A waterstop structure adaptable to large deformation and its welding method

Abstract

This invention discloses a water-stopping structure adaptable to large deformations and its welding method. The water-stopping structure is arranged at the construction joint or expansion joint of a hydraulic concrete structure and is made of copper alloy. The cross-section of the water-stopping structure has at least one nose structure, with a height H ≥ 100 mm, a width W ≥ 30 mm, and a height-to-width ratio H:W > 3:1. Through a multi-nose, graded deformation structure design, the maximum adaptable displacement of the water-stopping system can be increased, the permeability coefficient can be reduced, and the adaptability to extreme foundation deformation and temperature stress can be significantly enhanced. The welding method includes surface treatment and laser welding. Laser power, welding speed, defocusing amount, and shielding gas flow rate are optimized for water-stopping structures of different thicknesses. An underwater laser welding process is also provided, achieving high-quality welding underwater by constructing local bubble cavities.

Description

Technical Field

[0001] This invention relates to the field of hydraulic structure engineering and metal material connection technology, specifically to a water-stopping structure that can adapt to large deformations and its welding method, and in particular to a copper alloy water-stopping structure that can adapt to large deformations in concrete structure joints and its laser welding process. Background Technology

[0002] In water conservancy and hydropower projects, concrete structures such as dams, spillways, gate chambers, underground powerhouses, and water conveyance structures typically have numerous construction joints, expansion joints, and settlement joints. These structural joints are prone to forming seepage channels under temperature changes, structural settlement, and water pressure; therefore, water-stopping structures must be installed to prevent leakage. Metal water-stopping structures are widely used in water conservancy and hydropower projects due to their good corrosion resistance, aging resistance, and certain deformation adaptability, with copper water-stopping structures being the most common.

[0003] The copper waterstop structures commonly used in existing engineering projects are usually made of pure copper and connected at construction joints through lap joints, brazing, or manual arc welding. Although this type of waterstop structure can play a certain role in preventing seepage under general engineering conditions, there are still insurmountable defects in actual operation: with the continuous increase in the scale of large-scale water conservancy and hydropower projects, the construction conditions are becoming more complex. The dam structure often bears complex stresses, water pressures, and uneven settlement. Large displacements and deformations may occur at the structural joints. Traditional copper waterstop structures have certain limitations in terms of material strength and deformation adaptability. Moreover, when the structural joint undergoes large opening and closing deformations, stress concentration is prone to occur in the waterstop structure and its welded parts, which can lead to weld cracking or failure of the waterstop structure, making it difficult to meet the long-term service requirements under large deformation conditions.

[0004] To meet service requirements under conditions of large deformation, designing a taller or multiple "nose" structures for the water-stopping system is a feasible technical solution, but it is almost impossible to apply in actual engineering. The main reason is: In actual construction, the space at concrete construction joints or structural joints is usually narrow and the construction environment is complex, often accompanied by problems such as dense reinforcement, formwork restrictions, and limited working space. Traditional waterstop structure connection methods mostly rely on manual welding or brazing processes, which are difficult to operate in narrow spaces. The welding quality is easily affected by factors such as operating conditions, construction environment, and worker experience, resulting in unstable weld formation, numerous welding defects, and difficulty in ensuring the sealing performance of the waterstop structure. At the same time, traditional welding methods have a large heat input, which can easily cause local deformation of the waterstop structure, thereby further affecting the overall quality of the waterstop structure. This type of welding process has more prominent limitations when dealing with taller waterstop "nose" structures or multiple "nose" structures (where the operating space available for welding is even narrower), and may even be impossible to weld.

[0005] On the other hand, a more complex "nose" structure will lead to more complex processing techniques during manufacturing, which will have a more adverse impact on the properties of the metal material itself. During the engineering operation phase, some waterstop structures are in a humid or even underwater environment for a long time, making them more susceptible to corrosion and deterioration. When a waterstop structure is damaged due to corrosion, fatigue, or structural deformation during service, existing repair technologies usually require lowering the water level or carrying out large-scale drainage construction to carry out repair work, which is not only time-consuming but also costly. In an underwater environment, because water has a significant interference effect on the welding process, traditional welding methods are difficult to achieve stable construction. Therefore, for damaged waterstop structures already in an underwater environment, there is currently a lack of efficient and reliable repair technologies.

[0006] Existing water-stop structures in water conservancy and hydropower projects still have significant shortcomings in terms of material systems, connection methods, and construction adaptability, especially in adapting to large deformation conditions, achieving high-quality welding in confined spaces, and repairing underwater water-stop structures, where there are obvious technical bottlenecks. Therefore, it is necessary to develop a new water-stop material system and its welding process to improve the adaptability of water-stop structures under complex working conditions and to achieve high-quality connection and repair technologies that can be implemented in underwater environments. Summary of the Invention

[0007] The purpose of this invention is to address the problems of insufficient deformation adaptability of existing water-stop structures, unstable welding quality in narrow spaces, and difficulties in underwater repair, by providing a water-stop structure and its welding method that can adapt to large deformations.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, a water-stopping structure adaptable to large deformation is provided. The water-stopping structure is arranged at the construction joint or expansion joint of the hydraulic concrete structure. The water-stopping structure is made of copper alloy material. The cross-section of the water-stopping structure has at least one nose structure. The height H of the nose structure is ≥100mm, the width W is ≥30mm, and the height-to-width ratio H:W is >3:1.

[0009] Furthermore, the water-stopping structure is provided with 1 to 3 nose structures, namely a single nose structure, a double nose structure, or a triple nose structure, which are used to achieve displacement adaptability of 20-30mm, 30-50mm, and 50-80mm, respectively.

[0010] Furthermore, for hydraulic concrete structures in seawater or high-sulfate saline conditions, the water-stopping structure uses a copper alloy material containing 0.02% to 0.05% arsenic; for hydraulic concrete structures in low-temperature regions, 1.0% to 2.0% nickel is added to the copper alloy material of the water-stopping structure.

[0011] Furthermore, the thickness of the water-stopping structure is 0.5mm to 2mm, and the following conditions are followed when designing the thickness of the water-stopping structure: δ=P·L / (2[σ]), In the formula, P is the design water pressure, L is the support length of the stop structure, and [σ] is the allowable stress of the material.

[0012] Secondly, a welding method for a waterstop structure that can adapt to large deformations is provided, the welding method comprising the following steps: (1) Perform surface treatment on the weld area of ​​the waterstop structure to remove the oxide layer and oil stains; (2) The treated joint area is welded using laser welding equipment. The laser power, welding speed, defocusing amount and protective gas flow rate are selected according to the thickness of the waterstop structure and the working environment. (3) After welding is completed, the sealing of the welded area is tested and the structure is fixed.

[0013] Furthermore, the surface treatment includes the following process: grinding the weld area with 120-180 grit alumina sandpaper or stainless steel wire wheel until the metal is exposed, extending the grinding range to at least 20mm on each side of the weld area; for areas with severe oil contamination, soaking in a 10-15% nitric acid solution at 25-30°C for 5-8 minutes, rinsing with deionized water until the pH is neutral, and then drying to ensure that the residual salt content does not exceed 50mg / m²; welding is performed within 4 hours after surface treatment. If this time is exceeded or the area is contaminated again, the surface treatment must be repeated.

[0014] Furthermore, in a normal air environment, the welding process parameters should be selected according to the following requirements: (1) When the thickness of the water-stop structure is <0.8mm, the laser power is 250-300W, the welding speed is 3-4m / min, the defocusing amount is +1mm, and the protective gas flow rate is 8-10L / min; (2) When the thickness of the water-stop structure is 0.8 to 1.5 mm, the laser power is 350-400 W, the welding speed is 1.5 to 1.8 m / min, the defocusing amount is zero, and the protective gas flow rate is 12 to 15 L / min; (3) When the thickness of the water-stop structure is 1.5-2.0mm, the laser power is 400-450W, the welding speed is 1.2-1.5m / min, the defocusing amount is -1mm to -1.5mm, and the protective gas flow rate is 12-15L / min.

[0015] Furthermore, for underwater welding operations, the laser power should be no less than 250W, and a localized bubble cavity should be constructed by injecting inert gas through a double-layer gas nozzle: water depth D. hWhen the depth is ≤3m, the inert gas flow rate is 12-15 L / min, where 3 < water depth D. h When the depth is ≤5m, the inert gas flow rate is 18~20L / min, and the water depth D is ≤5m. h When the water depth is greater than 5m, for every 1m increase in water depth, the laser power increases by 15-20W or the welding speed decreases by 0.2m / min.

[0016] Furthermore, when performing welding operations in confined spaces, a compact welding head is used in conjunction with a curved light guide system, and a magnetic track-assisted positioning or a multi-axis articulated robot welding system is employed for welding.

[0017] Furthermore, the sealing test adopts a vacuum test or a pneumatic test. The vacuum test requires a pressure drop of no more than 5%, and the pneumatic test allows an air bubble quantity of ≤1 bubble / minute. The tensile strength of the water-stop structure is ≥180MPa, the elongation after fracture is ≥15%, and there are no cracks larger than 0.5mm in the weld area after the bending test.

[0018] Compared with existing technologies, the beneficial effects of this invention are: 1. This water-stopping structure, adapted to large deformations, through its multi-nose-shaped graded deformation structure design, can increase the maximum adaptable displacement of the water-stopping system, reduce the permeability coefficient, and significantly enhance its adaptability to extreme foundation deformation and temperature stress; the water-stopping structure, by limiting its height-to-width ratio, ensures uniform stress distribution during deformation; 2. This method can weld water-stopping structures in confined spaces, with high energy density and a small heat-affected zone, effectively reducing welding deformation. Combined with automated and robotic welding systems, it can significantly improve the first-pass yield of welds and construction efficiency; 3. This method's unique underwater laser welding process, through the construction of local bubble cavities and parameter matching optimization, achieves high-quality repair of underwater damaged water-stopping structures without drainage, providing a new technical means for emergency repairs of dilapidated reservoirs and hydropower stations. It can effectively shorten the construction period, reduce project costs, and has extremely high engineering application value and economic benefits. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a nose-stopping structure that adapts to large deformations according to the present invention; Figure 2 This is a schematic diagram of a two-nose water-stopping structure that adapts to large deformations according to the present invention; Figure 3 This is a schematic diagram of a three-nose water-stopping structure adapted to large deformation according to the present invention; Figure 4 This is a schematic diagram of the water-stopping structure in Embodiment 3 of the present invention; In the diagram: 1. Water-stopping structure; 2. Nose structure. All dimensions in the diagram are in mm. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Example 1: A water-stopping structure adaptable to large deformations is provided, combined with Figures 1-3 As shown, the water-stopping structure 1 is arranged at the construction joint or expansion joint of the hydraulic concrete structure. The water-stopping structure 1 is made of copper alloy material. The cross-section of the water-stopping structure 1 has at least one nose structure 2. The height H of the nose structure 2 is ≥100mm, the width W is ≥30mm, and the height-to-width ratio H:W is >3:1.

[0023] This adaptable water-stopping structure, through its multi-nose, graded deformation design, increases the maximum adaptable displacement of the water-stopping system, reduces the permeability coefficient, and significantly enhances its adaptability to extreme foundation deformation and temperature stress. Furthermore, the water-stopping structure's defined aspect ratio ensures uniform stress distribution during deformation.

[0024] Furthermore, based on the expected deformation of the project, the water-stopping structure 1 may be provided with 1 to 3 nose structures 2, namely a single nose structure, a double nose structure, or a triple nose structure, to achieve displacement adaptability of 20-30mm, 30-50mm, and 50-80mm, respectively.

[0025] Specifically, the single-nose structure adopts a symmetrical arc design. When the joint (construction joint or expansion joint) undergoes shear deformation, the nose can achieve 20-30mm horizontal displacement compensation through elastic bending, which is suitable for small aqueducts, culverts and other scenarios with small deformation.

[0026] The double-nose structure, through the coordinated deformation of the intermediate connecting section, enhances the displacement adaptability to 30-50mm, making it suitable for transverse joints in gravity dams and expansion joints in powerhouses. The triple-nose structure introduces a graded deformation mechanism; when a large displacement exceeding 50mm occurs, the noses sequentially yield and absorb energy, preventing overall structural damage. It can adapt to displacements of 50-80mm, making it suitable for extreme deformation areas such as perimeter joints of arch dams and anti-seepage walls of high earth-rock dams.

[0027] Furthermore, for hydraulic concrete structures in seawater or high-sulfate saline conditions, the water-stopping structure uses a copper alloy material containing 0.02% to 0.05% arsenic; for hydraulic concrete structures in low-temperature regions, 1.0% to 2.0% nickel is added to the copper alloy material of the water-stopping structure.

[0028] Using deoxidized copper containing 0.02-0.05% arsenic can effectively inhibit dezincification corrosion. Using a copper alloy with 1.0-2.0% nickel can reduce the embrittlement temperature of the water-stop structure to below -40°C.

[0029] Furthermore, the thickness of the water-stopping structure is optimized within the range of 0.5mm to 2mm based on water pressure and deformation mode. The following conditions are followed when designing the thickness of the water-stopping structure: δ=P·L / (2[σ]), In the formula, P is the design water pressure, L is the support length of the stop structure, and [σ] is the allowable stress of the material.

[0030] For environments with predominantly shear deformation and low water head, thin-walled waterstop structures of 0.5–0.8 mm are selected to enhance flexibility and absorb displacement energy through material extension. For high-water-head areas or areas requiring resistance to dynamic loads, thick plates of 1.5–2.0 mm are selected to utilize their rigidity to resist seepage pressure and prevent the waterstop structure from bulging and failing.

[0031] Example 2: For the water-stopping structure in Example 1, a welding method for a water-stopping structure that can adapt to large deformations is provided.

[0032] The welding method includes the following steps: (1) Perform surface treatment on the weld area of ​​the waterstop structure to remove the oxide layer and oil stains; (2) The treated joint area is welded using laser welding equipment. The laser power, welding speed, defocusing amount and protective gas flow rate are selected according to the thickness of the waterstop structure and the working environment. (3) After welding is completed, the sealing of the welded area is tested and the structure is fixed.

[0033] This laser welding method can weld water-stop structures in confined spaces. It has high energy density and a small heat-affected zone, which can effectively reduce welding deformation. Combined with automated and robotic welding systems, it can significantly improve the first-pass yield of welds and construction efficiency.

[0034] Specifically, the surface treatment includes the following process: using 120-180 grit alumina sandpaper or stainless steel wire wheel to grind the weld area, grinding back and forth along the joint direction, extending the grinding range to more than 20mm on both sides of the weld area, until the metal color is exposed and a uniform rough surface is formed. This treatment can improve the laser energy absorption efficiency.

[0035] For areas with severe oil stains, use a 10-15% nitric acid solution or a special metal cleaner for chemical cleaning. Soak at 25-30°C for 5-8 minutes, then rinse with deionized water until the pH is neutral, and then dry with compressed air to ensure that the residual salt content does not exceed 50 mg / m².

[0036] Welding must be performed within 4 hours after surface treatment to avoid secondary oxidation; if this time is exceeded or the surface is contaminated again, the surface treatment must be repeated.

[0037] Laser welding equipment is used to weld the surface-treated seams; preferably, the laser is a fiber laser or a semiconductor laser.

[0038] In a normal air environment, select welding process parameters according to the following requirements: (1) When the thickness of the water-stop structure is <0.8mm, the laser power is 250-300W, the welding speed is 3-4m / min, the defocusing amount is +1mm, and the protective gas flow rate is 8-10L / min; (2) When the thickness of the water-stop structure is 0.8 to 1.5 mm, the laser power is 350-400 W, the welding speed is 1.5 to 1.8 m / min, the defocusing amount is zero, and the protective gas flow rate is 12 to 15 L / min; (3) When the thickness of the water-stop structure is 1.5-2.0mm, the laser power is 400-450W, the welding speed is 1.2-1.5m / min, the defocusing amount is -1mm to -1.5mm, and the protective gas flow rate is 12-15L / min.

[0039] Furthermore, for underwater welding operations, a dual-layer gas nozzle is used to inject inert gas to construct a local bubble cavity, forming a local gas protective environment to achieve stable welding.

[0040] Specifically, at a water depth of 3m, the inert gas flow rate is 12-15L / min, which can form a stable bubble zone with a diameter of 80-100mm. The cavity stabilization time can reach 45 seconds, which is sufficient to complete the continuous welding of a 1.5m long weld. At a water depth of 5m, the inert gas flow rate is 18-20L / min to resist water pressure.

[0041] This method, targeting the welding of underwater waterproofing structures, achieves high-quality repair of damaged underwater waterproofing structures without drainage by constructing local bubble cavities and optimizing parameter matching. It provides a new technical means for emergency repairs of dilapidated reservoirs and hydropower stations. This method can effectively shorten the construction period and reduce project costs, demonstrating extremely high engineering application value and economic benefits.

[0042] For underwater welding, process parameters in an air environment need to be adjusted to compensate for water cooling and energy attenuation. Specifically, for every 1m increase in water depth, laser energy decreases by approximately 8-10%, requiring a corresponding increase in power of 15-20W or a decrease in speed of 0.2m / min. It is particularly important to note that effective penetration cannot be achieved with power below 250W; therefore, the underwater laser power should be higher than 250W. By combining these parameters, the problem of high-quality underwater welding, which is impossible with traditional methods, can be effectively solved.

[0043] Furthermore, when performing welding operations in confined spaces, a compact welding head is used in conjunction with a curved light guide system, and a magnetic track-assisted positioning or a multi-axis articulated robot welding system is employed for welding.

[0044] Specifically, a compact welding head combined with a 90° curved light guide system enables accessible welding in confined areas. A magnetic track is used for assisted positioning; the track is fixed to the structural surface via a magnetic base, and the laser head slides along the track to achieve uniform welding. For complex weld trajectories, a 6-axis articulated robot welding system is used, coupled with a vision positioning system to identify weld position deviations in real time, achieving integrated operation of the welding process.

[0045] Furthermore, the sealing test adopts a vacuum test or a pneumatic test. The vacuum test requires a pressure drop of no more than 5%, and the pneumatic test allows an air bubble quantity of ≤1 bubble / minute. The tensile strength of the water-stop structure is ≥180MPa, the elongation after fracture is ≥15%, and there are no cracks larger than 0.5mm in the weld area after the bending test.

[0046] Specifically, the sealing test employs a dual-method verification. The vacuum test involves creating a sealed cavity by attaching sealing strips to both sides of the weld, evacuating to -0.09 MPa, and observing for 30 minutes. A pressure drop of no more than 5% is considered acceptable. The pneumatic test involves introducing 0.3 MPa compressed air into the pre-drilled test hole in the weld and observing the escape of bubbles underwater. The allowable bubble count is ≤1 bubble / minute. For welds in critical areas, helium mass spectrometry leak detection is required, and the leakage rate must be controlled within 1×10⁻⁶. -9 Pa·m 3The sealing speed is below [value missing], meeting nuclear-grade sealing standards. Mechanical performance testing includes tensile and bending tests. The tensile test requires a tensile strength ≥180MPa and an elongation after fracture ≥15%. The bending test requires a mandrel diameter of 3 times the plate thickness, and no cracks >0.5mm in the weld area after a 180° bend. After passing the tests, the water-stop structure is precisely installed and embedded into the concrete structure using a three-dimensional coordinate positioning method.

[0047] Example 3: This example uses the water-stopping structure applied to the panel joints and perimeter joints of a large hydropower station rockfill dam to illustrate its structure and construction method in detail.

[0048] The maximum deformation at this location is 75mm, and it must withstand a high water head pressure exceeding 100m. Based on these conditions, a three-nose copper alloy waterstop structure was selected. The material is a copper alloy with 1.5% added nickel to adapt to low-temperature environments, reducing its embrittlement temperature to below -40℃. Figure 4 As shown, the height H of each nose structure 2 is designed to be 180mm, and the width W is 45mm, with the height-to-width ratio strictly controlled at 4:1 to optimize stress distribution. The welding space for this shape is narrow, making traditional manual welding impossible. Considering both water pressure and deformation requirements, the thickness is calculated using the formula δ=P·L / (2[σ]), with P=0.8MPa, L=300mm, and [σ]=120MPa, resulting in a theoretical thickness of 1.0mm. However, considering the dynamic load in an area with an earthquake intensity of 8 degrees, an additional 20% thickness margin is added, ultimately optimizing the thickness of the waterstop structure to 1.8mm. This ensures that the maximum stress resisting water pressure does not exceed 60% of the material's yield strength while maintaining necessary flexibility.

[0049] During construction, the overlapping area of ​​the waterstop structure was first treated. Operators used 180-grit alumina sandpaper to repeatedly grind along the joint direction, extending the area to 25mm on each side of the weld, until a metallic luster was exposed. Subsequently, the area was soaked in a 12% nitric acid solution at 28°C for 6 minutes, rinsed with deionized water until the pH was neutral, and dried with compressed air. After treatment, welding was carried out within 2 hours to prevent oxidation. Welding was performed using a 600W fiber laser with an output power of 420W, a welding speed of 1.5m / min, a defocusing depth of -1mm, and pure argon gas as the shielding gas, with a stable flow rate of 12L / min. The entire welding process was executed by a 6-axis robot system, which used visual positioning to identify the weld trajectory in real time.

[0050] After welding, the weld was inspected for quality. First, a vacuum test was conducted. Sealing strips were applied to both sides of the weld to form a sealed cavity. A vacuum was drawn to -0.09 MPa and held for 30 minutes. The pressure drop was only 2%, far exceeding the 5% standard. Subsequently, samples were taken for mechanical property testing. The results showed that the weld tensile strength reached 198 MPa, the elongation after fracture was 16%, and no cracks longer than 0.2 mm appeared in the weld area after the bending test. Finally, the water-stop structure was installed in the concrete joint using a three-dimensional coordinate method. Monitoring data after water impoundment showed that the water-stop system remained intact even when the actual displacement of the structural joint reached 68 mm.

[0051] Example 4: This example is applied to the bottom plate of the spillway gate of a water conservancy project. The original copper waterstop structure developed a 1.2m long crack after long-term operation. Since water supply could not be stopped for repairs, it was decided to use the underwater laser welding technology of this invention for repair.

[0052] First, an ROV underwater robot performs a 3D scan of the damaged area to create a digital model of the damage morphology. Based on the model, a 1.5mm thick, shape-matched copper alloy repair piece is prefabricated on land, with a 30° bevel machined at its edges to increase the welding fusion area. Divers then deploy underwater laser welding equipment. The equipment uses a waterproof modified 600W fiber laser equipped with a specially designed double-layer gas nozzle. Based on a water depth of 20m, the welding parameters are adjusted as follows: laser power 500W, welding speed 1.0m / min, and defocusing depth -1mm. Argon is used as the shielding gas, with a total flow rate set at 18L / min to create a stable local bubble cavity. During welding, the diver covers the repair piece onto the damaged crack, activates the laser welding system, and performs circumferential welding along the bevel. During the welding process, the continuously sprayed gas successfully displaces the local water, creating a dry working area. The cavity stabilization time was measured at 50 seconds, ensuring effective laser energy transmission and a stable molten pool. After welding, observe underwater for 30 minutes. If no air bubbles escape, the seal is confirmed to be qualified.

[0053] Example 5: This example is applied to the expansion joint of a pumped storage power station. The working space at this location is only 600mm wide and 1200mm high, making traditional manual welding difficult. The structural joint is designed to deform by ±40mm, and a double-nose water-stop structure is selected. The height of the nose structure is 150mm, the width is 40mm, and the thickness of the water-stop structure is 1.2mm.

[0054] During construction, a compact laser welding head was used in conjunction with a 90° curved light guide system. Due to space constraints preventing the use of large robots, a magnetic track-assisted positioning system was employed instead. The aluminum alloy track was attached to the surface of the hydraulic concrete structure via a magnetic base. The laser head was mounted on the track slider and driven by a servo motor, with the welding speed set at 2.0 m / min. A 350W laser power was selected, with a defocusing amount of 0 mm and a shielding gas flow rate of 10 L / min. After welding, a gas pressure test was performed. Compressed air at 0.3 MPa was introduced into the test hole, and soapy water was applied for observation; no bubbles were generated. The welding quality was good.

[0055] All the raw materials listed in this invention, as well as the upper and lower limits and ranges of the raw materials and the upper and lower limits and ranges of the process parameters, can realize this invention. Examples are not listed one by one here.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water-stopping structure adaptable to large deformations, characterized in that, The water-stopping structure is arranged at the construction joint or expansion joint of the hydraulic concrete structure. The water-stopping structure is made of copper alloy material. The cross-section of the water-stopping structure has at least one nose structure. The height H of the nose structure is ≥100mm, the width W is ≥30mm, and the height-to-width ratio H:W is >3:

1.

2. The water-stopping structure adaptable to large deformation according to claim 1, characterized in that, The water-stopping structure has 1 to 3 nose structures, namely a single nose structure, a double nose structure, or a triple nose structure, which are used to achieve displacement adaptability of 20-30mm, 30-50mm, and 50-80mm, respectively.

3. The water-stopping structure adaptable to large deformation according to claim 1, characterized in that, For hydraulic concrete structures in seawater or high-sulfate saline conditions, the water-stopping structure uses a copper alloy material containing 0.02-0.05% arsenic; for hydraulic concrete structures in low-temperature regions, 1.0-2.0% nickel is added to the copper alloy material of the water-stopping structure.

4. The water-stopping structure adaptable to large deformation according to claim 1, characterized in that, The thickness of the water-stopping structure is 0.5mm to 2mm. When designing the thickness of the water-stopping structure, the following conditions shall be followed: δ=P·L / (2[σ]), In the formula, P is the design water pressure, L is the support length of the stop structure, and [σ] is the allowable stress of the material.

5. The welding method for the waterstop structure adaptable to large deformation according to any one of claims 1 to 4, characterized in that, The welding method includes the following steps: (1) Perform surface treatment on the weld area of ​​the waterstop structure to remove the oxide layer and oil stains; (2) The treated joint area is welded using laser welding equipment. The laser power, welding speed, defocusing amount and protective gas flow rate are selected according to the thickness of the waterstop structure and the working environment. (3) After welding is completed, the sealing of the welded area is tested and the structure is fixed.

6. The welding method for the waterstop structure adaptable to large deformation according to claim 5, characterized in that, The surface treatment includes the following steps: Grind the weld area with 120-180 grit alumina sandpaper or stainless steel wire wheel until the metal is exposed, extending the grinding range to at least 20mm on both sides of the weld area; For areas with severe oil contamination, soak in a 10-15% nitric acid solution at 25-30℃ for 5-8 minutes, then rinse with deionized water until the pH is neutral, and blow dry, ensuring the residual salt content does not exceed 50mg / m²; Welding should be performed within 4 hours after surface treatment. If this time is exceeded or the area is contaminated again, the surface treatment should be repeated.

7. The welding method for the waterstop structure adaptable to large deformation according to claim 5, characterized in that, In a normal air environment, select welding process parameters according to the following requirements: (1) When the thickness of the water-stopping structure is <0.8mm, the laser power is 250-300W, the welding speed is 3-4m / min, the defocusing amount is +1mm, and the protective gas flow rate is 8-10L / min; (2) When the thickness of the water-stop structure is 0.8 to 1.5 mm, the laser power is 350-400 W, the welding speed is 1.5 to 1.8 m / min, the defocusing amount is zero, and the protective gas flow rate is 12 to 15 L / min; (3) When the thickness of the water-stop structure is 1.5-2.0mm, the laser power is 400-450W, the welding speed is 1.2-1.5m / min, the defocusing amount is -1mm to -1.5mm, and the protective gas flow rate is 12-15L / min.

8. The welding method for the waterstop structure adaptable to large deformation according to claim 5, characterized in that, For underwater welding operations, the laser power should be no less than 250W, and a localized bubble cavity should be constructed by injecting inert gas through a double-layer gas nozzle: water depth D. h When the depth is ≤3m, the inert gas flow rate is 12-15 L / min, where 3 < water depth D. h When the depth is ≤5m, the inert gas flow rate is 18~20L / min, and the water depth D is ≤5m. h When the water depth is greater than 5m, for every 1m increase in water depth, the laser power increases by 15-20W or the welding speed decreases by 0.2m / min.

9. The welding method for the waterstop structure adaptable to large deformation according to claim 5, characterized in that, When performing welding operations in confined spaces, a compact welding head is used in conjunction with a curved light guide system, and a magnetic track-assisted positioning or a multi-axis articulated robot welding system is employed for welding.

10. The welding method for the waterstop structure adaptable to large deformation according to claim 5, characterized in that, The sealing performance is tested using either a vacuum test or a pneumatic test. The vacuum test requires a pressure drop of no more than 5%, while the pneumatic test allows for an air bubble count of ≤1 bubble per minute. The tensile strength of the water-stop structure is ≥180MPa, the elongation after fracture is ≥15%, and there are no cracks larger than 0.5mm in the weld area after the bending test.

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