Device and method for actively repairing microcracks on surface of iced water concrete structure

Abstract

The invention discloses a device and a method for actively repairing microcracks on the surface of an ice-coated water work concrete structure, belongs to the technical field of intelligent repairing of concrete, and comprises a semi-embedded distributed optical fiber sensing system and a device for repairing the microcracks on the surface of the concrete. Wherein the semi-embedded distributed optical fiber sensing system is arranged on the surface of a hydraulic concrete structure to complete positioning of concrete microcracks; the concrete surface micro-crack repairing device can melt surface ice in a short time and send a repairing material to the concrete surface micro-crack position, and accurate repairing of the concrete surface micro-crack is achieved. By combining a distributed optical fiber sensing technology and a micro-crack repairing device, the problem that micro-cracks on the surface of an ice coated concrete structure are difficult to find and repair in time can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent concrete repair, in particular to a technology for repairing micro-cracks on the surface of a hydraulic concrete structure, and more particularly to a device and method for actively repairing micro-cracks on the surface of an ice-covered hydraulic concrete structure. Background Art

[0002] In cold-region water conservancy projects, hydraulic concrete structures, serving as the core load-bearing systems of infrastructure such as water transfer hubs, dam spillways, and diversion channels, are exposed to extreme low temperatures and the harsh environment of freeze-thaw cycles for long periods of time. These structures generally face significant challenges during operation, including the synergistic damage of icing and microcracks. First, when dense ice forms on the surface of the structure, the effectiveness of traditional non-destructive testing methods (such as infrared thermal imaging and ultrasonic testing) is significantly reduced. The ice not only blocks the direct coupling between the sensor and the concrete surface, but its own mechanical response also interferes with the identification of crack signature signals, resulting in an extremely high rate of missed detection. Second, existing repair processes are not adaptable to low temperatures. Conventional solutions such as carbon fiber cloth bonding and epoxy grouting require pre-ice breaking. The impact loads generated by mechanical ice-breaking operations can easily cause surface spalling of the concrete and even the expansion of deep cracks. Especially in ultra-low temperature environments, the curing time of epoxy resin is extended to several times that of normal temperature conditions, seriously affecting the timeliness of repairs.

[0003] More seriously, complex physical and chemical interactions exist at the interface between the ice layer and concrete: the expansion stress generated by the phase transition of the ice and the stress concentration effect of existing microcracks cause the crack propagation rate to increase several times compared to normal temperature environments. At the same time, low-temperature brittleness reduces the interfacial bond strength between the repair material and the substrate, making interlayer delamination failure very likely to occur. The current step-by-step approach of "de-icing first, then repairing" in engineering practice not only requires a large amount of manpower and material resources for periodic ice-breaking operations, but also makes it difficult to achieve real-time damage blocking due to the misalignment between the repair window and the ice regeneration cycle. Therefore, there is an urgent need to develop an active repair technology system that integrates intelligent ice layer sensing, non-destructive de-icing, and low-temperature rapid repair to fundamentally address the technical bottlenecks in the full lifecycle maintenance of hydraulic concrete structures in cold regions.

[0004] The present invention discloses an active repair device and method for microcracks on the surface of an ice-covered hydraulic concrete structure, comprising: a semi-embedded distributed fiber optic sensing system and a concrete surface microcrack repair device. The semi-embedded distributed fiber optic sensing system is arranged on the surface of the hydraulic concrete structure to locate the concrete microcracks; the concrete surface microcrack repair device can quickly melt the ice on the surface and deliver the repair material to the concrete surface microcracks, achieving precise repair of the concrete surface microcracks. The present invention combines distributed fiber optic sensing technology with the microcrack repair device to solve the problem of difficult detection and timely repair of microcracks on the surface of ice-covered hydraulic concrete structures.

[0005] After review, very few published patents involve active repair methods for surface microcracks in ice-covered hydraulic concrete structures. Some relevant patents are shown below:

[0006] CN118911473B discloses a method for repairing concrete cracks at low temperature, its application and concrete crack repair agent. This solution reduces the viscosity of the repair material and improves its early strength and adaptability by adding a low-temperature early strength agent with a bench-like structure component to the repair material. The repair material has simple components and good compatibility with the concrete at the crack, which can effectively solve the problems of poor adaptability, high viscosity and low strength of the repair material.

[0007] CN119797822A discloses a concrete micro-crack mist vaporization repair material and its preparation and use method. The patent mainly comprises the following steps: the sealing cover of the mist vaporization device and the exhaust cover of the exhaust device are tightly fitted on the two ends of the concrete crack; a sealing coating is applied to the concrete cracks not covered by the sealing cover or the exhaust cover; the mist vaporization device is used to mist vaporize the A liquid, B liquid and C powder of the concrete micro-crack mist vaporization repair material, and the exhaust device is used to perform exhaust treatment at the same time, so that the tiny droplets or aerosols obtained by the mist vaporization treatment fully cover the cross-section of the concrete crack due to the pressure difference and convection, which can effectively increase the penetration depth of the slurry and evenly distribute it in the form of tiny droplets or aerosols to ensure that the repair liquid fully covers the inside of the crack.

[0008] CN218324052U discloses a hydraulic concrete seamless crack repair structure comprising a concrete substrate and a crack formed in the concrete substrate. The bottom of the crack is provided with a grouting layer with adjustable viscosity, the top of the crack is provided with a V-shaped groove filled with a first repair material layer, and the top of the V-shaped groove is coated with a second repair material layer having the same color and appearance as the concrete substrate. The top surface of the second repair material layer is flush with the top surface of the concrete substrate. The hydraulic concrete seamless crack repair structure described in this patent has the advantages of low crack repair cost and no secondary cracking after repair.

[0009] The above patents are aimed at repairing hydraulic concrete structures under different conditions. However, in high-cold environments, hydraulic concrete structures face serious threats of synergistic damage from icing and microcracks during long-term operation. The above CN118911473B discloses a method for repairing concrete cracks at low temperatures, its application, and a concrete crack repair agent method. Although it is in a low-temperature environment, it mainly focuses on material design and still has difficulty in solving the limitations and difficulties of crack detection and repair under icing conditions. Summary of the Invention

[0010] According to the above-mentioned problems of the existing surface micro-crack repair technology of hydraulic concrete structures in cold regions and the like such as extremely high missed detection rate and poor repair timeliness, a device and method for actively repairing surface micro-cracks of ice-covered hydraulic concrete structures are provided to solve the technical bottleneck of full life cycle maintenance of hydraulic concrete structures in cold regions.

[0011] The present invention provides an active repair device for micro-cracks on the surface of an ice-covered hydraulic concrete structure, which is characterized in that the active repair device for micro-cracks on the surface of an ice-covered hydraulic concrete structure comprises an integrated ice melting and repair probe, an electric wire, and a generator.

[0012] Furthermore, the generator is connected to the ice melting and repair integrated probe through electric wires.

[0013] Furthermore, when microcracks appear on the concrete surface, they are sensed by the semi-embedded distributed fiber optic sensing system. The ice melting and repair integrated probe is then placed close to the ice layer. After heating, it continuously approaches the microcracks on the concrete surface as the ice layer melts.

[0014] Preferably, the semi-buried distributed optical fiber sensing system adopts distributed optical fiber strain sensing technology, or may be a distributed optical fiber acoustic signal sensing system that can reduce ice cracking noise, or optical fiber strain / acoustic signal combined sensing technology.

[0015] Furthermore, the semi-embedded distributed optical fiber sensing system includes a fiber core and an antifreeze cladding, the antifreeze cladding wraps the fiber core and is placed in epoxy curing glue, the epoxy curing glue is filled in the grooves on the concrete surface, and a layer of low-temperature resistant epoxy curing glue is brushed on the surface.

[0016] Preferably, the low-temperature resistant epoxy curing adhesive may also be various solid thermal insulation materials with hardness.

[0017] Furthermore, the ice melting and repairing integrated probe includes a metal shell, a resistance wire, a liquid outlet, an air inlet, a water shut-off valve, a rubber water hose, a repair material stagnation cavity, a heat insulation layer, a drug outlet chamber, and a repair material stagnation chamber.

[0018] Furthermore, the resistance wire is built into the metal shell, and heat is transferred to the ice layer through the metal shell by heating, thereby achieving the purpose of melting the nearby ice.

[0019] Furthermore, the water generated after the ice melts is sprayed out of the water closing valve through the liquid outlet and the rubber water pipe, and the gas passes through the air inlet and the medicine outlet chamber to provide pressure for drainage.

[0020] Furthermore, while the gas is flowing from the air inlet and through the discharge chamber, the repair capsules in the repair material retardation chamber are ejected from the discharge chamber and attached to the surface of the microcracks. After being heated by the resistance wire, the capsules melt and release the crack repair material, completing the microcrack repair.

[0021] Furthermore, the repair material retardation chamber is wrapped by the repair material retardation inner cavity, the material of the repair material retardation inner cavity is a heat-insulating material, and a heat-insulating layer is provided at the bottom to prevent the repair capsule from melting prematurely.

[0022] A method for actively repairing surface microcracks of an ice-covered hydraulic concrete structure, characterized in that the method comprises the following steps:

[0023] S1: Arrange a semi-buried distributed optical fiber sensing system on the concrete surface;

[0024] S2: Locate microcracks based on optical fiber signals;

[0025] S3: Repair cracks under the ice using an integrated ice melting and repair probe;

[0026] S4: Check the completeness of the semi-buried distributed optical fiber sensing system;

[0027] Furthermore, the step S1 also includes taking anti-cracking measures such as water spraying when grooving the surface, and the grooving depth is not greater than 3 times the diameter of the optical fiber.

[0028] Furthermore, the step S2 also includes adopting a peak positioning method, using the peak position of the optical fiber strain, frequency shift and other parameter curves as the positioning position of the microcrack.

[0029] Furthermore, step S3 also includes melting the ice layer and repairing simultaneously. After the ice melting and repairing integrated probe contacts the concrete surface, the repair time should last for at least 5 minutes.

[0030] Furthermore, in step S4, the strain sensitivity and temperature sensitivity of the optical fiber should be checked.

[0031] Furthermore, in step S4, point sensors should be implanted on the repaired surface to monitor the repair effect of the cracks.

[0032] Compared with the prior art, the advantages and positive effects of the present invention are:

[0033] The present invention provides a device and method for actively repairing surface microcracks of ice-covered hydraulic concrete structures. Compared with the existing technology, the present invention integrates a "semi-embedded distributed optical fiber sensing system" and a "repair device" to achieve closed-loop control of "crack perception-ice melting intervention-precise repair", breaking through the inefficient mode of traditional staged processing; the optical fiber sensing system adopts a semi-embedded layout, which not only avoids the complexity of fully embedded construction, but also improves the spatial positioning accuracy of cracks; the repair device can quickly melt and remove ice, solving the problem that traditional methods cannot directly detect and repair due to ice; through the timely repair of microcracks, the core path of moisture infiltration into the concrete is blocked, reducing the risk of secondary disasters caused by frost heave cracking, and through technical integration and innovative design, it has significant advantages in detection accuracy, environmental adaptability, repair efficiency and economy, providing a reliable intelligent solution for the long-life and safe operation of hydraulic concrete structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A schematic diagram of the active repair of surface microcracks in an ice-covered hydraulic concrete structure provided in Example 1;

[0036] Figure 2 A schematic diagram of a semi-buried distributed optical fiber sensing system provided in Example 1;

[0037] Figure 3 A schematic diagram of the structure of an integrated ice melting and repair probe provided in Example 1;

[0038] Figure 4 A schematic diagram of the active repair of micro-cracks on the surface of an ice-coated concrete pipe structure provided in Example 2;

[0039] Figure 5 A schematic diagram of active repair of surface microcracks in an ice-covered concrete tunnel structure provided in Example 3;

[0040] Figure 6 A schematic diagram of active repair of surface microcracks in an ice-covered concrete arch dam structure provided in Example 4;

[0041] In the above figures, 1. Concrete; 2. Ice layer; 3. Semi-embedded distributed fiber optic sensing system; 31. Fiber core; 32. Antifreeze coating; 33. Epoxy curing adhesive; 34. Low-temperature resistant epoxy curing adhesive; 4. Microcracks; 5. Ice-melting repair integrated probe; 51. Metal casing; 52. Resistance wire; 53. Liquid outlet; 54. Air inlet; 55. Water shut-off valve; 56. Rubber hose; 57. Repair material stagnation cavity; 58. Insulation layer; 59. Drug discharge chamber; 510. Repair material stagnation chamber; 6. Electric wires; 7. Generator; 8. Concrete pipe; 9. Concrete tunnel; 10. Concrete arch dam. DETAILED DESCRIPTION

[0042] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other in the absence of conflict.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Example 1: Active repair of microcracks on the surface of ice-covered concrete pipe structures

[0045] 1. Arrangement of a semi-embedded distributed optical fiber sensing system (3): A groove is formed along the axial direction on the surface of the concrete pipe (8), with the groove depth being twice the diameter of the fiber core (31). The groove is filled with epoxy curing glue (33), and the sensing optical fiber consisting of the fiber core (31) and the antifreeze cladding (32) is embedded in the groove. The surface is then coated with low-temperature resistant epoxy curing glue (34). During the grooving process, water spraying is used to cool the concrete (1) surface to prevent new cracks from forming due to thermal stress from the grooving.

[0046] 2. Locating the microcrack (4): The distributed fiber optic sensing system (3) monitors the fiber strain signal in real time. When a peak in the strain curve is detected, the precise location of the microcrack (4) is determined by combining the frequency shift parameter. The positioning results show that the crack is located at the top of the concrete pipe (8), 2.5 meters from the interface.

[0047] 3. Operation of the ice-melting and repairing integrated probe (5): Connect the ice-melting and repairing integrated probe (5) to the generator (7) via the wire (6), and start the resistance wire (52) to heat the metal shell (51). Place the probe close to the surface of the ice layer (2), and the heat conduction will gradually melt the ice layer (2). During the melting process, the probe moves along the optical fiber positioning direction until it approaches the position of the microcrack (4). The melted water of the ice layer is discharged through the liquid outlet (53) through the rubber hose (56), and the gas enters the medicine outlet chamber (59) from the air inlet (54), pushing the repair capsule in the repair material retardation chamber (510) to spray out. After the capsule adheres to the surface of the microcrack (4), the resistance wire (52) heats the capsule again to melt it, releasing the repair material to fill the crack. The repair lasts for 8 minutes to ensure that the material is completely solidified.

[0048] 4. Check the integrity of the sensing system: After the repair is completed, test the strain sensitivity and temperature sensitivity of the optical fiber (31) to confirm the signal stability. Implant point sensors in the repair area to continuously monitor the repair effect.

[0049] Example 2: Active repair of surface microcracks in ice-covered concrete tunnel structures

[0050] 1. Arrangement of a semi-embedded distributed optical fiber sensing system (3): An annular groove is formed in the vault and sidewalls of the concrete tunnel (9), with the groove depth being 2.5 times the diameter of the fiber core (31). The fiber core (31) and the antifreeze cladding (32) are embedded in epoxy curing adhesive (33), and the surface is covered with low-temperature resistant epoxy curing adhesive (34). Intermittent water spray cooling is used during the groove formation to prevent localized overheating that may cause cracking in the concrete (1).

[0051] 2. Locating the microcrack (4): The distributed fiber optic sensing system (3) detected a continuous frequency shift anomaly in the side wall area. Combined with the strain peak positioning, it was determined that the microcrack (4) was located in the middle of the third section of the tunnel (9) side wall, with a length of about 1.2 cm.

[0052] 3. Operation of the integrated ice-melting and repair probe (5): Adjust the probe (5) angle to accommodate the curved surface of the tunnel (9) and start the generator (7) to supply power. The resistance wire (52) heats the metal shell (51) to 80°C, melting the ice layer (2) and then moving the probe along the crack. The repair capsule is ejected through the discharge chamber (59), covers the crack, and is heated until the capsule is completely melted. The repair process lasts for 6 minutes, during which the air pressure is adjusted through the air inlet (54) to ensure uniform penetration of the repair material.

[0053] 4. Check the integrity of the sensing system: Recalibrate the optical fiber (31) signal after repair to check whether the temperature sensitivity is affected by the repair process. Install redundant optical fiber nodes in the repair area to improve monitoring redundancy.

[0054] Example 3: Active repair of surface microcracks in ice-covered concrete arch dam structures

[0055] 1. Arrange a semi-embedded distributed optical fiber sensing system (3): A groove is vertically opened on the water-facing surface of the concrete arch dam (10). The groove depth is three times the diameter of the fiber core (31). A segmented filling process is used: first, epoxy curing glue (33) is injected, and then the sensing fiber is embedded and then coated with low-temperature resistant epoxy curing glue (34). Low-temperature water mist is sprayed during the groove opening to prevent brittle peeling of the concrete (1) surface.

[0056] 2. Locating microcracks (4): The optical fiber sensing system (3) detected a double peak in the strain curve at the lower part of the water-facing surface. Combined with the acoustic signal analysis, it was confirmed that the microcracks (4) were located at the junction of the dam body and the bedrock, with a depth of about 0.5 mm.

[0057] 3. Operation of the integrated ice-melting repair probe (5): A probe (5) with a curved metal shell (51) is customized for the curved surface of the dam. After starting the heating, the probe slowly moves along the crack direction, and the meltwater from the ice layer (2) is controlled and discharged through the water shut-off valve (55). After the repair capsule is ejected from the discharge chamber (59), it is locally heated to 60°C through the resistance wire (52), causing the repair material to solidify rapidly. The repair time is extended to 10 minutes to ensure that deep cracks are densely filled.

[0058] 4. Check the integrity of the sensing system: After the repair, the strain data before and after the repair are compared through the distributed optical fiber (31) to verify the crack closure effect. Temperature and humidity sensors are deployed on the surface of the repair area to monitor the impact of the environment on the repair material in real time.

Claims

1. An active repair device for micro-cracks on the surface of ice-covered hydraulic concrete structure, characterized in that: The device for actively repairing microcracks on the surface of an ice-covered hydraulic concrete structure comprises an integrated ice-melting and repairing probe (5), an electric wire (6), and a generator (7). The generator (7) is connected to the integrated ice-melting and repairing probe (5) via the electric wire (6); when microcracks (4) appear on the surface of the concrete (1), they are sensed by the semi-embedded distributed optical fiber sensing system (3), and then the integrated ice-melting and repairing probe (5) is placed close to the ice layer (2). After heating, the probe continuously approaches the microcracks (4) on the surface of the concrete (1) as the ice layer (2) melts. The semi-embedded distributed optical fiber sensing system (3) comprises a fiber core (31) and an antifreeze cladding (32), wherein the antifreeze cladding (32) wraps the fiber core (31) and is placed in an epoxy curing adhesive (33), the epoxy curing adhesive (33) is filled in a groove on the surface of the concrete (1), and a layer of low-temperature resistant epoxy curing adhesive (34) is brushed on the surface. The ice melting and repairing integrated probe (5) comprises a metal shell (51), a resistance wire (52), a liquid outlet (53), an air inlet (54), a water shut-off valve (55), a rubber hose (56), a repair material retardation cavity (57), a heat insulating layer (58), a medicine outlet chamber (59), and a repair material retardation chamber (510); wherein the resistance wire (52) is built into the metal shell (51), and heat is transferred to the ice layer (2) through the metal shell (51) by heating, thereby achieving the purpose of melting the nearby ice body; water generated after the ice body melts is ejected out of the water shut-off valve (55) through the liquid outlet (53) and the rubber hose (56), and the gas From the air inlet (54) and through the medicine outlet chamber (59), pressure is provided for drainage; at the same time, in the process of gas from the air inlet (54) and through the medicine outlet chamber (59), the repair capsule in the repair material retardation chamber (510) is ejected from the medicine outlet chamber (59) and attached to the surface of the microcrack (4). After being heated by the resistance wire (52), the capsule melts and releases the crack repair substance, completing the repair of the microcrack (4); the repair material retardation chamber (510) is wrapped by the repair material retardation cavity (57), the material of the repair material retardation cavity (57) is a heat-insulating material, and a heat-insulating layer (58) is provided at the bottom to prevent the repair capsule from melting prematurely.

2. A method for actively repairing micro-cracks on the surface of ice-covered hydraulic concrete structures, characterized in that: The method comprises the following steps: S1: Arrange a semi-buried distributed optical fiber sensing system (3) on the surface of concrete (1); S2: Locate microcracks based on optical fiber signals (4); S3: Repair the cracks under the ice layer (2) using the ice melting and repairing integrated probe (5); S4: Check the completeness of the semi-buried distributed optical fiber sensing system (3).

3. The method for actively repairing surface microcracks of an ice-coated hydraulic concrete structure according to claim 2, characterized in that: The step S1 also includes taking anti-cracking measures such as water spraying when grooving the surface, and the grooving depth is not greater than 3 times the diameter of the optical fiber.

4. The method for actively repairing surface microcracks of an ice-coated hydraulic concrete structure according to claim 2, characterized in that: The step S2 further includes adopting a peak positioning method, using the peak position of the optical fiber strain, frequency shift and other parameter curves as the positioning position of the microcrack.

5. The method for actively repairing surface microcracks of ice-coated hydraulic concrete structures according to claim 2, characterized in that: The step S3 also includes melting the ice layer and repairing simultaneously. After the ice melting and repairing integrated probe (5) contacts the surface of the concrete (1), the repair time should last for at least 5 minutes.

6. The method for actively repairing surface microcracks of an ice-coated hydraulic concrete structure according to claim 2, characterized in that: In step S4, the strain sensitivity and temperature sensitivity of the optical fiber should be checked.

7. The method for actively repairing surface microcracks of an ice-coated hydraulic concrete structure according to claim 2, characterized in that: In step S4, point sensors should be implanted on the repaired surface to monitor the repair effect of the crack.

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