Device and method for detecting pipeline grouting compactness based on optical fiber sensor

Abstract

The invention provides a pipeline grouting compactness detection device and method based on an optical fiber sensor, and relates to the field of bridge concrete prefabricated component detection. The inflatable capsule is tightly attached to the inner wall of the pipeline, good contact and a stable measurement environment are ensured, the temperature sensing optical fibers are evenly arranged on the outer surface of the inflatable capsule and penetrate into the prestressed pipeline together with the inflatable capsule, and the temperature sensing optical fibers are firmly attached to the inner wall of the pipeline, so that the temperature change in the pipeline can be accurately sensed; performing data acquisition and analysis by using an optical fiber temperature monitoring system, acquiring a temperature signal fed back by the temperature sensing optical fiber in real time, and performing analysis; the temperature rise curve of each measuring point is concerned, the temperature change in the grouting process is reflected in real time, the compactness and uniformity of grouting are indirectly evaluated, the temperature change is monitored in real time, a scientific basis is provided for evaluating the grouting effect, and the quality and safety of the prestressed pipeline are ensured.

Description

Technical Field

[0001] The invention relates to the field of bridge concrete prefabricated component detection, and in particular to a pipeline grouting density detection device and method based on an optical fiber sensor. Background Art

[0002] Prestressed concrete beams are widely used in civil engineering structures such as bridges and buildings because of their excellent mechanical properties such as high strength, low deadweight and fatigue resistance. Post-tensioned bonded prestressed concrete bridges account for the vast majority of prestressed concrete bridges in my country. Prestressed pipe grouting is a very critical process in its construction process. The grouting material can not only protect the prestressed tendons from corrosion by the external environment, but also make the prestress evenly distributed in the structure. Its density will greatly affect the performance of the prestressed tendons during service. If there are void defects and non-density in the pipeline, it will affect the coordinated deformation of the prestressed tendons and the bridge as a whole, which is not conducive to the stress of the structure. At the same time, it will also make it impossible to form an effective protective layer around the steel strands, which is easy to cause corrosion of the highly taut steel strands, reduce the effective prestress of the bridge as a whole, and seriously endanger the safety and durability of the bridge. Ensuring the consistency of the grouting density of the prestressed pipe is a key and difficult problem in construction control. At present, there is no universal and effective method at home and abroad.

[0003] In the prior art, the detection methods can be roughly divided into: 1) detection methods based on electromagnetic waves; 2) detection methods based on ultrasonic waves; 3) detection methods based on radiation (X-rays, gamma rays, etc.); 4) detection methods based on impact elastic waves. Among the current detection methods, the detection methods based on various waves have their own defects, resulting in low detection accuracy. Among them, the detection method based on electromagnetic waves is not suitable for iron corrugated pipes, nor is it suitable for conditions with dense steel bars; the impact echo method uses low-frequency waves, resulting in very low resolution and difficulty in detecting double-layer prestressed pipes and plastic pipes. Relevant foreign studies have also shown that the impact echo method is not very effective in detecting the key density of plastic ducts; high-energy rays can form images of prestressed ducts on the screen or film, which is based on the differences in density and thickness of prestressed ducts, slurry and concrete. The detection technology has high accuracy, but the test equipment is complex, the detection cost is high, and it is difficult to detect on a large scale; the ultrasonic method for detecting the density of prestressed pipe grouting is divided into ultrasonic transmission method and ultrasonic echo method. The ultrasonic transmission method is sometimes difficult to achieve the conditions that require two working surfaces in actual detection; the ultrasonic echo method has problems such as long ultrasonic propagation path and low signal-to-noise ratio.

[0004] The current method for detecting the density of grouting of prestressed pipes using distributed optical fiber sensors (patent authorization number CN 109030561 B) includes a sensor made by combining a sensing optical fiber and a heating wire, which is fixed on a steel strand through a wire clip to realize the arrangement of the sensor along the prestressed pipe; during the data acquisition process, the heating wire is energized and heated by a temperature regulating device, and the temperature at the location of the grouting defect in the prestressed pipe will be significantly different from the temperature at other locations along the way. The temperature value along the pipe is read and analyzed using a data acquisition instrument, so that the density of grouting of the prestressed pipe can be judged, and the location of the grouting defect and the length, cross-sectional area and other parameters of the grouting defect can be identified. However, in this method, the distributed sensing optical fiber is arranged on the steel strand, and after the steel strand is tensioned, its position will be located below the pipe, so it can only detect the grouting situation within a certain height from the outer periphery of the steel strand, but cannot determine the filling density of the slurry in the entire pipe. Moreover, all the above methods detect the density of the pipe slurry filling after the grouting is completed. Although some methods can guarantee a certain accuracy, they cannot monitor the grouting situation in the pipe in real time during the grouting process. Summary of the invention

[0005] The main purpose of the present invention is to provide a device and method for detecting the density of pipeline grouting based on optical fiber sensors, so as to solve the problem that the prior art cannot accurately judge and implement the detection of the slurry filling density in the entire pipeline. The technical solution sets a temperature sensing optical fiber in the prestressed pipeline to monitor the density of the pipeline grouting process and then accurately and reasonably control the grouting process, thereby obtaining precise grouting control parameters, improving the quality of prestressed construction, enabling it to better coordinate stress and deformation with the bridge beam body, and improving safety performance during the service life.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a pipeline grouting density detection device based on optical fiber sensor, comprising: The inflatable capsule is arranged inside the pipe and has an inflation / deflation nozzle. After inflation, the inflatable capsule fits tightly against the inner wall of the pipe. The temperature sensing optical fiber is evenly arranged on the outer surface of the air-filled capsule along the axial direction through the adhesive coating, and extends into the pipeline together with the air-filled capsule. A number of evenly distributed measuring points are arranged on the temperature sensing optical fiber; An optical fiber transmission signal line is arranged at the grouting opening in the pipeline; The optical fiber temperature monitoring system is electrically connected to the temperature sensing optical fiber through the optical fiber transmission signal line, and is used to collect the temperature signal of the temperature sensing optical fiber and detect the temperature rise curve of each measuring point in real time during the grouting process.

[0007] In the preferred embodiment, at least two temperature sensing optical fibers are arranged along the entire length of each pipeline, and are arranged on the outer wall of the inflatable capsule at equal intervals, with their axes being parallel to the axis of the inflatable capsule; One end of each temperature sensing optical fiber extends to the vicinity of the inflation / deflation nozzle and is provided with a reserved section; the other end extends to the tail end of the inflation capsule.

[0008] In a preferred embodiment, the temperature sensing optical fiber is provided with a plurality of evenly distributed measuring points, including: According to the number of temperature sensing optical fibers m and the number of measuring points n, each measuring point covers the same inflatable capsule area. As a principle, set it evenly; The area of ​​the inflatable capsule is the axial area where the inflatable capsule fits tightly against the inner wall of the pipe after inflation. The calculation formula is: ; Wherein, is the axial area of ​​the inflatable capsule after inflation, is the same area covered for each measuring point, is the same inflatable capsule area covered for each measuring point, and is the number of measuring points on each temperature sensing optical fiber.

[0009] In the preferred embodiment, the temperature sensing optical fiber is provided with a plurality of evenly distributed measuring points, and further comprises: according to the number m of the temperature sensing optical fibers, the distance between the measuring points is l, and the temperature sensing optical fibers are staggered, then the staggered distance is .

[0010] In the preferred solution, the measuring points on the temperature optical fiber are connected in series, the temperature resolution can reach 0.01°C, and a single temperature optical fiber is used for temperature monitoring and signal transmission.

[0011] In the preferred solution, the data analysis terminal obtains the temperature sensing optical fiber and draws the temperature rise curve, and adjusts the grouting parameters in real time according to the preset parameters. The grouting parameters include the grouting rate, grouting pressure and grouting time; According to the 3δ principle, the position of the curve segment in the pipeline line shape is intercepted and the results of each measuring point are compared; If the difference of the temperature rise curve output by each measuring point is within the preset error range, the pipeline grouting density is good, and the relevant parameters are recorded and the grouting is terminated; If the difference in the temperature rise curves output by each measuring point exceeds the preset error range, the alarm operation is activated.

[0012] In a preferred embodiment, the adhesive coating is an acrylic structural adhesive.

[0013] A method for detecting the density of pipeline grouting using an optical fiber sensor, which is applied to a device for detecting the density of pipeline grouting using an optical fiber sensor, comprises the following steps: S1: Fix one side of the temperature sensing optical fiber to the outer surface of the inflatable capsule in a straight line direction, and set reserved sections at both ends; fix the temperature sensing optical fiber to the outer wall of the inflatable capsule through a sticky coating, and the other side of the temperature sensing optical fiber is in contact with the atmosphere and coated with a sticky coating, and the inflatable capsule is inserted from one end of the pipeline; wherein, during the insertion process, keep the two optical fibers evenly arranged on the inner wall of the pipeline until the tail of the inflatable capsule passes through the tail end of the pipeline; S2: Fill the inflatable capsule with rated air pressure through the inflating nozzle to ensure that the inflatable capsule fits tightly against the inner wall of the pipe and maintains this for a certain period of time so that the temperature sensing optical fiber can be tightly bonded to the inner wall of the pipe through the adhesive coating. The air capsule is then depressurized and pulled out; S3: Make a signal transmission joint on the reserved section of the temperature sensing optical fiber, then carry out the processes of prestressed steel strand insertion and anchor tensioning, transmit the data to the data analysis terminal through the optical fiber transmission signal line, and collect initial data before grouting; S4: During the grouting process, the grouting parameters are adjusted in real time according to the temperature rise curve output by the temperature sensing optical fiber measuring point, including the grouting rate, grouting pressure and grouting time. The position of the curve segment in the pipeline line shape is intercepted according to the 3δ principle, and the results of each measuring point are compared; S5: If the difference of the temperature rise curve output by each measuring point is within the preset error range, the density of the pipeline grouting is good, and the grouting parameters are recorded after the grouting is completed; if the difference of the temperature rise curve output by each measuring point exceeds the preset error range, the alarm operation is activated.

[0014] The present invention provides a detection device and method for pipeline grouting density based on optical fiber sensor. By using an inflatable capsule to fit closely with the inner wall of the pipeline, good contact and a stable measurement environment are ensured. The temperature sensing optical fiber is evenly arranged on the outer surface of the inflatable capsule to accurately sense the temperature changes of the outer surface of the capsule and the surrounding environment. The temperature sensing optical fiber is firmly attached to the inner wall of the prestressed pipeline to improve the reliability of measurement. Then, the optical fiber temperature monitoring system is used for data collection and analysis. The temperature signal fed back by the temperature sensing optical fiber is collected in real time and analyzed. The temperature rise curve of each measuring point is paid attention to, and the temperature change during the grouting process is reflected in real time. The density and uniformity of the grouting are indirectly evaluated. By real-time monitoring of temperature changes, a scientific basis is provided for evaluating the effect of grouting, and the quality and safety of the prestressed pipeline are ensured. By analyzing the temperature rise curve, it is judged whether the grouting is uniform and dense, the construction process is optimized, and the overall performance of the structure is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 is a schematic diagram of the interior of the inflatable capsule of the present invention (not inflated); Figure 2is a schematic diagram of the interior of the inflatable capsule of the present invention (inflated); Figure 3 is a schematic diagram of the interior of the present invention (with the inflatable capsule extracted); Figure 4 The present invention is Figure 3 Middle AA section; Figure 5 It is a schematic diagram of the linear structure of the prestressed pipeline to which the present invention is directed; Figure 6 It is a working state diagram of the present invention during application (the top part appears to be not dense); In the figure: pipeline 1; temperature sensing optical fiber 2; optical fiber transmission signal line 3; inflatable capsule 4; inflation / deflation nozzle 5; optical fiber temperature monitoring system 6; prestressed steel bundle 7; grouting material 8. DETAILED DESCRIPTION

[0016] The present invention is described in detail and completely below in conjunction with the accompanying drawings. A person of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly pointed out that the technical solutions and technical features provided in each part of the present invention, including the following description, can be combined with each other without conflict.

[0017] In addition, the embodiments of the present invention involved in the following description are generally only a part of the embodiments of the present invention, rather than all the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and implementations, and its specific implementation process is as follows: Example 1 like Figure 1-6 As shown, a pipeline grouting density detection device and detection method based on optical fiber sensor, comprising: The inflatable capsule 4 is arranged inside the pipe 1, and the inflatable capsule 4 has an inflation / deflation nozzle. After inflation, the inflatable capsule is closely attached to the inner wall of the pipe 1; The temperature sensing optical fiber 2 is evenly arranged on the outer surface of the inflatable capsule 4 along the axial direction through the adhesive coating, and extends into the pipeline together with the inflatable capsule 4. A plurality of evenly distributed measuring points are arranged on the temperature sensing optical fiber 2; An optical fiber transmission signal line 3 is arranged at the grouting opening of the pipeline 1; The optical fiber temperature monitoring system 6 is electrically connected to the temperature sensing optical fiber 2 through the optical fiber transmission signal line 3, and is used to collect the temperature signal of the temperature sensing optical fiber 2, and detect the temperature rise curve of each measuring point in real time during the grouting process.

[0019] In this embodiment, the inflatable capsule 4 is closely fitted to the inner wall of the pipeline 1 to ensure good contact and a stable measurement environment. The temperature sensing optical fiber is evenly arranged on the outer surface of the inflatable capsule 4 to accurately sense the temperature changes of the outer surface of the capsule and the surrounding environment. The temperature sensing optical fiber is firmly attached to the inner wall of the prestressed pipeline to improve the reliability of the measurement. Then, the optical fiber temperature monitoring system 6 is used for data collection and analysis to collect and analyze the temperature signal fed back by the temperature sensing optical fiber in real time. The temperature rise curve of each measuring point is paid attention to to reflect the temperature changes during the grouting process in real time, and the density and uniformity of the grouting are indirectly evaluated. By real-time monitoring of temperature changes, a scientific basis is provided for evaluating the effect of grouting, and the quality and safety of the prestressed pipeline are ensured. By analyzing the temperature rise curve, it is judged whether the grouting is uniform and dense, the construction process is optimized, and the overall performance of the structure is improved.

[0020] In a preferred embodiment, the adhesive coating is an acrylic structural adhesive.

[0021] In the preferred embodiment, at least two temperature sensing optical fibers 2 are arranged along the entire length of each pipeline, and are arranged on the outer wall of the inflatable capsule 4 at equal intervals along the circumferential direction of the inscribed circle of the inflatable capsule 4, and the axis is parallel to the axis of the inflatable capsule; One end of each temperature sensing optical fiber 2 extends to the vicinity of the inflation / deflation nozzle and is provided with a reserved section; the other end extends to the tail end of the inflation capsule 4 .

[0022] like Figure 4 The figure can also be regarded as a schematic diagram of the position of the optical fiber in the pipeline after the inflatable capsule 4 is pulled out, and the temperature sensing optical fibers 2 are arranged at equal intervals in this circumferential direction.

[0023] like Figure 1-2 As shown, in this embodiment, two temperature sensing optical fibers 2 are used for illustration.

[0024] The pipe 1 is a corrugated pipe with a reserved section of at least 1 cm in length, in order to facilitate the connection of sensor reading equipment or necessary adjustments and maintenance. The other end of the temperature sensing optical fiber 2 extends to the tail end of the inflatable capsule 4, ensuring that the temperature within the entire length of the capsule and the temperature changes of the inflatable capsule during inflation, use and deflation are accurately monitored.

[0025] The inflatable capsule 4 needs to have a certain axial rigidity so that it can smoothly extend into the tail end of the corrugated tube, while also preventing the temperature sensing optical fiber from being damaged due to large axial tensile deformation when the capsule is inflated.

[0026] By setting temperature sensing optical fibers at equal intervals on the outer wall of the capsule, detailed information on the temperature distribution on the capsule surface can be obtained more accurately, which helps to evaluate the thermal performance and safety of the capsule.

[0027] In the preferred embodiment, a number of evenly distributed measuring points are arranged on the temperature sensing optical fiber 2, including: According to the number m of the temperature sensing optical fibers 2 and the number n of the measuring points, each measuring point covers the same area of ​​the inflatable capsule 4. As a principle, set it evenly; The area of ​​the air capsule 4 is the axial area where the air capsule 4 and the inner wall of the pipe 1 are closely fitted after inflation. The calculation formula is: ; In the formula, is the axial area of ​​the inflatable capsule after inflation, To cover the same area for each measuring point, For each measuring point, cover the same inflatable capsule 4 area, is the number of measuring points on each temperature sensing optical fiber.

[0028] In this embodiment, Figure 4 The figure shows the arrangement of the optical fiber in the prestressed pipe 1 after the inflatable capsule 4 is extracted. The number of measuring points (n) and the number of temperature sensing optical fibers (m) jointly determine the temperature monitoring density of the entire inflatable capsule 4. Each measuring point is responsible for monitoring an equal amount of capsule surface area, thereby ensuring uniformity, accuracy and continuity of temperature monitoring.

[0029] Furthermore, the area of ​​the inflatable capsule 4 takes into account factors such as the diameter and length of the capsule and the degree of expansion after inflation.

[0030] In the preferred embodiment, a plurality of evenly distributed measuring points are arranged on the temperature sensing optical fiber 2, and the method further comprises: according to the number m of the temperature sensing optical fibers 2, the distance between the measuring points is l, and the temperature sensing optical fibers 2 are staggered, and the staggered distance is .

[0031] In this embodiment, the premise is that the temperature sensing optical fibers are evenly distributed in the inner circle of the pipeline, and then evenly staggered, which can ensure that the monitoring area is fully and evenly monitored in temperature, thereby improving the safety and reliability of the system.

[0032] Furthermore, the evenly staggered, adjacent optical fibers may not be arranged completely parallel, but may have a certain offset so as to better cover the monitoring area.

[0033] In the preferred solution, the measuring points on the temperature optical fiber are connected in series, and the temperature resolution can reach 0.01°C. The optical fiber temperature measurement system is an optical instrument that uses optical fiber as a sensor for temperature perception. The system uses a single optical fiber to simultaneously monitor temperature and transmit signals.

[0034] In the preferred embodiment, the optical fiber temperature monitoring system 6 obtains the temperature sensing optical fiber 2 and draws a temperature rise curve, and adjusts the grouting parameters in real time according to the preset parameters. The grouting parameters include the grouting rate, grouting pressure and grouting time; According to the 3δ principle, the position of the curve segment in the linear shape of pipeline 1 is intercepted, and the results of each measuring point are compared; If the difference of the temperature rise curve output by each measuring point is within the preset error range, the pipeline grouting density is good, and the relevant parameters are recorded and the grouting is terminated; If the difference in the temperature rise curves output by each measuring point exceeds the preset error range, the alarm operation will be activated.

[0035] In this embodiment, the optical fiber temperature monitoring system 6 obtains the temperature data of each measuring point on the temperature sensing optical fiber 2, draws a temperature rise curve, and reflects the temperature change over time during the pipeline grouting process in real time. According to the preset parameters (based on engineering experience or theoretical calculations), the grouting parameters are adjusted in real time.

[0036] In this embodiment, according to the 3δ principle (i.e., the three-times standard deviation principle in normal distribution), the system can identify the position of the curve segment in the linear shape of pipeline 1, thereby determining the most significant or critical area of ​​temperature change for more accurate analysis and evaluation. By comparing the results of each measuring point, the temperature change at different locations can be evaluated, and the uniformity and density of the current grouting process can be accurately obtained.

[0037] During the grouting process, when the optical fiber contacts the slurry, the temperature of the optical fiber measuring point will rise by 5-30℃ due to the hydration heat of the slurry. If there is a loose situation, that is, the optical fiber on the inner wall of the pipeline does not contact the slurry, the temperature of the measuring point is consistent with the temperature of the beam body. The accuracy of the optical fiber measuring point can reach 0.5℃. According to the test and simulation results, when the difference of the temperature rise curve output by the measuring point is within 3℃, the pipeline grouting density is good.

[0038] Otherwise, there may be incomplete grouting or other problems. In order to alert the operator, the system will start the alarm operation.

[0039] Furthermore, the alarm operation may include sound alarms, light prompts, or sending text messages or emails to operators, which helps to discover and solve problems in a timely manner and ensure the quality and safety of the project.

[0040] By real-time monitoring of temperature changes on the temperature sensing optical fiber, adjusting grouting parameters and evaluating grouting density according to the changes, an intelligent and automated monitoring and control method is provided for the pipeline grouting process, which greatly improves the quality and safety of the project and reduces the possibility of human error and misjudgment.

[0041] Example 2 In combination with Example 1, a method for detecting the density of pipeline grouting using an optical fiber sensor is further described, and is applied to a device for detecting the density of pipeline grouting using an optical fiber sensor in Example 1, and comprises the following steps: S1: Fix one side of the temperature sensing optical fiber 2 on the outer surface of the inflatable capsule 4 in a straight line direction, and set reserved sections at both ends; the other side of the temperature sensing optical fiber 2 is in contact with the atmosphere and coated with a sticky coating, and the inflatable capsule 4 is inserted from one end of the pipeline; wherein, during the insertion process, the two optical fibers are kept evenly arranged on the inner wall of the pipeline 1 until the tail of the inflatable capsule 4 passes through the tail end of the pipeline; S2: Fill the inflatable capsule 4 with rated air pressure through the inflating nozzle to ensure that the inflatable capsule 4 is tightly fitted to the inner wall of the pipe 1, and maintain it for a certain period of time so that the temperature sensing optical fiber 2 can be tightly bonded to the inner wall of the pipe 1, and then the air capsule 4 is depressurized and pulled out; S3: Make a signal transmission joint on the reserved section of the temperature sensing optical fiber 2, then carry out the processes of prestressed steel strand insertion and anchor tensioning, transmit the data to the optical fiber temperature monitoring system 6 through the optical fiber transmission signal line 3, and collect initial data before grouting; S4: During the grouting process, the grouting parameters are adjusted in real time according to the temperature rise curve output by the temperature sensing optical fiber 2 measuring point, including the grouting rate, grouting pressure and grouting time, and the position of the curve segment in the linear shape of the pipeline 1 is intercepted according to the 3δ principle, and the results of each measuring point are compared; S5: If the difference in the temperature rise curve output by each measuring point is within the preset error range, the pipeline grouting density is good, the relevant parameters are recorded and the grouting is terminated; if the difference in the temperature rise curve output by each measuring point exceeds the preset error range, the alarm operation is activated.

[0042] Step S1 ensures that the temperature sensing optical fiber can fit tightly against the inner wall of the pipe, thereby accurately monitoring the temperature changes during the grouting process.

[0043] Step S2 enables the temperature sensing optical fiber to be tightly bonded to the inner wall of the pipeline, ensuring the accuracy of temperature monitoring. At the same time, the extraction of the inflatable capsule provides space for subsequent grouting operations.

[0044] Steps S3-S5 realize real-time data collection and analysis, establish a signal transmission channel between the temperature sensing optical fiber and the data analysis terminal, monitor temperature changes in real time to evaluate the uniformity and density of the grouting process, and adjust grouting parameters as needed to ensure the grouting quality, thereby performing grouting density evaluation and alarm operation.

[0045] Through the above steps, an intelligent and automated monitoring and control method is provided, which improves the quality and safety of the project, has the advantages of simple operation and high accuracy, and is suitable for real-time monitoring and evaluation of various pipeline grouting projects.

[0046] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A pipeline grouting density detection device based on optical fiber sensor, characterized in that: include: The inflatable capsule (4) is arranged inside the pipe (1), and the inflatable capsule (4) has an inflation / deflation nozzle. After inflation, the inflatable capsule is tightly fitted to the inner wall of the pipe (1); The temperature sensing optical fiber (2) is evenly arranged on the outer surface of the inflatable capsule (4) along the axial direction through the adhesive coating, and extends into the pipeline together with the inflatable capsule (4). A plurality of evenly distributed measuring points are arranged on the temperature sensing optical fiber (2); An optical fiber transmission signal line (3) is arranged at the grouting opening in the pipeline (1); The optical fiber temperature monitoring system (6) is electrically connected to the temperature sensing optical fiber (2) via the optical fiber transmission signal line (3) and is used to collect the temperature signal of the temperature sensing optical fiber (2) and detect the temperature rise curve of each measuring point in real time during the grouting process.

2. The optical fiber sensor-based pipeline grouting density detection device according to claim 1 is characterized in that: No less than two temperature sensing optical fibers (2) are arranged along the entire length of each pipeline, and are arranged on the outer wall of the air-filled capsule at equal intervals, with their axes being parallel to the axis of the air-filled capsule; One end of each temperature sensing optical fiber (2) extends to the vicinity of the inflation / deflation nozzle and is provided with a reserved section; the other end extends to the rear end of the inflation capsule (4).

3. The pipeline grouting density detection device based on optical fiber sensor according to claim 2 is characterized in that: The temperature sensing optical fiber (2) is provided with a plurality of evenly distributed measuring points, including: According to the number m of the temperature sensing optical fibers (2) and the number n of the measuring points, each measuring point covers the same area of ​​the inflatable capsule (4). As a principle, set it evenly; The area of ​​the inflatable capsule (4) is the axial area where the inflatable capsule (4) and the inner wall of the pipe (1) are tightly fitted after inflation. The calculation formula is: ; In the formula, is the axial area of ​​the inflatable capsule after inflation, To cover the same area for each measuring point, For each measuring point, the same area of ​​the inflatable capsule (4) is covered. is the number of measuring points on each temperature sensing optical fiber.

4. The pipeline grouting density detection device based on optical fiber sensor according to claim 3 is characterized in that: The temperature sensing optical fiber (2) is provided with a plurality of evenly distributed measuring points, and further comprises: according to the number m of the temperature sensing optical fibers (2), the distance between the measuring points is l, and the temperature sensing optical fibers (2) are staggered, and the staggered distance is .

5. The pipeline grouting density detection device based on optical fiber sensor according to claim 4 is characterized in that: The measuring points on the temperature optical fiber are connected in series, and the temperature resolution can reach 0.01°C. The single temperature optical fiber is used for temperature monitoring and signal transmission.

6. The optical fiber sensor-based pipeline grouting density detection device according to claim 1, characterized in that: The data analysis terminal (6) obtains the temperature sensing optical fiber (2) and draws a temperature rise curve, and adjusts the grouting parameters in real time according to preset parameters, the grouting parameters including grouting rate, grouting pressure and grouting time; According to the 3δ principle, the position of the curve segment in the pipeline (1) line shape is intercepted and the results of each measuring point are compared; If the difference of the temperature rise curve output by each measuring point is within the preset error range, the pipeline grouting density is good, and the relevant parameters are recorded and the grouting is terminated; If the difference in the temperature rise curves output by each measuring point exceeds the preset error range, the alarm operation will be activated.

7. The pipeline grouting density detection device based on optical fiber sensor according to claim 1 is characterized in that: The adhesive coating is an acrylic structural adhesive.

8. A method for detecting the density of pipeline grouting using an optical fiber sensor, characterized in that: The optical fiber sensor-based pipeline grouting density detection device is applied to the above-mentioned pipeline grouting density detection device, comprising the following steps: S1: Fix one side of the temperature sensing optical fiber (2) on the outer surface of the inflatable capsule (4) in a straight line direction, and set reserved sections at both ends; fix the temperature sensing optical fiber (2) on the outer wall of the inflatable capsule (4) through an adhesive coating, and the other side of the temperature sensing optical fiber (2) is in contact with the atmosphere and coated with an adhesive coating, and the inflatable capsule (4) is inserted from one end of the pipeline; wherein, during the insertion process, the two optical fibers are kept evenly arranged on the inner wall of the pipeline (1) until the tail of the inflatable capsule (4) passes through the tail end of the pipeline; S2: Filling the inflatable capsule (4) with rated air pressure through the inflating nozzle to ensure that the inflatable capsule (4) is tightly fitted to the inner wall of the pipe (1), and maintaining the pressure for a certain period of time so that the temperature sensing optical fiber (2) can be tightly bonded to the inner wall of the pipe (1) through the adhesive coating, and then the air capsule (4) is depressurized and withdrawn; S3: making a signal transmission joint on the reserved section of the temperature sensing optical fiber (2), then carrying out the processes of inserting the prestressed steel strand and anchor tensioning, transmitting the data to the data analysis terminal (6) through the optical fiber transmission signal line (3), and collecting initial data before grouting; S4: During the grouting process, the grouting parameters are adjusted in real time according to the temperature rise curve output by the temperature sensing optical fiber (2) measuring point, including the grouting rate, grouting pressure and grouting time, and the position of the curve segment in the linear shape of the pipeline (1) is intercepted according to the 3δ principle, and the results of each measuring point are compared; S5: If the difference of the temperature rise curve output by each measuring point is within the preset error range, the density of the pipeline grouting is good, and the grouting parameters are recorded after the grouting is completed; if the difference of the temperature rise curve output by each measuring point exceeds the preset error range, the alarm operation is activated.

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