Underwater grouting self-compacting and induction heating rapid hardening system and method based on variable frequency electromagnetic drive

Abstract

The application discloses a kind of underwater grouting self-compacting and induction heating rapid setting system and method based on variable frequency electromagnetic drive, belong to bridge pile foundation reinforcement repair technical field;The above-mentioned method installs protective sleeve and injects grouting material containing multi-scale magnetic material;Low-frequency pulse magnetic field drives aggregate overturning to break flocculation, realizes self-compacting;Nano magnetic fluid cooperates to enhance rheological property;Switch high-frequency alternating magnetic field, utilize the eddy current and magnetic hysteresis loss of nano magnetic fluid to convert electromagnetic energy into heat energy, make slurry uniform temperature rise and accelerate solidification;Real-time monitoring temperature, combined with PID control algorithm dynamic adjustment heating power realizes closed-loop constant temperature maintenance;The above-mentioned system includes grouting module, variable frequency electromagnetic module, anti-backflow grouting channel and monitoring and closed-loop feedback module.The application improves underwater reinforcement quality and efficiency by underwater grouting self-compacting and induction heating rapid setting synergistic effect, solves the problem of traditional grouting segregation, poor compactness, slow solidification, enhances the integrity and durability of pile foundation.

Description

Technical Field

[0001] This invention relates to the field of bridge pile foundation reinforcement and repair technology, specifically to an underwater grouting self-compacting and induction heating rapid setting system and method based on variable frequency electromagnetic drive. Background Technology

[0002] In underwater engineering projects such as underwater pile foundation repair and reinforcement of bridges and sealing of karst water inrush, it is often necessary to inject repair mortar into the damaged area to restore the structural bearing capacity. Due to the special underwater environment, the repair operation faces the following technical challenges:

[0003] Traditional underwater grouting often uses mechanical vibrators for compaction, but in complex areas such as areas with dense reinforcement and irregular joints, the vibrators are difficult to reach, resulting in serious blind spots and easily causing voids and honeycomb defects, which affect the quality of reinforcement. The high-frequency physical impact generated by mechanical vibration may also cause secondary damage to the already damaged and fragile original structure.

[0004] In addition, the low temperature of the underwater environment significantly reduces the hydration reaction rate of conventional repair mortar, resulting in slow early strength development. Before it is fully cured, the mortar is easily diluted or washed away by the passive water environment, leading to material loss and reinforcement failure. Construction personnel can only judge the degree of curing based on experience, making it difficult to obtain real-time temperature and stress changes inside the structure and effectively control the curing process. This makes it very easy for thermal stress cracking to occur due to excessive internal and external temperature differences.

[0005] Currently, some existing technologies attempt to incorporate magnetic components into repair materials and use external magnetic fields to drive the material to move in order to achieve compaction or heating. For example, related patents disclose a method to use magnetic fields to drive magnetic particles to move in the slurry to improve fluidity. However, this method only targets a single function (compaction or heating) and does not achieve the synergy and switching of compaction and heating functions. Furthermore, it lacks real-time monitoring and closed-loop control of the curing process, making it difficult to meet the high-quality repair requirements under complex underwater working conditions.

[0006] Therefore, there is an urgent need for a grouting reinforcement technology that can achieve blind-zone-free self-compacting, active heating to promote coagulation, and intelligent control of the curing process in an underwater environment. Summary of the Invention

[0007] To address the issues mentioned in the background section regarding the repair and reinforcement of underwater bridge pile foundations, this invention provides a system and method for underwater grouting self-compacting and induction heating rapid setting based on variable frequency electromagnetic drive.

[0008] The above-mentioned objective of this application is achieved through the following technical solution:

[0009] A method for underwater grouting self-compacting and induction heating rapid setting based on variable frequency electromagnetic drive includes the following steps:

[0010] A protective sleeve is installed around the underwater diseased area, an electromagnetic coil array is arranged on the protective sleeve, and grouting material is injected into the sleeve. The grouting material is a micro-nano multi-scale magnetic response grouting material containing magnetic materials.

[0011] By applying a low-frequency pulsed alternating magnetic field through the electromagnetic coil array, the magnetic material in the grout is driven to generate magneto-induced micro-vibration, so that the grout self-fills and compacts under the drive of the magnetic field.

[0012] The low-frequency pulsed alternating magnetic field is switched to a high-frequency alternating magnetic field to induce heating of the compacted grout, so that the grout heats up uniformly from the inside and accelerates solidification.

[0013] The temperature parameters during the curing process of the grout are monitored in real time, and the output power of the high-frequency alternating magnetic field is dynamically adjusted according to the preset curing temperature curve to achieve closed-loop constant temperature curing.

[0014] By adopting the above technical solution, a protective sleeve is first installed around the underwater defect area, and an electromagnetic coil array is arranged. Micro-nano multi-scale magnetic response grout containing magnetic materials is injected into the sleeve, providing a material basis for subsequent magnetic compaction and induction heating. Then, a low-frequency pulsed alternating magnetic field is applied through the electromagnetic coil array to drive the magnetic materials in the grout to generate magnetostrictive micro-vibrations, allowing the grout to self-fill and compact under the drive of the magnetic field, solving the problems of blind spots and easy damage to the original structure in traditional mechanical vibration. Next, the low-frequency pulsed alternating magnetic field is switched to a high-frequency alternating magnetic field to induction heat the compacted grout, causing the grout to heat up uniformly from the inside and accelerate solidification, solving the problems of slow solidification and easy erosion in low-temperature underwater environments. Finally, the temperature parameters of the grout during the solidification process are monitored in real time, and the output power of the high-frequency alternating magnetic field is dynamically adjusted according to the preset solidification temperature curve to achieve closed-loop constant temperature curing, solving the problem of the inability to monitor and control the solidification process in real time. This forms a complete technical chain of "injection - magnetic vibration compaction - induction heating - closed-loop curing".

[0015] In a preferred embodiment, the present application may be further configured such that the grouting material comprises a fast-setting cement-based repair material, nanoscale magnetic fluid, and micron- or millimeter-scale magnetic aggregate;

[0016] The nanoscale magnetic fluid improves the rheological properties of the grouting material under a low-frequency pulsed alternating magnetic field and generates heat as a heat medium under a high-frequency alternating magnetic field.

[0017] The micron- or millimeter-sized magnetic aggregates generate macroscopic mechanical vibration force under a low-frequency pulsed alternating magnetic field.

[0018] By adopting the above technical solution, the grouting material is composed of fast-hardening cement-based repair material, nano-scale magnetic fluid, and micron- or millimeter-scale magnetic aggregate. The nano-scale magnetic fluid is composed of surface-modified iron oxide suspension. Under a low-frequency pulsed alternating magnetic field, it improves the rheological properties of the grouting material through microscopic perturbation. Under a high-frequency alternating magnetic field, it converts electromagnetic energy into heat energy as a heat medium through eddy current effect, Niehr relaxation, and hysteresis loss. The micron- or millimeter-scale magnetic aggregate generates high-frequency flipping and reciprocating displacement under a low-frequency pulsed alternating magnetic field, forming macroscopic mechanical vibration force. The two work together under different frequency magnetic fields: at low frequencies, they jointly achieve rheological improvement and compaction, and at high frequencies, they jointly achieve internal heating and curing.

[0019] In a preferred embodiment, this application can be further configured such that: applying a low-frequency pulsed alternating magnetic field through the electromagnetic coil array to drive the magnetic material in the grout to generate magneto-induced micro-vibrations specifically includes:

[0020] The low-frequency pulsed alternating magnetic field drives the micron- or millimeter-sized magnetic aggregates in the grout to generate high-frequency flipping and reciprocating displacement, breaking the flocculation structure of the grout to reduce the apparent viscosity, allowing the grout to penetrate into the dead corners of the structure and expel air bubbles.

[0021] The low-frequency pulsed alternating magnetic field simultaneously drives the nanoscale magnetofluid to generate microscopic disturbances. The synergistic effect of these microscopic disturbances and the macroscopic vibrations of the magnetic aggregates results in rheological improvements in the grouting material at both the macroscopic and microscopic scales.

[0022] By adopting the above technical solution, a low-frequency pulsed alternating magnetic field (10Hz-200Hz) drives micron- or millimeter-sized magnetic aggregates in the grout to generate high-frequency tumbling and reciprocating displacement, breaking the flocculation structure of the high-viscosity grout and instantly generating a "shear thinning" effect. The apparent viscosity is greatly reduced, allowing the grout to penetrate into the dead corners of the densely reinforced structure and expel air bubbles, achieving contactless self-compactment and eliminating the blind spots of mechanical vibration and the risk of secondary damage to the original structure. The low-frequency pulsed alternating magnetic field also drives nanoscale magnetofluid to generate microscopic disturbances. The synergistic effect of the microscopic disturbances and the macroscopic vibration of the magnetic aggregates enables the grout to achieve rheological improvement at both the macroscopic and microscopic scales, further enhancing the uniformity and thoroughness of the compaction effect.

[0023] In a preferred embodiment, this application can be further configured such that: switching the low-frequency pulsed alternating magnetic field to a high-frequency alternating magnetic field to induction heat the compacted grout material specifically includes:

[0024] The high-frequency alternating magnetic field acts on the nanoscale magnetic fluid inside the grout, causing the nanoscale magnetic fluid to generate eddy current effect, Niehr relaxation loss and hysteresis loss, converting electromagnetic energy into heat energy, so that the grout heats up uniformly from the inside to the outside to achieve in-situ solidification.

[0025] The high-frequency alternating magnetic field simultaneously drives micron- or millimeter-scale magnetic aggregates to generate an auxiliary thermal effect, which is superimposed on the thermal effect of nanoscale magnetic fluid.

[0026] By employing the above technical solution, a high-frequency alternating magnetic field (100kHz-400kHz) acts on the nanoscale magnetic fluid inside the grout, causing the nanoscale magnetic fluid to generate eddy current effects, Niehr relaxation losses, and hysteresis losses, converting electromagnetic energy into heat energy. This allows the grout to heat up uniformly from the inside out to achieve in-situ solidification. At the same time, the high-frequency alternating magnetic field also drives micron- or millimeter-scale magnetic aggregates to generate auxiliary heating effects. The auxiliary heating effects are superimposed with the heating effects of the nanoscale magnetic fluid, further improving heating efficiency and temperature uniformity. This in-situ heating directly stimulates the hydration reaction core, enabling the material to rapidly reach more than 70% of its design strength within tens of minutes, significantly shortening the vulnerable window period underwater and effectively resisting water erosion.

[0027] In a preferred embodiment, this application can be further configured as follows: the real-time monitoring of temperature parameters during the curing process of the grout, and the dynamic adjustment of the output power of the high-frequency alternating magnetic field according to a preset curing temperature curve, specifically includes:

[0028] Real-time acquisition of temperature field and strain data inside the grouting material;

[0029] Based on the comparison between the collected temperature data and the preset curing temperature curve, the output power of the high-frequency alternating magnetic field is dynamically adjusted using a PID control algorithm to maintain the internal temperature of the grout within the preset target range.

[0030] By adopting the above technical solution, fiber Bragg grating (FBG) temperature and strain sensors are used to collect real-time temperature field data and strain data inside the grouting material. The control system compares the collected temperature data with the preset curing temperature curve and uses a PID control algorithm to dynamically adjust the output power of the high-frequency alternating magnetic field, so that the internal temperature of the grouting material is maintained within the preset target range. This allows construction personnel to monitor the temperature changes inside the structure in real time and accurately control the heating power through the PID algorithm, effectively avoiding temperature cracks caused by excessive internal and external temperature differences in the repair of large-volume concrete, thus ensuring the quality of reinforcement.

[0031] The second objective of this invention is achieved through the following technical solution:

[0032] A self-compacting and induction heating rapid setting system for underwater grouting based on variable frequency electromagnetic drive includes:

[0033] The grouting module is used to inject grout containing magnetic materials into the protective sleeve surrounding the underwater defect area;

[0034] A variable frequency electromagnetic module is connected to the protective sleeve and disposed outside the protective sleeve, used to selectively generate a low-frequency pulsed alternating magnetic field or a high-frequency alternating magnetic field and act on the micro-nano multi-scale magnetic response grout.

[0035] The anti-backflow grouting channel is connected at one end to the grouting module and at the other end to the protective sleeve, and is used to pump the micro-nano multi-scale magnetic response grouting material into the interior of the protective sleeve.

[0036] A monitoring and closed-loop feedback module is installed on the inner wall of the protective sleeve and electrically connected to the frequency conversion electromagnetic module. It is used to collect temperature and strain parameters during the curing process of the grout in real time and dynamically adjust the output power of the frequency conversion electromagnetic module according to the collected parameters.

[0037] By adopting the above technical solution, the underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive consists of four core modules: grouting module, variable frequency electromagnetic module, anti-backflow grouting channel, and monitoring and closed-loop feedback module. The grouting module pumps micro-nano multi-scale magnetic response grout into the protective sleeve through the anti-backflow grouting channel to ensure that the high-viscosity grout does not cause pipe blockage or backflow in the dynamic water environment during underwater pumping. The variable frequency electromagnetic module selectively generates low-frequency pulsed alternating magnetic field or high-frequency alternating magnetic field to act on the grout. The monitoring and closed-loop feedback module collects temperature and strain parameters in real time and dynamically adjusts the output power of the variable frequency electromagnetic module according to the collected parameters. The four modules work together to form a complete automated reinforcement system from grouting, compaction, heating to closed-loop curing.

[0038] In a preferred embodiment, the present application may be further configured such that the frequency conversion electromagnetic module includes an adjustable frequency induction power supply and an electromagnetic coil array;

[0039] The adjustable frequency inductive power supply is disposed outside the protective sleeve and is electrically connected to the electromagnetic coil array;

[0040] The electromagnetic coil array is arranged around the outside of the protective sleeve and is electrically connected to the adjustable frequency inductive power supply.

[0041] By adopting the above technical solution, the frequency conversion electromagnetic module includes an adjustable frequency induction power supply and an electromagnetic coil array. The adjustable frequency induction power supply is located outside the protective sleeve and is electrically connected to the electromagnetic coil array. It is used to accurately output low-frequency pulse alternating magnetic fields (10Hz-200Hz) and high-frequency alternating magnetic fields (100kHz-400kHz) according to the needs of different stages. The electromagnetic coil array is arranged around the outside of the protective sleeve, and can be flexibly arranged in a modular manner that surrounds the outside of the sleeve or is flexibly attached. It realizes non-contact energy transfer, eliminates the need to place any electrical components inside the grouting material, and eliminates underwater electrical safety hazards.

[0042] In a preferred embodiment, the present application may be further configured such that the anti-backflow grouting channel includes a flexible grouting channel and a grout outlet nozzle;

[0043] One end of the flexible grouting channel is connected to the grouting module, and the other end is connected to the grout outlet nozzle;

[0044] The grout outlet nozzle is located inside the protective sleeve and connected to the flexible grouting channel. The grout outlet nozzle is equipped with a miniature one-way pressure valve.

[0045] By adopting the above technical solution, the anti-backflow grouting channel includes a flexible grouting channel and a grout outlet nozzle. One end of the flexible grouting channel is connected to the grouting module, and the other end is connected to the grout outlet nozzle, ensuring that high-viscosity grout can be pumped underwater over long distances. The grout outlet nozzle is set inside the protective sleeve and connected to the flexible grouting channel. The grout outlet nozzle is equipped with a miniature one-way pressure valve, which opens under pumping pressure to inject grout and automatically closes when pumping stops, effectively preventing external water pressure from pushing the grout back or causing backflow.

[0046] In a preferred embodiment, the present application may be further configured such that the monitoring and closed-loop feedback module includes a fiber Bragg grating temperature and strain sensor and a control module;

[0047] The fiber Bragg grating temperature and strain sensor is installed on the inner wall of the protective sleeve and is electrically connected to the control module to collect temperature field data and strain data inside the grouting material in real time.

[0048] The control module is electrically connected to the fiber Bragg grating temperature and strain sensor and the frequency conversion electromagnetic module, respectively, and is used to dynamically adjust the output power of the frequency conversion electromagnetic module according to the temperature parameters fed back by the fiber Bragg grating temperature and strain sensor.

[0049] By adopting the above technical solution, the monitoring and closed-loop feedback module includes a fiber Bragg grating (FBG) temperature and strain sensor and a control module. The fiber Bragg grating temperature and strain sensor is installed on the inner wall of the protective sleeve and is electrically connected to the control module. It is used to collect temperature field data and strain data inside the grouting material in real time at high frequency. The control module is electrically connected to both the sensor and the frequency conversion electromagnetic module. It is used to dynamically adjust the output power of the frequency conversion electromagnetic module according to the temperature parameters fed back by the sensor. The FBG sensor has the advantages of high precision, anti-electromagnetic interference, and good long-term stability. It is suitable for long-term monitoring in harsh underwater environments. The closed-loop control formed with the frequency conversion electromagnetic module ensures controllable quality throughout the entire life cycle.

[0050] In summary, this application includes at least one of the following beneficial technical effects:

[0051] 1. By driving the micron- or millimeter-sized magnetic aggregates in the grout with a low-frequency pulsed alternating magnetic field, high-frequency flipping and reciprocating displacement are generated, breaking the flocculation structure of the grout and producing a "shear thinning" effect. This allows the high-viscosity grout to penetrate into the densely reinforced areas and dead corners of irregular nodes and expel air bubbles, achieving non-contact all-round self-compacting. This avoids the blind spot problem of traditional mechanical vibration and secondary damage to the original damaged and fragile structure.

[0052] 2. By applying a high-frequency alternating magnetic field to the nanoscale magnetic fluid inside the grout, electromagnetic energy is converted into heat energy through eddy current effect, Niehr relaxation and hysteresis loss, so that the grout heats up uniformly from the inside to the outside and quickly reaches more than 70% of the design strength within tens of minutes. This greatly shortens the vulnerable window period underwater, effectively resists the scouring and dilution of dynamic water, and solves the problem of slow curing in low temperature deep water environment.

[0053] 3. Fiber Bragg grating (FBG) temperature and strain sensors are used to collect temperature field data inside the grout in real time. Combined with PID control algorithm, the output power of high frequency alternating magnetic field is dynamically adjusted so that the grout is always cured at a constant temperature according to the preset curing temperature curve. This effectively avoids thermal stress cracking caused by excessive internal and external temperature difference in large-volume underwater repair and ensures the long-term stability of reinforcement quality.

[0054] 4. The same electromagnetic coil array achieves two functions, low-frequency magnetic compaction and high-frequency induction heating, through frequency conversion control. The two functions are seamlessly connected in terms of timing and synergistically enhanced in terms of effect—first compaction and degassing, then heating and solidification. Moreover, multi-scale magnetic materials (nano-magnetic fluid and micro / millimeter-scale magnetic aggregates) work together in the two modes, resulting in a simple structure, precise control, and high reliability. Attached Figure Description

[0055] Figure 1 This is a flowchart of an embodiment of an underwater grouting self-compacting and induction heating rapid coagulation method based on variable frequency electromagnetic drive according to this application;

[0056] Figure 2 This is a flowchart illustrating the implementation of step S20 in an embodiment of an underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive.

[0057] Figure 3 This is a flowchart illustrating the implementation of step S30 in an embodiment of an underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive.

[0058] Figure 4 This is a flowchart illustrating the implementation of step S40 in an embodiment of an underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive.

[0059] Figure 5This is a schematic diagram of an embodiment of an underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive. Detailed Implementation

[0060] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0061] In one embodiment, such as Figure 1 As shown, this application discloses a method for underwater grouting self-compacting and induction heating rapid setting based on variable frequency electromagnetic drive, which specifically includes the following steps:

[0062] S10: Install a protective sleeve around the underwater diseased area, arrange an electromagnetic coil array on the protective sleeve, and inject grout into the sleeve. The grout is a micro-nano multi-scale magnetic response grout containing magnetic materials.

[0063] In this embodiment, the protective sleeve refers to a steel or composite material sleeve installed around the underwater bridge pile foundation or karst water inrush area to enclose the grouting space and prevent the grouting material from diffusing and being lost underwater; the electromagnetic coil array refers to multiple sets of induction coils surrounding the outside of the protective sleeve to generate a programmable frequency-converting alternating magnetic field; the micro-nano multi-scale magnetic response grouting material refers to an intelligent grouting material that incorporates nanoscale magnetic fluid and micron- or millimeter-scale magnetic aggregates into a high-viscosity, fast-hardening cement-based repair material.

[0064] Specifically, the construction workers first cleaned the underwater damaged area, removing loose concrete and attachments. Then, they installed a protective sleeve around the damaged area. The bottom of the sleeve was embedded in the riverbed or sealed to the existing structure, and the top was reserved for grouting ports and venting channels. An electromagnetic coil array was arranged around the outer wall of the protective sleeve, maintaining a set distance from the outer wall of the sleeve and being fixed by an insulating bracket. Micro-nano multi-scale magnetic response grouting material was prepared: surface-modified iron oxide nano-magnetic fluid and micron- or millimeter-sized magnetic iron powder aggregate were mixed into sulfoaluminate rapid-hardening cementitious material. After being stirred evenly, the mixture was pumped into the sleeve through the anti-backflow grouting channel. The grouting pressure was controlled so that the grout gradually filled the entire sleeve cavity from the bottom up until the grouting material overflowed evenly from the top vent.

[0065] S20: A low-frequency pulsed alternating magnetic field is applied through the electromagnetic coil array to drive the magnetic material in the grout to generate magneto-induced micro-vibrations, so that the grout self-fills and compacts under the drive of the magnetic field.

[0066] In this embodiment, magnetostrictive micro-vibration refers to the high-frequency flipping and reciprocating displacement generated by magnetic materials under the drive of an alternating magnetic field, which is used to break the flocculation structure of the slurry.

[0067] Specifically, after grouting is completed, the control system activates the variable frequency electromagnetic module, which outputs a low-frequency pulsed alternating magnetic field through an electromagnetic coil array. The magnetic field frequency is adjusted within the range of 10Hz to 200Hz, selecting appropriate frequency parameters based on the viscosity of the grout, aggregate particle size, and structural gap dimensions. Micron- or millimeter-sized magnetic aggregates are driven by magnetic force in the low-frequency pulsed alternating magnetic field, generating high-frequency flipping and reciprocating displacement, breaking the flocculation structure inside the high-viscosity grout, causing the grout to instantly produce a "shear thinning" effect, significantly reducing the apparent viscosity. Simultaneously, nanoscale magnetic fluid generates microscopic disturbances under the low-frequency pulsed alternating magnetic field, which synergistically work with the macroscopic vibration of the magnetic aggregate, enabling the grout to achieve rheological improvement at both the macroscopic and microscopic scales. The grout spontaneously seeps into structural dead corners such as densely reinforced areas and irregular nodes, like water, and discharges tiny air bubbles from the grout, achieving non-contact, all-round self-compacting. The application of the low-frequency pulsed alternating magnetic field continues until the grout fills the sleeve and no more air bubbles are discharged.

[0068] S30: The low-frequency pulsed alternating magnetic field is switched to a high-frequency alternating magnetic field to induce heating of the compacted grout, so that the grout is heated evenly from the inside and the curing is accelerated.

[0069] In this embodiment, the high-frequency alternating magnetic field refers to an alternating magnetic field with a frequency range of 100kHz to 400kHz, which is used to induction heat the grouting material. Induction heating refers to the conversion of electromagnetic energy into thermal energy by utilizing the eddy current effect, Nieer relaxation and hysteresis loss excited in the magnetic material by the high-frequency magnetic field, so that the grouting material is heated uniformly from the inside to the outside.

[0070] Specifically, after the air is compacted and vented, the control system switches the output of the electromagnetic coil array from a low-frequency pulsed alternating magnetic field to a high-frequency alternating magnetic field. The high-frequency alternating magnetic field acts on the nanoscale magnetic fluid inside the grout, exciting eddy current effects, Niehr relaxation, and hysteresis losses in the nanoscale magnetic particles, converting electromagnetic energy into heat energy, so that the grout heats up uniformly from the inside out, achieving in-situ heating and solidification. The high-frequency alternating magnetic field also drives the micron- or millimeter-scale magnetic aggregate to generate an auxiliary heating effect. The auxiliary heating effect is superimposed with the heating effect of the nanoscale magnetic fluid, further improving heating efficiency and temperature uniformity. In-situ heating directly stimulates the hydration reaction core, enabling the grout to quickly reach more than 70% of the design strength within tens of minutes, significantly shortening the vulnerable window period underwater and effectively resisting water erosion.

[0071] S40: Real-time monitoring of temperature parameters during the curing process of grouting material, and dynamic adjustment of the output power of high-frequency alternating magnetic field according to the preset curing temperature curve to achieve closed-loop constant temperature curing.

[0072] In this embodiment, the temperature parameter refers to the real-time temperature data collected by sensors inside the grout, which reflects its hydration reaction process and heat release state; the preset curing temperature curve is an ideal temperature rise path set according to the characteristics of the grout material and environmental conditions, which aims to optimize strength development and suppress temperature stress; closed-loop constant temperature curing refers to the process of monitoring the temperature inside the grout material in real time and dynamically adjusting the heating power so that the grout material always carries out the hydration reaction according to the preset curing temperature curve.

[0073] Specifically, fiber Bragg grating (FBG) temperature and strain sensors are pre-embedded in the inner wall of the protective sleeve or on the surface of the structure. These sensors collect real-time temperature and strain data from inside the grouting material at a high-frequency sampling rate (e.g., 1Hz) and transmit this data to the control system. The control system is pre-programmed with curing temperature curves based on different grouting material formulations and underwater environmental conditions. The control system compares the real-time temperature data with the pre-programmed curing temperature curves, uses a PID control algorithm to calculate the required heating power adjustment, and dynamically adjusts the output power of the high-frequency alternating magnetic field to maintain the internal temperature of the grouting material within the preset target range. Heating power is increased when the temperature is too low and decreased when the temperature is too high. After curing, the FBG sensors continue to monitor temperature and strain changes during the cooling phase. Once the internal temperature of the grouting material has dropped to a safe range and there is no abnormal strain development, the protective sleeve and electromagnetic coil array are removed, completing the underwater grouting reinforcement operation. Throughout the curing process, construction personnel can view the temperature curve, strain data, and heating power parameters in real-time through the control system, achieving transparent monitoring and digital management of the entire curing process.

[0074] In one embodiment, in step S10, the grouting material includes a fast-hardening cement-based repair material, nanoscale magnetic fluid, and micron- or millimeter-scale magnetic aggregate;

[0075] The nanoscale magnetic fluid improves the rheological properties of the grouting material under a low-frequency pulsed alternating magnetic field and generates heat as a heat medium under a high-frequency alternating magnetic field.

[0076] The micron- or millimeter-sized magnetic aggregates generate macroscopic mechanical vibration force under a low-frequency pulsed alternating magnetic field.

[0077] In this embodiment, a fast-setting cement-based repair material serves as the main matrix of the grout, providing basic mechanical properties and early strength development capability. Nanoscale magnetic fluid, after surface modification, is uniformly dispersed within the matrix. Under the action of a low-frequency pulsed alternating magnetic field, it reduces local viscous resistance through microscopic disturbances, and, in conjunction with the macroscopic vibration effect generated by micron- or millimeter-sized magnetic aggregates, enhances the grout's flow and filling capability in complex spaces. During the high-frequency alternating magnetic field stage, the nanoscale magnetic fluid, with its high specific surface area and excellent magnetocaloric conversion efficiency, becomes the main internal heat source, achieving rapid and uniform bulk heating. While the micron- or millimeter-sized magnetic aggregates have lower heat generation efficiency at this stage, their good thermal conductivity helps to conduct and distribute heat evenly within the grout, avoiding local overheating or concentrated temperature differences. Together, they ensure that the grout efficiently and stably completes the rapid setting and strength development process on a compacted foundation.

[0078] In one embodiment, such as Figure 2 As shown, in step S20, that is, applying a low-frequency pulsed alternating magnetic field through the electromagnetic coil array to drive the magnetic material in the grout to generate magneto-induced micro-vibrations, specifically includes:

[0079] S201: The low-frequency pulsed alternating magnetic field drives the micron- or millimeter-sized magnetic aggregates in the grout to generate high-frequency flipping and reciprocating displacement, breaking the flocculation structure of the grout to reduce the apparent viscosity, allowing the grout to penetrate into the dead corners of the structure and expel air bubbles.

[0080] In this embodiment, flocculation structure refers to the agglomerated network formed between particles in a high-viscosity cement-based slurry through physical or chemical forces. Flocculation structure hinders the flow of the slurry. Apparent viscosity refers to the viscosity value of the slurry under specific shear conditions. After the flocculation structure is broken, the apparent viscosity of the slurry decreases significantly, and the fluidity is greatly improved. Shear thinning refers to the non-Newtonian fluid behavior in which the viscosity of the slurry decreases with increasing shear rate. When magnetic aggregate moves under the drive of a magnetic field, shearing action is generated, and the slurry instantly changes from a high-viscosity state to a low-viscosity state.

[0081] Specifically, when a low-frequency pulsed alternating magnetic field is applied to the grout, the direction of the magnetic field changes periodically with the pulse frequency. Micron- or millimeter-sized magnetic aggregates are subjected to the combined action of magnetic torque and magnetic force in the alternating magnetic field, and the magnetization direction continuously flips as the direction of the magnetic field changes. Due to the large size of the magnetic aggregates, the inertial effect produces a delayed response when the direction of the magnetic field changes, thus forming a high-frequency flipping motion and reciprocating displacement. This mechanical motion generates local shear stress and stirring effect inside the grout, breaking the physical agglomeration and weak chemical bonds between cement particles, releasing the bound free water, and destroying the flocculation structure of the grout. The significant reduction in apparent viscosity gives the grout good fluidity and permeability, allowing it to penetrate into densely reinforced areas, irregular nodes, and narrow cracks under the drive of elevation difference and grouting pressure, while squeezing out air bubbles that were originally sealed in the dead corners, achieving complete filling of the defective areas. This process does not rely on mechanical vibrators and is completed entirely through non-contact magnetic drive.

[0082] S202: The low-frequency pulsed alternating magnetic field simultaneously drives the nanoscale magnetofluid to generate microscopic disturbances. The synergistic effect of these microscopic disturbances and the macroscopic vibrations of the magnetic aggregates allows the grouting material to achieve rheological improvement at both the macroscopic and microscopic scales.

[0083] In this embodiment, micro-perturbation refers to the enhanced Brownian motion and magnetic dipole interaction generated by nanoscale magnetic particles under the drive of an alternating magnetic field, with an action scale of nanometer to micrometer, much smaller than the macroscopic displacement amplitude of the magnetic aggregate; macroscopic vibration refers to the high-frequency flipping and reciprocating displacement generated by micrometer or millimeter-scale magnetic aggregate, with an action scale of millimeter to centimeter; synergistic effect refers to the mutual complementarity between micro-perturbation and macroscopic vibration in terms of spatial scale and action mechanism—macroscopic vibration breaks down large-scale flocculation networks and agglomerates, while micro-perturbation further disperses nanoscale and submicrometer-scale fine particles, so that the slurry obtains improved rheological properties at all scales.

[0084] Specifically, under the action of a low-frequency pulsed alternating magnetic field, the magnetic nanoparticles (particle size 10nm to 100nm) in the nanoscale magnetofluid also generate a magnetic response. Due to the extremely small size of the nanoparticles, the magnetization direction rapidly reverses with the change of the magnetic field, generating a Brownian motion enhancement effect and interaction between magnetic dipoles in the slurry, forming a continuous high-frequency microscopic disturbance. The microscopic disturbance reduces the frictional resistance and agglomeration tendency between nanoscale and submicron-scale particles in the slurry, destroying the flocculation structure at the microscale of the slurry. At the same time, the macroscopic vibration generated by the micron- or millimeter-scale magnetic aggregate in step S21 breaks the flocculation network and particle agglomerates at the macroscopic scale, while the microscopic disturbance of the nanoscale magnetofluid further disperses the fine particles at the microscopic scale. The two different scales of magnetostriction work together to improve the rheology of the grout at both the macroscopic and microscopic scales, significantly enhancing the grout's fluidity, permeability, and filling uniformity. This multi-scale synergistic effect ensures that the grout can penetrate into all the tiny spaces of densely reinforced areas and irregular nodes without any dead angles, providing a uniform and dense material basis for subsequent induction heating curing.

[0085] In one embodiment, such as Figure 3 As shown, in step S30, namely, switching the low-frequency pulsed alternating magnetic field to a high-frequency alternating magnetic field to induction heat the compacted grout, specifically includes:

[0086] S301: The high-frequency alternating magnetic field acts on the nanoscale magnetic fluid inside the grout, causing the nanoscale magnetic fluid to generate eddy current effect, Niehr relaxation loss and hysteresis loss, converting electromagnetic energy into heat energy, so that the grout heats up uniformly from the inside to the outside to achieve in-situ solidification.

[0087] In this embodiment, the eddy current effect refers to the closed-loop current induced by the high-frequency alternating magnetic field inside the conductive nanomagnetic nanoparticles. When the current flows through the internal resistance of the particles, Joule heating is generated. Niehr relaxation refers to the process by which the magnetic moment of the nanomagnetic particles relaxes from the direction of the applied magnetic field back to the direction of easy magnetization after the external high-frequency alternating magnetic field is removed. The energy consumed in the process is converted into heat energy. Hysteresis loss refers to the energy loss corresponding to the area enclosed by the hysteresis loop when the magnetic particles are repeatedly magnetized in the alternating magnetic field. This part of the energy is also converted into heat energy. The three thermal effects act simultaneously under the high-frequency magnetic field, making the nanomagnetic particles a micro heat source uniformly distributed inside the slurry.

[0088] Specifically, when the electromagnetic coil array switches from low-frequency output to high-frequency output, the high-frequency alternating magnetic field penetrates the protective sleeve and acts on the grouting material; the magnetic nanoparticles in the nanoscale magnetofluid inside the grouting material undergo rapid and repeated magnetization in the high-frequency alternating magnetic field; on the one hand, eddy currents are generated in the conductive material inside the particles, and when the current flows within the finite volume of the nanoparticles, it overcomes the resistance and generates Joule heat; on the other hand, the magnetic moment of the nanoparticles continuously deviates from and relaxes back to the easy magnetization direction when the direction of the alternating magnetic field switches, and each relaxation process is accompanied by energy loss and released in the form of heat; at the same time, the particles' The hysteresis loss generated by the repeated magnetization process also contributes additional heat; the superposition of the three thermal effects causes the nano-magnetic particles to form uniformly distributed micro-heat sources inside the grout, and heat is transferred outward from these micro-heat sources; since the micro-heat sources are uniformly dispersed throughout the grout, the grout achieves uniform heating from the inside out, which is different from the traditional external heating method and avoids the temperature gradient and surface overheating and insufficient internal temperature caused by heat conduction from the outside to the inside; the in-situ heating method directly stimulates the core of the cement hydration reaction, enabling the grout to quickly reach more than 70% of the design strength within tens of minutes.

[0089] S302: The high-frequency alternating magnetic field simultaneously drives micron- or millimeter-scale magnetic aggregates to generate an auxiliary thermal effect, which is superimposed on the thermal effect of nanoscale magnetic fluid.

[0090] In this embodiment, the auxiliary thermal effect refers to the heat generated by the eddy current effect in the micron- or millimeter-sized magnetic aggregate in the high-frequency alternating magnetic field. The heating mechanism is the same as that of the thermal effect of nanoscale magnetic fluid. However, due to the larger size of the magnetic aggregate, the eddy current path is longer and the resistance is smaller, so the generated Joule heat is distributed on another scale. Superposition means that the two thermal effects complement each other in space and accumulate each other in terms of heat, jointly improving the overall heating rate and temperature uniformity of the grout.

[0091] Specifically, under the influence of a high-frequency alternating magnetic field, the micron- or millimeter-sized magnetic aggregates in the grout are also subjected to electromagnetic induction, generating eddy currents within them. When these currents flow through the internal resistance of the aggregates, Joule heating is generated. This thermal effect, supplementing the nanoscale magnetic fluid thermal effect, contributes additional heat on a macroscopic scale. The nanoscale magnetic fluid provides micro-heat sources uniformly distributed throughout the grout, achieving uniform overall heating. Meanwhile, the micron- or millimeter-sized magnetic aggregates provide localized heat sources concentrated within larger particles. The two superimpose to form a multi-scale heat source distribution ranging from micron to millimeter in space. The heat is accumulated, further improving heating efficiency and temperature uniformity. The combined effect of multiple heat sources enables the grout to quickly enter a high-temperature curing state after compaction. The nano-magnetic fluid ensures that the grout matrix is ​​heated uniformly, while the magnetic aggregate forms a local heat-enhancing zone around it, promoting the hydration reaction and strength development at the interface between the aggregate and the cement matrix, so that the entire grout can achieve a uniform and sufficient curing effect in a short time. After the multi-scale thermal effects are superimposed, the temperature field of the grout tends to stabilize, providing a uniform initial temperature distribution for subsequent closed-loop constant temperature curing.

[0092] In one embodiment, such as Figure 4 As shown, in step S40, which involves real-time monitoring of the temperature parameters during the curing process of the grouting material and dynamically adjusting the output power of the high-frequency alternating magnetic field according to the preset curing temperature curve, the specific steps include:

[0093] S401: Real-time acquisition of temperature field data and strain data inside the grouting material.

[0094] In this embodiment, temperature field data refers to the temperature distribution information at different locations inside the grout, including the temperature value of each measuring point and its change over time; strain data refers to the deformation information of the grout during the curing process caused by temperature changes, chemical shrinkage, or volume changes.

[0095] Specifically, during the installation of the protective sleeve, fiber Bragg grating temperature and strain sensors are arranged at preset spatial positions on the inner wall of the protective sleeve or embedded at different depths within the grouting material. This ensures that the sensors can cover the central area, edge area, and critical parts where temperature gradients may occur within the grouting body. The sensors are connected to a fiber optic demodulator via fiber optic leads extending from the protective sleeve. During grouting and curing, the fiber optic demodulator continuously emits a broadband light source and receives the light signals reflected by the sensors. Based on the offset of the reflected wavelength, it calculates the temperature and strain values ​​at each measuring point in real time. The sensors continuously collect data at a sampling frequency of not less than 1 Hz, forming temperature field data and strain data inside the grouting material, which are then transmitted to the control system for storage and display. The FBG sensor has the advantages of high precision, resistance to electromagnetic interference, and good long-term stability, enabling reliable measurement in strong magnetic field environments and harsh underwater conditions.

[0096] S402: Based on the comparison between the collected temperature data and the preset curing temperature curve, the output power of the high-frequency alternating magnetic field is dynamically adjusted using a PID control algorithm to maintain the internal temperature of the grout within the preset target range.

[0097] In this embodiment, the curing temperature curve refers to the temperature-time target curve pre-defined based on factors such as different grout formulations, underwater ambient temperature, and structural volume. It reflects the temperature change path required for the grout to reach its design strength from the start of curing. The PID control algorithm refers to the proportional-integral-derivative control algorithm, which calculates the proportional, integral, and derivative control components by comparing the deviation between the actual temperature and the target temperature, and outputs the corresponding heating power adjustment amount to enable the actual temperature to track the target temperature quickly and stably.

[0098] Specifically, the control system stores a curing temperature curve for the current grout formulation. This curve includes target temperature values ​​and allowable deviation ranges for different time points. At the start of curing, the control system compares the real-time temperature data collected by fiber Bragg grating temperature and strain sensors with the target temperature at the current time point in the curing temperature curve, calculating the temperature deviation. The PID control algorithm calculates the control output in real-time based on the deviation: the proportional component responds to the current deviation, with larger deviations resulting in greater heating power adjustments; the integral component eliminates accumulated deviations, ensuring the temperature does not deviate from the target during long-term curing; the derivative component predicts the deviation trend, suppressing temperature overshoot and oscillations; and the control output is converted into a high-frequency alternating magnetic field output power adjustment signal and sent. The adjustable frequency induction power supply to the variable frequency electromagnetic module increases or decreases the output power of the electromagnetic coil array in real time. When the actual temperature is lower than the target temperature, the PID algorithm outputs a positive control quantity to increase the heating power, causing the temperature to rise. When the actual temperature is higher than the target temperature, it outputs a negative control quantity to decrease the heating power or stop heating, causing the temperature to fall naturally. When the temperature approaches the target value, the control quantity tends to stabilize, keeping the temperature stable within the preset range. This ensures that the grouting material is always in the optimal temperature environment throughout the curing process, effectively avoiding slow curing due to excessively low temperatures or thermal stress cracking due to excessively high temperatures, thus guaranteeing the quality of underwater grouting reinforcement. After curing is completed, the control system automatically records all temperature and strain data, generating a curing process log for use in construction quality assessment.

[0099] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0100] In one embodiment, a self-compacting and induction heating rapid-setting underwater grouting system based on variable frequency electromagnetic drive is provided. This system corresponds one-to-one with the self-compacting and induction heating rapid-setting underwater grouting method based on variable frequency electromagnetic drive described in the above embodiments. Figure 5 As shown, the underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive includes:

[0101] The grouting module is used to inject grout containing magnetic materials into the protective sleeve surrounding the underwater defect area;

[0102] A variable frequency electromagnetic module is connected to the protective sleeve and disposed outside the protective sleeve, used to selectively generate a low-frequency pulsed alternating magnetic field or a high-frequency alternating magnetic field and act on the micro-nano multi-scale magnetic response grout.

[0103] The anti-backflow grouting channel is connected at one end to the grouting module and at the other end to the protective sleeve, and is used to pump the micro-nano multi-scale magnetic response grouting material into the interior of the protective sleeve.

[0104] A monitoring and closed-loop feedback module is installed on the inner wall of the protective sleeve and electrically connected to the frequency conversion electromagnetic module. It is used to collect temperature and strain parameters during the curing process of the grout in real time and dynamically adjust the output power of the frequency conversion electromagnetic module according to the collected parameters.

[0105] In this embodiment, the grouting module refers to the equipment assembly used to pump the prepared micro-nano multi-scale magnetic response grouting material into the protective sleeve at a set pressure and flow rate, including a storage tank, a pumping device, and a pipe interface; the frequency conversion electromagnetic module refers to the electrical system that can output alternating current of different frequencies according to control commands and drive an electromagnetic coil array to generate a magnetic field of corresponding frequencies, including an adjustable frequency induction power supply and an electromagnetic coil array; the anti-backflow grouting channel refers to the grout delivery channel connecting the grouting module and the protective sleeve, used to ensure unidirectional flow of the grout; the monitoring and closed-loop feedback module refers to the real-time monitoring and power regulation unit based on fiber Bragg grating temperature and strain sensors and a control system.

[0106] Specifically, the grouting module is equipped with a grout mixing tank and a screw pump. The pre-prepared micro-nano multi-scale magnetic response grout in the mixing tank is pumped through an anti-backflow grouting channel to the protective sleeve. The pumping pressure and flow rate are adjusted according to the grouting depth and grout viscosity. The variable frequency electromagnetic module includes a tunable frequency induction power supply and an electromagnetic coil array. The tunable frequency induction power supply is positioned on or below the water surface outside the protective sleeve. The electromagnetic coil array is arranged around the outer wall of the protective sleeve. The tunable frequency induction power supply outputs a low frequency (10) according to control commands. An alternating current (Hz to 200Hz) or high-frequency (100kHz to 400kHz) is applied to an electromagnetic coil array, driving the coils to generate an alternating magnetic field of the corresponding frequency. The anti-backflow grouting channel includes a flexible grouting channel and a grout outlet nozzle. One end of the flexible grouting channel is connected to the grouting module, and the other end is connected to the grout outlet nozzle. The grout outlet nozzle is located inside the protective sleeve and is equipped with a miniature one-way pressure valve. When the pumping pressure exceeds the threshold, the one-way valve opens, and the grout is injected forward into the protective sleeve. When pumping stops, the one-way valve... The system automatically closes under spring force and external water pressure to prevent external water pressure from causing the grout to backflow or overflow. The monitoring and closed-loop feedback module includes a fiber Bragg grating (FBG) temperature and strain sensor and a control module. The FBG temperature and strain sensor is installed on the inner wall of the protective sleeve and is electrically connected to the control module. It is used to collect real-time temperature field data and strain data inside the grout. The sensor continuously collects data at a sampling frequency of not less than 1Hz and transmits it to the control module via optical fiber. The control module is electrically connected to the FBG temperature and strain sensor and the frequency conversion electromagnetic module. It is used to receive the temperature parameters fed back by the sensor, compare the real-time temperature with the preset curing temperature curve, and use a PID control algorithm to dynamically adjust the output power of the adjustable frequency induction power supply to maintain the internal temperature of the grout within the preset target range. The grouting module, the frequency conversion electromagnetic module, the anti-backflow grouting channel, and the monitoring and closed-loop feedback module are electrically connected and transmit signals through waterproof cables and optical fibers. All modules work together to form a complete closed-loop grouting reinforcement system.

[0107] Specific limitations regarding the underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive can be found in the limitations of the underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive mentioned above, and will not be repeated here. Each module in the aforementioned underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive can be implemented entirely or partially through hardware and combinations thereof. These modules can be embedded in the processor of the control device or independent of it.

[0108] The present invention and its embodiments have been described above. This description is not restrictive. The accompanying drawings are only one embodiment of the present invention. The actual structure is not limited to this. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A method for underwater grouting self-compacting and induction heating rapid setting based on variable frequency electromagnetic drive, characterized in that, The underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive includes the following steps: A protective sleeve is installed around the underwater diseased area, an electromagnetic coil array is arranged on the protective sleeve, and grouting material is injected into the sleeve. The grouting material is a micro-nano multi-scale magnetic response grouting material containing magnetic materials. By applying a low-frequency pulsed alternating magnetic field through the electromagnetic coil array, the magnetic material in the grout is driven to generate magneto-induced micro-vibration, so that the grout self-fills and compacts under the drive of the magnetic field. The low-frequency pulsed alternating magnetic field is switched to a high-frequency alternating magnetic field to induce heating of the compacted grout, so that the grout heats up uniformly from the inside and accelerates solidification. The temperature parameters during the curing process of the grout are monitored in real time, and the output power of the high-frequency alternating magnetic field is dynamically adjusted according to the preset curing temperature curve to achieve closed-loop constant temperature curing.

2. The underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive according to claim 1, characterized in that: The grouting material includes fast-hardening cement-based repair materials, nano-scale magnetic fluid, and micron- or millimeter-scale magnetic aggregates. The nanoscale magnetic fluid improves the rheological properties of the grouting material under a low-frequency pulsed alternating magnetic field and generates heat as a heat medium under a high-frequency alternating magnetic field. The micron- or millimeter-sized magnetic aggregates generate macroscopic mechanical vibration force under a low-frequency pulsed alternating magnetic field.

3. The underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive according to claim 1, characterized in that, The step of applying a low-frequency pulsed alternating magnetic field through the electromagnetic coil array to drive the magnetic material in the grout to generate magneto-induced micro-vibrations specifically includes: The low-frequency pulsed alternating magnetic field drives the micron- or millimeter-sized magnetic aggregates in the grout to generate high-frequency flipping and reciprocating displacement, breaking the flocculation structure of the grout to reduce the apparent viscosity, allowing the grout to penetrate into the dead corners of the structure and expel air bubbles. The low-frequency pulsed alternating magnetic field simultaneously drives the nanoscale magnetofluid to generate microscopic disturbances. The synergistic effect of these microscopic disturbances and the macroscopic vibrations of the magnetic aggregates results in rheological improvements in the grouting material at both the macroscopic and microscopic scales.

4. The underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive according to claim 1, characterized in that, The step of switching the low-frequency pulsed alternating magnetic field to a high-frequency alternating magnetic field to induction heat the compacted grout material specifically includes: The high-frequency alternating magnetic field acts on the nanoscale magnetic fluid inside the grout, causing the nanoscale magnetic fluid to generate eddy current effect, Niehr relaxation loss and hysteresis loss, converting electromagnetic energy into heat energy, so that the grout heats up uniformly from the inside to the outside to achieve in-situ solidification. The high-frequency alternating magnetic field simultaneously drives micron- or millimeter-scale magnetic aggregates to generate an auxiliary thermal effect, which is superimposed on the thermal effect of nanoscale magnetic fluid.

5. The underwater grouting self-compacting and induction heating rapid setting method based on variable frequency electromagnetic drive according to claim 1, characterized in that, The real-time monitoring of temperature parameters during the curing process of the grout, and the dynamic adjustment of the output power of the high-frequency alternating magnetic field according to the preset curing temperature curve, specifically includes: Real-time acquisition of temperature field and strain data inside the grouting material; Based on the comparison between the collected temperature data and the preset curing temperature curve, the output power of the high-frequency alternating magnetic field is dynamically adjusted using a PID control algorithm to maintain the internal temperature of the grout within the preset target range.

6. A self-compacting and induction heating rapid setting system for underwater grouting based on variable frequency electromagnetic drive, characterized in that, include: The grouting module is used to inject grout containing magnetic materials into the protective sleeve surrounding the underwater defect area; A variable frequency electromagnetic module is connected to the protective sleeve and disposed outside the protective sleeve, used to selectively generate a low-frequency pulsed alternating magnetic field or a high-frequency alternating magnetic field and act on the micro-nano multi-scale magnetic response grout. The anti-backflow grouting channel is connected at one end to the grouting module and at the other end to the protective sleeve, and is used to pump the micro-nano multi-scale magnetic response grouting material into the interior of the protective sleeve. A monitoring and closed-loop feedback module is installed on the inner wall of the protective sleeve and electrically connected to the frequency conversion electromagnetic module. It is used to collect temperature and strain parameters during the curing process of the grout in real time and dynamically adjust the output power of the frequency conversion electromagnetic module according to the collected parameters.

7. The underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive according to claim 6, characterized in that: The frequency conversion electromagnetic module includes an adjustable frequency induction power supply and an electromagnetic coil array. The adjustable frequency inductive power supply is disposed outside the protective sleeve and is electrically connected to the electromagnetic coil array; The electromagnetic coil array is arranged around the outside of the protective sleeve and is electrically connected to the adjustable frequency inductive power supply.

8. The underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive according to claim 6, characterized in that: The anti-backflow grouting channel includes a flexible grouting channel and a grout outlet nozzle; One end of the flexible grouting channel is connected to the grouting module, and the other end is connected to the grout outlet nozzle; The grout outlet nozzle is located inside the protective sleeve and connected to the flexible grouting channel. The grout outlet nozzle is equipped with a miniature one-way pressure valve.

9. The underwater grouting self-compacting and induction heating rapid setting system based on variable frequency electromagnetic drive according to claim 6, characterized in that: The monitoring and closed-loop feedback module includes a fiber Bragg grating temperature and strain sensor and a control module. The fiber Bragg grating temperature and strain sensor is installed on the inner wall of the protective sleeve and is electrically connected to the control module to collect temperature field data and strain data inside the grouting material in real time. The control module is electrically connected to the fiber Bragg grating temperature and strain sensor and the frequency conversion electromagnetic module, respectively, and is used to dynamically adjust the output power of the frequency conversion electromagnetic module according to the temperature parameters fed back by the fiber Bragg grating temperature and strain sensor.

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