surface of the rubber waterstop is arranged on the inner wall of the embedded groove, the outer wall of the rubber waterstop is arranged on the polyurea waterproof coating, the outer wall of the polyurea waterproof coating is arranged on the inner wall of the embedded groove, the inner wall of the embedded groove is arranged with shrinkage concrete, a grouting pipe is arranged on the back of the rubber waterstop, a sealing screw cap is arranged on the outer wall of the grouting pipe, and a polyurethane topcoat is arranged on the upper surface of the polyurea waterproof coating.

[0005] Preferably, the expansion joint of the aqueduct body is filled with a closed-cell foam board, and the upper surface of the closed-cell foam board is provided with a polyurethane sealant.

[0006] Preferably, the bottom end of the grouting pipe passes through the shrinkage concrete and is arranged inside the polyurea waterproof coating, and the grouting pipe is used for later injection of polyurea slurry to repair leakage of the polyurea waterproof coating.

[0007] Preferably, the bottom end of the grouting pipe is arranged inside the shrinkage concrete, and the grouting pipe is used to inject polyurea slurry to fill the gaps in the shrinkage concrete with the polyurea slurry.

[0008] Preferably, the upper surface of the polyurea waterproof coating is sprinkled with corundum, and the corundum is located on the lower surface of the polyurethane topcoat.

[0009] Preferably, the polyurea waterproof coating and the concrete base surface of the inner wall of the embedded groove opened in the aqueduct body form a chemical bonding interface through a polyurethane primer.

[0010] A construction method for a double water-stop structure of an aqueduct expansion joint comprises the following steps: S1. Surface treatment: slot the main body of the aqueduct, clean up the debris in the expansion joint, shot blast the concrete surface to a roughness of CSP ≥ 3, and reserve a pre-buried groove for the water stop; S2, rubber water stop installation, align the center line of the rubber water stop with the center line of the expansion joint, use hot melt welding technology to connect the rubber water stop joints, if 2 is repaired later, embed 3 in the back of the water stop, with a spacing of 1-1.5m; S3. Construction of polyurea waterproof layer: Apply epoxy primer to cover the exposed part of rubber water stop and the areas on both sides of the seam, and spray the polyurea waterproof coating material in layers to form a U-shaped wrapping structure. Sprinkle corundum on the surface of the polyurea waterproof coating before it is completely dry. S4. Filling and protection: fill the expansion joint with closed-cell foam board, pour polyurethane sealant on the top, and pour shrinkage concrete to cover the embedded groove. If the shrinkage concrete is repaired in the later stage, embed the grouting pipe in the compensation position of the shrinkage concrete before pouring, with a spacing of 1-1.5m, and vibrate it to make it dense, and then apply polyurethane topcoat on the surface of the polyurea waterproof coating.

[0011] Preferably, when the bottom end of the grouting pipe is located inside the polyurea waterproof coating, the leakage path is blocked by unscrewing the sealing cap and injecting polyurethane, and when the bottom end of the grouting pipe is located inside the shrinkage concrete, repair is performed by injecting polyurea slurry.

[0012] Preferably, the shrinkage concrete contains 8% to 12% of an expansion agent.

[0013] Preferably, the humidity of the base surface before spraying the polyurea waterproof coating is ≤5%, and the spraying environment temperature is ≥10°C.

[0014] The present invention provides a double water-stopping structure for an aqueduct expansion joint and a construction method thereof, which has the following beneficial effects: 1. The present invention enhances the adhesion between the polyurea waterproof coating and the base layer and the rubber waterstop by applying an epoxy primer to cover the exposed part of the rubber waterstop and the areas on both sides of the joint, seals the pores of the base layer to prevent water penetration, and sprays the polyurea waterproof coating material in layers to form a U-shaped wrapping structure, covering the exposed part of the waterstop and the concrete joint to improve the sealing of the joint.

[0015] 2. In the present invention, the rubber waterstop is embedded in the expansion joint gap to absorb expansion and contraction deformation, and adapts to the residual deformation by spraying the polyurea waterproof coating, enabling the polyurea and the waterstop to deform synergistically. The two achieve a gradual release of displacement through the elastic modulus gradient, avoiding the tearing of the coating caused by displacement differences.

[0016] 3. In the present invention, the polyurea slurry is input through the grouting pipe to fill the leakage channels, prevent water leakage, maintain the waterproof performance, avoid damage to the aqueduct structure. When the bottom end is inside the shrinkage concrete, the polyurea slurry is injected to fill the gap, enhance the compactness, waterproof and anti-seepage ability of the concrete, improve the strength and stability, ensure the safety of the aqueduct, extend the service life, thereby achieving the effect of improving the service life and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a partial structural schematic diagram of the grouting pipe of an embodiment of a double waterstop structure for the expansion joint of an aqueduct according to the present invention; Figure 2 It is a partial structural schematic diagram of the grouting pipe of another embodiment of a double waterstop structure for the expansion joint of an aqueduct according to the present invention; Figure 3 It is a flow chart of a double waterstop structure and construction method for the expansion joint of an aqueduct according to the present invention.

[0018] Among them, 1. Aqueduct main body; 2. Polyurea waterproof coating; 3. Grouting pipe; 4. Sealing nut; 5. Closed-cell foam board; 6. Polyurethane sealant; 7. Rubber waterstop; 8. Shrinkage concrete; 9. Polyurethane topcoat. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the scope of protection of the present invention.

[0020] Please refer to the attached Figure 1 and the attached Figure 2, an embodiment of the present invention provides a double water stop structure and construction method for the expansion joint of a aqueduct. A double water stop structure for the expansion joint of an aqueduct includes an aqueduct main body 1. An embedded groove is formed inside the aqueduct main body 1. A rubber water stop 7 is arranged on the inner wall of the aqueduct main body 1. The middle part of the rubber water stop 7 is provided with a U-shaped convex structure, which is located in the middle of the expansion joint. The lower surface of the rubber water stop 7 is arranged on the inner wall of the embedded groove. A polyurea waterproof coating 2 is arranged on the outer wall of the rubber water stop 7. The outer wall of the polyurea waterproof coating 2 is arranged on the inner wall of the embedded groove. The inner wall of the embedded groove is provided with shrinkage concrete 8. A grouting pipe 3 is arranged on the back of the rubber water stop 7. A sealing nut 4 is arranged on the outer wall of the grouting pipe 3. A polyurethane topcoat 9 is arranged on the upper surface of the polyurea waterproof coating 2.

[0021] Specifically, embedded grooves are opened on both sides of the expansion joint of the aqueduct main body 1 to ensure that the water stop is closely fitted with the concrete after installation, and to determine the installation position of the rubber water stop 7, avoiding the leakage risk caused by displacement deviation. At the same time, it provides a space basis for the pouring of shrinkage concrete 8. The rubber water stop 7 is made of chloroprene rubber or ethylene propylene diene monomer rubber, and a U-shaped convex structure is arranged in the middle, which can be embedded into the expansion joint gap to absorb 30% - 50% of the expansion deformation, adapt to temperature stress and foundation settlement, and block more than 80% of the hydrostatic pressure. Then, by spraying the polyurea waterproof coating 2, it can deform synchronously with the rubber water stop 7. The polyurea waterproof coating 2 wraps around the U-shaped part to enhance the interfacial bonding with the rubber water stop 7 through physical coating, and the two sides are transitioned by slopes to improve the structural durability through stress dispersion and enhance the edge sealing performance. Among them, the rubber water stop 7 bears the main displacement (±30% - ±50%), and the polyurea waterproof coating 2 covers the surface and adapts to the residual deformation of ±20% - ±30%. The two achieve the step-by-step release of displacement through the elastic modulus gradient, avoiding the coating tear caused by displacement difference, covering the exposed part of the rubber water stop 7 and the concrete joint, filling micro-cracks, and eliminating weak points such as the joints and installation gaps of the rubber water stop 7; Pouring shrinkage concrete 8 in the embedded groove can fill the voids in the embedded groove subsequently, prevent the concrete from drying shrinkage and cracking, and the grouting pipe 3 serves as a redundant repair channel. Polyurea slurry can be injected later, which is convenient for subsequent repair, significantly improving the service life and reliability of the water stop structure. Combining the above, a three-level protection mechanism of "water stop isolation by water stop - anti-seepage by polyurea - repair by grouting" is formed, significantly improving the service life and reliability.

[0022] Applying a polyurethane topcoat 9 on the surface of the polyurea waterproof coating 2 enhances the anti-ultraviolet ability and temperature difference tolerance, prevents the aging and cracking of the polyurea waterproof coating 2, and extends the service life of the waterproof layer.

[0023] Refer to the attached Figure 1 , the expansion joint of the aqueduct main body 1 is filled with a closed-cell foam board 5, and a polyurethane sealant 6 is arranged on the upper surface of the closed-cell foam board 5.

[0024] Specifically, the closed-cell foam board 5 is filled in the expansion joint of the aqueduct main body 1, mainly playing the roles of buffering and isolation. Since the aqueduct main body 1 will be affected by factors such as temperature changes and water flow impacts during operation, resulting in structural expansion and contraction deformation, the closed-cell foam board 5 has good elasticity and compressibility, can adapt to the deformation of the expansion joint, avoid damage caused by the mutual extrusion of the structures on both sides of the expansion joint, and it can also effectively isolate the concrete on both sides of the expansion joint, prevent the friction and collision between concretes, and extend the service life of the aqueduct main body 1; Moreover, there is a lot of water flow in the aqueduct main body 1. If the expansion joint is not tightly sealed, it is easy to cause water leakage, affecting the normal use of the aqueduct main body 1. The polyurethane sealant 6 has excellent water resistance, adhesiveness and elasticity, can closely adhere to the closed-cell foam board 5 and the concrete surfaces on both sides of the expansion joint, form an effective waterproof barrier, prevent water from penetrating into the interior of the expansion joint, and ensure the waterproof performance of the aqueduct main body 1.

[0025] Refer to the appendix Figure 1 , the bottom end of the grouting pipe 3 penetrates through the shrinkage concrete 8 and is arranged inside the polyurea waterproof coating 2. The grouting pipe 3 is used for injecting polyurea slurry in the later stage to repair the leakage of the polyurea waterproof coating 2.

[0026] Specifically, the polyurea waterproof coating 2 has good waterproof performance, but due to the long-term influence of the external environment, it may age and be damaged, resulting in leakage. At this time, injecting polyurethane slurry through the grouting pipe 3 can quickly and accurately repair the leakage. The polyurethane slurry can fill the gaps, holes and other defects in the polyurea waterproof coating 2, block the leakage channel, and promptly restore the waterproof function of the waterproof coating, avoiding further expansion of the leakage and causing damage to the aqueduct structure.

[0027] Refer to the appendix Figure 2 , the bottom end of the grouting pipe 3 is arranged inside the shrinkage concrete 8. The grouting pipe 3 is used for injecting polyurea slurry, and the gaps in the shrinkage concrete 8 are filled with the polyurea slurry.

[0028] Specifically, the bottom end of the grouting pipe 3 is arranged inside the shrinkage concrete 8 and polyurea slurry is injected. The gaps in the shrinkage concrete 8 are filled with the polyurea slurry, thereby enhancing the density of the concrete, improving its waterproof performance, effectively avoiding the damage to the concrete structure caused by water infiltration, and then ensuring the structural stability and durability of the shrinkage concrete 8.

[0029] Refer to the appendix Figure 1 , emery is spread on the upper surface of the polyurea waterproof coating 2, and the emery is located on the lower surface of the polyurethane topcoat 9.

[0030] Specifically, the corundum can significantly increase the roughness and friction of the surface of the polyurea waterproof coating 2, enhance the wear resistance of the polyurea waterproof coating 2, effectively resist external friction and wear, and extend the service life of the polyurea waterproof coating 2. The polyurethane topcoat 9 provides additional protection for the corundum and the polyurea waterproof coating 2 to prevent them from being damaged by external factors such as ultraviolet rays and chemical erosion, maintain the waterproof performance and overall structural integrity of the coating, and ensure the long-term stable operation of the waterproof system.

[0031] See attached Figure 1 The polyurea waterproof coating 2 and the concrete base surface of the inner wall of the embedded groove opened by the aqueduct body 1 form a chemical bonding interface through the polyurethane primer.

[0032] Specifically, the polyurea waterproof coating 2 and the concrete base surface of the inner wall of the embedded groove of the aqueduct main body 1 form a chemical bonding interface through the polyurethane primer, which can greatly enhance the bonding force between the two, ensure that the polyurea waterproof coating 2 is firmly attached to the concrete base surface, effectively prevent the coating from falling off or separating, and ensure the integrity of the waterproof system. In addition, during the operation of the aqueduct main body 1, facing factors such as temperature changes, water flow impact, and structural deformation, the chemical bonding interface can enable the polyurea waterproof coating 2 to stably play a waterproof role, prevent moisture from penetrating into the internal structure of the aqueduct main body 1, and avoid damage to the concrete in the expansion joint due to long-term water erosion, thereby ensuring the structural safety and service life of the aqueduct main body 1.

[0033] See attached Figure 3 , a construction method of a double water-stop structure for an aqueduct expansion joint, comprising the following steps: S1, base surface treatment, slotting the aqueduct body 1, cleaning the debris in the expansion joint, shot blasting the concrete base surface to a roughness of CSP ≥ 3, and reserving a pre-buried groove for the water stop; S2, rubber water stop installation, align the center line of the rubber water stop 7 with the center line of the expansion joint, use hot melt welding technology to connect the rubber water stop 7 joints, if 2 is repaired later, embed 3 in the back of the water stop, with a spacing of 1-1.5m; S3, polyurea waterproof layer construction, brushing epoxy primer to cover the exposed part of the rubber water stop 7 and the areas on both sides of the seam, and spraying the material of the polyurea waterproof coating 2 in layers to form a U-shaped wrapping structure, and spreading corundum when the surface of the polyurea waterproof coating 2 is not completely dry; S4, filling and protection, filling the closed-cell foam board 5 in the expansion joint, pouring polyurethane sealant 6 on the top, and pouring shrinkage concrete 8 to cover the embedded groove. If the shrinkage concrete 8 is repaired in the later stage, the grouting pipe 3 will be embedded in the compensation position of the shrinkage concrete 8 before pouring, with a spacing of 1-1.5m, and compacted by vibration, and then apply polyurethane topcoat 9 on the surface of the polyurea waterproof coating 2.

[0034] Specifically, in S1, the aqueduct body 1 is grooved and the debris in the expansion joint is cleaned to remove impurities that affect the waterproof effect, creating good conditions for subsequent construction. Then, the concrete base surface is shot blasted to a roughness CSP ≥ 3 to increase the roughness of the concrete surface and improve the bonding force with subsequent waterproof materials, so that the waterproof materials can adhere better and reduce the risk of falling off. The reserved embedded groove for the rubber waterstop 7 provides a precise position for the installation of the rubber waterstop 7, ensuring the standard installation of the waterstop, ensuring the stability of the overall waterproof structure, and effectively improving the waterproof performance of the expansion joint of the aqueduct 1; In S2, the center line of the rubber water stop 7 is aligned with the center line of the expansion joint, ensuring the correct position of the water stop in the expansion joint, so that the water stop effect can be effectively exerted, and the joints of the rubber water stop 7 are connected by hot melt welding process to ensure the integrity of the rubber water stop 7 and avoid water leakage at the joints. The grouting pipe 3 is pre-buried on the back of the rubber water stop 7 to provide a repair method for the polyurea waterproof coating 2 in the later stage when leakage occurs. The leakage gap is filled by grouting to maintain the effectiveness of the waterproof system and extend the waterproof service life of the aqueduct 1. In S3, epoxy primer is applied to cover the exposed part of the rubber water stop 7 and the areas on both sides of the seam, which can enhance the bonding force between the polyurea waterproof coating 2 and the base layer, close the tiny pores of the base layer, and prevent water penetration. The materials of the polyurea waterproof coating 2 are sprayed in layers to form a U-shaped wrapping structure, which can wrap the expansion joint and the rubber water stop 7 in all directions, effectively preventing water from invading. When the surface of the polyurea waterproof coating 2 is not completely dry, corundum is sprinkled, which increases the roughness and wear resistance of the coating surface, improves the anti-slip performance, makes the surface of the aqueduct 1 more durable, and improves the comprehensive performance of the polyurea waterproof layer. In S4, the closed-cell foam board 5 is filled to play a buffering role, adapting to the expansion and contraction deformation of the aqueduct 1 and avoiding mutual squeezing and damage of the structures on both sides of the expansion joint. The polyurethane sealant 6 is poured on the top to further enhance the sealing effect at the expansion joint and prevent moisture leakage. The shrinkage concrete 8 is poured to cover the embedded groove and vibrate it to make it dense, which enhances the integrity and stability of the structure. The grouting pipe 3 is embedded in the compensation position of the shrinkage concrete 8 before pouring to provide a repair method for the concrete when cracks occur in the later stage, thereby ensuring the durability of the concrete structure. Then, the polyurethane topcoat 9 is applied to protect the polyurea waterproof coating 2 from erosion by ultraviolet rays, chemicals, etc., extend the service life of the waterproof coating, and ensure the long-term stability of the waterproof performance of the aqueduct 1.

[0035] When the bottom end of the grouting pipe 3 is located inside the polyurea waterproof coating 2, the leakage path is blocked by unscrewing the sealing screw cap 4 and injecting polyurea slurry. When the bottom end of the grouting pipe 3 is located inside the shrinkage concrete 8, repair is performed by injecting polyurea slurry.

[0036] Specifically, during the construction of the double water stop structure for the expansion joint of the aqueduct 1, a grouting pipe 3 is embedded at the back of the rubber water stop belt 7 to ensure that the bottom end of the grouting pipe 3 penetrates through the shrinkage concrete 8 and is arranged inside the polyurea waterproof coating 2. At the same time, it is arranged at an interval of 1 - 1.5 m. When the polyurea waterproof coating 2 leaks due to aging, displacement or accidental damage, find the grouting pipe 3 at the corresponding position, unscrew the sealing nut 4, and inject polyurea slurry into the grouting pipe 3 through the grouting equipment. The polyurea slurry flows along the grouting pipe 3 into the leakage area of the polyurea waterproof coating 2, which can accurately fill the leakage channels such as gaps and holes in the polyurea waterproof coating 2, quickly and effectively prevent water from leaking continuously, maintain the waterproof performance of the polyurea waterproof coating 2, and avoid damage to the aqueduct structure caused by leakage. When the bottom end is inside the shrinkage concrete 8, first, before pouring the shrinkage concrete 8, at an interval of 1 - 1.5 m, embed the grouting pipe 3 at the position where the shrinkage concrete 8 needs to be compensated and repaired, ensure that the bottom end of the grouting pipe is inside the shrinkage concrete 8, and when the shrinkage concrete 8 has gaps or other situations that need to be repaired, slowly inject polyurea slurry into the pipe through the grouting pipe 3, so that the polyurea slurry fills the gaps inside the shrinkage concrete 8 under the action of the polyurea slurry. As the polyurea slurry fills and blocks these tiny pores, the concrete structure becomes more dense, reducing the channels for water penetration, enhancing the density of the concrete, improving its waterproof and impermeability capabilities, and at the same time enhancing the structural strength and stability of the shrinkage concrete 8, ensuring the safety of the overall aqueduct structure and extending the service life of the aqueduct 1.

[0037] The shrinkage concrete 8 contains 8% - 12% expansion agent.

[0038] Specifically, the shrinkage concrete 8 contains 8% - 12% expansion agent. The expansion agent can compensate for the shrinkage of the concrete during the hardening process, reduce the cracks generated due to shrinkage, improve the density and impermeability of the concrete, and enhance the integrity of the structure.

[0039] Before spraying the polyurea waterproof coating 2, the humidity of the base surface ≤ 5%, and the spraying environment temperature ≥ 10℃.

[0040] Specifically, before spraying the polyurea waterproof coating 2, reducing the humidity can avoid the formation of a barrier of water between the coating and the base surface, ensure their close fit, prevent the coating from bulging and falling off, and controlling the temperature ensures that the polyurea material can be normally cured into a film, avoiding slow curing, insufficient strength or defects caused by too low temperature, enabling the polyurea waterproof coating 2 to have good waterproof performance and durability, thereby effectively preventing water from penetrating into the aqueduct structure and ensuring the normal use and structural safety of the aqueduct.

[0041] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A double water-stop structure for an aqueduct expansion joint, comprising an aqueduct body (1), characterized in that: An embedded groove is provided inside the aqueduct body (1), and a rubber water stop (7) is provided on the inner wall of the aqueduct body (1). A U-shaped protrusion structure is provided in the middle of the rubber water stop (7), and slopes are provided on both sides, which are located in the middle of the expansion joint. The lower surface of the rubber water stop (7) is arranged on the inner wall of the embedded groove, and a polyurea waterproof coating (2) is provided on the outer wall of the rubber water stop (7). The outer wall of the polyurea waterproof coating (2) is arranged on the inner wall of the embedded groove. The inner wall of the embedded groove is provided with shrinkage concrete (8). A grouting pipe (3) is provided on the back of the rubber water stop (7), and a sealing screw cap (4) is provided on the outer wall of the grouting pipe (3). A polyurethane topcoat (9) is provided on the upper surface of the polyurea waterproof coating (2).

2. The double water-stop structure for aqueduct expansion joint according to claim 1, characterized in that: The expansion joint of the aqueduct body (1) is filled with a closed-cell foam board (5), and the upper surface of the closed-cell foam board (5) is provided with a polyurethane sealant (6).

3. The double water-stop structure for aqueduct expansion joint according to claim 1 is characterized in that: The bottom end of the grouting pipe (3) penetrates through the shrinkage concrete (8) and is arranged inside the polyurea waterproof coating (2). The grouting pipe (3) is used for later injection of polyurea slurry to repair leakage of the polyurea waterproof coating (2).

4. The double water-stop structure for aqueduct expansion joint according to claim 1, characterized in that: The bottom end of the grouting pipe (3) is arranged inside the shrinkage concrete (8), and the grouting pipe (3) is used to inject polyurea slurry to fill the gaps in the shrinkage concrete (8) with the polyurea slurry.

5. The double water-stop structure for aqueduct expansion joint according to claim 1 is characterized in that: The upper surface of the polyurea waterproof coating (2) is sprinkled with corundum, and the corundum is located on the lower surface of the polyurethane topcoat (9).

6. The double water-stop structure for aqueduct expansion joint according to claim 1, characterized in that: The polyurea waterproof coating (2) and the concrete base surface of the inner wall of the embedded channel provided in the aqueduct body (1) form a chemical bonding interface through a polyurethane primer.

7. A construction method for a double water-stop structure of an aqueduct expansion joint, characterized in that: A double water-stopping structure for an aqueduct expansion joint as claimed in any one of claims 1 to 6 comprises the following steps: S1. Surface treatment: slot the aqueduct body (1), clean the debris in the expansion joint, and perform shot blasting on the concrete surface to a roughness of CSP ≥ 3, and reserve a pre-buried groove for the water stop; S2, rubber water stop installation, align the center line of the rubber water stop (7) with the center line of the expansion joint, and connect the joint of the rubber water stop (7) by hot melt welding. If 2 is repaired later, 3 is embedded in the back of the water stop, with a spacing of 1-1.5m; S3, construction of the polyurea waterproof layer, applying epoxy primer to cover the exposed part of the rubber water stop (7) and the areas on both sides of the seam, and spraying the material of the polyurea waterproof coating (2) in layers to form a U-shaped wrapping structure, and spreading corundum on the surface of the polyurea waterproof coating (2) before it is completely dry; S4, filling and protection, filling the expansion joint with closed-cell foam board (5), pouring polyurethane sealant (6) on the top, and pouring shrinkage concrete (8) to cover the embedded groove. If the shrinkage concrete (8) is repaired at a later stage, the grouting pipe (3) is embedded in the back compensation position of the adhesive water stop (7) before pouring, with a spacing of 1-1.5m, and vibrated to make it dense, and then apply polyurethane topcoat (9) on the surface of the polyurea waterproof coating (2).

8. The construction method of the double water-stop structure of aqueduct expansion joint according to claim 7 is characterized in that: When the bottom end of the grouting pipe (3) is located inside the polyurea waterproof coating (2), the leakage path is blocked by injecting polyurethane by unscrewing the sealing screw cap (4), and when the bottom end of the grouting pipe (3) is located inside the shrinkage concrete (8), repair is performed by injecting polyurea slurry.

9. The construction method of the double water-stop structure of aqueduct expansion joint according to claim 8 is characterized in that: The shrinkage concrete (8) contains 8% to 12% of an expansion agent.

10. The construction method of the double water-stop structure of aqueduct expansion joint according to claim 7, characterized in that: Before spraying the polyurea waterproof coating (2), the base surface humidity is ≤5%, and the spraying environment temperature is ≥10°C.

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