Mounting method of steel wire absolute stress monitoring sensor in PCCP (prestressed concrete cylinder pipe) wire winding process

Abstract

The invention discloses a method for installing a steel wire absolute stress monitoring sensor in a PCCP (prestressed concrete cylinder pipe) wire winding process, which comprises the following steps of: firstly, pre-installing a special protective sleeve at a sensor connecting line, and welding a flange plate structure on a dry powder cylinder; a sensor is sleeved with a prestressed steel beam in advance, a wire winding process is started, and when a steel wire is wound around a sensor pre-embedded hole, the sensor is sent out by rotating a flange plate structure; the sensor moves along with the steel wire and is just embedded into the preformed hole along with winding of the steel wire, and installation of the sensor is completed. And repeating the steps to complete the installation work of the rest sensors. According to the method for installing the steel wire absolute stress monitoring sensor in the PCCP wire winding process, the defects in an existing installation technology are overcome, the influence on the quality of an original PCCP is small, inconvenience caused by a sensor connecting line to PCCP production and construction is avoided, and the electromagnetic elastic absolute stress sensor is conveniently, orderly and efficiently installed in the PCCP wire winding process.

Description

Technical Field

[0001] The present invention belongs to the technical field of prestressed concrete cylinder pipe production, and in particular relates to a method for installing a steel wire absolute stress monitoring sensor in a PCCP pipe wire winding process. Background Art

[0002] Prestressed Concrete Cylinder Pipe (PCCP) is a pipe made by spirally wrapping prestressed high-strength steel wire around a concrete core with a steel cylinder, then covering it with a protective mortar layer. PCCP boasts advantages such as long life, good earthquake resistance, and leak resistance, making it widely used in water supply and drainage projects. The strength of PCCP pipes depends on the high-strength steel wire, which creates uniform prestressing force throughout the pipe core, compensating for the tensile stresses generated by internal pressure and external loads. However, during production, construction, and operation, various factors can cause damage or corrosion to the steel wire, leading to wire breakage and a decrease in pipe strength. As the number of locally broken wires increases, the PCCP pipe wall yields, ultimately causing leaks and bursts.

[0003] At present, water conservancy projects at home and abroad generally use regular or real-time assessments of the health status of PCCP pipes, including percussion echo detection method (Luo Jianjun, Yao Xuande, Zhang Dongsheng, et al. Field test study on the spectrum response of broken wires in large-diameter PCCP pipelines [J]. China Civil Engineering Journal, 2016, 49(9): 110-116), far-field eddy current electromagnetic detection method (patent publication number CN210088480U), fiber optic sensor monitoring method (patent publication number CN222718007U), hydrophone monitoring method (patent publication number CN104504380A), ultrasonic and X-ray detection method (patent publication number CN109854861A), etc. However, the existing PCCP pipe detection methods all have some key problems. For example, although these methods can determine the broken wire situation, they cannot accurately measure the stress of the prestressed steel strands, and thus cannot predict or intervene in the broken wire situation in advance; secondly, the existing detection methods need to be measured in the pipeline, and contact with the liquid in the pipeline may affect the performance of the sensor. The electromagnetic elastic stress sensor is installed in the prestressed steel wire during the PCCP pipe winding process. It does not come into contact with the liquid in the pipeline, ensuring the sensor performance. It can also obtain the steel wire stress at each measuring point and accurately prevent wire breakage through real-time data.

[0004] During the PCCP pipe winding process, there are challenges such as how to accurately and systematically install electromagnetic elastic stress sensors and how to ensure sensor performance during the subsequent spraying process. Therefore, a convenient and feasible installation method for electromagnetic elastic stress sensors for monitoring absolute wire stress is urgently needed to address the key bottlenecks in the application of this technology in engineering projects. Summary of the Invention

[0005] In order to address the shortcomings of the existing PCCP pipe steel wire absolute stress monitoring sensor installation technology, the present invention provides a method for installing a steel wire absolute stress monitoring sensor in the PCCP pipe wire winding process, which can quickly and easily install an electromagnetic elastic stress sensor in the PCCP pipe wire winding process.

[0006] A method for installing a steel wire absolute stress monitoring sensor in a PCCP pipe winding process includes the following steps: (1) Set sensor embedded holes at selected locations on the PCCP pipe wall; (2) A rotatable flange is fixed by welding a connecting rod below the axis of the beam outlet hole of the steel wire dry powder cylinder; (3) Place an appropriate number of electromagnetic elastic stress sensors on the prestressed steel wire in sequence, lead one end of the steel wire from the dry powder tube beam hole, pass through the transmission hole on the flange, and embed it into the anchor head reserved hole at the head end of the PCCP tube core and install the anchor head to fix it; (4) Start winding the wire on the PCCP pipe. When the wire is wound around the embedded hole of the sensor, rotate the flange 180 degrees counterclockwise to allow an electromagnetic elastic stress sensor to pass through another transmission hole on the flange. After passing through, rotate the flange 180 degrees clockwise. (5) Adjust the contact position between the steel wire and the PCCP pipe wall by rotating the wire winding machine forward or reversely, and install the electromagnetic elastic stress sensor into the sensor embedded hole; (6) Continue winding the wire and install the remaining electromagnetic elastic stress sensors according to steps (4) and (5); (7) When the steel wire is wound to the end of the PCCP pipe, insert the steel wire into the anchor head reserved hole at the end of the PCCP pipe core, cut the steel wire and install the anchor head to complete the wire winding work.

[0007] Furthermore, before the wire winding process, 10 to 15 cm of the connecting wire at one end of the electromagnetic elastic stress sensor is reserved, and a special protective cover is installed at the connecting wire. The main body of the protective cover is a spiral structure and one end is a hexagonal seal, so that it forms an enclosed state, which is used to protect the sensor connecting wire from being contaminated by the coating during the subsequent spraying process.

[0008] Furthermore, when the electromagnetic elastic stress sensor is put on the prestressed steel wire, the protective cover at the connecting line naturally droops; when the electromagnetic elastic stress sensor is installed in the sensor embedded hole, the protective cover at the connecting line is perpendicular to the PCCP pipe wall and faces outward.

[0009] Furthermore, a rotating shaft is provided at the center of the flange, a transmission hole for the steel wire to pass through is located above the rotating shaft, and a transmission hole for the sensor to pass through is located below the rotating shaft, and the two transmission holes are connected by a semicircular slit.

[0010] Furthermore, the rotating shaft adopts a damping shaft, which generates damping through the friction force locked between the gasket and the nut. One end of the connecting rod is connected to the flange through the damping shaft, and the other end is fixedly connected to the dry powder cylinder.

[0011] Furthermore, the electromagnetic elastic stress sensor includes a cylindrical frame and a magnetic field generating element and an intelligent sensing element installed and fixed on the cylindrical frame. The magnetic field generating element is controlled by a remote control end and is used to generate a magnetic field at the steel wire of the measured section, thereby magnetizing the steel wire; the intelligent sensing element generates a magnetic characteristic signal representing the magnetic induction intensity of the steel wire at the measured section through electromagnetic induction.

[0012] Furthermore, the magnetic field generating element adopts an excitation coil, the cylindrical skeleton has a through hole for the steel wire to pass through, and there are two layers of annular cavities around the through hole, wherein the intelligent sensing element is located in the inner cavity, and the excitation coil is wound in the outer cavity. The excitation coil generates a magnetic field under the excitation of the excitation signal of the remote control end.

[0013] Preferably, to ensure the accuracy of the measurement results, a plurality of electromagnetic elastic stress sensors are installed on the steel wire of the measured section, and the sensors are evenly spaced a certain number of degrees apart.

[0014] Based on the above technical solution, the present invention has the following beneficial technical effects: 1. Solve the inconvenient installation problem of electromagnetic elastic stress sensors. This invention only requires the installation of the sensor to be controlled by a flange device and integrated into the PCCP pipe winding process, effectively solving the installation problem of electromagnetic elastic stress sensors.

[0015] 2. Short installation time and simple construction. The installation and construction technology of the present invention is simple, and only one staff member is required to operate the entire process. During installation, only the installation of the sensor needs to be adjusted through the winding machine, so the installation of the sensor can be completed more conveniently.

[0016] 3. Minimal impact on the quality of the original PCCP pipe. This invention only requires a 3cm pre-buried hole to be reserved at the designated location on the PCCP pipe core, which has minimal impact on the quality of the PCCP pipe. After installing the sensor, the spraying process can proceed normally.

[0017] 4. Simple structure and cost saving. The flange and sensor connecting wire protective cover of the present invention are simple and practical, and both the protective cover and the flange can be reused, thus saving cost.

[0018] 5. This solution addresses the inconvenience caused by sensor cables during PCCP pipe production and construction. This invention reserves 10-15 cm of cable at the sensor location. A cable protection sleeve protects the cable from damage during the wire wrapping and spraying process, allowing workers to connect the cable at the construction site without disrupting the entire production and construction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the electromagnetic elastic stress sensor connecting wire protective cover in the present invention.

[0020] Figure 2 The figure is a schematic diagram of the structure and threading of the rotatable flange in the present invention.

[0021] Figure 3 Schematic diagram of the installation structure of the electromagnetic elastic stress sensor in the present invention.

[0022] Figure 4 Schematic diagram of the PCCP pipe wire wrapping after the sensor is installed in the present invention.

[0023] In the figure: 1—protective sleeve, 2—sensor connecting line, 3—electromagnetic elastic stress sensor, 4—dry powder cylinder, 5—flange, 6—steel wire transmission hole, 7—sensor transmission hole, 8—rotating shaft, 9—steel wire, 10—connecting rod, 11—sensor embedded hole, F represents stress. DETAILED DESCRIPTION

[0024] In order to describe the present invention more specifically, the technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The method for installing a steel wire absolute stress monitoring sensor in a PCCP pipe winding process of the present invention specifically comprises the following steps: (1) Before the winding process, a sensor embedded hole 11 is set at a selected position on the PCCP pipe wall, such as Figure 4 shown.

[0026] (2) Reserve 10~15cm of the sensor connecting line 2 at one end of the electromagnetic elastic stress sensor 3, and install a special protective cover 1 at the connecting line, such as Figure 1 As shown; in this embodiment, the main body of the protective sleeve 1 is a spiral structure and one end is a hexagonal seal, so that it forms an enclosed state, which is used to protect the sensor connecting line 2 from being covered by the coating during the subsequent spraying process.

[0027] (3) Use welding to fix the flange 5 to the position 12.5 cm below the axis of the beam outlet of the steel wire dry powder cylinder 4 through the connecting rod 10, as shown in the following figure: Figure 2As shown; in this embodiment, a rotating shaft 8 is provided at the center of the flange 5, a wire transmission hole 6 for the steel wire to pass through is located above the rotating shaft 8, and a sensor transmission hole 7 for the sensor to pass through is located below the rotating shaft 8, and the wire transmission hole 6 and the sensor transmission hole 7 are connected by a semicircular slit; the rotating shaft 8 adopts a damping shaft, which generates damping through the friction force locked between the gasket and the nut, and one end of the connecting rod 10 is connected to the flange 5 through the damping shaft, and the other end is fixedly connected to the dry powder cylinder 4.

[0028] (4) Place an appropriate number of electromagnetic elastic stress sensors 3 on the prestressed steel wire 9 in sequence, and let the protective cover 1 of the sensor connecting wire 2 droop naturally, as shown in the following figure: Figure 2 shown.

[0029] (5) Lead one end of the steel wire 9 out of the beam outlet hole of the dry powder cylinder 4 and pass through the steel wire transmission hole 6 on the flange 5, as shown in the figure. Figure 2 As shown, it is then embedded into the anchor head reserved hole at the head end of the PCCP tube core and fixed with the anchor head.

[0030] (6) Start winding the wire on the PCCP pipe. When the steel wire 9 is wound around the embedded sensor hole 11, rotate the flange 5 180 degrees counterclockwise to allow an electromagnetic elastic stress sensor 3 and its connecting wire 2 to pass through the sensor transmission hole 7. After passing through, rotate the flange 5 180 degrees clockwise to prevent other sensors from passing through.

[0031] (7) Adjust the contact position between the steel wire 9 and the PCCP pipe wall by rotating the wire winding machine forward or reversely, and install the electromagnetic elastic stress sensor 3 in the sensor embedded hole 11, as shown in the figure. Figure 4 As shown, the protective cover 1 of the sensor connecting line 2 is perpendicular to the pipe wall and faces outward.

[0032] (8) Continue winding the steel wire 9 and install the remaining electromagnetic elastic stress sensors 3 according to the above steps (6) and (7).

[0033] (9) When the steel wire 9 is wound to the end of the PCCP pipe, insert the steel wire 9 into the anchor head reserved hole at the end of the PCCP pipe core, cut the steel wire and install the anchor head to complete the wire winding work.

[0034] The electromagnetic elastic stress sensor 3 in this embodiment includes a cylindrical frame and a magnetic field generating element and an intelligent sensing element installed and fixed on the cylindrical frame. The magnetic field generating element is controlled by a remote control terminal and is used to generate a magnetic field at the steel wire in the measured section area, thereby magnetizing the steel wire 9; the intelligent sensing element generates a magnetic characteristic signal representing the magnetic field strength at the steel wire in the measured section through electromagnetic induction.

[0035] like Figure 3As shown, in this embodiment, the magnetic field generating element adopts an excitation coil, and the cylindrical skeleton has a through hole for the load-bearing component (prestressed steel wire 9) to pass through. There are two layers of annular cavities around the through hole, wherein the intelligent sensing element is wound in the inner cavity and the excitation coil is wound in the outer cavity. The excitation coil generates a magnetic field under the excitation of the excitation signal of the remote control end.

[0036] In order to ensure the accuracy of the measurement results in this embodiment, four electromagnetic elastic stress sensors 3 are installed on the steel wire 9 of the measured section, and the sensors are spaced 90 degrees apart.

[0037] In the PCCP pipe break monitoring application scenario, this embodiment pre-calibrates the sensor in the laboratory using the steel wire used in the pipeline to be tested, obtaining a magnetic signature signal-stress relationship curve and coefficient. Then, an electromagnetic elastic stress sensor is used as the primary detection tool and installed on the prestressed steel wire of the PCCP pipeline. An excitation signal is sent to the sensor via a remote control terminal. Under the magnetoelastic effect, the steel wire generates a corresponding magnetic induction intensity due to the external force. The sensor senses the magnetic induction intensity, calculates the magnetic signature signal, and transmits the signal to the magnetoelastic instrument. Based on the results of the previous laboratory calibration, the magnetoelastic instrument processes the received monitoring signal and converts it into stress data of the prestressed steel wire. The stress data is then stored in the magnetoelastic instrument's memory. The user can control the operation of the entire device through the remote control terminal and observe the current and historical stress data of the PCCP pipeline. Based on this data, the PCCP pipeline breakage situation (time, location, and number of wire breaks) can be monitored in real time and the safe operation of the PCCP pipeline can be evaluated, while also providing an early warning function for PCCP pipeline burst disasters.

[0038] The working principle of the electromagnetic elastic stress sensor in this embodiment is as follows: under the action of an external force, a certain external excitation magnetic field is applied to the prestressed steel wire. When its stress changes, its magnetic properties also change, causing the distribution of the magnetic field in the adjacent area to change. This change is closely related to the magnetic properties of the steel wire material; the intelligent sensing element in the electromagnetic elastic strain sensor measures the magnetic field response and outputs a magnetic characteristic signal. After signal processing, the magnetic characteristic quantity of the prestressed steel wire is obtained. There is a one-to-one correspondence between this magnetic characteristic quantity and the stress of the steel wire, and the absolute stress value of the prestressed steel wire can be obtained.

[0039] This embodiment solves the inconvenient installation of electromagnetic elastic stress sensors. Sensor installation is controlled solely through a flange device and integrated into the PCCP pipe winding process, effectively resolving the installation issues. Installation is time-efficient and simple, requiring only one operator to perform the entire process. Installation requires only adjusting the sensor using the winding machine, making sensor installation convenient. The sensor also has minimal impact on the quality of the original PCCP pipe, requiring only a 3-cm pre-buried hole at a designated location on the PCCP pipe core. After the sensor is installed, the spray coating process can proceed normally. The structure is simple and cost-effective. The flange and sensor cable protective cover are simple and practical, and both the cover and flange are reusable, saving costs. Furthermore, this embodiment addresses the inconvenience caused by sensor cable connections during PCCP pipe production and construction. A 10-15 cm cable is reserved at the sensor location, protected from damage during the winding and spray coating processes by a cable protective cover. Connections can be made by on-site personnel without disrupting the entire production and construction process.

[0040] The above description of the embodiments is intended to facilitate understanding and application of the present invention by those skilled in the art. It is apparent that those skilled in the art can readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without requiring creative effort. Therefore, the present invention is not limited to the above embodiments. Any improvements or modifications made by those skilled in the art based on the disclosure of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for installing a steel wire absolute stress monitoring sensor during a PCCP pipe winding process, comprising the following steps: (1) Set sensor embedded holes at selected locations on the PCCP pipe wall; (2) A rotatable flange is fixed by welding a connecting rod below the axis of the beam outlet hole of the steel wire dry powder cylinder; (3) Place an appropriate number of electromagnetic elastic stress sensors on the prestressed steel wire in sequence, lead one end of the steel wire from the dry powder tube beam hole, pass through the transmission hole on the flange, and embed it into the anchor head reserved hole at the head end of the PCCP tube core and install the anchor head to fix it; (4) Start winding the wire on the PCCP pipe. When the wire is wound around the embedded hole of the sensor, rotate the flange 180 degrees counterclockwise to allow an electromagnetic elastic stress sensor to pass through another transmission hole on the flange. After passing through, rotate the flange 180 degrees clockwise. (5) Adjust the contact position between the steel wire and the PCCP pipe wall by rotating the wire winding machine forward or reversely, and install the electromagnetic elastic stress sensor into the sensor embedded hole; (6) Continue winding the wire and install the remaining electromagnetic elastic stress sensors according to steps (4) and (5); (7) When the steel wire is wound to the end of the PCCP pipe, insert the steel wire into the anchor head reserved hole at the end of the PCCP pipe core, cut the steel wire and install the anchor head to complete the wire winding work.

2. The method for installing a sensor for monitoring steel wire absolute stress during the PCCP pipe winding process according to claim 1, characterized in that: Before the wire winding process, 10 to 15 cm of the connecting wire at one end of the electromagnetic elastic stress sensor is reserved, and a special protective cover is installed at the connecting wire. The main body of the protective cover has a spiral structure and a hexagonal seal at one end, forming an enclosed state to protect the sensor connecting wire from being contaminated by the coating during the subsequent spraying process.

3. The method for installing a sensor for monitoring steel wire absolute stress during the PCCP pipe winding process according to claim 2, characterized in that: When the electromagnetic elastic stress sensor is put on the prestressed steel wire, the protective cover at the connecting line naturally droops; when the electromagnetic elastic stress sensor is installed in the sensor embedded hole, the protective cover at the connecting line is perpendicular to the PCCP pipe wall and faces outward.

4. The method for installing a sensor for monitoring steel wire absolute stress during the PCCP pipe winding process according to claim 1, characterized in that: A rotating shaft is provided at the center of the flange, a transmission hole for the steel wire to pass through is located above the rotating shaft, and a transmission hole for the sensor to pass through is located below the rotating shaft, and the two transmission holes are connected by a semicircular slit.

5. The method for installing a sensor for monitoring steel wire absolute stress during the PCCP pipe winding process according to claim 4, characterized in that: The rotating shaft adopts a damping shaft, which generates damping through the friction force locked between the gasket and the nut. One end of the connecting rod is connected to the flange through the damping shaft, and the other end is fixedly connected to the dry powder cylinder.

6. The method for installing a sensor for monitoring steel wire absolute stress during the PCCP pipe winding process according to claim 1, characterized in that: The electromagnetic elastic stress sensor includes a cylindrical frame and a magnetic field generating element and an intelligent sensing element installed and fixed on the cylindrical frame. The magnetic field generating element is controlled by a remote control terminal and is used to generate a magnetic field at the steel wire of the measured section, thereby magnetizing the steel wire; the intelligent sensing element generates a magnetic characteristic signal representing the magnetic induction intensity of the steel wire at the measured section through electromagnetic induction.

7. The method for installing a sensor for monitoring steel wire absolute stress during the PCCP pipe winding process according to claim 6, characterized in that: The magnetic field generating element adopts an excitation coil. The cylindrical skeleton has a through hole for the steel wire to pass through. There are two layers of annular cavities around the through hole. The intelligent sensing element is located in the inner cavity, and the excitation coil is wound in the outer cavity. The excitation coil generates a magnetic field under the excitation of the excitation signal of the remote control end.

8. The method for installing a sensor for monitoring steel wire absolute stress during the PCCP pipe winding process according to claim 1, characterized in that: A number of electromagnetic elastic stress sensors are installed on the steel wire of the tested section, and the sensors are evenly spaced at a certain interval.

Images