Online verification device and method for acoustic monitoring device of broken wires of PCCP

Abstract

The present invention relates to an on-line verification device and method for a PCCP broken wire acoustic monitoring device. The device includes a simulated broken wire and guided wave device, a distributed acoustic monitoring device, a vibration signal acquisition device, and a signal comparison and inspection system. The simulated broken wire and guided wave device is configured to simulate the process of prestressed steel wire breakage and transmit the mechanical vibration signal generated by the broken wire to the pipe wall and the water in the pipe. The distributed acoustic monitoring device is configured to use a distributed sensing system along the axial direction of the pipeline to detect in real time the mechanical vibration signal generated by the broken wire. The vibration signal acquisition device is configured to detect in real time the mechanical vibration signal generated by the broken wire or the pulsating signal in the water at a typical cross-section of the pipeline. The signal comparison and inspection system is configured to compare and analyze the signals collected by the distributed acoustic monitoring device and the vibration signal acquisition device, evaluate the hardware sensing accuracy, software analysis accuracy, and positioning error of the distributed acoustic monitoring device, and realize the on-line verification of the distributed acoustic monitoring device.

Description

Technical Field

[0001] The present invention relates to an on - line verification device and method for a PCCP broken wire acoustic monitoring device, and relates to the field of PCCP monitoring. Background Art

[0002] Prestressed Concrete Cylinder Pipe (PCCP for short) is a composite pipe made up of several materials such as a steel cylinder, high - strength prestressed steel wires, a concrete pipe core, and a mortar protective layer. It can give full play to the characteristics of concrete's compressive strength, steel wires' tensile strength, and the steel cylinder's impermeability. However, under the action of internal water pressure and earth pressure, cracks may occur on the outer wall of the pipeline. Affected by factors such as groundwater and external electric fields, there is a risk that the prestressed steel wires inside the pipe wall may be corroded and even broken. By applying acoustic - optic fiber monitoring technology to monitor the number of broken prestressed steel bars for timely warning, it is possible to avoid the occurrence of pipe burst accidents.

[0003] In recent years, China has made much progress in the hardware manufacturing of acoustic - optic fiber monitoring systems (including acoustic - optic fibers themselves) and the software development of corresponding data analysis. However, due to the lack of inspection methods for identifying the broken wire monitoring system applicable to PCCP water conveyance projects, it has an adverse impact on the commercial application and promotion of domestic acoustic - optic fiber monitoring systems. This patent aims to provide a device and method for on - site inspection of the sensing accuracy and software analysis ability of the PCCP broken wire monitoring system. Summary of the Invention

[0004] Aiming at the above problems, the object of the present invention is to provide an on - line verification device and method for a PCCP broken wire acoustic monitoring device with improved verification effect.

[0005] In order to achieve the above - mentioned invention object, the technical solution adopted by the present invention is as follows:

[0006] In the first aspect, the present invention provides an on - line verification device for a PCCP broken wire acoustic monitoring device, which device includes a simulated broken wire and guided wave device, a distributed acoustic monitoring device, a vibration signal acquisition device, and a signal comparison and inspection system;

[0007] The simulated broken wire and guided wave device is configured to simulate the process of prestressed steel wire breakage and transmit the mechanical vibration signal generated by the broken wire to the pipe wall and the water in the pipe;

[0008] The distributed acoustic monitoring device is configured to use a distributed sensing system to detect in real - time the mechanical vibration signal generated by the broken wire along the axial direction of the pipeline;

[0009] The vibration signal acquisition device is configured to detect in real - time the mechanical vibration signal generated by the broken wire or the pulsating signal in water at a typical cross - section of the pipeline;

[0010] The signal comparison and inspection system is configured to compare and analyze the signals collected by the distributed acoustic monitoring device and the vibration signal acquisition device, and evaluate the hardware perception accuracy, software analysis accuracy and positioning error of the distributed acoustic monitoring device, so as to realize the online verification of the distributed acoustic monitoring device.

[0011] Further, the simulated wire break and guided wave device includes a self-balancing frame, a steel wire, a jack, a guided wave rod and an electrochemical corrosion system; the electrochemical corrosion system includes a corrosion water tank, a corrosion liquid, a power supply and a conductor used as an electrode;

[0012] The bottom of the self-balancing frame is fixed to the steel pipe section through anchor bolts, and an extension section is arranged at the side end of the self-balancing frame to connect the steel pipe section;

[0013] One end of the steel wire is anchored to one side end of the self-balancing frame, and the other end of the steel wire is anchored to the other side end of the self-balancing frame through the jack;

[0014] The steel wire is immersed in the corrosion water tank, and the corrosion liquid is arranged in the corrosion water tank to form a loop of power supply -> conductor -> corrosion liquid -> steel wire -> power supply. Among them, the occurrence time of the simulated wire break is controlled by controlling the potential of the conductor of the electrochemical corrosion system, the substance concentration and temperature of the corrosion liquid, and the rate of the load applied by the jack. The signal generated by the wire break is transmitted into the steel pipe section through the extension section, the guided wave rod and the anchor bolt.

[0015] Further, the guided wave rod is formed by connecting two symmetrical arc rod sections and a straight rod section. One end of the guided wave rod is in close contact with the exhaust valve main pipe through bolts, and the other end of the guided wave rod is in close contact with the self-balancing frame through bolts. A cushion layer is also arranged between the bottom of the self-balancing frame and the steel pipe section.

[0016] Further, the distributed acoustic monitoring device includes an acoustic-optical fiber signal acquisition system, an optical cable reel, an acoustic-optical fiber and a terminal box;

[0017] The acoustic-optical fiber is arranged in the pipeline and is used to sense the mechanical vibration signal generated by the wire break;

[0018] The optical cable reel is used to adjust the length of the acoustic-optical fiber cable so as to test the positioning accuracy of the wire break monitoring;

[0019] The acoustic-optical fiber signal acquisition system is used to collect the mechanical vibration signals detected by the acoustic-optical fiber, identify the wire break signals and obtain the wire break positioning results in the pipeline.

[0020] The terminal box is used to place the reflector at the end of the acoustic-optical fiber and protect the end of the optical fiber from damage at the same time.

[0021] Furthermore, the vibration signal acquisition device includes a vibration signal acquisition system, a vibration sensor or an underwater acoustic sensor;

[0022] The vibration sensor is fixedly arranged on the outer surface of the metal component of the pipeline exhaust valve, so that the vibration signal received by the vibration sensor is consistent with the characteristics of the prestressed steel wire fracture signal;

[0023] The underwater acoustic sensor is arranged in the water body of the pipeline and is used to receive the pulsating signal in the water;

[0024] The vibration signal acquisition system is used to receive the signals of the vibration sensor or the underwater acoustic sensor.

[0025] In a second aspect, the present invention also provides an online verification method for an online verification device of a PCCP broken wire acoustic monitoring device, including:

[0026] Arrange the acoustic fiber to be verified in the pipeline and arrange a simulated broken wire and guided wave device;

[0027] Generate a simulated broken wire vibration signal on the outer side of the pipeline through the simulated broken wire and guided wave device, and the signal is transmitted to the steel pipe section through the waveguide rod and the anchor bolt and then received by the acoustic fiber signal acquisition system and the vibration signal acquisition system;

[0028] Realize the online verification of the distributed acoustic monitoring device by comparing the monitoring results of the acoustic fiber with the monitoring results of the vibration signal acquisition system.

[0029] Furthermore, realizing the online verification of the distributed acoustic monitoring device by comparing the monitoring results of the acoustic fiber with the monitoring results of the vibration signal acquisition system includes:

[0030] By controlling the water conveyance flow rate to 0, carry out a simulated broken wire test, compare the monitoring results of the acoustic fiber with the monitoring results of the vibration signal acquisition system, and judge the signal perception ability of the acoustic monitoring device;

[0031] By adjusting the length of the optical fiber in the optical cable reel and repeating the simulated broken wire test, check the positioning accuracy of the acoustic monitoring device;

[0032] By controlling the water conveyance flow rate to the normal water conveyance flow rate or superimposing a water hammer condition, carry out a simulated broken wire test, compare the monitoring results of the acoustic fiber with the monitoring results of the vibration signal acquisition system, and judge the software analysis ability of the acoustic monitoring device.

[0033] Furthermore, judging the signal perception ability of the distributed acoustic monitoring device includes:

[0034] The relative error is obtained from the weighted average of the normalized broken wire signal energy ratio A1, the normalized signal peak frequency ratio A2, the normalized signal spectrum centroid corresponding frequency ratio A3, the normalized signal margin index ratio A4, and the normalized signal kurtosis index ratio A5 between the results of the acoustic fiber optic monitoring and the vibration signal acquisition system. If the relative error is smaller, it indicates that the perception accuracies of the broken wire signals obtained by the acoustic monitoring device and the vibration signal acquisition device are closer, and the signal perception ability of the acoustic monitoring device is better. Among them, the relative error calculation formula is:

[0035]

[0036] In the formula, i refers to the serial numbers of the 5 indicators, with values ranging from 1 to 5, p refers to the signal perception ability, and Δ p refers to the relative error of the signal perception accuracy of the acoustic monitoring device, and k refers to the weights of the 5 indicators in calculating the weighted average.

[0037] Furthermore, by adjusting the fiber length in the cable drum, the simulated broken wire test is repeated to check the positioning accuracy of the acoustic monitoring device, including: when the fiber length of the first cable drum is L1, the fiber length of the second cable drum is L2, the fiber length laid in the pipeline is L3, and the cable laying distance between two exhaust valves is L0, then the evaluation of the positioning relative error for the acoustic fiber optic to obtain the broken wire signal is calculated according to the following formula:

[0038]

[0039] In the formula, X represents the broken wire positioning result given by the acoustic fiber optic;

[0040] The relative error is calculated through the above formula. If the value of the relative error is smaller, it indicates that the positioning accuracy of the acoustic monitoring device is higher.

[0041] Furthermore, to judge the software analysis ability of the distributed acoustic monitoring device, through conducting multiple tests under different working conditions of the pipeline, calculate the relative error and repeatability index of the acoustic monitoring device's ability to perceive and locate the fracture of the prestressed steel wire. If the relative error of the system is larger and the repeatability index is smaller under a certain working condition, it indicates that the system is more affected by this working condition and has a lower ability to perceive or locate the fracture of the prestressed steel wire. Among them, the calculation formulas for the relative error, repeatability index, and positioning error are:

[0042] For the software system under normal working conditions:

[0043] Relative error of perception ability |Δ pv -Δ p0 |;

[0044] Repeatability index of perception ability:

[0045] Relative error of positioning accuracy |Δ lv -Δ l0 |;

[0046] Repeatability index of positioning accuracy:

[0047] Under normal operating conditions and superimposed water hammer conditions of the software system:

[0048] Relative error of sensing ability |Δ ph -Δ p0 |;

[0049] Repeatability index of sensing ability:

[0050] Relative error of positioning accuracy |Δ lh -Δ l0 |;

[0051] Repeatability index of positioning accuracy:

[0052] In the formula, Δ p0 , σ p0 are respectively the average value and standard deviation of the relative error of signal sensing when the water flow velocity in the pipe is 0; Δ pv , σ pv are respectively the average value and standard deviation of the relative error of signal sensing under normal water conveyance conditions; Δ ph , σ ph are respectively the average value and standard deviation of the relative error of signal sensing under normal water conveyance conditions superimposed with water hammer conditions; Δ l0 , σ l0 are respectively the average value and standard deviation of the relative error of signal positioning when the water flow velocity in the pipe is 0; Δ lv , σ lv are respectively the average value and standard deviation of the relative error of signal positioning under normal water conveyance conditions; Δ lh , σ lh are respectively the average value and standard deviation of the relative error of signal positioning under normal water conveyance conditions superimposed with water hammer conditions.

[0053] Due to the adoption of the above technical solutions, the present invention has the following characteristics:

[0054] 1. The present invention simulates the wire breakage of the actual operating PCCP by means of artificial accelerated corrosion wire breakage, eliminating the environmental noise introduced by artificial mechanical wire breakage, so that the monitoring system can obtain a wire breakage signal closer to the real situation, which is very effective for quickly obtaining the wire breakage signal and comparing and analyzing the characteristics of the wire breakage signal.

[0055] 2. The simulated broken wire and guided wave device of the present invention is installed on the outer side of the pipeline. The broken wire vibration signal is transmitted to the pipeline structure through the guided wave rod and the anchor bolt. This device does not damage the pipeline structure and does not affect the water conveyance operation of the pipeline. At the same time, the broken wire vibration signal can be completely transmitted to each position of the pipeline and received by the acoustic fiber optic, vibration sensor or underwater acoustic sensor.

[0056] 3. By changing the lengths of the upstream and downstream optical cable outgoing lines, the present invention can achieve the purpose of conducting multiple groups of verification tests at different positions of the acoustic fiber optic, thereby improving the verification effect.

[0057] 4. The present invention provides a method for evaluating the software analysis ability of the distributed acoustic monitoring device. By conducting multiple tests under different working conditions of the pipeline, the relative error and repeatability index of the acoustic monitoring device's ability to sense and locate the fracture of the prestressed steel wire are calculated to evaluate the effect of the software analysis ability of the acoustic monitoring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0059] Figure 1 is the layout diagram of the simulated broken wire and guided wave device along the longitudinal section of the pipeline in the embodiment of the present invention.

[0060] Figure 2 is the composition structure diagram of the simulated broken wire and guided wave device in the embodiment of the present invention.

[0061] Figure 3 is the composition structure diagram of the guided wave rod in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" as used herein may also include the plural forms. The terms "comprising", "including", "containing", and "having" are inclusive and thus specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the particular order described or illustrated, unless the order of performance is clearly indicated. It should also be understood that alternative steps may be used.

[0063] Although terms such as first, second, and third may be used herein to describe multiple elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another. Unless the context clearly indicates otherwise, terms such as "first", "second", and other numerical terms do not imply an order or sequence when used herein. Thus, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0064] For ease of description, spatial relative relationship terms may be used herein to describe the relationship of one element or feature shown in the figure to another element or feature, such as "inner", "outer", "inner side", "outer side", "below", "above", etc. Such spatial relative relationship terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure.

[0065] The present invention aims to provide a device and method for on-site inspection of the sensing accuracy and software analysis ability of a PCCP broken wire acoustic monitoring device. The difficulties lie in three aspects: the first aspect is how to simulate the broken wire signal; the second aspect is how to transmit the simulated broken wire signal to the acoustic fiber; the third aspect is how to extract the simulated broken wire signal from complex water flow noise.

[0066] The on-line verification device and method for the PCCP broken wire acoustic monitoring device provided by the present invention, the method includes: arranging the acoustic fiber to be verified in the pipeline and arranging the simulated broken wire and guided wave device; generating a simulated broken wire vibration signal outside the pipeline through the simulated broken wire and guided wave device, and the signal is transmitted to the steel pipe section through the waveguide rod and the anchor bolt and then received by the acoustic fiber signal acquisition system and the vibration signal acquisition system; the on-line verification of the distributed acoustic monitoring device is realized by comparing the monitoring results of the acoustic fiber monitoring and the monitoring results of the vibration signal acquisition system. Therefore, the present invention generates a real broken wire signal by the way of artificial accelerated corrosion broken wire and transmits it to the PCCP pipe wall and the water body in the pipe, and verifies and identifies the performance of the distributed acoustic monitoring device by comparing the monitoring results of the distributed acoustic monitoring device and the vibration signal acquisition system, so as to lay a foundation for the standardized production, inspection and application of domestic acoustic fiber monitoring systems.

[0067] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be fully conveyed to those skilled in the art.

[0068] As Figure 1 shown, the on-line verification device of the PCCP broken wire acoustic monitoring device provided in this embodiment includes: a simulated broken wire and guided wave device 1, a distributed acoustic monitoring device 2, a vibration signal acquisition device 3, and a signal comparison and inspection system.

[0069] The simulated broken wire and guided wave device 1 is configured to simulate the process of the prestressed steel wire breaking and transmit the mechanical vibration signal generated by the broken wire to the pipe wall and the water in the pipe.

[0070] The distributed acoustic monitoring device 2 is configured to apply a distributed sensing system along the axial direction of the pipeline to detect in real time the mechanical vibration signal generated by the broken wire.

[0071] The vibration signal acquisition device 3 is configured to apply sensors on typical cross-sections of the pipeline to detect in real time the mechanical vibration signal generated by the broken wire or the pulsating signal in the water. Among them, the typical cross-section of the pipeline in this embodiment is the cross-section near the exhaust valve where the simulated broken wire and guided wave device 1 is provided.

[0072] The signal comparison and inspection system is configured to compare and analyze the signals collected by the distributed acoustic monitoring device 2 and the vibration signal acquisition device 3 to realize the on-line verification of the distributed acoustic monitoring device 2.

[0073] A preferred embodiment of this embodiment, as Figure 2 shown, the simulated broken wire and guided wave device 1 includes a self-balancing frame 11, a steel wire 12, a jack 13, a guided wave rod 14, and an electrochemical corrosion system 15. Among them, the electrochemical corrosion system 15 includes a corrosion water tank 151, a corrosion liquid 152, a power supply 153, and a conductor 154 used as an electrode.

[0074] The self-balancing frame 11 adopts a rectangular frame. The bottom of the rectangular frame is fixed to the steel pipe section through anchor bolts, and an extension section is provided at the side end of the rectangular frame to connect the steel pipe section. One end of the steel wire 12 is anchored to one side end of the self-balancing frame 11, and the other end of the steel wire 12 is anchored to the other side end of the self-balancing frame 11 through a jack 13. The corrosion water tank 151 is fixed to the self-balancing frame 11, and the steel wire 12 is immersed in the corrosion water tank 151. A corrosion liquid 152 is provided in the corrosion water tank 151 to form a loop of power supply 153 -> electrode (conductor) 154 -> corrosion liquid 152 -> steel wire 12 -> power supply 153. The jack 13 is used to gradually apply a tensile force to the steel wire 12 until the steel wire 12 breaks. During use, the occurrence time of the simulated wire break is controlled by controlling the potential of the electrode 154 (conductor), the material concentration of the corrosion liquid 152, the rate of the load applied by the jack 13, and the temperature of the corrosion liquid 152. The mechanical vibration signal generated by the wire break is transmitted into the steel pipe section (exhaust valve metal component) through the extension section, the waveguide rod 14, and the anchor bolt, and then transmitted into the distributed acoustic monitoring device 2. Further, a cushion layer 16 is also provided between the bottom of the self-balancing frame 11 and the steel pipe section. The main functions of the cushion layer 16 are as follows: First, by reducing friction of the cushion layer 16, it is possible to avoid, as much as possible, the vibration signal generated by the fracture of the prestressed steel wire from being transmitted from the self-balancing frame to the concrete structure on the outer layer of the pipeline. The vibration signal generated by the wire break is transmitted to the metal structure of the pipeline through the waveguide rod 14, which can ensure that the characteristics of the vibration signal received inside the pipeline do not change; Second, it is possible to avoid the vibration signal generated by the vibration or cracking of the concrete on the outer layer of the pipeline from being transmitted to the self-balancing frame 11, affecting the verification effect of the wire break monitoring system. Then, the cushion layer 16 can also play a leveling role, and the self-balancing frame 11 can be horizontally placed on the cushion layer.

[0075] As Figure 3 shown, the waveguide rod 14 is formed by connecting two symmetric arc rod segments 141 (corresponding central angle 90° ≤ θ ≤ 180°) and a straight rod segment 142. One end of the waveguide rod 14 is made to be in close contact with the main exhaust valve pipe through a bolt, and the other end of the waveguide rod 14 is in close contact with the self-balancing frame 11 through a bolt.

[0076] In a preferred implementation manner of this embodiment, the distributed acoustic monitoring device 2 includes an acoustic-optical fiber monitoring system 21, an optical cable reel 22-1, an optical cable reel 22-2, an acoustic-optical fiber 23, and a terminal box 24.

[0077] The acoustic-optical fiber 23 is arranged inside the pipeline and is used to sense the mechanical vibration signal generated by the wire break;

[0078] The two optical cable reels are used to adjust the length of the optical cable of the acoustic-optical fiber 23 so as to test the positioning accuracy of the wire break monitoring.

[0079] The acoustic fiber optic monitoring system 21 is used to analyze and process the mechanical vibration signals detected by the acoustic fiber optic 23, identify the broken wire signals, and obtain the broken wire positioning results inside the pipeline.

[0080] The terminal box 24 is used to place the mirror at the end of the acoustic fiber optic, and at the same time protect the end of the optical fiber from being damaged.

[0081] In a preferred embodiment of this embodiment, the vibration signal acquisition device 3 can adopt a vibration sensor 31 or an underwater acoustic sensor 32 and a vibration signal acquisition system 33.

[0082] Among them, the vibration sensor 31 is arranged on the outer surface of the metal component of the pipeline exhaust valve, so that the vibration signals received by the vibration sensor 31 are consistent with the characteristics of the prestressed steel wire fracture signals. At the same time, the vibration sensor 31 needs to be fastened to the surface of the exhaust valve to ensure that the complete broken wire vibration signals can be received.

[0083] The underwater acoustic sensor 32 is arranged in the water body inside the pipeline and does not need to be fixed to the inner wall of the pipeline. The vibration signals generated by the fracture of the prestressed steel wire are transmitted to the pipeline through the waveguide rod 14, and then transmitted to the water body inside the pipeline. The underwater acoustic sensor 32 directly receives the pulsating signals in the water.

[0084] The vibration signal acquisition system 33 is used to receive the signals of the vibration sensor 31 or the underwater acoustic sensor 32.

[0085] In a preferred embodiment of this embodiment, the signal comparison and inspection system is used to judge the analysis ability of the acoustic monitoring device for the perception and positioning of the prestressed steel wire fracture. By changing the outlet lengths of the optical cable upstream and downstream, multiple tests are carried out under different working conditions of the pipeline, and the broken wire signals collected by the acoustic fiber optic 23, the vibration sensor 31 or the underwater acoustic sensor 32 are compared and analyzed. The relative error and repeatability index of the perception and positioning ability of the acoustic monitoring device for the prestressed steel wire fracture are calculated, etc., to evaluate the effect of the software analysis ability of the acoustic monitoring device.

[0086] Example 2: As Figure 1 shown, the on-line verification method of the PCCP broken wire acoustic monitoring device provided in this embodiment includes:

[0087] S1. Before the inspection, arrange the acoustic fiber optic 23 to be verified inside the pipeline, and use two exhaust valves B and C along the pipeline and other wellheads to lead out the wire and reserve a certain length for adjustment. The reserved optical cable reels 22 at the two wire outlet ports are used to adjust the optical cable length; there should be at least an exhaust valve well or a maintenance well containing the exhaust valve A between the two wire outlet ports, which is used to arrange the simulated broken wire and waveguide device 1.

[0088] S2. During inspection, simulate wire breakage through the wire breakage and guided wave device 1. Transmit the mechanical vibration signal generated by the wire breakage into the steel pipe section (exhaust valve metal component) through the waveguide rod 14 and the anchor bolt, and then it is received by the acoustic fiber optic 23, the vibration sensor 31, and the underwater acoustic sensor 32.

[0089] As Figure 1 shown, during inspection, arrange vibration sensors (frequency response range 0 - 20 kHz) that have passed standardized inspection on the steel pipe section (exhaust valve metal component) and the self - balancing frame 11, or arrange underwater acoustic sensors (0 - 20 kHz) inside the pipeline to collect the signals transmitted to the steel pipe. Online verification of the performance of the acoustic monitoring device is achieved by comparing the monitoring results of the acoustic fiber optic with those of the vibration sensor or the underwater acoustic sensor, and the applicability of the acoustic monitoring device in the PCCP water conveyance project is judged. The specific process includes:

[0090] S21. During inspection, by controlling the water conveyance flow rate to 0, conduct a simulated wire breakage test, and compare the monitoring results of the acoustic fiber optic with those of the vibration sensor or the underwater acoustic sensor to judge the signal perception ability of the acoustic fiber optic monitoring system.

[0091] Specifically, for the wire breakage signals collected by the acoustic fiber optic monitoring system and the vibration sensor or the underwater acoustic sensor (with the same duration, assume the signal duration obtained by the acoustic fiber optic is t1, and the duration obtained by the vibration sensor / underwater acoustic sensor is t2, then 0.9 < t1 / t2 < 1.1), after filtering to obtain the signals in the range of (0 - 20 kHz), respectively, count the following indicators as shown in Table 1.

[0092] Table 1

[0093]

[0094] The weighted average of A1 - A5 is used to judge the signal perception accuracy, and its relative error is calculated according to the following formula:

[0095]

[0096] In the formula, i refers to the serial number of the 5 indicators in Table 1, and the value range is 1 - 5. p refers to the signal perception ability, and Δ p is the relative error of the signal perception accuracy of the acoustic monitoring device, which is compared with the positioning relative error Δ l of the signal in step S22, and the parameter k refers to the weight of each of the 5 indicators in calculating the weighted average.

[0097] In the table:

[0098]

[0099] Wherein, T refers to the signal duration, x(t) refers to the data of the normalized broken wire signal, RMS refers to the energy of the normalized broken wire signal, also known as the root mean square value of the signal, L refers to the normalized signal margin index, K refers to the normalized signal kurtosis index, and x avg refers to the mean value of the normalized signal.

[0100] Substitute the broken wire signal data collected by the acoustic monitoring device and the vibration sensor / underwater acoustic sensor into the above formula for calculation to obtain the relative error. If the relative error is smaller, it indicates that the perception accuracy of the acoustic monitoring device and the vibration sensor / underwater acoustic sensor for receiving the broken wire signal is close, and the perception ability of the acoustic monitoring device is better.

[0101] S22. By adjusting the optical fiber length in the optical cable reels at both outlet ends, repeat the simulated broken wire test to check the positioning accuracy of the acoustic monitoring device. The total length of the acoustic optical fiber monitoring should not be shorter than 10 km.

[0102] Specifically, assume that the optical fiber length of the first optical cable reel 22-1 is L1, the optical fiber length of the second optical cable reel 22-2 is L2, the optical fiber length laid in the pipeline is L3, and the optical cable laying distance between the exhaust valve well A and the exhaust valve well B is L0. Then, the evaluation of the positioning relative error of the broken wire signal obtained by the acoustic optical fiber is calculated according to the following formula:

[0103]

[0104] Wherein, X represents the broken wire positioning result given by the acoustic optical fiber.

[0105] Calculate the relative error through the above formula. If the value of the relative error is smaller, it indicates that the positioning accuracy of the acoustic optical fiber monitoring system is higher.

[0106] S23. By controlling the water conveyance flow rate to the normal water conveyance flow rate or superimposing the water hammer condition, carry out the simulated broken wire test, compare the monitoring results of the acoustic optical fiber with the monitoring results of the vibration sensor or the underwater acoustic sensor, to judge the software analysis ability of the acoustic monitoring device, and judge the analysis ability of the system for the prestressed steel wire fracture signal by calculating the relative error and repeatability index of the system under different conditions. Specifically:

[0107] 1) Under the condition that the water flow velocity in the pipeline is 0 (when the optical fiber is bonded to the inner wall of the pipe, the pipe can be empty), carry out n times of simulated broken wire tests. During the test, the lengths of L1 and L2 can be changed, and the signal results are shown in Table 2.

[0108] Table 2

[0109] Test 1 Test 2 ... Test n Average value Standard deviation Relative error of signal perception <![CDATA[Δ p01 > <![CDATA[Δ p02 > ... <![CDATA[Δ p0n > <![CDATA[Δ p0 > <![CDATA[σ p0 > Relative positioning error <![CDATA[Δ l01 > <![CDATA[Δ l02 > ... <![CDATA[Δ l0n > <![CDATA[Δ l0 > <![CDATA[σ l0 >

[0110] 2) Under the condition that the water flow velocity in the pipe is v (normal water conveyance condition), conduct n simulated wire breakage tests. In the tests, the lengths of L1 and L2 can be changed, and the signal results are shown in Table 3.

[0111] Table 3

[0112] Test 1 Test 2 ... Test n Average value Standard deviation Relative error of signal perception <![CDATA[Δ pv1 > <![CDATA[Δ pv2 > ... <![CDATA[Δ pvn > <![CDATA[Δ pv > <![CDATA[σ pv > Relative positioning error <![CDATA[Δ lv1 > <![CDATA[Δ lv2 > ... <![CDATA[Δ lvn > <![CDATA[Δ lv > <![CDATA[σ lv >

[0113] 3) Superimpose the water hammer condition under the condition that the water flow velocity in the pipe is v (normal water conveyance condition). In the tests, the lengths of L1 and L2 can be changed, conduct n simulated wire breakage tests, and the signal results are shown in Table 4.

[0114] Table 4

[0115] Test 1 Test 2 ... Test n Average value Standard deviation Relative error of signal perception <![CDATA[Δ ph1 > <![CDATA[Δ ph2 > ... <![CDATA[Δ phn > <![CDATA[Δ ph > <![CDATA[σ ph > Relative positioning error <![CDATA[Δ lh1 > <![CDATA[Δ lh2 > ... <![CDATA[Δ lhn > <![CDATA[Δ lh > <![CDATA[σ lh >

[0116] 4) The relative perception error Δ p0 , repeatability index 1 - σ p0 / Δ p0 , positioning error Δ l0 , repeatability index 1 - σ l0 / Δ l0 .

[0117] The software system is analyzed under normal conditions:

[0118] Relative perception error of perception ability |Δ pv - Δ p0 |;

[0119] Repeatability index of perception ability:

[0120] Relative positioning accuracy error |Δ lv - Δ l0 |;

[0121] Repeatability index of positioning accuracy:

[0122] The software system is analyzed under the normal condition superimposed with the water hammer condition:

[0123] Relative perception error of perception ability |Δ ph - Δ p0 |;

[0124] Repeatability index of perception ability:

[0125] Relative positioning accuracy error |Δ lh - Δ l0 |;

[0126] Repeatability index of positioning accuracy:

[0127] In the above formula, Δ p0 and σ p0 are respectively the average value and the standard deviation of the relative error of signal perception under the condition that the water flow velocity in the pipe is 0 (when the optical fiber is bonded to the inner wall of the pipe, the pipe can be empty); Δ pv and σ pv are respectively the average value and the standard deviation of the relative error of signal perception under normal water conveyance conditions; Δ ph and σ ph are respectively the average value and the standard deviation of the relative error of signal perception under the condition of normal water conveyance conditions superimposed with water hammer conditions; Δ l0 and σ l0 are respectively the average value and the standard deviation of the relative error of signal positioning under the condition that the water flow velocity in the pipe is 0 (when the optical fiber is bonded to the inner wall of the pipe, the pipe can be empty); Δ lv and σ lv are respectively the average value and the standard deviation of the relative error of signal positioning under normal water conveyance conditions; Δ lh and σ lh are respectively the average value and the standard deviation of the relative error of signal positioning under the condition of normal water conveyance conditions superimposed with water hammer conditions.

[0128] By calculating the relative error and repeatability index of the perception and recognition of the fracture of the prestressed steel wire by the acoustic monitoring device under different water flow conditions, if the relative error of the system is larger and the repeatability index is smaller under a certain condition, it indicates that the system is greatly affected by this condition and the ability to perceive or locate the fracture of the prestressed steel wire is lower. The positioning error is to judge the error size of the position where the fracture of the prestressed steel wire of the PCCP occurs under the influence of normal conditions or normal conditions superimposed with water hammer conditions.

[0129] Each embodiment in this specification is described in a progressive manner. For the same or similar parts between each embodiment, reference can be made to each other. The key point of each embodiment is to illustrate the differences from other embodiments. In the description of this specification, the description referring to terms such as "one embodiment" and "some implementations" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An on-line verification device for a PCCP broken wire acoustic monitoring device, characterized in that The device includes a simulated wire breakage and guided wave device, a distributed acoustic monitoring device, a vibration signal acquisition device, and a signal comparison and verification system; The simulated wire breakage and guided wave device is configured to simulate the process of prestressed steel wire breakage and transmit the mechanical vibration signal generated by the wire breakage to the pipe wall and the water in the pipe; The distributed acoustic monitoring device is configured to use a distributed sensing system to detect the mechanical vibration signal generated by the wire breakage in real time along the axial direction of the pipeline; The vibration signal acquisition device is configured to detect the mechanical vibration signal generated by the wire breakage or the pulsating signal in the water in real time at a typical cross-section of the pipeline. Among them: the vibration signal acquisition device includes a vibration signal acquisition system, a vibration sensor or an underwater acoustic sensor; the vibration sensor is fixedly arranged on the outer surface of the metal component of the pipeline exhaust valve, so that the vibration signal received by the vibration sensor is consistent with the characteristics of the prestressed steel wire breakage signal; the underwater acoustic sensor is arranged in the water in the pipeline for receiving the pulsating signal in the water; the vibration signal acquisition system is used to receive the signals of the vibration sensor or the underwater acoustic sensor; The signal comparison and verification system is configured to compare and analyze the signals collected by the distributed acoustic monitoring device and the vibration signal acquisition device, and evaluate the hardware sensing accuracy, software analysis accuracy and positioning error of the distributed acoustic monitoring device, so as to realize the online verification of the distributed acoustic monitoring device.

2. The on-line verification device for a PCCP broken wire acoustic monitoring device according to claim 1, characterized in that The simulated wire breakage and guided wave device includes a self-balancing frame, a steel wire, a jack, a guided wave rod and an electrochemical corrosion system; the electrochemical corrosion system includes a corrosion water tank, a corrosion liquid, a power supply and a conductor used as an electrode; The bottom of the self-balancing frame is fixed to the steel pipe section through anchor bolts, and an extension section is arranged at the side end of the self-balancing frame to connect the steel pipe section; One end of the steel wire is anchored to one side end of the self-balancing frame, and the other end of the steel wire is anchored to the other side end of the self-balancing frame through the jack; The steel wire is immersed in the corrosion water tank, and the corrosion liquid is arranged in the corrosion water tank to form a loop of power supply -> conductor -> corrosion liquid -> steel wire -> power supply. Among them, by controlling the potential of the conductor of the electrochemical corrosion system, the substance concentration and temperature of the corrosion liquid, and the rate of the load applied by the jack, the occurrence time of the simulated wire breakage is controlled, and the signal generated by the wire breakage is transmitted into the steel pipe section through the extension section, the guided wave rod and the anchor bolt.

3. The on-line verification device for a PCCP broken wire acoustic monitoring device according to claim 2, characterized in that The guided wave rod is composed of two symmetric arc rod segments and a straight rod segment connected. One end of the guided wave rod is in close contact with the main pipe of the exhaust valve through bolts, and the other end of the guided wave rod is in close contact with the self-balancing frame through bolts. A cushion layer is also arranged between the bottom of the self-balancing frame and the steel pipe section.

4. The on-line verification device for a PCCP broken wire acoustic monitoring device according to claim 1, characterized in that The distributed acoustic monitoring device includes an acoustic-optic fiber signal acquisition system, an optical cable reel, an acoustic-optic fiber and a terminal box; The acoustic-optic fiber is arranged in the pipeline for sensing the mechanical vibration signal generated by the wire breakage; The optical cable reel is used to adjust the length of the acoustic-optic fiber optical cable so as to test the positioning accuracy of the wire breakage monitoring; The acoustic fiber optic signal acquisition system is used to collect the mechanical vibration signals detected by the acoustic fiber optic, identify the broken wire signals and obtain the positioning results of the broken wires in the pipeline. The terminal box is used to place the mirror at the end of the acoustic fiber optic and protect the end of the optical fiber from being damaged at the same time.

5. An on-line verification method for an on-line verification device for a PCCP broken wire acoustic monitoring device according to any one of claims 2 to 4, characterized in that It includes: Arrange the acoustic fiber optic to be verified in the pipeline and arrange the simulated broken wire and guided wave device. Generate simulated broken wire vibration signals outside the pipeline through the simulated broken wire and guided wave device, and the signals are transmitted to the steel pipe section through the waveguide rod and the anchor bolt and then received by the acoustic fiber optic signal acquisition system and the vibration signal acquisition system. Realize the on-line verification of the distributed acoustic monitoring device by comparing the monitoring results of the acoustic fiber optic with those of the vibration signal acquisition system.

6. The on-line verification method according to claim 5, characterized in that Realize the on-line verification of the distributed acoustic monitoring device by comparing the monitoring results of the acoustic fiber optic with those of the vibration signal acquisition system, including: By controlling the water delivery flow rate to 0, conduct the simulated broken wire test, compare the monitoring results of the acoustic fiber optic with those of the vibration signal acquisition system, and judge the signal perception ability of the acoustic monitoring device. By adjusting the length of the optical fiber in the optical cable reel and repeating the simulated broken wire test, verify the positioning accuracy of the acoustic monitoring device. By controlling the water delivery flow rate to the normal water delivery flow rate or superimposing the water hammer condition, conduct the simulated broken wire test, compare the monitoring results of the acoustic fiber optic with those of the vibration signal acquisition system, and judge the software analysis ability of the acoustic monitoring device.

7. The on-line verification method according to claim 6, characterized in that Judging the signal perception ability of the acoustic monitoring device includes: Obtain the relative error according to the weighted average of the normalized broken wire signal energy ratio A1, the normalized signal peak frequency ratio A2, the normalized signal spectrum centroid corresponding frequency ratio A3, the normalized signal margin index ratio A4 and the normalized signal kurtosis index ratio A5 between the monitoring results of the acoustic fiber optic and the vibration signal acquisition system. If the relative error is smaller, it indicates that the perception accuracy of the broken wire signals obtained by the acoustic monitoring device and the vibration signal acquisition device is closer, and then it is judged that the signal perception ability of the acoustic monitoring device is better. Among them, the relative error calculation formula is: ， In the formula, i refers to the numbers of 5 indicators, with values ranging from 1 to 5, p refers to the signal perception ability, refers to the relative error of the signal perception accuracy of the acoustic monitoring device, k refers to the respective weights of the 5 indicators in calculating the weighted average.

8. The on-line verification method according to claim 6, characterized in that By adjusting the length of the optical fiber in the optical cable reel and repeating the simulated broken wire test, verify the positioning accuracy of the acoustic monitoring device, including: when the optical fiber length of the first optical cable reel is L1, the optical fiber length of the second optical cable reel is L2, the optical fiber length arranged in the pipeline is L3, and the optical cable laying distance between two exhaust valves is L0, then the evaluation of the positioning relative error of the broken wire signal obtained by the acoustic fiber optic is calculated according to the following formula: In the formula, X represents the broken wire positioning result given by the acoustic optical fiber; Calculate the relative error through the above formula. If the value of the relative error is smaller, it indicates that the positioning accuracy of the acoustic monitoring device is higher.

9. The on-line verification method of the PCCP broken wire acoustic monitoring device according to claim 6, characterized in that, Judging the software analysis ability of the acoustic monitoring device. By conducting multiple tests under different conditions of the pipeline, calculate the relative error and repeatability index of the acoustic monitoring device's perception and positioning ability for the prestressed steel wire fracture. If the relative error of the system is larger and the repeatability index is smaller under a certain condition, it indicates that the system is more affected by this condition and the ability to perceive or position the prestressed steel wire fracture is lower. Among them: the calculation formulas of the relative error, the repeatability index and the positioning error are: The software system is under normal conditions: Relative error of perception ability ; Perception ability repeatability index: ; Relative error of positioning accuracy ; Positioning accuracy repeatability index: The software system is under the condition of normal conditions superimposed with water hammer conditions: Relative error of perception ability ; Perception ability repeatability index: ; Relative error of positioning accuracy ; Positioning accuracy repeatability index: ; Wherein, and are respectively the average value and the standard deviation of the relative error of signal perception under the condition that the water flow velocity in the pipe is 0; and are respectively the average value and the standard deviation of the relative error of signal perception under normal water conveyance conditions; and are respectively the average value and the standard deviation of the relative error of signal perception under the condition of normal water conveyance conditions superimposed with water hammer conditions; and are respectively the average value and the standard deviation of the relative error of signal positioning under the condition that the water flow velocity in the pipe is 0; and are respectively the average value and the standard deviation of the relative error of signal positioning under normal water conveyance conditions; and are respectively the average value and the standard deviation of the relative error of signal positioning under the condition of normal water conveyance conditions superimposed with water hammer conditions.

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