Pre-stressed steel cylinder concrete pipe water hammer real-time distinguishing and positioning system for hydraulic monitoring and installation and use method of pre-stressed steel cylinder concrete pipe water hammer real-time distinguishing and positioning system

Abstract

The invention discloses a prestressed concrete cylinder pipe water hammer real-time distinguishing and positioning system for hydraulic monitoring and a mounting and using method, the system comprises a plurality of sensors located on a concrete cylinder pipe, the concrete cylinder pipe is also provided with a flow velocity meter, and the flow velocity meter and the sensors are both connected with an acquisition device. The high-frequency pressure pulsation sensors and the flow meters are reasonably arranged in the PCCP, high-frequency change data of the water pressure and the flow speed in the PCCP can be obtained in real time, compared with a traditional water pressure test or static monitoring method, the dynamic fluctuation process of the water pressure and the flow speed can be captured, the hydraulic boundary condition change in pipeline operation can be comprehensively reflected, and the method is suitable for popularization and application. And data support is provided for hydraulic analysis and safety evaluation.

Description

Technical Field

[0001] The present invention relates to a prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring and an installation and use method thereof, belonging to the technical field of pipeline hydraulic monitoring. Background Art

[0002] Prestressed Concrete Cylinder Pipe (PCCP) is a composite pressure pipe commonly used in long-distance water transmission projects and urban water supply systems. It is mainly composed of a steel cylinder, inner and outer concrete layers, prestressed steel wire and a mortar protective layer. It has good pressure-bearing performance and structural stability.

[0003] After PCCP pipeline construction is completed, a hydrostatic test is typically required to verify the pipeline's sealing and load-bearing capacity. Traditional hydrostatic testing methods rely on conventional pressure gauges installed at pressure testing devices or pressure measuring points. However, conventional pressure gauges suffer from limited range, slow response, and an inability to capture dynamic fluctuations in water pressure. These gauges are unable to fully reflect pressure anomalies that may occur during pipeline operation, particularly transient hydraulic events such as water hammer. Furthermore, during actual operation, PCCP pipelines may experience some water hammer. Water hammer is a phenomenon in which rapid changes in water flow within the pipeline, caused by irregular valve opening and closing, lead to dramatic fluctuations in water pressure. Pipeline bursts in certain PCCP pipelines have demonstrated that water hammer can cause internal water pressure to far exceed the designed operating pressure, potentially causing a burst. Therefore, real-time monitoring of internal pipeline water pressure and flow rate changes can help promptly identify water hammer and implement effective control measures to prevent serious safety issues such as bursts.

[0004] At present, some technical solutions have attempted to monitor water hammer by deploying pressure sensors or flow meters in the pipeline network, but there are still the following shortcomings: (1) The sensor installation method is mostly external or relies on flange joints, which is complex to construct, has poor sealing, and may damage the integrity of the pipeline structure; (2) Most water hammer identification and monitoring solutions only collect a single physical quantity (such as water pressure), which cannot reflect the contribution of pipeline flow rate changes to water hammer identification and is difficult to effectively identify the location of water hammer; (3) Some high-end monitoring systems rely on complex modeling or digital twin platforms, which have high actual engineering adaptability and deployment costs; (4) PCCP pipelines have high structural rigidity and thick pipe walls, and are prone to exhibiting the characteristics of delayed pressure and flow rate response under the action of water hammer. Existing water hammer monitoring methods are difficult to adapt to their dynamic response characteristics and are not suitable for water hammer monitoring and positioning of large-diameter PCCP pipelines.

[0005] Therefore, there is an urgent need to develop a PCCP hydraulic monitoring technology solution with strong structural adaptability, convenient installation, sensitive response, and the ability to identify and locate water hammer, so as to provide data support and judgment basis for the safe operation of the pipeline system and enhance the early warning capability of water hammer and its potential damage. Summary of the Invention

[0006] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring and an installation and use method.

[0007] Technical solution: To solve the above technical problems, the present invention provides a real-time water hammer identification and positioning system for prestressed steel cylinder concrete pipes for hydraulic monitoring, comprising a plurality of pressure sensors located on the prestressed steel cylinder concrete pipes, and a flow meter is also provided inside the prestressed steel cylinder concrete pipes, and both the flow meter and the pressure sensor are connected to a collection device.

[0008] Preferably, the prestressed steel cylinder concrete pipe comprises a concrete pipe core, a steel cylinder is provided on the inner wall of the concrete pipe core, a mounting hole is provided on the steel cylinder, a pressure sensor is installed in the mounting hole, and the pressure sensor is sealed in the prestressed steel cylinder concrete pipe by flexible mortar.

[0009] A method for installing a prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring includes the following steps:

[0010] S1: Make a socket steel ring, a spigot steel ring and a steel cylinder for connecting pipe joints, and weld the socket steel ring and the spigot steel ring to both ends of the steel cylinder respectively;

[0011] S2: According to the material and wall thickness of the socket steel plate, select an appropriate drilling tool to drill a hole in the socket steel plate to install the high-frequency pressure pulsation sensor and provide a channel for the cable of the flow meter. Then clean the hole and tap the hole.

[0012] S3: Make a sensor mounting connector for installing a high-frequency pressure pulsation sensor and a cable connection component for leading out the flow meter cable;

[0013] S4: Connect the sensor mounting connector and the outgoing line connection member to the corresponding positions of the socket steel ring respectively, and install protective bolts to prevent concrete slurry from entering the hole;

[0014] S5: pouring core concrete;

[0015] S6: The cured tube core is placed on a rotating table and wound with prestressed steel wire;

[0016] S7: roller sprayed mortar protective layer;

[0017] S8: spraying epoxy coal tar anti-corrosion coating;

[0018] S9: On-site piping installation;

[0019] S10: After the pipeline is installed and positioned, remove the protective bolts and install the high-frequency pressure pulsation sensor;

[0020] S11: Install the flow meter and lead the flow meter cable to the outside of the pipeline;

[0021] S12: Use cement and epoxy resin mixed grouting material in a 1:1 ratio to seal the holes, and finally grout the pipe joints.

[0022] Preferably, in step S11, the installation step of the flow meter includes:

[0023] S111. Install the steel hoop support: First, install the steel hoop support along the inner side of the pipe in a circumferential direction. The steel hoop support is composed of multiple support blocks, which are connected by bolts. The first and last support blocks are connected by long bolts. The nuts of the long bolts are adjustable. By tightening the nuts, the steel hoop support can be expanded outward and tightly attached to the pipe wall, ensuring that the support is firmly installed inside the pipe.

[0024] S112. Install the flow meter bracket: Weld the steel bracket for installing the flow meter to the steel hoop bracket at the bottom of the pipeline. Then, fix the flow meter to the steel bracket with screws to ensure that the installation position of the flow meter is accurate and stable to avoid loosening during the water flow in the pipeline.

[0025] S113. Secure the flowmeter cable: Insert the plugging bolts into the flowmeter cable in advance and secure the cable along the pipe wall to the steel hoop bracket. To ensure a secure installation, tightly wrap the cable around the steel hoop bracket using tying or clipping, distributing it evenly along the bracket. The cable starts at the flowmeter at the bottom of the pipe, gradually passes through the pipe wall, and finally wraps around the outlet connection component at the top of the pipe.

[0026] S114. Lead the cable out of the pipe. The current meter cable is led out of the pipe through the inner hole of the outlet connecting component and connected to the external collector.

[0027] A method for using a prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring, comprising the following steps:

[0028] (a) Using a high-frequency pressure pulsation sensor and a flow meter installed inside a prestressed concrete cylinder pipe, water pressure and flow rate data at each measuring point inside the pipe are collected synchronously and in real time;

[0029] (b) Determine the initial steady-state reference pressure and reference flow rate of the pipeline based on the water pressure data and flow rate data collected in real time. Specifically, the initial moment of data collection is used as the starting point of the steady-state stage of pipeline operation. During this initial stage, the pipeline system has not been disturbed and no water hammer has occurred. The average value of the pressure and flow rate data at each measuring point during this period can be defined as the initial steady-state reference pressure and reference flow rate of the pipeline. Subsequently, the rate of change and amplitude of change of the pressure and flow rate at each measuring point in the pipeline are calculated. Specifically, the agreed initial stage is used as the steady-state operation stage. Starting from the starting moment of pipeline operation data collection, the pipeline system has not experienced any water hammer events or any disturbances, and the pressure and flow rate are in a stable state. This can be directly defined as the initial steady-state operating condition of the system. The average value of the data during this stage is used as the reference pressure and reference flow rate.

[0030] (c) Calculate the pressure-velocity coupled water hammer discrimination index (WHI) used to determine whether water hammer occurs in the pipeline in real time. The calculation formula is:

[0031]

[0032] Among them, ΔP(t) is the pressure change rate at any moment in the pipeline. This value is calculated by the data collected synchronously by multiple high-frequency pressure pulsation sensors at that location, and then obtained by weighted average. max is the maximum value of the pressure change rate; ΔV(t) is the flow rate change rate at any moment, ΔV max is the maximum value of the flow velocity change rate; k1 and k2 are weight coefficients, and the value range of k1 and k2 is 0-1, preferably 0.5; in the present invention, multiple high-frequency pressure pulsation sensors are arranged at each socket joint to capture the water pressure change signals at different positions of the cross section; for each joint, the pressure change rate ΔP(t) is calculated for the pressure data collected by all its sensors, and then the results of each sensor are averaged to obtain a unified and representative pressure change rate of the joint, which is used for the subsequent calculation and determination of the water hammer index WHI;

[0033] (d) When WHI(t) reaches or exceeds the set threshold, it is determined that water hammer occurs and the location of the water hammer is further determined. The specific determination method is: the absolute time t when the pressure change rate reaches 50% of its maximum change P , and the absolute time t when the flow rate change rate reaches 50% of its maximum change V Compare. If t P Earlier than t VIf the time difference exceeds the preset time threshold Δt, it is determined that water hammer has occurred at the remote end, otherwise it is determined that water hammer has occurred locally. The moment corresponding to the 50% maximum change is selected as the characteristic time point, which is determined based on the typical fluctuation characteristics of the pressure and flow rate response curves during the water hammer process. Compared with directly using the maximum value point, the 50% change point has stronger stability and repeatability, and can more accurately reflect the starting stage of the fluctuation trend, avoiding misjudgment due to local spikes or numerical jitter. In addition, during the propagation of water hammer waves, since the propagation speed of the pressure wave is much higher than the response speed of the flow rate change, if t at a certain measuring point P +Δt is significantly earlier than t V , indicating that the pressure wave is the far-end water hammer propagating here, while the local point has not yet produced a significant flow velocity response, and it can be determined to be the far-end response location; on the contrary, if the pressure and flow velocity changes are almost synchronous, or the flow velocity changes slightly earlier than the pressure fluctuation, it indicates that the water hammer is very likely to originate from this measuring point, and it is determined to be a local water hammer. P +Δt and t V The relationship between them can realize the automatic identification of the water hammer location.

[0034] Preferably, the time threshold Δt in step (d) is determined according to the inner diameter of the pipeline, the length of the pipe section, and the propagation speed of the pressure wave, and specifically satisfies the following relationship:

[0035]

[0036] Where L is the distance between adjacent sensors; C is the propagation velocity of the pressure wave in the pipeline; D is the inner diameter of the pipeline; α is the dimensionless proportional correction coefficient, which ranges from 0.2 to 0.5 and is set based on pipeline structure and operating conditions. It is used to reflect the hysteresis characteristics of flow velocity changes caused by fluid inertia effects.

[0037] The present invention synchronously collects high-frequency pressure pulsation and flow rate data, and proposes a water hammer discrimination index WHI based on the coupling characteristics of the two; it clearly proposes to identify the location of water hammer occurrence (i.e., water hammer occurring locally or transmitted from a remote location) based on the characteristic moment difference between the pressure change rate and the flow rate change rate. Existing solutions have not fully considered how monitoring sensors cooperate with the PCCP pipeline production process; this solution takes into account the applicability issues in actual engineering applications. Processes such as pre-embedding of sensors and layout of brackets can be seamlessly connected with the existing PCCP manufacturing process, and only a small amount of structural adjustment is required, thereby reducing construction complexity, saving costs, and ensuring the long-term stability of the system. Compared with the complex external sensor installation method in the existing technology, this solution is simpler and more economical.

[0038] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0039] (1) Realize real-time monitoring and dynamic perception of pipeline hydraulic status: By rationally disposing high-frequency pressure pulsation sensors and flowmeters inside the PCCP pipeline, the present invention can obtain high-frequency change data of water pressure and flow velocity inside the pipeline in real time. Compared with traditional water pressure testing or static monitoring methods, it can capture the dynamic fluctuation process of water pressure and flow velocity, comprehensively reflect the changes in hydraulic boundary conditions during pipeline operation, and provide data support for hydraulic analysis and safety assessment.

[0040] (2) Rapid identification, precise location, and risk warning of water hammer: This invention synchronously collects high-frequency pressure pulsation and flow rate data, and proposes a method for identifying water hammer using the water hammer discrimination index (WHI) based on the pressure-flow rate coupling response mechanism. Furthermore, a method for identifying the location of water hammer based on the characteristic moment difference between the pressure change rate and the flow rate change rate is proposed. This technology can provide timely and visual risk feedback to pipeline operation managers, assisting them in carrying out early warning responses and regulatory decisions, and improving the safety and intelligence level of the pipeline network system.

[0041] (3) Good feasibility and engineering adaptability: The high-frequency pressure pulsation sensor and flow meter used in the present invention are easy to install and do not affect the structural integrity and normal function of the PCCP pipeline during the construction process. The pre-embedded sensors and bracket layout can be implemented in combination with the existing PCCP manufacturing process. The construction process is mature and reliable, does not cause much impact on the existing PCCP production line, and is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a production flow chart of a prestressed steel cylinder concrete pipe for hydraulic monitoring proposed by the present invention.

[0043] Figure 2 This is a schematic structural diagram of a steel cylinder, a socket steel ring, and a spigot steel ring according to an embodiment of the present invention.

[0044] Figure 3 This is a cross-sectional view of a socket steel ring after a hole is opened in an embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram of the hole positions of the socket steel ring in accordance with an embodiment of the present invention.

[0046] Figure 5 This is a structural diagram, a cross-sectional diagram, and a structural diagram of a protective bolt of a sensor mounting joint according to an embodiment of the present invention.

[0047] Figure 6 This is a structural diagram of an outgoing line connection component according to an embodiment of the present invention.

[0048] Figure 7 Schematic diagram of the winding process of embodiment 1 of the present invention.

[0049] Figure 8 This is a structural diagram of a high-frequency pressure pulsation sensor according to an embodiment of the present invention and a cross-sectional diagram of the pipeline structure after the high-frequency pressure pulsation sensor is installed.

[0050] Figure 9 This is a schematic diagram of installing a steel hoop bracket according to embodiment 1 of the present invention.

[0051] Figure 10 This is a schematic diagram of installing a flow meter according to embodiment 1 of the present invention.

[0052] Figure 11 This is a cross-sectional view of the pipeline structure where the flow meter is installed according to the first embodiment of the present invention.

[0053] Figure 12 This is the water pressure fluctuation variation pattern during the entire process monitored by Example 1 of the present invention during a water pressure test of a PCCP pipeline.

[0054] Figure 13 Schematic diagram of five sections of PCCP pipelines and monitoring points for hydraulic monitoring in Example 2 of the present invention.

[0055] Figure 14 This is a diagram of water pressure fluctuations during the entire water hammer test of four joints in Example 2 of the present invention.

[0056] Figure 15 This is a flow velocity fluctuation diagram of the entire process of the water hammer test of four joints in Example 2 of the present invention.

[0057] Figure 16 This is a flow chart for calculating the water hammer index WHI of the present invention.

[0058] Figure 17 Water hammer index (WHI) diagram of the entire water hammer test process for four joints in Example 2 of the present invention.

[0059] In the figure: socket steel ring 1; plug steel ring 2; steel cylinder 3; plug steel ring opening 4; first opening position 5; second opening position 6; third opening position 7; sensor mounting joint connection section 8; sensor mounting joint exposed joint section 9; outgoing line connecting member connection section 11; outgoing line connecting member exposed joint section 12; blocking bolt 13; tube core 14; steel wire 15; stress generating device 16; external cable 17; connection section 18; threaded section 19; pressure inlet hole 20; bracket block 21; bolt 22; screw 23; nut 24; steel bracket 25; screw 26; flow meter 27; flow meter cable 28; flexible mortar 29. DETAILED DESCRIPTION

[0060] The present invention will be further described below with reference to the accompanying drawings.

[0061] Example 1:

[0062] like Figures 1 to 11As shown, this embodiment provides a new type of prestressed steel cylinder concrete pipe with a pipe length of 5m for hydraulic monitoring and a manufacturing method thereof. The corresponding pipeline construction process of this embodiment is as follows Figure 1 As shown, the specific steps include:

[0063] Step (1): Make the socket and spigot steel rings for connecting pipe joints. At the same time, make the steel cylinder, roll the steel strip into 1.5mm long strips, and weld the steel plate joints. Then weld the socket steel ring 1 and spigot steel ring 2 to the two ends of the steel cylinder 3 after coil welding, as shown in the following figure. Figure 2 shown.

[0064] Step (2): According to the material and wall thickness of the socket steel plate, select a suitable drilling tool to punch 4 holes in the socket steel plate. The hole diameter is 18mm, which is convenient for the subsequent installation of the high-frequency pressure pulsation sensor and provides a channel for the cable of the flow meter to be connected to the external collector. The specific location of the hole is as follows: Figure 3 As shown. Then, use a cleaning tool to clean the hole, and use a tapping tool of corresponding specifications to tap the hole with a tapping pitch of 1.5mm. The hole opening position is shown in the schematic diagram of the overall cross section of the pipeline. Figure 4 As shown, the first opening position 5 is used to install the outlet connection component, and the second opening position 6 and the third opening position 7 are used to install the sensor installation joint. A total of two high-frequency pressure sensors and one flow meter are installed in the entire pipeline.

[0065] Step (3): Prepare two sensor mounting connectors and one outgoing line connection component. Figure 5 As shown, the sensor mounting joint consists of an embedded connection section 8 and an exposed joint section 9. The embedded connection section 8 is externally threaded with a thread size of M18×1.5, which matches the size of the socket steel plate opening. The exposed joint section 9 is not threaded. The entire sensor mounting joint is internally threaded with a thread size of M11×1.5, which matches the size of the thread section of the high-frequency pressure pulsation sensor. The embedded connection section 8 is buried in the concrete near the socket, and the exposed joint section 9 is exposed outside the socket steel plate. The outgoing line connection component is as shown in FIG. Figure 6 As shown, its structure is similar to that of the sensor mounting connector, but the length of its embedded connection section 12 is greater than the thickness of the inner concrete layer near the socket. The extended portion is used to tighten the plugging bolt 13 to prevent leakage of the plugging fluid during injection. Both the sensor mounting connector and the outgoing cable connection must be equipped with a protective bolt to protect the internal thread during subsequent concrete pouring.

[0066] Step (4): pouring the core concrete. Before the formal pouring, screw the protective bolts into the internal threads of the two sensor installation joints and one outlet connection component respectively to prevent the concrete slurry from entering the internal threaded hole and damaging the thread during the pouring process. In addition, an anchoring device for the prestressed steel wire needs to be buried on the outside of the core concrete. Use the vertical vibration method to pour the core concrete. The steel cylinder welded with the socket steel ring 2 and the plug steel ring 1 is hoisted into the core casting inner mold for accurate positioning. The socket ring should coincide with the bottom mold working surface. Mix the concrete strictly according to the C55 model concrete batching list, and pour the concrete along the inner and outer walls of the steel mold so that the steel cylinder is embedded in the concrete. Start the vibrator while pouring to ensure that the concrete is poured densely. The inner diameter of the concrete core is 3000mm, the inner diameter of the steel cylinder is 3140mm, and the thickness of the core is 220mm. After pouring, the core concrete is steam cured. When the concrete strength reaches 70% of the design strength, proceed to the next step.

[0067] Step (5): Winding the prestressed steel wire. Figure 7 As shown, the cured pipe core is placed on a prestressed wire winding table. Before the wire winding operation, a layer of cement slurry is sprayed on the surface of the pipe core. The wire winding table base rotates, driving the pipe core 14 to rotate at a speed v3. The stress generating device 16 rotates at a speed v2 and advances along the pipe axis at a speed v1. The rotation speed v2 of the stress generating device 16 is controlled to be less than the rotation speed v3 of the rotating table. This allows the 7mm diameter high-strength steel wire 15 (elastic modulus 205000MPa, tensile strength 1570MPa) to generate a prestress of 1100MPa (70% of the steel wire tensile strength) and is wound around the outer surface of the pipe core concrete at a pitch of 14.2mm. The wire winding process also requires full monitoring of stress fluctuations.

[0068] Step (6): Roller-spray the mortar protective layer. Roller-spray the mortar protective layer. Prepare the mortar according to the M45 mortar strength, and control the total thickness of the mortar protective layer after roller spraying to be no less than 30 mm.

[0069] Step (7): Roller spray epoxy coal tar anti-corrosion coating.

[0070] Step (8): After the epoxy coal tar anti-corrosion coating is dried, the completed pipeline is transported to the project site for installation. The shape of the high-frequency pressure pulsation sensor and its cross-sectional view after installation in the pipeline are shown in the figure below. Figure 8As shown in the figure, the high-frequency pressure pulsation sensor used in this embodiment includes a connecting section 18 and a threaded section 19. The connecting section 18 is used to connect to the external cable 17. An electronic sensor element is embedded within the connecting section 18, which senses water pressure changes and converts the water pressure signal into an electrical signal. The length of the threaded section 19 should be the same as the internal threaded section of the sensor mounting connector. A pressure inlet hole 20 is provided at the end of the threaded section, flush with the inner concrete surface. The pressure inlet hole 20 is in contact with the water and senses water pressure changes. When installing the high-frequency pressure pulsation sensor, the protective bolts must be removed from the sensor mounting connector. Solid or liquid tape must be used to seal the threads. If liquid tape is used, the liquid tape should be evenly applied to the threaded section 19 of the high-frequency pressure pulsation sensor. After screwing the threaded section 19 into the internal threaded section of the sensor mounting connector, the tape must be allowed to cure for at least 24 hours to ensure effective sealing before proceeding to the next step.

[0071] Step (9): Install the flow meter, which mainly includes the following steps:

[0072] S1. Install the steel hoop support. First, install the steel hoop support along the circumferential direction on the inner side of the pipe. Figure 9 As shown, the steel hoop bracket is composed of multiple bracket blocks 21, which are connected by bolts 22, and the head and tail brackets are connected by screws 23. The nut 24 is adjustable. By screwing the nut 24, the steel hoop bracket can be stretched outward and close to the pipe wall, ensuring that the bracket is firmly installed inside the pipe.

[0073] S2. Install the flow meter bracket. Figure 10 As shown, a steel bracket 25 for installing a flow meter 27 is welded to the steel hoop bracket at the bottom of the pipeline. Subsequently, the flow meter is fixed to the steel bracket 25 by screws 26 to ensure that the installation position of the flow meter is accurate and stable to avoid loosening during the water flow through the pipeline.

[0074] S3. Fix the velocity meter cable. Insert the plugging bolt 13 into the velocity meter cable in advance, and fix the cable along the pipe wall to the steel hoop bracket. To ensure the stable installation of the cable, use methods such as tying or snapping to tightly wrap the cable around the holes of the steel hoop bracket 21 and evenly distribute it along the bracket. The cable starts from the velocity meter at the bottom of the pipe, gradually passes through the pipe wall, and finally wraps around the pipe top outlet connection component;

[0075] S4. Lead the cable out of the pipe. The current meter cable is led out of the pipe through the inner hole of the outlet connection component and connected to the external data collector.

[0076] Step (10): Seal the outlet connection components and grout the pipeline joints. Figure 11As shown, after the flowmeter cable 28 is extended outside the pipe, the plugging bolt 13 is tightened onto the protruding threaded section of the outlet connection component to ensure sealing performance and prevent leakage of the plugging fluid during the grouting process. Subsequently, a grouting material composed of a 1:1 mixture of cement and epoxy resin is used to seal the inner hole of the outlet connection component, ensuring that the grouting material is fully filled. After the grouting material has completely solidified, the joints of the PCCP pipe joints are filled with flexible mortar 29. Simultaneously, during the pipeline backfill process, the cable is extended to the ground and connected to an external data acquisition device for real-time data collection.

[0077] In the first embodiment of the present invention, the water pressure fluctuation curve of the whole process is monitored during the water pressure test of the PCCP pipeline. Figure 12 As shown, the measurement point 1 records Figure 4 The water pressure data at position 6, measured at point 2, is Figure 4 The water pressure data at position 7 in the figure. As can be seen from the figure, the embodiment of the present invention can completely record the pressure fluctuations during the entire water pressure test process, realizing real-time monitoring and accurate perception of the hydraulic characteristics of the PCCP pipeline.

[0078] Example 2:

[0079] Since water hammer experiments have not yet been conducted under field monitoring conditions, to verify the effectiveness of the proposed real-time water hammer identification and location method, a numerical simulation analysis of water hammer events was proposed. By constructing a water hammer propagation model for a typical PCCP pipeline structure within a simulation environment, the propagation of water hammer waves within the pipeline and the dynamic response of pressure and flow velocity at each measuring point were simulated. Raw monitoring data was generated based on this data to calculate the water hammer identification index (WHI) and determine the location of water hammer.

[0080] In this embodiment, a pipeline simulation model with a total length of 25m, which is composed of 5 sections of equal length PCCP pipes, is established. The structure is shown in the figure below. Figure 13 As shown, the high-frequency pressure pulsation sensor and the flow meter outlet connection component position of each pipeline are the same as those in the first embodiment, see Figure 4 .

[0081] A method for using a prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring, characterized by comprising the following steps:

[0082] (a) Using a high-frequency pressure pulsation sensor and a flow meter installed inside a prestressed concrete cylinder pipe, water pressure and flow rate data at each measuring point inside the pipe are collected synchronously and in real time;

[0083] (b) Determine the initial steady-state baseline pressure and baseline flow rate of the pipeline based on the real-time collected water pressure data and flow rate data. Specifically, the initial moment of data collection is used as the starting point of the steady-state phase of pipeline operation. During this initial phase, the pipeline system has not been disturbed and no water hammer has occurred. The average value of the pressure and flow rate data at each measuring point during this period can be defined as the initial steady-state baseline pressure and baseline flow rate of the pipeline. Subsequently, the rate of change and the amplitude of the change of the pressure and flow rate at each measuring point in the pipeline are calculated.

[0084] (c) Calculate the pressure-velocity coupled water hammer discrimination index (WHI) used to determine whether water hammer occurs in the pipeline in real time. The calculation formula is:

[0085]

[0086] Among them, ΔP(t) is the pressure change rate at any time in the pipeline. This value is calculated by the data collected synchronously by multiple high-frequency pressure pulsation sensors at this position, and then obtained by weighted average. ΔP max is the maximum value of the pressure change rate; ΔV(t) is the flow rate change rate at any moment, ΔV max is the maximum value of the flow velocity change rate; k1 and k2 are weight coefficients, and the value range of k1 and k2 are both 0 to 1, k1 + k2 = 1, and preferably 0.5;

[0087] (d) When WHI(t) reaches or exceeds the set threshold, it is determined that water hammer occurs and the location of the water hammer is further determined. The specific determination method is: the absolute time tP when the pressure change rate reaches 50% of its maximum change and the absolute time t V Compare. If t P Earlier than t V If the time difference between the pressure change rate and the flow rate change rate exceeds a preset time threshold Δt, water hammer is determined to have occurred at a location farther from the current monitoring point. Specifically, if the pressure change rate reaches 50% of its maximum change earlier than the flow rate change rate reaches 50% of its maximum change, and exceeds the set time threshold Δt, water hammer is determined to have occurred at a remote location. Otherwise, water hammer is determined to have occurred at the current monitoring point. The time threshold Δt in step (d) is determined based on the inner diameter of the pipeline, the length of the pipe section, and the propagation speed of the pressure wave, specifically satisfying the following relationship:

[0088]

[0089] Where L is the distance between adjacent sensors; C is the propagation velocity of the pressure wave in the pipeline; D is the inner diameter of the pipeline; α is the dimensionless proportional correction coefficient, which ranges from 0.2 to 0.5 and is set based on pipeline structure and operating conditions. It is used to reflect the hysteresis characteristics of flow velocity changes caused by fluid inertia effects.

[0090] Model establishment and parameter setting:

[0091] A three-dimensional fluid-structure interaction model was established using ANSYS Fluent, combining the volume control method to simulate the pressure fluctuations and flow velocity transient response during water hammer wave propagation. The model used the same single pipe dimensions as in Example 1: a length of 5 m and an inner diameter of 3 m. The fluid was incompressible water, with an initial pressure of 400 kPa and a steady-state flow velocity of 1.5 m / s. The material parameters used in the model are shown in Table 1.

[0092] Table 1

[0093]

[0094]

[0095] Meshing and solution methods:

[0096] Structured meshing is used, tetrahedral mesh is used for the fluid domain, and the joint location and the area around the measuring point are refined. The minimum unit size is 0.05m to ensure the time accuracy and spatial resolution during the propagation of water hammer waves. Transient analysis is used for solution, and the time step is set to 1×10 -5 s, the total simulation time is 0.5 s, and the pressure-velocity coupling algorithm adopts the SIMPLE method.

[0097] Boundary conditions and water hammer event settings:

[0098] The left end of the pipeline was set as a pressure-stabilized inlet with a flow rate of 1.5 m / s and a static pressure of 400 kPa, while the right end was set as a normal-pressure outlet. A water hammer event was simulated by instantaneously closing the valve (connector No. 2) between pipes II and III at 0.1 seconds, generating a typical positive water hammer wave. Two monitoring points were placed at each connection (at a 45-degree angle between the pipe waist and the pipe top) to record the high-frequency pressure response. A velocity sampling point was also set at the pipe bottom to capture the flow velocity evolution.

[0099] Simulation output and data post-processing:

[0100] After the simulation is completed, the pressure and flow rate data of each joint position are extracted, and the sampling frequency is set to 10000Hz. The pressure fluctuation curve and flow rate fluctuation curve of all joints are drawn as follows Figure 14 and Figure 15 As shown. Figure 16The process shown calculates the WHI index for the extracted pressure fluctuation curves and flow velocity fluctuation curves of all joints throughout the entire process and determines whether water hammer occurs and where it occurs.

[0101] The simulation and calculation results show that the pressure peak at joint 2 (valve position) appears first, and the flow rate drops significantly earlier than other joints, which is consistent with the local water hammer characteristics. The pressure peaks at joints 3 and 1 are later, and the flow rate lags significantly, which is consistent with the remote response law. The pressure change at joint 4 is weaker and occurs later, indicating that the energy gradually decays during the propagation of the water hammer wave. Figure 17 As shown in Table 2, the WHI index at all monitoring points was above the discrimination threshold (0.5), effectively reflecting water hammer events. Based on a comparison of the lead times of pressure and velocity changes, the water hammer was accurately located at joint 2 (corresponding to the local occurrence of water hammer). This example validates the applicability and accuracy of the proposed pressure-velocity coupling discrimination algorithm in a typical PCCP structure pipeline, demonstrating its excellent engineering adaptability and monitoring accuracy for large-diameter, long-distance water pipelines.

[0102] Table 2

[0103] Connector number Water Hammer Index (WHI) <![CDATA[t P +△t]]> <![CDATA[t V ]]> Positioning results Connector No. 1 0.605 (water hammer occurs) 0.105521s 0.151130s Water hammer occurs at the far end Connector No. 2 0.819 (water hammer occurs) 0.100520s 0.100420s Water hammer occurs locally Connector No. 3 0.605 (water hammer occurs) 0.105521s 0.151130s Water hammer occurs at the far end Connector No. 4 0.610 (water hammer occurs) 0.110522s 0.156031s Water hammer occurs at the far end

[0104] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A real-time water hammer identification and positioning system for prestressed concrete cylinder pipes for hydraulic monitoring, characterized by: It includes several pressure sensors located on the prestressed steel cylinder concrete pipe. A flow meter is also arranged in the prestressed steel cylinder concrete pipe. Both the flow meter and the pressure sensor are connected to the collection device.

2. The prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring according to claim 1 is characterized by: The prestressed steel cylinder concrete pipe comprises a concrete pipe core, a steel cylinder is provided on the inner wall of the concrete pipe core, a mounting hole is provided on the steel cylinder, a pressure sensor is installed in the mounting hole, and the pressure sensor is sealed in the prestressed steel cylinder concrete pipe by flexible mortar.

3. A method for installing a prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring according to claim 1 or 2, characterized in that: The following steps are involved: S1: Make a socket steel ring, a spigot steel ring and a steel cylinder for connecting pipe joints, and weld the socket steel ring and the spigot steel ring to both ends of the steel cylinder respectively; S2: According to the material and wall thickness of the socket steel plate, select an appropriate drilling tool to drill a hole in the socket steel plate to install the high-frequency pressure pulsation sensor and provide a channel for the cable of the flow meter. Then clean the hole and tap the hole. S3: Make a sensor mounting connector for installing a high-frequency pressure pulsation sensor and a cable connection component for leading out the flow meter cable; S4: Connect the sensor mounting connector and the outgoing line connection member to the corresponding positions of the socket steel ring respectively, and install protective bolts to prevent concrete slurry from entering the hole; S5: pouring core concrete; S6: The cured tube core is placed on a rotating table and wound with prestressed steel wire; S7: roller sprayed mortar protective layer; S8: spraying epoxy coal tar anti-corrosion coating; S9: On-site piping installation; S10: After the pipeline is installed and positioned, remove the protective bolts and install the high-frequency pressure pulsation sensor; S11: Install the flow meter and lead the flow meter cable to the outside of the pipeline; S12: Use cement and epoxy resin mixed grouting material in a 1:1 ratio to seal the holes, and finally grout the pipe joints.

4. The installation method of the prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring according to claim 3 is characterized in that: In step S11, the installation steps of the flow meter include: S111. Install the steel hoop support: First, install the steel hoop support along the inner side of the pipe in a circumferential direction. The steel hoop support is composed of multiple support blocks, which are connected by bolts. The first and last support blocks are connected by long bolts. The nuts of the long bolts are adjustable. By tightening the nuts, the steel hoop support can be expanded outward and tightly attached to the pipe wall, ensuring that the support is firmly installed inside the pipe. S112. Install the flow meter bracket: Weld the steel bracket for installing the flow meter to the steel hoop bracket at the bottom of the pipeline. Then, fix the flow meter to the steel bracket with screws to ensure that the installation position of the flow meter is accurate and stable to avoid loosening during the water flow in the pipeline. S113. Secure the flowmeter cable: Insert the plugging bolts into the flowmeter cable in advance and secure the cable along the pipe wall to the steel hoop bracket. To ensure a secure installation, tightly wrap the cable around the steel hoop bracket using tying or clipping, distributing it evenly along the bracket. The cable starts at the flowmeter at the bottom of the pipe, gradually passes through the pipe wall, and finally wraps around the outlet connection component at the top of the pipe. S114. Lead the cable out of the pipe. The current meter cable is led out of the pipe through the inner hole of the outlet connecting component and connected to the external collector.

5. A method for using the prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring according to claim 1 or 2, characterized in that: The following steps are involved: (a) Using a high-frequency pressure pulsation sensor and a flow meter installed inside a prestressed concrete cylinder pipe, water pressure and flow rate data at each measuring point inside the pipe are collected synchronously and in real time; (b) Determine the initial steady-state baseline pressure and baseline flow rate of the pipeline based on the real-time collected water pressure data and flow rate data. Specifically, the initial moment of data collection is used as the starting point of the steady-state phase of pipeline operation. During this initial phase, the pipeline system has not been disturbed and no water hammer has occurred. The average value of the pressure and flow rate data at each measuring point during this period can be defined as the initial steady-state baseline pressure and baseline flow rate of the pipeline. Subsequently, the rate of change and the amplitude of the change of the pressure and flow rate at each measuring point in the pipeline are calculated. (c) Calculate the pressure-velocity coupled water hammer discrimination index (WHI) used to determine in real time whether water hammer has occurred in the pipeline. The calculation formula is: Among them, ΔP(t) is the pressure change rate at any time in the pipeline. This value is calculated by the data collected synchronously by multiple high-frequency pressure pulsation sensors at this position, and then obtained by weighted average. ΔP max is the maximum value of the pressure change rate; ΔV(t) is the flow rate change rate at any moment, ΔV max is the maximum value of the flow velocity change rate; k1 and k2 are weight coefficients, and the value range of k1 and k2 are both 0 to 1, k1 + k2 = 1, and preferably 0.5; (d) When WHI(t) reaches or exceeds the set threshold, it is determined that water hammer occurs and the location of the water hammer is further determined. The specific determination method is: the absolute time t when the pressure change rate reaches 50% of its maximum change P , and the absolute time t when the flow rate change rate reaches 50% of its maximum change V For comparison, if t P Earlier than t V If the time difference exceeds the preset time threshold Δt, it is determined that water hammer occurs at the remote end; otherwise, it is determined that water hammer occurs locally.

6. The method for using the prestressed steel cylinder concrete pipe water hammer real-time identification and positioning system for hydraulic monitoring according to claim 5 is characterized in that: The time threshold Δt in step (d) is determined based on the inner diameter of the pipeline, the length of the pipe section, and the propagation speed of the pressure wave, and specifically satisfies the following relationship: Where L is the distance between adjacent sensors; C is the propagation velocity of the pressure wave in the pipeline; D is the inner diameter of the pipeline; α is the dimensionless proportional correction coefficient, which ranges from 0.2 to 0.5 and is set based on pipeline structure and operating conditions. It is used to reflect the hysteresis characteristics of flow velocity changes caused by fluid inertia effects.

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