Hydropower station steel bifurcated pipe differential graded loading and unloading hydrostatic test method, system and equipment and storage medium

Abstract

The invention relates to the technical field of hydropower station pressure steel pipe detection, in particular to a hydropower station steel branch pipe differential graded loading and unloading hydrostatic test method, system and equipment and a storage medium. The hydraulic test process is scientifically divided into a low-pressure stage, a medium-pressure stage and a high-pressure stage, differentiated boosting amplitude and speed control strategies are adopted in the different stages, the technical limitation of a traditional uniform graded boosting method is broken through, and an innovative control mode of low-pressure fast rising and high-pressure slow rising is achieved. The large boosting amplitude and the high boosting speed are adopted in the low-pressure stage, the bearing allowance of the steel branch pipe in the elastic deformation stage is fully utilized, and the test efficiency is remarkably improved; and in the high-pressure stage, the small pressure increasing amplitude and the slow pressure increasing speed are adopted, the sensitive characteristic when the steel is close to the yield strength is effectively adapted, and the local stress concentration and plastic deformation risks are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection of pressure steel pipes of hydropower stations, and in particular to a method, system and device for differential grading loading and unloading water pressure test of steel bifurcated pipes of hydropower stations, and a storage medium. BACKGROUND

[0002] With the vigorous development of domestic hydropower engineering construction, high water head and large capacity power stations are increasing, and the application of large steel bifurcated pipes is becoming more and more common. The HD value of more than 4000m〃m is not uncommon. As a key component of the water delivery system of a hydropower station, the pressure bearing performance of the steel bifurcated pipe is directly related to the safe operation of the power station.

[0003] Water pressure test is an important means to test the structural strength and sealing performance of steel bifurcated pipes, and is also a necessary procedure to ensure the safe operation of steel bifurcated pipes. However, the traditional water pressure test method usually adopts uniform grading pressure or pressure relief, and does not fully consider the stress characteristics of steel bifurcated pipes at different pressure stages, resulting in low test efficiency, poor safety, and even possible damage to the structure of steel bifurcated pipes.

[0004] In the prior art, the pressure increasing and pressure relief process of water pressure test usually adopts fixed grading amplitude and speed, and lacks differential strategies for low pressure and high pressure stages. In particular, at high pressure stage, the stress borne by steel bifurcated pipe approaches its limit value, and the steel gradually approaches the yield strength. If the pressure increasing interval is too large, the speed is too fast, or the pressure holding time is insufficient, it may cause the local structure region to enter the plastic deformation stage, causing irreversible damage or destruction. In addition, the traditional method lacks special emergency plans, and does not systematically combine nondestructive testing and acoustic emission monitoring technology, resulting in frequent problems such as low defect identification rate. SUMMARY

[0005] In view of the problems existing in the prior art, the present application is proposed.

[0006] Therefore, the problem to be solved by the present application is how to solve the technical problem that the pressure increasing strategy in the traditional water pressure test method is single and cannot be differentially controlled according to the material mechanics characteristics at different pressure stages. Through the innovative strategy of "low pressure fast rising and high pressure slow rising", the test efficiency is improved under the premise of ensuring the safety of the structure, and a scientific and reliable technical solution is provided for the water pressure test of steel bifurcated pipes.

[0007] To solve the above technical problems, the present application provides the following technical solutions:

[0008] In a first aspect, the present application provides a method for differential grading loading and unloading water pressure test of steel bifurcated pipes of hydropower stations, which comprises: obtaining a design pressure parameter of a steel bifurcated pipe, and dividing the water pressure test process into a low pressure stage, a medium pressure stage and a high pressure stage according to the design pressure;

[0009] The low pressure stage adopts a larger step-up amplitude per stage to rapidly step up the voltage;

[0010] The medium pressure stage adopts a medium step-up amplitude per stage to gradually step up the voltage;

[0011] The high pressure stage adopts a smaller step-up amplitude per stage to slowly step up the voltage;

[0012] The steel bifurcated pipe hydraulic test is performed according to the differentiated and staged loading and unloading strategy.

[0013] As a preferred scheme of the water power station steel bifurcated pipe differentiated and staged loading and unloading hydraulic test method, the low pressure stage is 0% to 40% of the design pressure, the medium pressure stage is 40% to 70% of the design pressure, and the high pressure stage is 70% to 100% of the design pressure.

[0014] As a preferred scheme of the water power station steel bifurcated pipe differentiated and staged loading and unloading hydraulic test method, the low pressure stage step-up speed is controlled at 0.03-0.05 MPa / min, the medium pressure stage step-up speed is controlled at 0.03 MPa / min, and the high pressure stage step-up speed is controlled at 0.01-0.03 MPa / min.

[0015] As a preferred scheme of the water power station steel bifurcated pipe differentiated and staged loading and unloading hydraulic test method, the low pressure stage step-up amplitude per stage is 2-4 times of that of the high pressure stage, and the corresponding step-up amplitude is adopted in the 0.5-2 MPa step-up interval of each stage.

[0016] As a preferred scheme of the water power station steel bifurcated pipe differentiated and staged loading and unloading hydraulic test method, the step-up time per stage is not less than 30 minutes, the weld, pipeline and support state are checked during the step-up time, and the water inflow and outflow are recorded to draw a water inflow-pressure curve.

[0017] As a preferred scheme of the water power station steel bifurcated pipe differentiated and staged loading and unloading hydraulic test method, the unloading process adopts a differentiated and staged pressure relief strategy corresponding to the loading, the hydraulic test is performed twice in a complete pressure cycle process, and the steel bifurcated pipe residual stress is tested before and after the test.

[0018] As a preferred scheme of the water power station steel bifurcated pipe differentiated and staged loading and unloading hydraulic test method, the step-up and pressure relief processes adopt two standard pressure gauges with a maximum test pressure of 1.5 times and an accuracy of not less than 1.6 levels in parallel monitoring, and the acoustic emission monitoring technology is adopted to monitor the structural defects in real time during the test process.

[0019] In a second aspect, the embodiments of the present application provide a water test system for steel bifurcated pipes of a hydropower station, which comprises a parameter acquisition module, a pressure control module, and a test execution module.

[0020] The pressure control module is configured to adopt a larger pressure increase per stage and a faster pressure increase speed in the low pressure stage, adopt a medium pressure increase per stage and a transition pressure increase speed in the medium pressure stage, and adopt a smaller pressure increase per stage and a slow pressure increase speed in the high pressure stage.

[0021] The test execution module is configured to perform the water test of the steel bifurcated pipe according to the differential and hierarchical loading and unloading strategy.

[0022] In a third aspect, the embodiments of the present application provide a computer device, which comprises a memory and a processor, and the memory stores a computer program.

[0023] In a fourth aspect, the embodiments of the present application provide a computer readable storage medium, which stores a computer program.

[0024] The present application has the following beneficial effects: The present application realizes a technical breakthrough in the water test of the steel bifurcated pipe of the hydropower station by using the differential and hierarchical loading and unloading strategy. The present application divides the water test process into the low pressure stage, the medium pressure stage, and the high pressure stage, and adopts different pressure increase amplitudes and speed control strategies in different stages. The present application breaks through the technical limitations of the traditional uniform hierarchical pressure increase method, realizes the innovative control mode of “low pressure fast increase and high pressure slow increase”, and effectively solves the technical contradiction between low efficiency in the low pressure stage and poor safety in the high pressure stage in the traditional method. By using a larger pressure increase amplitude and a faster pressure increase speed in the low pressure stage, the present application fully utilizes the bearing capacity of the steel bifurcated pipe in the elastic deformation stage, significantly shortens the test period, and improves the test efficiency. By using a smaller pressure increase amplitude and a slow pressure increase speed in the high pressure stage, the present application effectively adapts to the sensitive characteristics of the steel near the yield strength, avoids the risk of local stress concentration and plastic deformation, and ensures the structural safety. By introducing the intelligent adaptive loading mechanism and the real-time monitoring technology, the present application can automatically adjust the test parameters when detecting stress anomalies or acoustic emission signals, realizes the intelligent control and safety warning of the test process, and achieves the balance and unity of efficiency and safety which is difficult to achieve by the traditional method. The present application provides a scientific and reliable technical solution for the quality control of the steel bifurcated pipe of the hydropower station. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0026] Figure 1 Flow chart of the method for differentiating and grading loading and unloading water pressure test of steel bifurcated pipe of hydropower station;

[0027] Figure 2 Computer equipment diagram of the method for differentiating and grading loading and unloading water pressure test of steel bifurcated pipe of hydropower station;

[0028] Figure 3 Arrangement diagram of steel bifurcated pipe water pressure test system of the method for differentiating and grading loading and unloading water pressure test of steel bifurcated pipe of hydropower station;

[0029] Figure 4 Differentiation and grading loading and unloading curve schematic diagram of the method for differentiating and grading loading and unloading water pressure test of steel bifurcated pipe of hydropower station;

[0030] Figure 5 Pressure stage and pressure rate relationship curve schematic diagram of the method for differentiating and grading loading and unloading water pressure test of steel bifurcated pipe of hydropower station;

[0031] Figure 6 Another differentiation and grading loading and unloading control flow chart of the method for differentiating and grading loading and unloading water pressure test of steel bifurcated pipe of hydropower station. DETAILED DESCRIPTION

[0032] In order to make the above objectives, features and advantages of the present application more apparent and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0033] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from the description, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0034] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is the embodiment independent or selectively exclusive of other embodiments.

[0035] Embodiment 1

[0036] Referring to Figures 1-2 , for the first embodiment of the application, the embodiment provides a method for differentiating and grading loading and unloading of a water pressure test of a steel bifurcated pipe of a hydropower station, comprising,

[0037] S100: obtaining a design pressure parameter of the steel bifurcated pipe, and dividing a water pressure test process into a low pressure stage, a medium pressure stage and a high pressure stage according to the design pressure;

[0038] S200: using a larger pressure increasing amplitude per stage to rapidly increase the pressure in the low pressure stage; using a medium pressure increasing amplitude per stage to transitionally increase the pressure in the medium pressure stage; and using a smaller pressure increasing amplitude per stage to slowly increase the pressure in the high pressure stage;

[0039] S300: performing the water pressure test of the steel bifurcated pipe according to the differentiating and grading loading and unloading strategy.

[0040] The steam pipeline of a thermal power plant is a thick-walled pipe. During its operation, the parameters such as the temperature, pressure and medium flow rate inside and outside the pipeline change greatly, so that the temperature and stress of the steel bifurcated pipe change greatly. As a key pressure-bearing component of a water conveying system, the steel bifurcated pipe of a hydropower station mainly faces the following core technical problems in the process of the water pressure test: the traditional uniform grading pressure increasing method cannot effectively adapt to the change of the material mechanics characteristics of the steel bifurcated pipe in different pressure stages. In the low pressure stage, the test efficiency is low due to the overly conservative pressure increasing strategy, and in the high pressure stage, the lack of fine control may cause local stress concentration and plastic deformation risk. Especially for a large steel bifurcated pipe with an HD value exceeding 4000 m〃m, the stress distribution is complex in the high pressure state, and the traditional method is difficult to effectively control the stress relaxation and creep phenomenon, which is easy to cause structural damage.

[0041] Through the steps of S100-S300, the application constructs a complete differentiating and grading loading and unloading technical scheme. The step S100 lays a foundation for the subsequent differentiating control by obtaining the design pressure parameter of the steel bifurcated pipe and scientifically dividing the pressure stages; the step S200 realizes the core strategy of “low pressure fast rising and high pressure slow rising”, improves the test efficiency by a larger pressure increasing amplitude per stage in the low pressure stage, ensures the structural safety by a smaller pressure increasing amplitude per stage in the high pressure stage, and realizes smooth conversion in the medium pressure stage as a transition interval; and the step S300 implements the differentiating strategy, and ensures the safety and effectiveness of the test through accurate pressure control and monitoring means. The whole technical scheme not only solves the problem of low test efficiency of the traditional method, but also effectively avoids the risk of structural damage that may occur in the high pressure stage, and realizes the balance and unity of efficiency and safety.

[0042] Embodiment 2

[0043] Referring to Figures 2-6 , for the second embodiment of the application.

[0044] In the embodiments of the present application, the step S100 of acquiring the steel bifurcated pipe design pressure parameter and dividing the pressure stages includes the following steps A1-A2:

[0045] A1: The low pressure stage is 0%-40% of the design pressure, the medium pressure stage is 40%-70% of the design pressure, and the high pressure stage is 70%-100% of the design pressure.

[0046] Specifically, the division of the pressure stages is based on the mechanical properties and load-carrying capacity variation law of the steel bifurcated pipe. The low pressure stage (0%-40% of the design pressure) corresponds to the elastic deformation stage of the steel bifurcated pipe, at which time the material is in a linear elastic state, the stress and strain are in a proportional relationship, and the structure has good deformation recovery ability. In this stage, the main function of the steel bifurcated pipe is to verify the overall sealing and exclude the gas in the pipe, and to prepare for subsequent pressurization. The medium pressure stage (40%-70% of the design pressure) is the transition interval from elastic deformation to plastic deformation, and the material begins to have micro-plastic deformation, but still maintains good load-carrying capacity. The high pressure stage (70%-100% of the design pressure) is a critical test period for the load-carrying capacity of the steel bifurcated pipe, at which time the stress level is close to the yield strength of the material, and stress relaxation and creep phenomena are prone to occur.

[0047] The technical basis for the division of the pressure stages is derived from the nonlinear characteristics of the stress-strain relationship of the steel bifurcated pipe. According to the steel bifurcated pipe hydrostatic test procedure of the pumped storage power station, the mechanical behavior of the steel bifurcated pipe under different pressures is obviously different. In the range of 0%-40% of the design pressure, the steel bifurcated pipe is in an elastic working state, at which time the elastic modulus of the material remains stable, and the strain increment is proportional to the stress increment. In the range of 40%-70% of the design pressure, the material gradually enters the elastic-plastic transition zone, the elastic modulus begins to decrease, and micro-plastic deformation may occur in local areas. In the range of 70%-100% of the design pressure, the material is close to the yield state, plastic deformation dominates, and the structure becomes extremely sensitive to load increments.

[0048] In an alternative embodiment, for steel bifurcated pipes of different materials, the division ratio of the pressure stages can be adjusted according to the material properties. For example, for high-strength steel material HD950CF, due to its high yield strength (≥950 MPa), the upper limit of the medium pressure stage can be appropriately increased to 75% of the design pressure; for ordinary carbon steel material, the division ratio should be kept conservative. This material adaptive stage division method can better match the actual load-carrying characteristics of different steel bifurcated pipes. For the crescent rib made of HD780CF-Z35 tear-resistant steel plate, since its material properties are different from those of the main pipe, its stress state and deformation characteristics need to be considered separately.

[0049] In another alternative embodiment, the division of the pressure stages can also consider the geometric dimensions and structural characteristics of the steel bifurcated pipe. For large steel bifurcated pipes (outer diameter > 3000 mm), due to their large wall thickness, the stress distribution is more complex, and a transition sub-stage can be added to the high-pressure stage, such as 70% ~ 85% and 85% ~ 100% design pressure, to achieve more precise pressure control. For a steel bifurcated pipe in a certain pumped storage power station project, the inlet inner diameter is φ3978.6 mm, the outlet inner diameter is φ2763.8 mm, and the wall thickness is 60 mm, which belongs to a large thick-walled steel bifurcated pipe, and requires a more detailed division of the pressure stages.

[0050] It should be noted that the division of the pressure stages also needs to consider the actual working conditions of the steel bifurcated pipe. According to the actual situation of a certain pumped storage power station project, the design pressure of the steel bifurcated pipe is 9.5 MPa, then the low-pressure stage corresponds to 0-3.8 MPa, the medium-pressure stage corresponds to 3.8-6.65 MPa, and the high-pressure stage corresponds to 6.65-9.5 MPa. This stage division method based on actual engineering parameters has stronger pertinence and practicality.

[0051] A2: According to the design parameters and engineering requirements of the steel bifurcated pipe, determine the specific test pressure value and safety factor.

[0052] Specifically, the determination of the test pressure follows the requirements of relevant specifications. For steel bifurcated pipes that do not consider the sharing of internal water pressure by surrounding rock, the water pressure test pressure value is 1.25 times the design value of the highest internal water pressure in normal operation conditions, and is not less than the design value of the highest internal water pressure in special operation conditions. For steel bifurcated pipes that consider the sharing of internal water pressure by surrounding rock, the test pressure value is determined by finite element calculation according to the shape of the underground buried steel bifurcated pipe, test conditions, and water pressure test working resistance limit. According to the design parameters of a certain pumped storage power station, the test pressure is determined to be 9.5 MPa.

[0053] The determination of the test pressure value needs to consider multiple technical factors. First, the material properties of the steel bifurcated pipe, including basic mechanical parameters such as yield strength, tensile strength, and elastic modulus. For HD950CF material, the yield strength is ≥ 950 MPa, the tensile strength is ≥ 1000 MPa, and it has good carrying capacity. Second, the geometric parameters of the steel bifurcated pipe, including structural characteristics such as inner diameter, wall thickness, and bifurcation angle. The maximum outer dimensions of the Tiantai steel bifurcated pipe are 5564 mm × 6211 mm × 5227 mm, and the total weight is 43.51 tons, which belongs to a large heavy load structure.

[0054] In the process of determining the test pressure, the manufacturing process and quality control requirements of the steel bifurcated pipe also need to be considered. According to the hydraulic test regulations, after the steel bifurcated pipe is completed, the material, size, and welding quality should be inspected and qualified to meet the design and GB 50766 requirements. The appearance inspection and non-destructive testing of the weld should comply with the relevant provisions of GB 50766 to ensure the integrity and safety of the structure.

[0055] It should be noted that the determination of the test pressure needs to consider multiple factors. First, the accuracy of the design pressure needs to be based on the actual operating conditions and water level variation range of the hydropower station. Second, the rationality of the safety factor needs to ensure the safety and reliability of the test while avoiding overly conservative test conditions. Finally, the feasibility of the test conditions, including the carrying capacity of the test site and the performance parameters of the pressurizing equipment, needs to be considered. For the steel bifurcated pipe of a certain pumped storage power station, the test is conducted in a factory, and the test conditions and equipment capacity of the factory need to be considered.

[0056] In the embodiments of the present application, the differential pressure boosting control strategy in step S200 includes the following steps B1-B3:

[0057] B1: The pressure boosting speed is controlled at 0.03-0.05 MPa / min in the low pressure stage, 0.03 MPa / min in the medium pressure stage, and 0.01-0.03 MPa / min in the high pressure stage.

[0058] Specifically, the control of the pressure boosting speed is based on the stress response characteristics of the steel bifurcated pipe in different pressure stages. In the low pressure stage, since the material is in an elastic deformation state, the stress change is relatively stable, and a faster pressure boosting speed (0.03-0.05 MPa / min) can be used to improve the test efficiency. In the medium pressure stage, the material starts to enter the elastic-plastic transition zone, and a moderate pressure boosting speed (0.03 MPa / min) is needed to ensure the uniformity of the stress distribution. In the high pressure stage, since the stress level is close to the material limit, a slower pressure boosting speed (0.01-0.03 MPa / min) must be used to avoid stress sudden changes and local damage.

[0059] The technical principle of the pressure boosting speed is based on the creep characteristics and stress relaxation behavior of the material. In a high pressure state, the steel material will exhibit time-dependent deformation, i.e., the creep phenomenon, which is characterized by an increase in deformation over time under constant load. According to the hydraulic test regulations for the steel bifurcated pipe of a pumped storage power station, the pressure should be slowly boosted or reduced at a speed not greater than 0.05 MPa / min, which is a safety threshold determined based on a large amount of test data and engineering experience. If the pressure boosting speed is too fast, the material will not have enough time to adjust the creep, which will lead to local stress concentration and increase the risk of structural failure.

[0060] The setting of the low-pressure stage pressure-rising speed is not simply pursuing efficiency, but is based on scientific considerations such as material elastic deformation adaptability, exhaust and sealing verification. In the low-pressure range, the steel bifurcated pipe is in the elastic deformation stage, but there may still be residual stress inside it, and avoiding local stress superposition to cause structural abnormalities due to too fast pressure rising; at the same time, slow pressure rising can ensure that the residual trace of bubbles slowly escapes in the low-pressure stage, and further verify the reliability of the structural sealing.

[0061] The stress level in the high-pressure stage is close to the material yield strength, and too fast pressure rising will cause stress transmission lag, forming a local high stress area. From the aspects of low-speed pressure rising to inhibit defect expansion, stress distribution uniformization and material creep behavior management, the reliability of verifying the ultimate bearing capacity of the structure is ensured. According to the analysis of the relationship between the material properties of the steel bifurcated pipe and the water pressure test, taking high-strength low-alloy steel HD950CF as an example, its stress-strain curve shows significant nonlinear characteristics in the water pressure test.

[0062] In an alternative embodiment, the pressure-rising speed can be dynamically adjusted according to real-time monitored stress data. When the stress growth rate of a certain area is monitored to exceed the preset threshold, the pressure-rising speed can be appropriately reduced; when the stress distribution is relatively uniform, the pressure-rising speed can be appropriately increased within a safe range. This adaptive control method can better adapt to the actual characteristics of different steel bifurcated pipes. Combined with the intelligent adaptive loading mechanism, when local stress concentration is monitored, the next stage pressure rising amplitude is reduced by 30% and the speed is reduced by 50%; when acoustic emission anomaly occurs, the loading is suspended and the pressure stabilization is prolonged to 60 minutes.

[0063] In another alternative embodiment, the control of the pressure-rising speed can also consider the influence of environmental temperature. According to the water pressure test regulation of the steel bifurcated pipe of pumped storage power stations, the environmental temperature should not be lower than 5℃, and the test water temperature should not be lower than 5℃. In a low-temperature environment, the toughness of the material decreases, and a slower pressure-rising speed should be used; in a high-temperature environment, the creep sensitivity of the material increases, and the pressure-rising speed also needs to be reduced. The temperature-compensated pressure-rising speed control method can improve the adaptability and safety of the test.

[0064] It should be noted that the control of the pressure-rising speed also needs to consider the specific structural characteristics of the steel bifurcated pipe. For the steel bifurcated pipe of a certain pumped storage power station, it adopts a crescent rib structure, and the rib plate thickness is 145mm, much thicker than the main pipe wall thickness, so the deformation coordination between the rib plate and the main pipe needs special attention during pressure rising. Too fast pressure rising may cause uneven stress distribution between the rib plate and the main pipe, affecting the overall stability of the structure.

[0065] B2: The pressure rising amplitude of each stage in the low-pressure stage is 2-4 times that of the high-pressure stage, and the corresponding pressure rising amplitude is used in the 0.5-2MPa pressure rising interval of each stage.

[0066] Specifically, the differentiated design of the pressure increase amplitude is the core technical feature of the present application. In the low pressure stage, a larger pressure increase amplitude (usually 1.5-2.0 MPa) can be used to quickly pass through this stage and improve test efficiency due to the larger bearing margin of the material. In the high pressure stage, a smaller pressure increase amplitude (usually 0.5-1.0 MPa) must be used to accurately control stress growth and avoid overloading damage as the material approaches the limit state. The pressure increase amplitude in the medium pressure stage (usually 1.0-1.5 MPa) is between the two, achieving a smooth transition.

[0067] The determination of the pressure increase amplitude ratio is based on the stress-strain relationship of the material and safety margin considerations. According to the mechanical properties of steel, in the elastic stage, the stress and strain are linearly related, and the material has good deformation recovery ability, so it can withstand a larger stress increment; when approaching the yield point, the stress-strain curve begins to bend, and the material becomes sensitive to stress increment, so a smaller stress increment must be used to avoid entering the plastic deformation zone.

[0068] According to the specific requirements of the steel bifurcated pipe hydrostatic test outline of a certain pumped storage power station, the test process for a design pressure of 9.5 MPa is as follows: in the low pressure stage (0-4 MPa), the pressure is increased by 2 MPa per stage, and the pressure is stabilized for 15 min; in the medium pressure stage (4-7 MPa), the pressure is increased by 1 MPa per stage, and the pressure is stabilized for 15 min; in the high pressure stage (7-9.5 MPa), the pressure is increased by 0.5 MPa per stage, and the highest pressure is stabilized for 30 min. This stepwise pressure increase amplitude design ensures both test efficiency and structural safety.

[0069] The differentiation of the pressure increase amplitude also needs to consider the geometric characteristics and stress distribution of the steel bifurcated pipe. As a complex spatial structure, the steel bifurcated pipe has a clear stress distribution inhomogeneity, and stress concentration is easily generated at bifurcated parts, ribbed plate and main pipe connection parts, etc. These areas are more sensitive to pressure increase amplitude and require more conservative control strategies. According to the finite element analysis results, the maximum stress of the steel bifurcated pipe usually occurs near the waist line turning angle, and the stress concentration factor of this area can reach 2-3 times.

[0070] In an alternative embodiment, the pressure increase amplitude can be adjusted in real time according to stress monitoring data. By arranging strain gauges at key positions, real-time monitoring of stress changes can be achieved, and when an abnormal stress growth in a certain area is found, the pressure increase amplitude can be adjusted in time. This feedback control method can better protect the structural safety.

[0071] In another alternative embodiment, the setting of the pressure increase amplitude can also take into account the manufacturing quality and defect conditions of the steel bifurcated pipe. For steel bifurcated pipes with high weld quality and no obvious defects, a standard pressure increase amplitude can be used; for steel bifurcated pipes with slight defects but still within the allowable range, the pressure increase amplitude should be appropriately reduced to increase the safety margin. This quality adaptive control strategy can improve the relevance and safety of the test.

[0072] It should be noted that the selection of the pressure increase amplitude also needs to consider the performance and control accuracy of the test equipment. The pressurization system should be able to accurately control the pressure increment to avoid pressure overshoot due to equipment performance limitations. At the same time, the pressure control system should have rapid response capability to adjust the pressure increase amplitude or stop the pressure increase in time when abnormalities are found.

[0073] B3: The pressure stabilizing time after pressure increase is not less than 30 minutes, and during the pressure stabilizing period, the welds, pipelines and support states are checked, and the water inflow and outflow are recorded to draw the water volume-pressure curve.

[0074] Specifically, the setting of the pressure stabilizing time is based on the stress stabilization requirements of the steel bifurcated pipe and the time requirements of the inspection work. A pressure stabilizing time of 30 minutes can ensure that the steel bifurcated pipe reaches a stress equilibrium state under the new pressure level, especially at high pressure stages, which is crucial for observing creep deformation and stress relaxation phenomena. According to the Pumped Storage Power Station Steel Bifurcated Pipe Hydrostatic Test Regulations, the pressure stabilizing time of each stage should not be less than 30 minutes, which is the minimum time requirement based on a large amount of test data statistical analysis.

[0075] During the pressure stabilizing period, the inspectors need to conduct detailed inspections of various parts of the steel bifurcated pipe, including the deformation of the welds, the sealing of the pipeline connections, the stability of the supports, etc. The key inspection points include the obtuse angle area of the steel bifurcated pipe, the waistline corner point, the peak stress area, the crescent rib plate and the rib plate beside the pipe shell area, etc. These parts bear higher stress during the hydrostatic test and are prone to abnormal deformation or damage.

[0076] The drawing of the water volume-pressure curve is an important means of evaluating the structural integrity of the steel bifurcated pipe. In ideal conditions, the volume change of the steel bifurcated pipe in the elastic deformation stage should have a linear relationship with the pressure; if the curve shows abnormal changes, such as a sudden increase in slope, it may indicate that the structure has been damaged or leaked. By comparing the water volume-pressure curves of different pressure cycles, the fatigue characteristics and damage accumulation of the structure can be evaluated. During each pressure increase and decrease process, the water inflow and outflow should be measured, and the water volume-pressure relationship curve should be drawn.

[0077] The determination of the stabilization time also needs to consider the material properties and structural characteristics of the steel bifurcated pipe. For large thick-walled steel bifurcated pipes, due to their large heat capacity and complex stress transmission path, it takes a long time to reach stress equilibrium, so the stabilization time may need to be extended. For the steel bifurcated pipe of a certain pumped storage power station, considering its large size (total weight of 43.51 tons), it is recommended to extend the stabilization time to 45-60 minutes at the key pressure points.

[0078] In an alternative embodiment, the stabilization time can be dynamically adjusted according to stress monitoring data. By monitoring the stress change rate, when the stress change rate decreases below a preset threshold, it indicates that the structure has reached a stable state, and the next stage of pressure increase can be entered; if the stress is still changing, the stabilization time needs to be extended. This adaptive stabilization strategy can better ensure the accuracy and safety of the test.

[0079] In another alternative embodiment, more detailed detection work can be carried out during the stabilization period, including non-destructive testing, acoustic emission monitoring, temperature field measurement, etc. These detection means can provide more comprehensive structure state information, and provide more reliable basis for test safety evaluation.

[0080] It should be noted that the length of the stabilization time also needs to be adjusted according to the specific characteristics of the steel bifurcated pipe. For large steel bifurcated pipes, due to their large heat capacity, it takes a long time to reach temperature equilibrium, so the stabilization time may need to be extended; for thin-walled steel bifurcated pipes, due to their fast stress response, the stabilization time can be appropriately shortened. In addition, at key pressure points (such as 70% and 90% design pressure), it is recommended to extend the stabilization time to 45-60 minutes for more detailed inspection and monitoring.

[0081] In the embodiments of the present application, the execution of the differentiated grading unloading strategy in step S300 includes the following steps C1-C2:

[0082] C1: Also includes that the unloading process adopts a differentiated grading pressure relief strategy corresponding to the loading, the hydrostatic test is carried out twice complete pressure cycle process, and the steel bifurcated pipe residual stress test is carried out before and after the test.

[0083] Specifically, the differentiated control of the unloading process is also important, and needs to follow the gradient principle opposite to the loading process. In the unloading process of the high pressure stage, a smaller pressure relief amplitude and a slower pressure relief speed are adopted to avoid stress mutation caused by sudden pressure drop; in the low pressure stage, a larger pressure relief amplitude and a faster pressure relief speed can be adopted to improve the test efficiency. According to the hydrostatic test outline of the steel bifurcated pipe of a certain pumped storage power station, the pressure relief speed should be no more than 0.4 MPa / min, and the pressure is unloaded by 2.0 MPa each time, and the pressure is stabilized for 15 minutes. This symmetrical differentiated strategy can ensure that the stress state of the steel bifurcated pipe is always within a controllable range during the entire test process.

[0084] The control strategy of the unloading process is embodied as follows: in the high-pressure stage (10-7 MPa), each stage is depressurized by 0.5 MPa at a speed of 0.01 MPa / min, and the pressure is stabilized for not less than 30 minutes; in the medium-pressure stage (7-4 MPa), each stage is depressurized by 1 MPa at a speed of 0.03 MPa / min, and the pressure is stabilized for not less than 30 minutes; in the low-pressure stage (4-0 MPa), each stage is depressurized by 2 MPa at a speed of 0.05 MPa / min, and the pressure is stabilized for not less than 30 minutes. This gradient unloading strategy can effectively control the stress release process and avoid structural damage caused by rapid unloading.

[0085] The purpose of the two complete pressure cycles is to evaluate the fatigue characteristics and structural stability of the steel bifurcated pipe. The first cycle is mainly used to eliminate residual stress and initial defects in the manufacturing process, and the second cycle is used to verify the load-carrying capacity of the structure after experiencing the pressure history. By comparing the test data of the two cycles, the fatigue damage degree and remaining life of the structure can be evaluated. According to the water pressure test procedure for steel bifurcated pipes of pumped storage power stations, the water pressure test should be carried out for two complete pressure cycles, and the test data of the two tests should be collected.

[0086] Residual stress testing is an important indicator for evaluating the effectiveness of the water pressure test. The residual stress before the test is mainly caused by the heat effect during welding and plastic deformation during machining; the change of residual stress after the test reflects the effect of the water pressure test on eliminating residual stress. Through non-destructive testing methods such as X-ray diffraction and indentation strain method, the distribution and change of residual stress can be quantitatively evaluated. Before the pre-test and after the completion of the water pressure test, the residual stress of the steel bifurcated pipe should be tested, and the test data should be compared and analyzed.

[0087] The technical requirements for residual stress detection include: detecting the welding residual stress of the steel bifurcated pipe before and after the water pressure test, using non-destructive testing methods such as X-ray diffraction and indentation strain method; the welding residual stress measuring points should be selected in the representative weld or its vicinity; before testing the residual stress, the strain release coefficient calibration should be carried out according to the material of the bifurcated pipe. These technical requirements ensure the accuracy and reliability of the residual stress detection.

[0088] In an alternative embodiment, the unloading process can include an intermediate pressure holding segment, i.e. a short pressure holding at some key pressure points (such as 50% design pressure) to observe the elastic recovery characteristics of the structure. If the permanent deformation is found to exceed the allowable range, the test should be stopped immediately and the structure should be evaluated. This segmented pressure holding unloading strategy can provide more detailed information on the performance of the structure.

[0089] In another alternative embodiment, for a special important steel bifurcated pipe, three or more pressure cycles can be performed to obtain more reliable fatigue property data. The maximum pressure of each cycle can be gradually increased, eventually reaching 1.25 times the design pressure, to fully verify the ultimate load-carrying capacity of the structure. This progressive cycle test method can more comprehensively evaluate the structural performance.

[0090] It should be noted that the control of the unloading process also requires strict monitoring and safety protection measures. Too fast unloading speed can cause tensile stress inside the structure, which may trigger crack propagation in the defect area. Therefore, the unloading process also needs to use real-time monitoring means such as acoustic emission monitoring to ensure the safety of the structure.

[0091] C2: Also includes that the pressure increasing and pressure releasing processes are monitored by two standard pressure gauges with a range of 1.5 times the maximum test pressure and an accuracy of not less than 1.6 grade, and the acoustic emission monitoring technology is used to monitor the structural defects in real time during the test process.

[0092] Specifically, the design of the pressure monitoring system needs to ensure the accuracy and reliability of the measurement. Two pressure gauges are used in parallel to provide redundancy protection, so that if one fails, the other can still work normally to ensure the continuity and safety of the test. The range of the pressure gauge is selected to be 1.5 times the maximum test pressure, so that the pressure gauge works within its best accuracy range throughout the test process, avoiding measurement errors caused by too small range. According to the water pressure test regulation for steel bifurcated pipe of pumped storage power station, the pressure measurement of the pressurizing system should use standard pressure gauges with an accuracy of not less than 1.6 grade, and the range should be 1.5 times the maximum test pressure.

[0093] The installation and calibration of the pressure gauge are very strict. The pressure gauge should be installed with two, showing the test pressure at the same time, to ensure the reliability of the pressure test during the test process. Before the test, the pressure gauge needs to be calibrated to ensure its accuracy meets the requirements. Calibration should be carried out by a qualified measurement institution, and the pressure gauge can only be used within the valid period of the calibration certificate. The installation position of the pressure gauge should be convenient for observation, avoiding the influence of vibration and temperature change.

[0094] Acoustic emission monitoring technology is an advanced structural health monitoring method, which can detect micro-damage and crack propagation inside the steel bifurcated pipe in real time. When the material undergoes plastic deformation, crack initiation or propagation, acoustic emission signals will be released, and through the arrangement of acoustic emission sensors on the surface of the steel bifurcated pipe, these damage signs can be found in time. The advantage of acoustic emission monitoring is its real-time and sensitivity, which can find micro-defects before macro-damage occurs. According to the water pressure test regulation for steel bifurcated pipe of pumped storage power station, acoustic emission monitoring technology should be used for defect monitoring during the water pressure test of large steel bifurcated pipe, and the specific method is referred to NB / T 35110.

[0095] The arrangement of the acoustic emission monitoring system needs to consider the geometric characteristics and stress distribution of the steel bifurcated pipe. More sensors are usually arranged in stress concentration areas (such as the bifurcation, near the weld) and the number of sensors is appropriately reduced in areas with relatively uniform stress. For a steel bifurcated pipe of a certain pumped storage power station, acoustic emission sensors should be mainly arranged in key positions such as obtuse angle area, waist line corner point, peak stress area, crescent rib plate and rib plate side shell area. The frequency response range of the sensor should cover the typical frequency band of acoustic emission of steel (usually 20 kHz-1 MHz), and the sampling frequency should not be less than 1 MHz to ensure the integrity of the signal.

[0096] The processing and analysis of acoustic emission signals require professional software and algorithm support. Acoustic emission signals usually contain a large amount of noise and interference, which need to be extracted through filtering, denoising and other preprocessing techniques. Signal characteristic parameters include ring count, amplitude, duration, energy, etc., which can reflect the nature and severity of damage. By establishing the correspondence between acoustic emission signals and damage state, quantitative evaluation and early warning of damage can be realized.

[0097] In an alternative embodiment, strain monitoring technology can be combined to arrange strain gauges at key positions of the steel bifurcated pipe to monitor stress changes in real time. The arrangement of strain gauges should consider the principal stress direction and stress gradient, and a three-way strain cloth arrangement is usually used to obtain complete stress state information. Strain monitoring data can be verified with acoustic emission signals to improve the accuracy of damage identification. According to the steel bifurcated pipe hydrostatic test procedure of pumped storage power stations, stress and strain monitoring of steel bifurcated pipes should select key sections such as rib plate, main cone, main branch cone intersection and branch cone, and according to the stress distribution characteristics of the bifurcated pipe, the measuring points can be set at 1 / 4 or 1 / 2 of the selected section.

[0098] The technical requirements of the strain monitoring system include: the stress and strain monitoring instrument and the resistance strain gauge should meet the requirements of QJ 3156, the measurement range should meet ±10000με, and the resolution should not be greater than 1με; all stress and strain measuring points should use an automatic digital measurement system with a sampling rate not less than 10 Hz; the stress and strain measuring points on the inner and outer walls of the pipe shell should be arranged correspondingly to test the membrane stress and local bending stress; the stress and strain measuring point arrangement should correspond to the calculation prototype measuring point arrangement.

[0099] In another alternative embodiment, distributed strain monitoring can be carried out using optical fiber sensing technology. Optical fiber sensors have the advantages of anti-electromagnetic interference, high temperature resistance and long distance distributed measurement, and are particularly suitable for comprehensive monitoring of large steel bifurcated pipes. By laying an optical fiber sensor network on the surface of the steel bifurcated pipe, the strain distribution map of the structure can be obtained, providing detailed data support for stress analysis. Optical fiber sensing technology can also detect temperature changes, providing a data basis for thermal stress analysis.

[0100] Deformation monitoring is an important part of hydrostatic testing, which can directly reflect the deformation behavior of steel bifurcated pipe under pressure. According to the steel bifurcated pipe hydrostatic testing procedure of pumped storage power station, displacement sensors should be used for deformation monitoring, and the resolution should not be greater than 0.01mm. Deformation monitoring should be set up at the top and bottom of the outside of the steel bifurcated pipe, the waist line angle point of the intersecting line of the main and branch cone, and the rib plate waist line. Measuring points can also be set at other parts such as the muff. The displacement sensor installation bracket should be stable and have no constraint with the bifurcated pipe body.

[0101] Temperature monitoring is also an important part of hydrostatic testing, especially for large thick-walled steel bifurcated pipes, temperature change will cause significant thermal stress. According to the steel bifurcated pipe hydrostatic testing procedure of pumped storage power station, during the hydrostatic test, the test water temperature monitoring temperature sensor should be placed inside the steel bifurcated pipe; the environmental temperature should not be less than 5℃, and the test water temperature should not be less than 5℃; the related monitoring instruments of hydrostatic test should consider temperature compensation, and the monitoring results should be corrected.

[0102] It should be noted that the processing and analysis of monitoring data are also important. A perfect data acquisition and processing system should be established to record real-time pressure, strain, acoustic emission and other monitoring signals, and comprehensive analysis should be carried out through data fusion technology. When abnormal signals are detected, the system should be able to automatically alarm and suggest corresponding treatment measures, such as pausing pressurization, prolonging the pressure stabilization time or emergency pressure relief, etc. The data processing system should also have the functions of historical data storage and query, providing data support for subsequent analysis and evaluation.

[0103] The linkage mechanism of monitoring data and loading and unloading strategy is an important technical feature of the invention. Through real-time monitoring data, the loading parameters are dynamically adjusted, and when abnormal stress growth is detected, how to automatically adjust the loading strategy, and the correlation algorithm of pressure gradient monitoring and loading rate adjustment, etc., all reflect the technical advantages of intelligent control. The specific linkage mechanism includes: when local stress concentration is detected, the next stage of pressure rise amplitude is reduced by 30%, and the speed is reduced by 50%; when acoustic emission anomaly occurs, loading is paused, and pressure stabilization is prolonged to 60 minutes; when the pressure gradient deviation exceeds ±15%, the flow and pressure are adjusted to ensure stability; when strain nonlinearity occurs, the pressure is automatically reduced by 10% and the fault is checked.

[0104] The material properties of steel bifurcated pipe are closely related to the water pressure test. Taking the low-alloy high-strength steel HD950CF (yield strength ≥ 950 MPa, tensile strength ≥ 1000 MPa) as an example, the stress-strain curve in the water pressure test presents a significant nonlinear characteristic. In the low-pressure stage, the mechanical properties are mainly elastic deformation, the strain and stress are linearly related, and the elastic strain range is 0% to 0.45%. In the medium-pressure stage, the mechanical properties partially enter the elastic-plastic transition zone, the strain rate decreases, the strain hardening effect appears, the tangent modulus decreases to 50-80 GPa, and the strain increment Δε is 0.45% to 0.7%. In the high-pressure stage, the mechanical properties are dominated by plastic deformation, the plastic strain accounts for ≥ 60%, and the strain increment Δε is 0.7% to 1.2%. The elastic-plastic transition, creep, and stress relaxation behavior of high-strength steel directly determine that a pressure increasing speed of ≤ 0.03 MPa / min should be used in the high-pressure stage, the plastic strain increment is limited within a safe threshold by using a fine grading strategy, and stress uniformization is achieved during the steady pressure stage, thereby providing key technical support for the safe operation of high-head power stations.

[0105] Referring to Figure 4 The differential grading loading and unloading curve of the water pressure test is shown in the figure, which clearly shows the core technical features of the present application. The horizontal axis of the figure represents the test time, and the vertical axis represents the test pressure. Different stages of the curve represent the differential pressure increasing strategy. In the low-pressure stage, the slope of the curve is large, indicating that the pressure increasing speed is fast; in the high-pressure stage, the slope of the curve is small, indicating that the pressure increasing speed is slow. Each pressure platform represents the steady pressure stage, and the width of the platform reflects the length of the steady pressure time. The technical principle and implementation process of differential grading loading and unloading can be intuitively understood through the figure.

[0106] Referring to Figure 5 The relationship curve between the pressure stage and the pressure increasing rate of the water pressure test is shown in the figure (taking the design pressure of 10 MPa as an example), which quantitatively displays the pressure increasing rate control strategy in different pressure stages. The figure clearly identifies the demarcation points of the low-pressure, medium-pressure, and high-pressure stages and their respective pressure increasing rate ranges, providing clear technical guidance for the test operation. The pressure increasing rate in the low-pressure stage (0-4 MPa) is 0.03-0.05 MPa / min, the pressure increasing rate in the medium-pressure stage (4-7 MPa) is 0.03 MPa / min, and the pressure increasing rate in the high-pressure stage (7-10 MPa) is 0.01-0.03 MPa / min.

[0107] Referring to Figure 6The illustrated hydrostatic test differential grading unloading control flowchart (taking the design pressure of 10 MPa as an example) shows the logical control flow of the entire test process, including pressure stage judgment, pressure increase parameter setting, safety monitoring, abnormality handling and other key links. The flowchart starts from test preparation, goes through pressure stage division, differential pressure increase control, pressure stabilization detection, abnormality handling, unloading control and other steps, and finally completes the entire test process. The design of the flowchart reflects the technical advantages of the application in automatic control, and can realize standardized and intelligent operation of the test process.

[0108] Safety protection measures are an important part of hydrostatic testing. According to the hydrostatic test procedure for steel bifurcated pipes of pumped storage power stations, special safety measures and emergency plans should be prepared before the test, the test personnel and equipment should be kept more than 5 meters away from the bifurcated pipe body, and safety barriers should be set up; when the test pressure reaches 70% of the maximum value, the test personnel should not approach the bifurcated pipe body. The test instruments should be installed and adjusted before the test, and the installed instruments and equipment and cable lines should be protected during the test. The stress-strain and deformation monitoring should set the warning value and monitor in real time.

[0109] Abnormal situation handling is a key measure to ensure test safety. When bulging, water seepage or abnormal situations are found during pressure stabilization, the pressure should be reduced and vented, the causes should be analyzed and effective measures should be taken, and then the pressure should be increased again. For the leakage positions found during the liquid pressure test of the component container or any defects exposed, the liquid pressure test should be performed again after the pressure is reduced and vented and the defects are repaired and qualified. For the defects found by the non-destructive testing process required after the liquid pressure test, it should be decided whether to perform the liquid pressure test again according to the severity of the defects and the repair depth.

[0110] Analysis and evaluation of test data is the final goal of hydrostatic testing. According to the hydrostatic test procedure for steel bifurcated pipes of pumped storage power stations, the result analysis should include the following main contents: the relationship curve of the stress of the inner and outer walls of the bifurcated pipe with the test pressure loading; stress distribution diagram and law analysis of the inner and outer walls of the bifurcated pipe; deformation monitoring result analysis of the bifurcated pipe; water quantity-pressure relationship curve; residual stress detection result analysis before and after the test; comparison and analysis of test results and design results. These analysis contents can comprehensively evaluate the structural performance and safety state of the steel bifurcated pipe.

[0111] In summary, the present invention effectively solves the technical defects of traditional water pressure testing methods through a differentiated graded loading and unloading strategy, ensuring structural safety while improving test efficiency. This method is based on the material mechanical properties of steel bifurcated pipes at different pressure stages, adopts the innovative strategy of "low pressure fast rise, high pressure slow rise", and combines advanced monitoring technology and intelligent control means to provide a scientific and reliable technical means for the quality control of steel bifurcated pipes in hydropower stations. This technical solution is not only suitable for factory inspection of newly built steel bifurcated pipes, but can also be used for regular inspection of in-service steel bifurcated pipes. It has broad application prospects and important engineering value. By implementing a differentiated graded loading and unloading water pressure test method, the test efficiency can be significantly improved by 20% to 30%, while ensuring structural safety, providing reliable protection for the safe operation of hydropower stations.

[0112] Example 3

[0113] The above is a schematic diagram of a method for differential, graded loading and unloading hydraulic pressure testing of steel bifurcated pipes at a hydropower station. It should be noted that the technical solution of this system for differential, graded loading and unloading hydraulic pressure testing of steel bifurcated pipes at a hydropower station is based on the same concept as the technical solution of the aforementioned method for differential, graded loading and unloading hydraulic pressure testing of steel bifurcated pipes at a hydropower station. For details not described in detail in the technical solution of the system for differential, graded loading and unloading hydraulic pressure testing of steel bifurcated pipes at a hydropower station in this embodiment, please refer to the description of the technical solution of the aforementioned method for differential, graded loading and unloading hydraulic pressure testing of steel bifurcated pipes at a hydropower station.

[0114] This embodiment also provides a differentiated graded loading and unloading hydraulic pressure testing system for steel bifurcated pipes in a hydropower station, comprising:

[0115] The parameter acquisition module is used to obtain the design pressure parameters of the steel bifurcated pipe and divide the water pressure test process into low pressure stage, medium pressure stage and high pressure stage according to the design pressure;

[0116] The pressure control module is used to quickly increase the pressure by using a larger pressure boost amplitude per stage in the low pressure stage, to perform transitional pressure boost by using a medium pressure boost amplitude per stage in the medium pressure stage, and to slowly increase the pressure by using a smaller pressure boost amplitude per stage in the high pressure stage;

[0117] The test execution module is used to perform hydraulic tests on steel bifurcated pipes according to differentiated graded loading and unloading strategies.

[0118] This embodiment also provides an electronic device suitable for the differentiated graded loading and unloading water pressure test of steel bifurcated pipes in hydropower stations, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement the differentiated graded loading and unloading water pressure test method for steel bifurcated pipes in hydropower stations as proposed in the above embodiment.

[0119] The embodiment also provides a storage medium, which stores a computer program, and the computer program is executed by a processor to implement the method for implementing the water pressure test of the steel bifurcated pipe of the hydropower station by differentiation and grading loading and unloading, which is proposed in the above embodiment.

[0120] The storage medium proposed in the embodiment belongs to the same inventive concept as the method for implementing the water pressure test of the steel bifurcated pipe of the hydropower station by differentiation and grading loading and unloading proposed in the above embodiment, and the technical details not described in the embodiment can be referred to the above embodiment, and the embodiment has the same beneficial effects as the above embodiment.

[0121] Through the above description of the embodiments, those skilled in the art can clearly understand that the present application can be realized by means of software and necessary universal hardware, and of course can also be realized by hardware. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, and the computer software product can be stored in a computer readable storage medium, such as a floppy disk, a read-only memory (ROM), a random access memory (RAM), a FLASH memory, a hard disk, or an optical disc, and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods of various embodiments of the present application.

[0122] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application but not limit the present application, and although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A differentiated graded loading and unloading hydraulic pressure test method for steel bifurcated pipes in a hydropower station, characterized by: Including, obtaining the design pressure parameters of the steel bifurcated pipe, and dividing the water pressure test process into low pressure stage, medium pressure stage and high pressure stage according to the design pressure; In the low pressure stage, a larger pressure increase amplitude per stage is used for rapid pressure increase; In the medium pressure stage, medium pressure increase amplitude per stage is used for transition pressure increase; In the high pressure stage, a smaller pressure increase amplitude per stage is used to increase the pressure slowly; The steel bifurcated pipe water pressure test was carried out according to the differentiated graded loading and unloading strategy.

2. The method for differential graded loading and unloading hydraulic pressure testing of steel bifurcated pipes in a hydropower station according to claim 1, characterized in that: The low pressure stage is 0% to 40% of the design pressure, the medium pressure stage is 40% to 70% of the design pressure, and the high pressure stage is 70% to 100% of the design pressure.

3. The differentiated graded loading and unloading hydraulic pressure test method for steel bifurcated pipes in a hydropower station according to claim 2, characterized in that: The pressure increasing speed in the low pressure stage is controlled at 0.03-0.05 MPa / min, the pressure increasing speed in the medium pressure stage is controlled at 0.03 MPa / min, and the pressure increasing speed in the high pressure stage is controlled at 0.01-0.03 MPa / min.

4. The method for differential graded loading and unloading hydraulic pressure testing of steel bifurcated pipes in a hydropower station according to claim 3, characterized in that: The pressure increase amplitude of each stage in the low-pressure stage is 2-4 times that of the high-pressure stage, and each stage adopts a corresponding pressure increase amplitude in the pressure increase interval of 0.5-2 MPa.

5. The differentiated graded loading and unloading hydraulic pressure test method for steel bifurcated pipes in a hydropower station according to claim 4, characterized in that: The pressure stabilization time after each level of pressure boosting shall be no less than 30 minutes. During the pressure stabilization period, the status of the welds, pipelines and brackets shall be checked, and the water inlet and outlet shall be recorded to draw a water volume-pressure curve.

6. The method for differential graded loading and unloading hydraulic pressure testing of steel bifurcated pipes in a hydropower station according to claim 5, characterized in that: It also includes the use of a differentiated graded pressure relief strategy corresponding to the loading process during the unloading process, two complete pressure cycle processes in the water pressure test, and residual stress testing of the steel bifurcation pipe before and after the test.

7. The method for differential graded loading and unloading hydraulic pressure testing of steel bifurcated pipes in a hydropower station according to claim 6, characterized in that: It also includes parallel monitoring of the pressure increase and pressure reduction processes using two standard pressure gauges with a range of 1.5 times the maximum test pressure and an accuracy of no less than level 1.6, and the use of acoustic emission monitoring technology to monitor structural defects in real time during the test.

8. A differentiated graded loading and unloading hydraulic pressure test system for steel bifurcated pipes in a hydropower station, based on the differentiated graded loading and unloading hydraulic pressure test method for steel bifurcated pipes in a hydropower station according to any one of claims 1 to 7, characterized in that: The system also includes a parameter acquisition module for acquiring design pressure parameters of the steel bifurcated pipe and dividing the water pressure test process into a low pressure stage, a medium pressure stage and a high pressure stage according to the design pressure; The pressure control module is used to quickly increase the pressure by using a larger pressure boost amplitude per stage in the low pressure stage, to perform transitional pressure boost by using a medium pressure boost amplitude per stage in the medium pressure stage, and to slowly increase the pressure by using a smaller pressure boost amplitude per stage in the high pressure stage; The test execution module is used to perform hydraulic tests on steel bifurcated pipes according to differentiated graded loading and unloading strategies.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the differentiated graded loading and unloading water pressure test method for the steel bifurcated pipe of a hydropower station according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the differentiated graded loading and unloading hydraulic pressure test method for steel bifurcated pipes in a hydropower station as described in any one of claims 1 to 7 are implemented.

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