Optical fiber monitoring device and method for deformation of ice-coated concrete structure

Abstract

The invention discloses an ice-coated concrete structure deformation optical fiber monitoring device and method, and relates to the technical field of structure health monitoring. The device comprises an air pump, a balancing weight, an armored optical fiber, an air cap, an injection type pump pipe and a spray gun, the air pump is connected with the spray gun so as to blow the optical fiber with the air cap and the balancing weight into a temperature control water pipe reserved in the structure; the injection type pump pipe is used for grouting and is integrated with a plurality of piezoelectric sensors. During operation, the temperature control water pipe is checked and used as a channel, the prestress optical fiber with the balancing weight is blown in, the injection type pump pipe is connected with the balancing weight, grouting materials are injected, meanwhile, the piezoelectric sensor is used for monitoring the grouting compactness and the interface bonding quality, and the optical fiber demodulator is started for long-term deformation and temperature monitoring. According to the invention, high-efficiency and reliable arrangement and grouting reinforcement of the sensors can be completed in the structure without large-area icebreaking or surface grooving under the severe icing condition, controllable construction quality and accurate monitoring of long-term deformation are realized, and the method has the advantages of good concealment, high sensitivity, strong engineering adaptability and the like.

Description

Technical Field

[0001] This invention belongs to the field of structural health monitoring technology, and in particular to a method for monitoring the deformation of concrete structures in cold regions, especially a fiber optic monitoring device and method for monitoring the deformation of icy concrete structures. Background Technology

[0002] In the field of long-term service performance and safety monitoring of concrete structures in cold regions, structural deformation monitoring, as an important means of condition perception and early warning, is crucial for ensuring the durability and safety of infrastructure under harsh environments such as ice, snow, and freeze-thaw cycles. Currently, deformation monitoring of icy concrete structures mainly relies on technologies such as surface-mounted sensors or embedding sensing elements in grooves in the structural surface. However, these traditional monitoring methods have a series of significant limitations under icy conditions in cold regions. The shortcomings of traditional methods are particularly prominent when dealing with concrete structures continuously covered by ice in winter: surface sensors require thorough removal of ice before installation, which is difficult to implement and can easily damage the structural surface beneath the ice layer; embedding sensors in grooves in the surface is complex to construct, weakens the structural cross-section, and may introduce new weak points for freeze-thaw damage. Furthermore, existing methods generally struggle to conduct long-term, stable, distributed, and highly sensitive monitoring within the structure, failing to accurately perceive the internal deformation development of concrete under the coupled effects of temperature stress and icing loads. This results in a passive and delayed assessment of the structural safety status, significantly limiting the reliability, real-time performance, and engineering applicability of health monitoring for concrete structures in cold regions.

[0003] A review reveals numerous publicly available methods for monitoring deformation of concrete structures in cold regions, but none specifically address fiber optic monitoring of deformation in icy concrete structures. Some publicly available related solutions are listed below:

[0004] Chinese patent CN120995641A discloses a method, system, equipment, and medium for assessing the icing failure of reinforced concrete poles. By analyzing the stress distribution and potential cracks of the poles under different loads, it can accurately predict their actual stress state. Chinese patent CN120649692A discloses an active repair device and method for microcracks on the surface of icy hydraulic concrete structures. Combining distributed fiber optic sensing technology and a microcrack repair device, it can address the problem of difficult detection and timely repair of microcracks on the surface of icy hydraulic concrete structures. However, the above technologies do not mention a method for monitoring the deformation of icy concrete structures. Therefore, there is an urgent need for a method for monitoring the internal deformation of icy concrete structures, capable of realizing the entire process from fiber optic sensor deployment and grouting consolidation to data acquisition and interpretation, achieving accurate, directional capture and long-term stable transmission of internal deformation information from sensors. Summary of the Invention

[0005] The purpose of this invention is to provide a method for monitoring the internal deformation of icy concrete structures, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A fiber optic monitoring device for deformation of icy concrete structures, characterized in that it includes an air pump, a counterweight, armored optical fiber, an air cap, an injection pump pipe, and a spray gun.

[0008] Preferably, the device further includes an integrated control unit, to which the air pump, spray gun and injection pump pipe are electrically connected, for the purpose of automating the fiber optic blowing and grouting process.

[0009] Preferably, the connection interface between the spray gun and the temperature-controlled water pipe is a quick-connect sealing joint, which is suitable for standard temperature-controlled water pipe ports of different diameters.

[0010] Preferably, the device is integrated into a portable engineering case, with dedicated storage compartments inside the case for armored optical fibers, counterweights, and pump tubes.

[0011] Furthermore, the air pump is connected to the spray gun and is used to blow the armored optical fiber into the pre-reserved temperature-controlled water pipe inside the concrete structure. The connection between the spray gun and the temperature-controlled water pipe forms a channel for blowing the armored optical fiber into the concrete structure.

[0012] Preferably, the air pump is a variable frequency speed control air pump, which can adjust the air pressure and flow rate of the blowing optical fiber according to the length and curvature of the temperature-controlled water pipe.

[0013] Preferably, the nozzle of the spray gun is a replaceable design, equipped with guide bushings of different inner diameters to accommodate temperature-controlled water pipes of different inner diameters.

[0014] Preferably, a real-time air pressure monitoring meter and a pressure stabilizing valve are installed on the connecting pipeline between the air pump and the spray gun.

[0015] Furthermore, an air cap is provided at the top of the armored optical fiber, the size of which is slightly smaller than the inner diameter of the temperature-controlled water pipe, for use in bringing the armored optical fiber into the temperature-controlled water pipe with the help of the airflow from the spray gun.

[0016] Preferably, the air cap is made of engineering plastic with a low coefficient of friction, and its outer surface is provided with spiral guide grooves to enhance its forward stability under the action of airflow.

[0017] Preferably, the air cap has a streamlined structure with a conical front end and a cylindrical rear end, and the conical angle is 30-45 degrees.

[0018] Preferably, the air cap is connected to the top of the armored optical fiber by a detachable mechanical clamp, which facilitates replacement when the optical fiber is damaged.

[0019] Furthermore, the armored optical fiber is provided with multiple counterweights in the middle to provide prestress for the optical fiber during the blowing into the temperature-controlled water pipe, in order to prevent the optical fiber from loosening and improve the initial monitoring sensitivity.

[0020] Preferably, the multiple counterweights are arranged at non-equidistant intervals along the length of the armored optical fiber, and are densely arranged in the preset bending section of the temperature-controlled water pipe.

[0021] Preferably, the counterweight is an openable clamp-type structure, which facilitates adjusting its installation position on the optical fiber on-site according to actual needs.

[0022] Preferably, the mass of each counterweight is adjustable to meet different prestressing requirements.

[0023] Furthermore, the counterweight is located at the "T"-shaped opening of the temperature-controlled water pipe on the surface of the concrete structure.

[0024] As a preferred option, for straight pipe sections that are not "T" shaped, auxiliary counterweight anchor points can be set at predetermined positions outside the pipe using special clamps, as needed for monitoring.

[0025] Furthermore, the counterweight includes a piezoelectric sensor slot, a steel block, and a concrete block. The piezoelectric sensor slot is a groove in the center of the steel block, used to connect to the first piezoelectric sensor on the injection pump pipe. The concrete block is slightly smaller than the air cap, and the properties of the concrete material used are similar to those of the subsequent grouting material.

[0026] Preferably, the steel block and the concrete block are bonded together with epoxy structural adhesive, and the bonding surface has an interlocking concave-convex structure.

[0027] Preferably, the inner wall of the piezoelectric sensor slot is plated with a conductive layer, which contacts the outer electrode of the first piezoelectric sensor to achieve good conduction of electrical signals.

[0028] Preferably, the concrete block is a small cylinder made of the same batch of concrete poured at the same time as the structure to be monitored, to ensure the highest consistency of material properties.

[0029] Furthermore, the injection pump pipe includes a tube, and a grout outlet is provided on the side of the end of the tube for filling the entire temperature-controlled water pipe with grout along the "T"-shaped opening of the temperature-controlled water pipe.

[0030] Preferably, the tube is made of a transparent or semi-transparent wear-resistant material, which facilitates direct observation of the flow state of the grout inside.

[0031] Preferably, the grout outlet is connected to a hose extension section, which can penetrate into the "T"-shaped opening during grouting to reduce grout splashing.

[0032] Furthermore, a magnetic block is provided at the end of the tube, which can press the first piezoelectric sensor into the piezoelectric sensor slot and connect them tightly, so as to ensure the effectiveness of the first piezoelectric sensor in testing the bonding performance between the concrete block and the grout.

[0033] Preferably, the detection end of the first piezoelectric sensor is hemispherical, matching the shape of the bottom of the groove in the piezoelectric sensor slot, to increase the contact area.

[0034] Furthermore, a second piezoelectric sensor is installed inside the pipe to test the density of the grout inside the pipe.

[0035] Preferably, the second piezoelectric sensor can be ring-shaped and sleeved on the inner wall of the pipe to sense the compaction state of the grouting material throughout the circumference of the pipe.

[0036] Preferably, multiple second piezoelectric sensors are arranged at intervals along the axial direction of the pipe to monitor the density change gradient of the grout during the pumping process.

[0037] Furthermore, a third piezoelectric sensor is installed inside the tube near the grout outlet, which can be carried into the temperature-controlled water pipe when the grout is poured in, and is used to test the density of the grout inside the temperature-controlled water pipe.

[0038] A fiber optic monitoring method for deformation of icy concrete structures, characterized in that the method includes:

[0039] S1. Inspect the temperature-controlled water pipes reserved during the pouring period of the concrete structure in the cold region to ensure that they are unobstructed, remove some of the surface ice, and ensure that the water injection valves are exposed; check the position of each "T" shaped opening of the temperature-controlled water pipe, then set the position of the counterweight block for the armored optical fiber, and install the air cap.

[0040] S2. Connect the spray gun to the temperature-controlled water pipe and block the water injection valve that is not in the air blowing path, and blow the armored optical fiber into the concrete structure.

[0041] S3. Open the water injection valve and connect the injection pump pipe to the counterweight along the "T" shaped opening of the temperature-controlled water pipe.

[0042] S4. A test device that connects the first piezoelectric sensor, the second piezoelectric sensor and the third piezoelectric sensor, and injects grout into the temperature-controlled water pipe through an injection pump pipe until it is completely filled;

[0043] S5. Start the fiber optic demodulator to begin monitoring the deformation of the ice-covered concrete structure.

[0044] Furthermore, step S1 is intended to use existing temperature-controlled water pipes as sensor channels, which can eliminate the need for de-icing and grooving on the structural surface.

[0045] Furthermore, step S4 is intended to monitor the entire process of grouting material being poured in and compacted.

[0046] Furthermore, step S5 also includes monitoring the temperature change conducted from the injection pump pipe to the interior of the concrete structure, thereby determining the temperature difference between the inside and outside.

[0047] Preferably, in step S1, an endoscope or a pipeline robot is used to conduct a video inspection of the inside of the temperature-controlled water pipe to accurately assess its patency.

[0048] As a preferred method, the surface ice is removed by electrothermal de-icing, which heats only the area around the water injection valve to avoid damaging the large-area ice layer.

[0049] Preferably, before installing the air cap, apply grease to the top section of the armored optical fiber to reduce its frictional resistance as it travels through the temperature-controlled water pipe.

[0050] Preferably, the sealing water injection valve uses a quick-sealing plug with a central hole, which is used to balance the air pressure inside and outside the pipeline during blowing.

[0051] Preferably, in step S3, after opening the water injection valve, a small amount of clean water is injected to rinse the inside of the temperature-controlled water pipe to remove any dust that may be generated during the blowing process.

[0052] Preferably, when connecting the injection pump tube to the counterweight, a laser line projector is used to assist in centering to ensure connection accuracy.

[0053] As a preferred option, for large-scale structures with multiple sets of temperature-controlled water pipes, multiple sets of injection pump pipes are connected and operated in parallel to improve efficiency.

[0054] Preferably, in step S4, the injection speed of the grout is dynamically adjusted based on the density signals fed back by the second and third piezoelectric sensors.

[0055] Preferably, the testing equipment is a multi-channel piezoelectric impedance analyzer, which can simultaneously acquire and analyze the impedance spectrum changes of three piezoelectric sensors to comprehensively evaluate the compactness and bonding performance.

[0056] Preferably, in step S5, the initial monitoring data of the fiber optic demodulator is compared and calibrated with the reference data of the structure in an ice-free state.

[0057] As a preferred approach, the monitored deformation data is coupled with the temperature data collected at the same time for analysis to eliminate the influence of temperature strain.

[0058] The technical effects and advantages of this invention are as follows:

[0059] 1. This invention utilizes existing temperature-controlled water pipes within the concrete structure as sensor deployment channels, achieving integration of the monitoring system with the main structure. Compared to traditional external methods that involve slotting or attaching sensors to the surface of ice-covered structures, this design eliminates the need for large-scale ice removal or damage to the structural surface, minimizing interference with the existing structure and reducing the difficulty of winter construction. Simultaneously, it enables quasi-distributed sensor deployment along critical paths within the structure, significantly improving the targeting and concealment of monitoring.

[0060] 2. The fiber optic air-blowing installation method based on air cap guidance and counterweight tensioning proposed in this invention enables efficient and damage-free installation of prestressed armored optical fibers in long-distance, curved, pre-reserved pipes. This method combines airflow delivery with mechanical counterweights to ensure the optical fiber remains taut within the pipe, preventing slackness. This directly improves the initial monitoring sensitivity and signal-to-noise ratio of the fiber optic sensor for micro-deformations in the structure, solving the engineering challenge of sensor installation in complex pipes.

[0061] 3. This invention integrates a grouting quality monitoring system with multiple piezoelectric sensors, enabling quantitative evaluation of the grouting reinforcement process. The first, second, and third piezoelectric sensors simultaneously sense the interface bonding performance, pumping density, and final compaction within the pipe, ensuring the synergistic working performance of the grouting material with the optical fiber, pipeline, and existing concrete, thus laying a physical foundation for long-term reliable monitoring data.

[0062] 4. This invention provides a complete method from sensor deployment and grouting consolidation to data acquisition, solving the problem of monitoring internal deformation of icy concrete structures in cold regions. The entire solution makes full use of existing infrastructure, is easy to construct, and achieves long-term, stable, and high-precision monitoring of internal structural deformation under harsh environments, demonstrating significant engineering practical value and reliability advantages. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the fiber optic monitoring device for deformation of ice-covered concrete structures according to the present invention.

[0064] Figure 2 This is a schematic diagram of the injection pump pipe and counterweight structure of the present invention.

[0065] Figure 3 A schematic diagram of the fiber optic monitoring device for deformation of icy concrete structures according to the present invention being fed into a temperature-controlled water pipe.

[0066] Figure 4 This is a schematic diagram of the injection pump tube and counterweight block of the present invention combined in a temperature-controlled water pipe.

[0067] Figure 5 This is a schematic diagram of the internal temperature-controlled water pipe of the ice-covered concrete structure of the present invention.

[0068] Figure 6 This is a schematic diagram showing the internal temperature-controlled water pipe of the ice-covered concrete structure of the present invention with armored optical fibers inserted.

[0069] Figure 7 This is a schematic diagram of the "T"-shaped inlet of the temperature-controlled water pipe of the present invention after grouting.

[0070] Figure 8 This is a flowchart of the fiber optic monitoring method for deformation of icy concrete structures according to the present invention.

[0071] Figure 9 This is a schematic diagram of the air cap structure of the present invention.

[0072] In the diagram: 11. Air pump; 12. Counterweight; 121. Piezoelectric sensor slot; 122. Steel block; 123. Concrete block; 13. Armored optical fiber; 14. Air cap; 15. Injection pump pipe; 16. Spray gun; 151. Pipe; 152. Grout outlet; 153. Magnetic block; 154. First piezoelectric sensor; 155. Second piezoelectric sensor; 156. Third piezoelectric sensor; 2. Temperature-controlled water pipe; 21. Water injection valve; 3. Concrete structure; 4. Ice covering. Detailed Implementation

[0073] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] It should be understood that the sensing principles, structures, and manufacturing methods of the first, second, and third piezoelectric sensors used in this invention are all common knowledge in the technical field. The piezoelectric ceramic sensing technology involved in the embodiments of this invention is not the innovation of this invention, nor is it the content claimed by this patent.

[0075] First Embodiment

[0076] To address the challenge of deploying highly sensitive sensing elements within icing structures using traditional methods, this embodiment details the specific manufacturing processes, material selections, and design parameters for each core component of the monitoring device, such as... Figure 1 , Figure 3 , Figure 5 , Figure 6 , Figure 9 .

[0077] (1) The gas cap (14) is machined from polytetrafluoroethylene rod, which has an extremely low coefficient of friction and good low-temperature resistance. Its main body is streamlined and has a total length of 40mm. It is divided into a conical section at the front and a cylindrical section at the rear. The conical section is 15mm long and has a cone angle of 35 degrees. The cylindrical section has a diameter of 22mm and a length of 25mm. Its diameter is 3mm smaller than the inner diameter (25mm) of the standard temperature-controlled water pipe (2) to ensure that the airflow passes through while providing effective guidance. The cylindrical section of the gas cap has a through hole with a diameter of 3.2mm along the axial direction. The hole wall is designed with anti-slip threads and is locked and fixed to the outer armor layer of the armored optical fiber (13) by an M3 set screw to ensure that it will not fall off under the impact of high-pressure airflow. A 5mm diameter hard alloy head is embedded at the apex of the conical front end of the gas cap to resist the impact of hard objects that may be encountered in the pipe.

[0078] (2) The steel block (122) of the counterweight (12) is forged from No. 45 steel and processed into a cylinder with an outer diameter of 28 mm and a thickness of 10 mm. A circular blind hole with a depth of 5 mm and a diameter of 10 mm is machined at the center of one end face as a slot (121) for the piezoelectric sensor. The bottom of the slot is flat to ensure good contact with the sensor. Two parallel annular grooves are machined on the outer cylindrical surface of the steel block for installing mating 304 stainless steel clamps. The clamps have a bolt locking mechanism to firmly clamp the steel block onto the optical fiber. The concrete block (123) is made of concrete mixture with the same mix ratio and aggregate particle size as the structure to be tested, and is cast into a cylindrical specimen with a diameter of 21 mm and a height of 10 mm. It is cured for 28 days. The concrete block (123) is bonded to the other end face of the steel block (122) using epoxy resin structural adhesive. The surface of the steel block is sandblasted before bonding to increase adhesion. The outer diameter of the concrete block is slightly smaller than the diameter of the air cap, ensuring that it can pass smoothly through the pipe, but can also be stuck at the "T" shaped opening.

[0079] (3) The tube (151) is a transparent polycarbonate tube with a wall thickness of 3mm, an inner diameter of 20mm, and a length of 1.2m, which facilitates observation of the internal condition. The grout outlet (152) is a short stainless steel tube with an inner diameter of 8mm, welded to the side of the end of the tube. Its axis forms a 45-degree angle with the axis of the tube to guide the grout to smoothly turn and inject into the "T"-shaped opening. The magnetic block (153) is a magnet embedded in the center of the end face of the tube, with a diameter of 15mm and a thickness of 5mm. Its magnetic force is sufficient to overcome the grouting pressure and maintain a tight adsorption with the steel block (122). The second piezoelectric sensor (155) is an annular piezoelectric ceramic sheet. Its inner diameter matches the outer diameter of the tube. It is tightly attached to the middle of the outer wall of the tube with epoxy glue and wrapped with a silicone protective sleeve. The third piezoelectric sensor (156) is a piezoelectric ceramic disc with a diameter of 8 mm and a thickness of 2 mm, encapsulated in a pressure-resistant nylon shell. Initially, it is temporarily fixed to the inner wall of the grout outlet (152) by a biodegradable water-soluble rubber plug.

[0080] Second Embodiment

[0081] For ultra-long temperature-controlled water pipe loops that may exceed 300 meters in length inside large hydropower dams, this embodiment details a segmented and graded air-blowing deployment method to ensure the success rate of fiber optic deployment and the quality of prestressing application. Figure 1 , Figure 3 , Figure 5 , Figure 6 , Figure 8 .

[0082] (1) Before installation, use an industrial hot air blower with a power of 3kW to inject hot air at 80°C from one end of the temperature-controlled water pipe (2) and continue to blow for 4-6 hours to ensure that the inner wall of the pipe is completely dry and free of condensation or residual ice, so as to minimize the frictional resistance when blowing optical fibers.

[0083] (2) Divide the ultra-long loop into several sections approximately 80-100 meters long. First, blow the first section of optical fiber from the starting end. At the "T" shaped opening at the end of the first section, arrange an operator in advance. When the air cap (14) carrying the optical fiber head arrives at the "T" shaped opening, the operator uses a special clamp to temporarily clamp the optical fiber to prevent it from retracting. Then, disconnect the spray gun (16) at the starting end and quickly connect it to the "T" shaped opening at the end of the first section, while the remaining part of the optical fiber is coiled on a freely rotating pay-off rack. Adjust the pressure of the air pump (11) to 0.5 MPa and start blowing from the new starting point to the next section. This process is repeated until the optical fiber runs through the entire loop.

[0084] (3) Dynamic adjustment and verification of prestress. At each stage of the relay blowing, the smoothness of the installation is initially judged by observing the tension of the wires on the wire-laying frame and listening to the friction sound of the optical fiber in the pipe. After the entire optical fiber is installed, a miniature tension meter with a force value display is connected to one end of the optical fiber. The optical fiber is slowly pulled, and the pulling force does not exceed 5% of its tensile strength. At the same time, the change in tension reading is observed. Since multiple counterweights (12) have been anchored in each "T" shaped opening, the optical fiber is naturally tensioned in the pipe. At this time, the tension meter will display a stable initial prestress value. This value is recorded as the initial prestress reference for subsequent monitoring.

[0085] Third Embodiment

[0086] To ensure the grout fills the complex piping network densely and works in harmony with the original structure, this embodiment details the specific process of using three piezoelectric sensors for real-time, closed-loop monitoring and feedback control, such as... Figure 2 , Figure 4 , Figure 7 , Figure 8 .

[0087] (1) Before grouting, the signal lines of the first piezoelectric sensor (154), the second piezoelectric sensor (155), and the third piezoelectric sensor (156) are connected to a multi-channel piezoelectric impedance analyzer. First, the system is calibrated by collecting the baseline impedance spectrum of each sensor in the air; the tube (151) is filled with standard grouting material, and the impedance spectrum characteristic value of the second sensor (155) in the "completely compacted" state is collected; a small piece of prepared grouting material test block is bonded to a simulated concrete block, and the signal difference between the two states of intact interface and debonding is tested using the first sensor (154). The above characteristic values ​​are set as the criterion threshold and input into the control system.

[0088] (2) Start the grouting pump and inject the grouting material at an initial speed (e.g., 5 L / min). The control system reads the data in real time:

[0089] The second sensor (155) signal monitors the continuity of the grout in the pump pipe. If the signal fluctuates violently or is interrupted periodically, it indicates that cavitation or material shortage may have occurred. The system will automatically alarm and briefly increase the pump pressure to eliminate the fault.

[0090] First sensor (154) signal: monitoring interface integration. After grouting begins, the system sends a high-frequency scanning signal to the first sensor to analyze its resonant frequency shift and impedance amplitude change. When the grout completely covers the concrete block (123) and forms a good bond, the signal characteristics will stabilize within the preset threshold range. If the signal consistently fails to reach this range, the system indicates that there may be a defect in the interface at that point.

[0091] Third sensor (156) signal tracking: After the grouting material pushes the third sensor (156) away from the discharge port, the sensor becomes a moving monitoring point. By analyzing the correlation between the wireless signal strength or the specific frequency vibration signal emitted by the sensor and the fiber optic vibration data, its position can be roughly tracked, thereby determining the advancing speed of the grouting front. When its signal finally stops and its characteristics stabilize, it indicates that the grouting in that area is complete.

[0092] (3) The control system dynamically adjusts the grouting pump frequency based on the comprehensive information from the second and third sensors. When the flow of grout at the far end of the pipeline is slow, the grouting speed is automatically reduced appropriately to avoid the formation of voids due to poor air venting at the front end caused by excessively fast grouting; when it is determined that the pipeline is about to be filled, it switches to the low-speed stable pressure grouting mode until the grout overflows at the outlet.

[0093] Fourth embodiment

[0094] To address the challenge of using large air pumps in situations involving small concrete components or densely packed temperature-controlled water pipe networks with limited operating space, this embodiment details a simplified, handheld device variant and its implementation method.

[0095] (1) The device omits the large independent air pump (11) and replaces it with a handheld air blowing unit that integrates a high-pressure air tank and a miniature pressure reducing valve. The unit weighs no more than 5 kg, the air tank has a volume of 2 liters, is pre-filled with high-pressure air at a pressure of 15 MPa, and can provide a stable and adjustable working airflow of 0.2-0.6 MPa through the pressure reducing valve. The spray gun (16) is directly integrated into this unit. The counterweight (12) can be made smaller, for example, the steel block (122) is reduced to 20 mm, and the concrete block (123) is reduced accordingly.

[0096] (2) When the "T" shaped openings of multiple temperature-controlled water pipes (2) are densely arranged on the structural surface, a method of back-blowing from the end valve of the pipe to the starting valve is adopted. First, counterweights (12) are placed at all the "T" shaped openings. Then, a short section of optical fiber is inserted through the end valve and an air cap (14) is installed, and the valve is sealed with a plug. Next, a handheld air blowing unit is connected to the starting valve for blowing. The airflow pushes the optical fiber to the end. When the air cap (14) on the optical fiber passes through each "T" shaped opening, it will push the pre-placed counterweights (12) to lock them in place and drag the optical fiber behind them, thereby efficiently completing the prestressing of multiple pipes in a narrow space.

[0097] (3) Small manual or electric hydraulic grouting guns are used instead of large pump stations for grouting, and the injection pump pipe (15) is also shortened and miniaturized accordingly. By precisely controlling the stroke of the grouting gun, low-flow slow grouting is achieved, which is especially suitable for pipes with small diameter or short length. With the help of piezoelectric sensors for monitoring, air bubbles or incomplete filling caused by grouting too fast are prevented.

[0098] Sixth Embodiment

[0099] During the deployment of armored optical fibers using the air-blowing method, the air cap (14) may become stuck due to unknown local deformation, residual foreign objects, or burrs on the edge of the "T"-shaped opening inside the temperature-controlled water pipe, preventing further progress. This embodiment details a specific method for diagnosis and treatment using the original device of this invention, without the need for external destructive tools.

[0100] (1) When the air pump (11) continues to work, but the speed at which the armored optical fiber (13) is released is found to be zero when observed from the spray gun (16), and the air pump pressure gauge reading rises abnormally and remains at a high level, it is initially determined that the air cap (14) is stuck somewhere in the pipeline. First, record the length (L1) of the optical fiber that has been blown in at this time. According to the design drawing of the temperature-controlled water pipe (2), the pipeline position corresponding to this length (L1) is usually located near a bend or a "T" shaped opening, which provides a preliminary location for the stuck point.

[0101] (2) Keep the spray gun (16) connected to the pipe, but quickly switch the spray gun (16) from the outlet end of the air pump (11) to the suction end of the air pump (11). If the air pump does not have this function, prepare a reversible fan. Start the suction mode of the air pump (11) and try to pull the air cap (14) back slightly by using negative pressure suction. The operation is as follows: after suctioning for 3-5 seconds, turn it off, and then switch to positive pressure blowing mode to blow at a lower pressure for 2-3 seconds. Repeat this alternating motion several times, using the alternating changes in airflow direction and slight vibration to make the air cap (14) disengage from the jamming point. During this process, closely observe whether the optical fiber moves forward or backward slightly.

[0102] (3) If the pulse backflushing method is ineffective, remove the spray gun (16) and connect the injection pump pipe (15) from the other end of the pipeline or the nearest upstream "T" port. At this time, the injection pump pipe (15) is not connected to the counterweight and is only used as a delivery pipeline. Pump a small amount (about 100-200ml) of low viscosity, high penetration special pipeline lubricant or mild cleaning agent into the temperature-controlled water pipe (2) through the tube (151) of the injection pump pipe (15). The liquid will flow to the stuck point under the action of airflow and gravity, lubricate the contact surface between the air cap (14) and the pipe wall, and may soften or loosen the small foreign objects at the stuck point. After waiting for about 5 minutes, try the pulse backflushing operation again from the original blowing end.

[0103] (4) If the jamming persists after lubrication, use a fiber optic clamp with a force gauge at the pipe inlet to try to pull the fiber back at a very slow speed and with a constant small force. At the same time, continuously introduce low-pressure airflow from the upstream "T" shaped opening to assist. If the fiber starts to move before the pulling force reaches the safety threshold, the installation is successful. If the fiber is undamaged and the air cap is intact, reduce the blowing pressure and try to continue the installation. If the air cap (14) is damaged but the fiber is intact, use a special tool to loosen the top screw of the air cap at the nearest operable "T" shaped opening, remove it, and replace it with a spare air cap. Then, starting from this "T" shaped opening, continue blowing towards the unfinished section.

[0104] If the optical fiber is determined to be damaged, the location of the damage point is recorded, and that section of fiber is cut off as a waste section. At the first "T" shaped opening upstream of the damage point, the remaining fiber end is re-installed with an air cap, and this "T" shaped opening is used as the new starting point for deployment to continue completing the sensing coverage of subsequent pipe sections.

[0105] (5) After successfully handling and completing the fiber optic cable installation, the pipeline must be cleaned before the grouting step (S4). A suitable amount of clean water is injected into the pipeline through the injection pump pipe (15) and the pipeline is blew with airflow to remove the residue of the lubricant or cleaning agent used previously, so as to ensure that the bonding performance of the subsequent grouting material (5) is not affected.

Claims

1. A fiber optic monitoring device for deformation of icy concrete structures, characterized in that, Includes an air pump (11), a counterweight (12), an armored optical fiber (13), an air cap (14), an injection pump pipe (15), and a spray gun (16). The air pump (11) is connected to the spray gun (16) to blow the armored optical fiber (13) into the temperature-controlled water pipe (2) reserved inside the concrete structure (3). The spray gun (16) is connected to the temperature-controlled water pipe (2) to form a channel for blowing the armored optical fiber (13) into the concrete structure (3).

2. The fiber optic monitoring device for deformation of icy concrete structures according to claim 1, characterized in that, The top of the armored optical fiber (13) is provided with an air cap (14), which is slightly smaller than the inner diameter of the temperature-controlled water pipe (2) and is used to bring the armored optical fiber (13) into the temperature-controlled water pipe (2) by means of the airflow of the spray gun (16). The armored optical fiber (13) is provided with multiple counterweights (12) in the middle to provide prestress for the optical fiber during the blowing into the temperature-controlled water pipe (2), so as to avoid optical fiber relaxation and improve the initial monitoring sensitivity.

3. The fiber optic monitoring device for deformation of icy concrete structures according to claim 1, characterized in that, The counterweight (12) is located at the "T"-shaped opening of the temperature-controlled water pipe (2) on the surface of the concrete structure (3); The counterweight (12) includes a piezoelectric sensor slot (121), a steel block (122) and a concrete block (123). The piezoelectric sensor slot (121) is a groove in the center of the steel block (122) for connecting to the first piezoelectric sensor (154) on the injection pump pipe (15). The concrete block (123) is slightly smaller than the air cap (14), and the properties of the concrete material used are similar to those of the subsequent grouting material.

4. The fiber optic monitoring device for deformation of icy concrete structures according to claim 1, characterized in that, The injection pump pipe (15) includes a pipe tube (151), and a grout outlet (152) is provided on the side of the end of the pipe tube (151) for filling the entire temperature-controlled water pipe (2) with grout along the "T"-shaped opening. The end of the tube (151) is provided with a magnetic block (153) which can press the first piezoelectric sensor (154) into the piezoelectric sensor slot (121) and connect them tightly to ensure the test effect of the first piezoelectric sensor (154) on the bonding performance between the concrete block (123) and the grout. A second piezoelectric sensor (155) is installed inside the tube (151) to test the density of the grout inside the tube (151); A third piezoelectric sensor (156) is installed inside the tube (151) near the grout outlet (152). It can be carried into the temperature-controlled water pipe (2) when the grout is poured in, and is used to test the density of the grout inside the temperature-controlled water pipe (2).

5. A fiber optic monitoring method for deformation of icy concrete structures, characterized in that, The method includes: S1. Check the temperature control water pipe (2) reserved during the pouring period of the cold region concrete structure to ensure that it is unobstructed, remove some of the surface ice (4), and ensure that the water injection valve (21) is exposed; check the "T" port position of the temperature control water pipe (2), then set the position of the counterweight block (12) of the armored optical fiber (3) and install the air cap (14). S2. Connect the spray gun (16) to the temperature-controlled water pipe (2) and block the water injection valve (21) that is not on the air blowing path, and blow the armored optical fiber (13) into the concrete structure (3). S3. Open the water injection valve (21) and connect the injection pump pipe (15) to the counterweight (12) along the "T" opening of the temperature-controlled water pipe (2); S4. A test device is connected to the first piezoelectric sensor (154), the second piezoelectric sensor (155) and the third piezoelectric sensor (156), and the grout is injected into the temperature-controlled water pipe (2) through the injection pump pipe (15) until it is completely filled; S5. Start the fiber optic demodulator and begin monitoring the deformation of the ice-covered concrete structure (3).

6. The fiber optic monitoring method for deformation of icy concrete structures according to claim 5, characterized in that, Step S1 is intended to use the existing temperature-controlled water pipe (2) as the sensor channel, which can eliminate the need for removing ice and grooving the structural surface.

7. The fiber optic monitoring method for deformation of icy concrete structures according to claim 5, characterized in that, Step S4 is intended to monitor the entire process of grouting material being poured in and compacted.

8. The fiber optic monitoring method for deformation of icy concrete structures according to claim 5, characterized in that, Step S5 also includes monitoring the temperature change conducted from the injection pump pipe (15) to the interior of the concrete structure (3) to determine the temperature difference between the inside and outside.

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