Test system and evaluation method for grouting diffusion of narrow crack under multi-field coupling

Abstract

The invention discloses a narrow crack grouting diffusion test system under multi-field coupling and an evaluation method, and relates to the technical field of grouting diffusion analysis. The system comprises a test bed, a crack simulation device, a grouting device, a water injection device, a drainage flow monitoring device and an integrated data acquisition and processing platform. The crack simulation device is provided with a grouting hole and a water injection hole, grouting and water injection processes under different crack conditions can be simulated, a self-heating optical fiber is further embedded in the crack simulation device, and the system is provided with a pressure sensor, a point type temperature sensor, a water flow velocity sensor, an image acquisition device and an optical fiber signal demodulator. Data such as temperature, pressure and diffusion images are collected in real time and fed back to the integrated data collecting and processing platform. The system simulates various complex dynamic water environments, analyzes the influence of factors such as crack width, roughness, water flow velocity, water pressure and temperature on a slurry diffusion rule, reveals a diffusion mechanism, optimizes grouting parameters, and provides a basis for material design and repair in engineering.

Description

Technical Field

[0001] This invention relates to the field of grout diffusion test analysis and evaluation technology, specifically to a grout diffusion test system and evaluation method for narrow cracks under multi-field coupling. Background Technology

[0002] As a crucial component of the subway civil engineering structure, the integral track bed of a subway tunnel is subject to various factors, including long-term train vibration, hydrogeological conditions, construction quality, and surrounding engineering activities. In some sections, the track bed may gradually decouple from the tunnel segments or invert structure, leading to separation or voids. Among these, the interface decoupling between the integral track bed and the tunnel segments is particularly severe, potentially causing localized settlement or heave, resulting in cracks or partial damage to the segments. This ultimately affects the structural integrity of the tunnel and track, as well as the smoothness of the track system and the overall safety of the subway. Once interface decoupling occurs, repair work becomes significantly more difficult and costly. It typically requires complex repair operations, such as injecting grouting materials at the interface, reinforcing the interface, or even replacing the entire track bed.

[0003] In some subway tunnels located in water-rich environments, after interfacial delamination, a narrow, water-filled fissure forms at the interlayer interface. Under these conditions, ordinary grouting materials are prone to segregation, material loss, loose gel structure, and even voids and insufficient durability. Therefore, when repairing overall track bed delamination defects, the diffusion behavior of the repair material within this narrow, water-filled fissure will significantly affect the repair outcome.

[0004] Currently, existing technologies have conducted relatively in-depth research on the water dispersion resistance of grouts, and various model test devices have been proposed to study the influence and diffusion mechanism of grouts with different water-cement ratios, different grouting pressures, and different crack openings. Although most existing studies on the diffusion mode of grout in dynamic water grouting focus on flat or intersecting cracks, obtaining information on the effects of various factors on grout diffusion, the crack interface characteristics and environmental characteristics in actual engineering projects are often highly complex.

[0005] For example, Chinese patent document CN105136641A discloses a model device for simulating a permeation grouting diffusion test under dynamic water conditions. This device includes a medium filling device, a grouting module, a water injection module, and a grouting parameter acquisition device. The grouting module includes a grouting hole located at the top of the medium filling device, connected to a grouting pump via a grouting pipe. The water injection module includes a water inlet on the side wall of the medium filling device, connected to a water supply device via a water supply pipe. The grouting parameter acquisition device is located on the side wall of the medium filling device. Grouting and water injection are simulated into the medium filling device via the grouting pump and the water supply device, and relevant parameters are collected using the grouting parameter acquisition device, thereby simulating a permeation grouting diffusion test under dynamic water conditions. However, this device only simulates simple porous grouting and cannot simulate complex grouting environments.

[0006] For example, Chinese patent document CN119534227A proposes an experimental device and method for grouting tunnels in composite strata under simulated dynamic water conditions. This device creates an adjustable dynamic water environment through a water supply and drainage system to simulate different seepage field conditions. It uses a transparent model box and disc-shaped glass particles to simulate complex strata, enabling visual observation of the grout diffusion process. While this device has advantages in simulating dynamic water conditions and composite strata, it lacks the ability to control parameters such as fracture width and roughness, making it difficult to study the diffusion mechanism of grout in fracture networks. Furthermore, it does not consider the impact of dynamic changes in water flow velocity on grout scouring, nor does it simulate the effects of chemical corrosion or temperature changes on grout solidification performance. The diffusion patterns of grouts with different properties often exhibit significant differences. Simultaneously, the scouring and dilution effects of water must be considered, placing higher demands on underwater non-dispersible toughness repair materials. Therefore, studying their diffusion patterns and key influencing factors is crucial. Model experiments, as an important means of exploring the diffusion characteristics of materials within structural fractures, still have insufficient research on the grouting environment and fracture interface characteristics.

[0007] Therefore, there is an urgent need to develop a grout diffusion test system and evaluation method that can simulate the grout diffusion process under complex dynamic water conditions. Summary of the Invention

[0008] The technical problem this invention aims to solve is to provide a multi-field coupled grout diffusion test system and evaluation method for narrow cracks. Its purpose is to address the shortcomings of existing technologies and solve the research problem of diffusion law of non-dispersible toughness repair materials in underwater repair engineering, especially in complex dynamic water environments. This invention provides an underwater non-dispersible toughness repair material diffusion test system that can simulate the grout diffusion process in complex dynamic water environments, study the influence of multi-field coupled factors such as crack width, roughness, water flow velocity, water pressure, temperature, and chloride erosion on the grout diffusion law, and investigate the diffusion mechanism and influence law of grout in crack structures, thereby providing a scientific basis for the design and optimization of repair materials in practical engineering.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a multi-field coupled grouting diffusion test system for narrow cracks, comprising a test bench, a crack simulation device, a grouting device, a water injection device, a drainage flow monitoring device, and an integrated data acquisition and processing platform; wherein:

[0011] The test bench includes a bench body; a crack simulation device is mounted on the bench body, specifically including a transparent base plate and a top plate, with the top plate covering the base plate. Rubber strips are installed around the edges of both plates to form a waterstop to prevent water or material slurry from overflowing from the perimeter. The opposite surfaces of the two plates are rough, and a crack is formed between the two plates. The bench body is equipped with a gap adjustment device to adjust the gap distance between the base plate and the top plate, used to adjust the width of the crack. The crack simulation device is equipped with grouting holes, which are connected to a grouting device through pipelines (e.g., high-pressure pipes) for simulating grouting into the crack simulation device.

[0012] The water injection device is used to simulate water injection into the fracture simulation device and control the temperature and flow rate of the injected water. The water injection device mainly consists of a water tank with heating and cooling functions, a water pressure pump, and a water flow rate regulator. The fracture simulation device is equipped with a water injection hole and a drain hole. The water injection hole is connected to the water pressure pump through a water injection pipe, and water is injected into the fracture through the water pressure pump. A point temperature sensor is installed on the outer wall of the water injection pipe connected to the water injection hole to monitor the changes in the water supply temperature in real time. The drain hole is connected to the drain flow monitoring device through a drain pipe (e.g., a corrugated pipe).

[0013] The base plate of the fracture simulation device is also embedded with a self-heating optical fiber, which is connected to an optical fiber signal demodulator to heat the slurry and measure the temperature change during the diffusion process. Pressure sensor connection holes are also provided on the base plate, which are connected to the pressure sensor through a pipe (such as a corrugated pipe).

[0014] An image acquisition device is fixedly installed on the main body of the frame. The image acquisition device is located directly above the center of the fracture simulation device and is set parallel to the fracture simulation device. It is used to acquire image data of slurry diffusion in the fracture.

[0015] The aforementioned fiber optic signal demodulator, point temperature sensor, pressure sensor, water flow velocity sensor, image acquisition device, and integrated data acquisition and processing platform constitute a data acquisition and monitoring unit.

[0016] In this invention, an image acquisition device is used to acquire image data of grout diffusion in the fissure; a self-heating optical fiber is heated during the simulated grouting process, and a fiber optic signal demodulator is used to acquire data on grout temperature changes and ambient temperature changes during grout diffusion; point-type temperature sensors installed through the injection holes acquire the initial water injection temperature for comparison and verification, further validating the temperature monitoring accuracy; a pressure sensor is used to monitor pressure changes during grout injection and diffusion in the fissure, especially the pressure change pattern during grouting; and a water flow velocity sensor is used to acquire water flow velocity.

[0017] The grout is heated during the diffusion process using a self-heating optical fiber and an optical fiber signal demodulator, and temperature changes under high temperature and high water temperature conditions are monitored in real time. The water flow rate is precisely controlled by a water pressure pump and a flow velocity sensor to simulate the grout diffusion process under different flow rate conditions. A pressure sensor is used to monitor the pressure changes perpendicular to the panel during grouting, ensuring that the overall pressure of the panel remains within a controllable range during the grouting process.

[0018] The data acquired by the data acquisition device (including the aforementioned sensors and image acquisition device) in this invention is transmitted to an integrated data acquisition and processing platform. The platform processor extracts features from the acquired geometric change data. Specifically, for image data, the slurry diffusion process captured in real time by the image acquisition device (camera) is two-dimensional or three-dimensional image data. The acquired image data is processed by the integrated data acquisition and processing platform to extract key features, such as diffusion radius, diffusion curvature, and diffusion speed, through image processing technology. The integrated data acquisition and processing platform also extracts data features at specific time points or stages based on the trend analysis of time-varying data such as temperature, pressure, and flow rate. Furthermore, it determines the impact of changes in the geometry of the fractures (such as fracture width and fracture surface roughness) on slurry diffusion through data analysis.

[0019] Furthermore, the gap adjustment device is an eccentric wheel structure, which includes a fixed bracket, a connecting rod, and an eccentric wheel;

[0020] One end of the fixed support is a free end, and the other end is connected to the main body of the platform. The eccentric wheel is rotatably mounted on the fixed support away from its free end via a rotating shaft. A fixed column is provided at the end of the fixed support near its free end. The eccentric wheel and the top plate of the fracture simulation device are respectively provided with a first connecting column and a second connecting column. The connecting rod is provided with a sliding groove. One end of the connecting rod sliding groove is fixed to the fixed support via the fixed column and can rotate around the fixed column. The first connecting column is movably engaged in the sliding groove. The other end of the connecting rod sliding groove is mounted on the top plate of the fracture simulation device via the second connecting column and can rotate around the second connecting column. The fixed support, the eccentric wheel, and the top plate of the fracture simulation device are connected and transmit motion through the fixed column, the rotating shaft, the first connecting column, and the second connecting column. When the eccentric wheel is rotated via the rotating shaft, the connecting rod produces a certain offset swing, thereby driving the top plate to move up and down to adjust the opening of the fracture.

[0021] The center hole of the eccentric wheel can precisely match the outer diameter of the rotating shaft. One end of the rotating shaft is inserted into the center hole of the eccentric wheel, ensuring there is no gap between the shaft and the eccentric wheel. The other end of the shaft is fixed to the bracket. The eccentric wheel and the rotating shaft are installed with bolts and nuts, ensuring that the eccentric wheel can rotate synchronously with the rotating shaft without slippage or loosening during rotation.

[0022] Furthermore, the test bench body is also equipped with a slide rail, and the top plate cooperates with the test bench through the slide rail to restrict the top plate to move only in the vertical direction.

[0023] Furthermore, the frame body is provided with an image acquisition device fixing mechanism for fixing the image acquisition device directly above the center of the fracture simulation device; the image acquisition device fixing mechanism includes a fixator, a lead screw, and a handwheel; one end of the lead screw is fixed to the frame body, the handwheel is installed at the bottom of the lead screw, the fixator is used to fix the image acquisition device, and the handwheel is rotated to drive the lead screw to move up and down along the axis, thereby adjusting the installation height of the image acquisition device.

[0024] Furthermore, the drainage flow monitoring device includes a graduated water collection cylinder, a timer, and a water level sensor. The timer starts timing when water inflow is detected, and the water level sensor is installed on the inner wall of the water collection cylinder to monitor the water level height, thereby calculating the real-time drainage volume and the water flow velocity. This serves two purposes: firstly, it is used to set the dynamic water flow velocity in the early stages of grouting in a dynamic water environment; secondly, it is used to record the drainage flow rate during static water diffusion tests.

[0025] Furthermore, the platform body is composed of several vertical rods, several horizontal rods, and a base plate support, which is used to place the crack simulation device.

[0026] Furthermore, the top and bottom plates of the crack simulation device are arc-shaped plates of the same size, and the bottom plate bracket of the platform body is an arc-shaped plate of the corresponding shape and size. The crack simulation device is set on the arc-shaped bottom plate bracket.

[0027] Furthermore, the top and bottom plates of the fracture simulation device are made of transparent acrylic sheets, allowing the diffusion of the slurry inside the device to be seen through the sheets.

[0028] Furthermore, the formulas for calculating the roughness of the bottom plate and top plate of the crack simulation device are as follows:

[0029]

[0030] Among them, R a Let L be the average roughness, L be the measurement length, and y(x) be the surface profile height.

[0031] Secondly, the present invention provides a method for evaluating the diffusion effect of grouting in narrow cracks under multi-field coupling, based on the multi-field coupling grouting diffusion test system for narrow cracks as described in the claims, specifically including the following steps:

[0032] S1. Data Acquisition: Image data of grout diffusion in the fissures is acquired using an image acquisition device; heating is achieved during the simulated grouting process using a self-heating optical fiber, and data on grout temperature changes and ambient temperature changes during grout diffusion are acquired using an optical fiber signal demodulator; the initial water injection temperature is acquired using point-type temperature sensors installed in the injection holes for comparison and verification, further validating the temperature monitoring accuracy; pressure changes of the grout in the fissures during injection and diffusion perpendicular to the panel are monitored using a pressure sensor; and water flow velocity is acquired using a water flow velocity sensor.

[0033] S2. Image Processing and Feature Extraction: Using image processing techniques, key features (such as diffusion radius, diffusion curvature, diffusion velocity, etc.) are extracted from two-dimensional or three-dimensional image data of the slurry diffusion process captured in real time by the image acquisition device. Trend analysis of the acquired temperature, pressure, and flow rate data over time is used to extract data features at specific time points or stages. Furthermore, the influence of changes in the geometry of the fractures (such as fracture width and fracture surface roughness) on slurry diffusion is determined through data analysis.

[0034] S3. Construct a slurry diffusion effect prediction model: Train the model using machine learning algorithms; adjust hyperparameters (such as the number of trees, maximum depth, minimum number of sample splits, etc.), find the optimal model configuration through cross-validation, and evaluate and optimize the model.

[0035] S4. Prediction and evaluation of grout diffusion effect: The optimized model is used to predict the effect of grout diffusion, and the grouting parameters are optimized based on the collected data.

[0036] The present invention has the following beneficial effects:

[0037] This invention provides a multi-field coupled grouting diffusion test system for narrow cracks. The system includes a test bench, a crack simulation device, a grouting device, a water injection device, a drainage flow monitoring device, and an integrated data acquisition and processing platform. The crack simulation device is equipped with grouting holes and water injection holes to simulate grouting and water injection processes under different crack conditions. The device also incorporates a self-heating optical fiber and is equipped with a pressure sensor, a point-type temperature sensor, a water flow velocity sensor, an image acquisition device, and an optical fiber signal demodulator to collect real-time data such as temperature, pressure, and diffusion images, and feed this data back to the integrated data acquisition and processing platform.

[0038] The grouting diffusion test system provided by this invention can simulate multi-field coupled environments, including temperature field, water flow velocity, and pressure field. A self-heating optical fiber is directly embedded in the base plate of the fracture simulation device, enabling real-time reflection of temperature changes in the fracture environment. The water flow velocity is precisely controlled by a precision water pressure pump and a water flow velocity sensor to simulate the grout diffusion process under different flow velocity conditions.

[0039] The grouting diffusion test system of this invention can adjust the crack width, roughness, temperature, water flow velocity, water pressure and chloride concentration (by adding chloride to the water) to achieve accurate simulation of multi-field coupled environment. This is more realistic and comprehensive than conventional single-factor, simplified crack model test systems, and can improve the reliability of diffusion law research.

[0040] The system's heavy-duty pressure sensors monitor pressure changes perpendicular to the panel during grouting, ensuring the overall panel pressure remains within a controllable range. In practical engineering, such as the separation layer between track bed and segments, cracks are often horizontal or near-horizontal. Grout is typically injected vertically to overcome gravity and fill the entire crack. Vertical grouting facilitates symmetrical diffusion, making it easier to analyze diffusion morphology and standardize comparisons of test results under different conditions. Furthermore, vertical grouting, combined with a visualization acrylic plate, allows for observation of grout diffusion boundaries and morphological changes within the cracks. The image acquisition device is positioned directly above the panel, ensuring flat image data acquisition and facilitating subsequent image recognition and analysis. Under grouting conditions, the panel experiences outward pressure; monitoring the vertical pressure helps determine abnormal bulging, excessive crack opening changes, or material overflow, aiding in model stability control. Simultaneously, the combination of drainage holes and a water collection cylinder facilitates diffusion range or seepage analysis. By combining drainage measurements with images, diffusion behavior can be evaluated from multiple dimensions, without relying on data from a single sensor.

[0041] This system analyzes real-time data collected during experiments to establish a predictive model for grout diffusion under different working conditions. The specific process includes: analyzing the diffusion patterns and influencing factors of the grout based on multi-field data such as temperature, pressure, and flow rate; training the predictive model using experimental data to optimize grout diffusion parameters (such as grout pressure, temperature, and flow rate) and improve repair effectiveness; dynamically adjusting grouting parameters based on experimental results; predicting the grout diffusion behavior using the predictive model; and providing real-time feedback to the experimental operating system for rapid adjustment of experimental conditions and optimization of repair results. In this way, the system can automatically evaluate the grout diffusion effect under different experimental conditions and propose optimal grouting parameters to improve the overall reinforcement effect.

[0042] Compared with traditional grouting diffusion devices such as CN105136641A, the device of this invention has achieved significant improvements in structural design, material adaptability, experimental condition simulation capabilities, and data acquisition methods. It can more realistically, comprehensively, and systematically reflect the diffusion behavior and performance of materials used in repairing peeling cracks in actual subway engineering. In this experimental system and scheme, the crack structure adopts an arc-shaped interface structure to simulate the peeling morphology between the overall subway track bed and tunnel segments. Compared with the cylindrical homogeneous container of CN105136641A, this better reflects the spatial characteristics and interface constraints of "narrow water-filled cracks between layers" in actual engineering. The design of this device aligns with current research needs on the diffusion, filling, and erosion resistance performance of underwater non-dispersible materials in dynamic water environments, representing a key technical focus not addressed in CN105136641A. This device offers strong controllability in grouting diffusion behavior. Through adjustable crack opening and roughness design, it can simulate various stages of disease development and peeling interface states, making it more suitable for system parameter research and pattern summarization. In contrast, CN105136641A lacks a dedicated crack structure and primarily uses porous media for grouting. Compared to CN105136641A's lateral water injection to simulate a simple flow environment, this device allows for controllable water flow path and velocity, simulating actual tunnel groundwater seepage and scouring environments. It is suitable for studying material diffusion, solidification, and deformation behavior under different dynamic water conditions, resulting in a more realistic dynamic water environment simulation. The device's acrylic plate is detachable, replaceable, and adjustable, facilitating multi-condition, multi-material, and multi-parameter diffusion behavior experiments with high efficiency. This device also features a more comprehensive monitoring system, supporting the installation of various sensors (pore pressure, water flow velocity, self-heating fiber optics, etc.) to achieve real-time dynamic monitoring of multiple points within the cracks, obtaining high-precision, multi-dimensional experimental data.

[0043] In summary, the multi-field coupled grouting diffusion test system for narrow cracks provided by this invention can simulate the grout diffusion process under complex dynamic water environment. By analyzing the influence of multi-field coupled factors such as crack width, roughness, water flow velocity, water pressure, temperature, and chloride salt corrosion on the grout diffusion law, as well as the diffusion mechanism and influence law of grout in crack structure, it can provide a scientific basis for the design and optimization of repair materials in actual engineering. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the grouting diffusion test system for narrow cracks under multi-field coupling provided in an embodiment of the present invention.

[0045] Figure 2 This is a schematic diagram of the structure of the test bench according to an embodiment of the present invention.

[0046] Figure 3 This is a schematic diagram of the eccentric wheel structure according to an embodiment of the present invention.

[0047] Figure 4 This is a schematic diagram of the structure of the crack simulation device according to an embodiment of the present invention.

[0048] Figure 5 This is a schematic diagram of the arrangement of the grouting holes, water injection holes, and water pressure sensor connection holes of the fracture simulation device according to an embodiment of the present invention.

[0049] Figure 6 This is a schematic diagram of the arrangement of the drainage holes and water collection cylinder of the fracture simulation device according to an embodiment of the present invention.

[0050] Figure 7 This is a schematic diagram of the arrangement structure of the point-type temperature sensor according to an embodiment of the present invention.

[0051] Figure 8 This is a schematic flowchart of the slurry diffusion test method according to an embodiment of the present invention.

[0052] Figure 9 This is a schematic diagram illustrating the process of processing and converting image data acquired by the camera in an embodiment of the present invention.

[0053] Figure Descriptions: 1. Test bench; 1-1. Base plate bracket; 1-2. Vertical rod; 1-3. Horizontal rod; 1-4. Base rod; 2. Crack simulation device; 2-1. Top plate; 2-2. Base plate; 2-3. Crack; 2-4. Grouting hole; 2-5. Water injection hole; 2-6. Pressure sensor connection hole; 2-7. Drainage hole; 3. Grouting device; 4. Water injection device; 5. Pressure sensor; 6. Camera; 7. Fiber optic signal demodulator; 8. Eccentric wheel structure; 8-1. Fixed bracket; 8-2. Connecting rod; 8-3. Eccentric wheel; 8-4. Fixed column; 8-5. Rotating shaft; 8-6. First connecting column; 8-7. Second connecting column; 9. Lead screw; 10. Water collection cylinder; 11. Slide rail; 12. Camera holder; 13. Self-heating fiber optic cable; 14. Point temperature sensor. Detailed Implementation

[0054] The technical solutions in the embodiments of the present invention will be further explained below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0055] Example 1

[0056] See Figure 1-7 This invention provides a multi-field coupled grouting diffusion test system for narrow cracks, comprising: a test bench 1, a crack simulation device 2, a grouting device 3, a water injection device 4, a drainage flow monitoring device, and an integrated data acquisition and processing platform; wherein:

[0057] The test bench 1 includes a bench body; the crack simulation device 2 is mounted on the bench body, specifically including a bottom plate 2-2 and a top plate 2-1. The top plate 2-1 covers the bottom plate 2-2. Rubber strips are provided around the edges of the two plates to form a waterstop to prevent water or material slurry from overflowing from the perimeter. The opposite side of the two plates is a rough surface, and a crack 2-3 is formed between the two plates. The bench body is provided with a gap adjustment device for adjusting the gap distance between the bottom plate 2-2 and the top plate 2-1, which is used to adjust the width of the crack 2-3. The crack simulation device is provided with a grouting hole 2-4, which is connected to a grouting device 3 through a pipeline (e.g., a high-pressure pipe) for simulating grouting into the crack simulation device 2.

[0058] Water injection device 4 is used to simulate water injection into fracture simulation device 2 and control the temperature and flow rate of the injected water. Water injection device 4 mainly consists of a water tank with heating and cooling functions, a water pressure pump, and a water flow rate regulator. Fracture simulation device 2 is provided with water injection hole 2-5 and drain hole 2-4. Water injection hole 2-5 is connected to water pressure pump through water injection pipe. Water is injected into the fracture through water pressure pump. Point temperature sensor 14 is installed on the outer wall of water injection pipe connected to water injection hole 2-5 for real-time monitoring of water supply temperature changes. Drain hole 2-7 is connected to drainage flow monitoring device through drainage pipe (e.g., corrugated pipe).

[0059] The base plate 2-2 of the fracture simulation device 2 is also embedded with a self-heating optical fiber 13, which is connected to the optical fiber signal demodulator 7 for heating the slurry and measuring the temperature change during the diffusion process; the base plate 2-2 is also provided with pressure sensor connection holes 2-6, which are connected to the pressure sensor 5 through a pipe (e.g., a corrugated pipe).

[0060] An image acquisition device is fixedly installed on the frame body. In this embodiment, it is a camera 6. The camera 6 is located directly above the center of the fracture simulation device 2 and is set parallel to the fracture simulation device 2. It is used to acquire image data of slurry diffusion in the fracture.

[0061] The fiber optic signal demodulator 7, point temperature sensor 14, pressure sensor 5, water flow velocity sensor (not shown in the figure), camera 6, and integrated data acquisition and processing platform are described. Figure 1 (Not shown in the image) forms a data acquisition and monitoring unit.

[0062] In this invention, camera 6 is used to acquire image data of grout diffusion in the fissure; self-heating optical fiber 13 is heated during the simulated grouting process, and the grout temperature change and ambient temperature change data during grout diffusion are acquired through optical fiber signal demodulator 7; the initial water injection temperature is acquired through point temperature sensors 14 installed through water injection holes 2-5 for comparison and verification, further verifying the temperature monitoring accuracy; pressure sensor 5 is used to monitor the pressure change during grout injection and diffusion in the fissure, especially the pressure change pattern during grouting; and water flow velocity sensor is used to acquire water flow velocity.

[0063] The grout is heated during the diffusion process using a self-heating optical fiber 13 and an optical fiber signal demodulator 7, and temperature changes under high temperature and high water temperature conditions are monitored in real time. The water flow rate is precisely controlled by a water pressure pump and a flow rate sensor to simulate the grout diffusion process under different flow rate conditions. The pressure sensor 5 is used to monitor the pressure changes perpendicular to the panel during the grouting process, ensuring that the overall pressure of the panel is within a controllable range during the grouting process.

[0064] The data acquired by the data acquisition device (including the aforementioned sensors and image acquisition device) in this invention is transmitted to an integrated data acquisition and processing platform. The platform processor extracts features from the acquired geometric change data. Specifically, for image data, the slurry diffusion process captured in real time by the image acquisition device (camera) is two-dimensional or three-dimensional image data. The acquired image data is processed by the integrated data acquisition and processing platform to extract key features, such as diffusion radius, diffusion curvature, and diffusion speed, through image processing technology. The integrated data acquisition and processing platform also extracts data features at specific time points or stages based on the trend analysis of time-varying data such as temperature, pressure, and flow rate. Furthermore, it determines the impact of changes in the geometry of the fractures (such as fracture width and fracture surface roughness) on slurry diffusion through data analysis.

[0065] In a preferred embodiment, the gap adjustment device in this embodiment is an eccentric wheel structure 8, which includes a fixed bracket 8-1, a connecting rod 8-2, and an eccentric wheel 8-3.

[0066] One end of the fixed bracket 8-1 is a free end, and the other end is connected to the platform body. In this embodiment, it is specifically fixedly connected to the arc-shaped base plate bracket 1-1. The eccentric wheel 8-3 is rotatably mounted on the fixed bracket 8-1 away from its free end via a rotating shaft 8-5. A fixed column 8-4 is provided at the end of the fixed bracket 8-1 near its free end. The eccentric wheel 8-3 and the top plate 2-1 of the crack simulation device 2 are respectively provided with a first connecting column 8-6 and a second connecting column 8-7. The connecting rod 8-2 is provided with a sliding groove. One end of the connecting rod sliding groove is fixed to the fixed bracket 8-1 via the fixed column 8-4 and can rotate around the fixed column 8-4. The first connecting column 8-6 is movably engaged in the groove, and the other end of the connecting rod groove is set on the top plate 2-1 of the fracture simulation device 2 through the second connecting column 8-7 and can rotate around the second connecting column 8-7; the fixed bracket 8-1, the eccentric wheel 8-3 and the top plate 2-1 of the fracture simulation device 2 are connected and transmit motion through the fixed column 8-4, the rotating shaft 8-5, the first connecting column 8-6 and the second connecting column 8-7; when the eccentric wheel is rotated through the rotating shaft 8-5, the connecting rod 8-2 produces a certain offset swing, thereby driving the top plate 2-1 to move up and down to adjust the opening of the fracture 2-3.

[0067] The center hole of the eccentric wheel 8-3 is precisely fitted with the outer diameter of the rotating shaft 8-5. One end of the rotating shaft 8-5 is inserted into the center hole of the eccentric wheel 8-3, ensuring there is no gap between the rotating shaft 8-5 and the eccentric wheel 8-3. The other end of the rotating shaft 8-5 is fixed to the bracket 8-1. The eccentric wheel 8-3 and the rotating shaft 8-3 are installed with bolts and nuts, ensuring that the eccentric wheel 8-3 can rotate synchronously with the rotating shaft 8-5 without slippage or loosening during rotation.

[0068] In this embodiment, the test bench body is also provided with a slide rail 11. The top plate 2-1 of the crack simulation device 2 cooperates with the test bench 1 through the slide rail 11, restricting the top plate 2-1 to move only in the vertical direction.

[0069] The frame body is also provided with an image acquisition device fixing mechanism. In this embodiment, it is a camera fixing mechanism used to fix the camera 6 directly above the center of the fracture simulation device 2. The camera fixing mechanism includes a camera holder 12, a lead screw 9, and a handwheel (not shown in the figure). One end of the lead screw 9 is fixed to the frame body, and the handwheel is installed at the bottom of the lead screw 9. The camera holder 12 is used to fix the camera 6. By rotating the handwheel, the lead screw 9 is moved up and down along the axial direction, thereby adjusting the installation height of the camera 6.

[0070] In this embodiment, the drainage flow monitoring device includes a graduated water collection cylinder 10, a timer, and a water level sensor (not shown in the figure). The timer starts timing when water inflow is detected. The water level sensor is installed on the inner wall of the water collection cylinder 10 to monitor the water level and calculate the real-time drainage volume, thereby calculating the water flow velocity. This serves two purposes: firstly, it is used to set the dynamic water flow velocity in the early stages of grouting in a dynamic water environment; secondly, it is used to record the drainage flow rate during static water diffusion tests.

[0071] In this embodiment, the platform body consists of several vertical rods 1-2 (in this embodiment, the number of vertical rods is 4 as shown in the figure; those skilled in the art will understand that the number of vertical rods is not limited to that shown in the figure), several horizontal rods 1-3 (in this embodiment, the number of horizontal rods is 4 as shown in the figure; those skilled in the art will understand that the number of horizontal rods is not limited to that shown in the figure), and a base plate bracket 1-1. The base plate bracket 1-1 is used to place the crack simulation device 2. For the stability of the platform body, the platform body is also provided with a base rod 1-4.

[0072] In a preferred embodiment, the top plate 2-1 and bottom plate 2-2 of the fracture simulation device 2 are arc-shaped plates of the same size, and the bottom plate bracket 1-1 of the platform body is an arc-shaped plate of the corresponding shape and size. The fracture simulation device 2 is mounted on the arc-shaped bottom plate bracket 1-1. Both the top plate 2-1 and bottom plate 2-2 of the fracture simulation device 2 are transparent acrylic plates, allowing the diffusion of the slurry inside the fracture simulation device 2 to be seen through the plates.

[0073] In specific operations, the acrylic plate with the required roughness is selected first. The acrylic base plate is first installed on the arc-shaped base plate bracket of the test bench. The opening between the top plate and the base plate is adjusted by rotating the rotating shaft of the eccentric wheel structure. The slide rail 11 on the bench body will restrict the top plate 2-1 to move only in the vertical direction. After the acrylic top plate moves to the fixed position, it is fixed with bolts to determine the width of the crack.

[0074] The crack opening can be precisely controlled via a rotating shaft and eccentric wheel adjustment mechanism, enabling dynamic adjustment of the crack width during the experiment. To more realistically simulate crack structures in actual engineering, the roughness of the crack interface is modeled using 3D modeling based on current roughness theory, and crack models with different roughnesses are manufactured using 3D printing technology. Based on the roughness distribution of cracks in actual engineering, 3D modeling software is used to create models with different roughness levels, and 3D printing technology is used to fabricate models with different roughnesses for experimental use.

[0075] In a preferred embodiment, the formulas for calculating the roughness of the top plate 2-1 and bottom plate 2-2 of the crack simulation device 2 in this embodiment are as follows:

[0076]

[0077] Among them, R a Let L be the average roughness, L be the measurement length, and y(x) be the surface profile height.

[0078] During the installation of the system, the base plate 2-2 of the crack simulation device 2 is placed on the arc-shaped base plate bracket of the test bench, so that the pressure sensor connection hole reserved on the acrylic base plate can extend from the bottom of the bracket and connect with the pressure sensor.

[0079] Rubber strips are attached to the perimeter of the acrylic base plate using flexible double-sided tape. The width and thickness of the rubber strips can be adjusted as needed. Double-sided tape is then attached above the rubber strips. The acrylic top plate is adjusted to the desired position and then fixed. After the acrylic base plate, rubber strips, and acrylic top plate are attached and fixed, the gaps are filled with silicone sealant to ensure the airtightness of the cracked structure.

[0080] Example 2

[0081] like Figure 8-9 As shown, this embodiment provides a method for evaluating the diffusion effect of grouting in narrow cracks under multi-field coupling using the multi-field coupled grouting diffusion test system provided in Embodiment 1, including the following steps:

[0082] S1. Data Acquisition: Image data of grout diffusion in the fissure is acquired through camera 6; heating is achieved through self-heating optical fiber during the simulated grouting process, and data on grout temperature changes and ambient temperature changes during grout diffusion are acquired through optical fiber signal demodulator; initial water injection temperature is acquired through point-type temperature sensors deployed in the water injection holes for comparison and verification, further validating the temperature monitoring accuracy; pressure changes of grout injected perpendicularly to the panel and diffused in the fissure are monitored through pressure sensor; and water flow velocity is acquired through water flow velocity sensor.

[0083] S2. Image Processing and Feature Extraction: Extract key features from the real-time 2D or 3D image data of the slurry diffusion process captured by the camera, such as diffusion radius, diffusion curvature, and diffusion speed; analyze the trends of the acquired time-varying data such as temperature, pressure, and flow rate to extract data features at specific time points or stages; and determine the impact of changes in the geometry of the cracks (such as crack width and crack surface roughness) on slurry diffusion through data analysis.

[0084] Since camera 6 captures the diffusion results projected onto a horizontal plane through the curved acrylic top plate, the curved surface diffusion needs to be mapped to a two-dimensional plane. Using the center of the curved acrylic top plate as the origin, line segments of equal length are marked radially from the center, and angles are marked along the arc direction from the center, also at equal intervals. During the diffusion process, the diffusion points at the slurry boundary are observed, and coordinate points are recorded according to the coordinate grid. Using these coordinate points, the diffusion range is transformed to a Cartesian coordinate plane, reconstructing the diffusion morphology. Through the diffusion morphology in the Cartesian coordinate system, the diffusion area, radial distribution pattern, and directional characteristics under different conditions are analyzed to obtain the diffusion law.

[0085] S3. Construct a slurry diffusion effect prediction model: Use machine learning algorithms to train the model; adjust hyperparameters, find the optimal model configuration through cross-validation, and evaluate and optimize the model.

[0086] As a preferred embodiment, this embodiment employs a random forest model to predict the effect of grout diffusion and optimizes grouting parameters based on data collected during the experiment. The specific process is as follows: First, data preparation is performed by inputting features such as temperature, pressure, flow rate, fracture aperture, fracture roughness, and experimental time to determine target variables such as grout diffusion area, diffusion rate, diffusion directionality, or classification labels. Second, data preprocessing is performed, removing outliers and filling missing values. Based on the experimental design and correlation analysis, the features most relevant to the diffusion process are selected, and the feature data is standardized to ensure that features of different dimensions do not have an unbalanced impact on the model. Next, model training is performed, dividing the data into training and testing sets, using 80% of the data for training and 20% for testing. Multiple decision trees are trained using the training set, and a robust random forest model is established by randomly selecting features and data subsets. Hyperparameters (such as the number of trees, maximum depth, minimum number of sample splits, etc.) are adjusted, and the optimal model configuration is found through cross-validation. Finally, the model is evaluated and optimized.

[0087] S4. Prediction and evaluation of grout diffusion effect: The optimized model is used to predict the effect of grout diffusion, and the grouting parameters are optimized based on the collected data.

[0088] The system provided by this invention analyzes real-time data collected during experiments to establish a predictive model for grout diffusion under different working conditions. Based on multi-field data such as temperature, pressure, and flow rate, the diffusion patterns and influencing factors of the grout are analyzed. The predictive model is trained using experimental data to optimize grout diffusion parameters (such as grout pressure, temperature, and flow rate) and improve repair effectiveness. Grouting parameters are dynamically adjusted based on experimental results. The system predicts the grout diffusion behavior using the predictive model and provides real-time feedback to the experimental operating system for rapid adjustment of experimental conditions and optimization of repair results. In this way, the system can automatically evaluate the grout diffusion effect under different experimental conditions and propose optimal grouting parameters to improve the overall reinforcement effect.

[0089] Therefore, this invention provides an underwater non-dispersible toughness repair material diffusion test system, capable of simulating the slurry diffusion process under complex dynamic water conditions. It investigates the influence of multiple coupled factors, such as crack width, roughness, water flow velocity, water pressure, temperature, and chloride erosion, on the slurry diffusion law, and studies the diffusion mechanism and influence law of slurry in cracked structures. Based on the data obtained from the test system, a slurry diffusion effect prediction model is constructed to predict the slurry diffusion effect, and grouting parameters are optimized based on the collected data, thus providing a scientific basis for the design and optimization of repair materials in practical engineering.

[0090] The above description is only a part of the preferred embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-field coupled grouting diffusion test system for narrow cracks, characterized in that, Includes a test bench, a crack simulation device, a grouting device, a water injection device, a drainage flow monitoring device, and an integrated data acquisition and processing platform; among which: The test bench includes a bench body; a crack simulation device is mounted on the bench body, specifically including a transparent base plate and a top plate, with the top plate covering the base plate. Rubber strips are installed around the edges of both plates to form a waterstop. The opposite surfaces of the two plates are rough, and a crack is formed between the two plates. The bench body is equipped with a gap adjustment device to adjust the gap distance between the base plate and the top plate, used to adjust the crack width. The crack simulation device is equipped with grouting holes, which are connected to a grouting device through pipelines for simulating grouting into the crack simulation device. The water injection device is used to simulate water injection into the fracture simulation device and control the temperature and flow rate of the injected water. The water injection device mainly consists of a water tank with heating and cooling functions, a water pressure pump, and a water flow rate regulator. The fracture simulation device is equipped with a water injection hole and a drain hole. The water injection hole is connected to the water pressure pump through a water injection pipe. A water flow rate sensor is installed in the water injection pipe. A point temperature sensor is installed on the outer wall of the water injection pipe connected to the water injection hole to monitor the changes in the water supply temperature in real time. The drain hole is connected to the drain flow monitoring device through a drain pipe. The base plate of the fracture simulation device is also embedded with a self-heating optical fiber, which is connected to an optical fiber signal demodulator to heat the slurry and measure the temperature change during the diffusion process. Pressure sensor connection holes are also provided on the base plate, which are connected to the pressure sensor through pipe fittings. An image acquisition device is fixedly installed on the main body of the frame. The image acquisition device is located directly above the center of the fracture simulation device and is set parallel to the fracture simulation device. It is used to acquire image data of slurry diffusion in the fracture. The aforementioned fiber optic signal demodulator, point temperature sensor, pressure sensor, water flow velocity sensor, image acquisition device, and integrated data acquisition and processing platform constitute a data acquisition and monitoring unit.

2. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 1, characterized in that, The gap adjustment device is an eccentric wheel structure, which includes a fixed bracket, a connecting rod, and an eccentric wheel. One end of the fixed support is a free end, and the other end is connected to the main body of the platform. The eccentric wheel is rotatably mounted on the fixed support away from its free end via a rotating shaft. A fixed column is provided at the end of the fixed support near its free end. The eccentric wheel and the top plate of the fracture simulation device are respectively provided with a first connecting column and a second connecting column. The connecting rod is provided with a sliding groove. One end of the connecting rod sliding groove is fixed to the fixed support via the fixed column and can rotate around the fixed column. The first connecting column is movably engaged in the sliding groove. The other end of the connecting rod sliding groove is mounted on the top plate of the fracture simulation device via the second connecting column and can rotate around the second connecting column. The fixed support, the eccentric wheel, and the top plate of the fracture simulation device are connected and transmit motion through the fixed column, the rotating shaft, the first connecting column, and the second connecting column. When the eccentric wheel is rotated via the rotating shaft, the connecting rod produces a certain offset swing, thereby driving the top plate to move up and down to adjust the opening of the fracture.

3. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 2, characterized in that, The test bench body is also equipped with a slide rail, and the top plate cooperates with the test bench through the slide rail to restrict the top plate to move only in the vertical direction.

4. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 1, characterized in that, The frame body is equipped with an image acquisition device fixing mechanism for fixing the image acquisition device directly above the center of the fracture simulation device. The image acquisition device fixing mechanism includes a fixator, a lead screw, and a handwheel. One end of the lead screw is fixed to the frame body, and the handwheel is installed at the bottom of the lead screw. The fixator is used to fix the image acquisition device. By rotating the handwheel, the lead screw is moved up and down along the axial direction, thereby adjusting the installation height of the image acquisition device.

5. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 1, characterized in that, The drainage flow monitoring device includes a graduated water collection cylinder, a timer, and a water level sensor. The timer starts timing when water inflow is detected. The water level sensor is installed on the inner wall of the water collection cylinder to monitor the water level and calculate the real-time drainage volume, thereby calculating the water flow rate.

6. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 1, characterized in that, The main body of the platform is composed of several vertical rods, several horizontal rods, and a base plate support, which is used to place the crack simulation device.

7. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 6, characterized in that, The top and bottom plates of the crack simulation device are arc-shaped plates of the same size, and the bottom plate bracket of the platform body is an arc-shaped plate of the corresponding shape and size. The crack simulation device is set on the arc-shaped bottom plate bracket.

8. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 1, characterized in that, The top and bottom plates of the fracture simulation device are made of transparent acrylic sheets, allowing the diffusion of the slurry inside the device to be seen through the sheets.

9. The multi-field coupled grouting diffusion test system for narrow cracks according to claim 1, characterized in that, The formulas for calculating the roughness of the bottom and top plates of the crack simulation device are as follows: Among them, R a Let L be the average roughness, L be the measurement length, and y(x) be the surface profile height.

10. A method for evaluating the diffusion effect of grouting in narrow cracks under multi-field coupling, characterized in that, The multi-field coupled grouting diffusion test system for narrow cracks according to any one of claims 1-8 specifically includes the following steps: S1. Data Acquisition: Image data of grout diffusion in the fissures is acquired using an image acquisition device; heating is achieved during the simulated grouting process using a self-heating optical fiber, and data on grout temperature changes and ambient temperature changes during grout diffusion are acquired using an optical fiber signal demodulator; the initial water injection temperature is acquired using point-type temperature sensors installed in the injection holes for comparison and verification, further validating the temperature monitoring accuracy; pressure changes of the grout in the fissures during injection and diffusion perpendicular to the panel are monitored using a pressure sensor; and water flow velocity is acquired using a water flow velocity sensor. S2. Image Processing and Feature Extraction: Extract key features from two-dimensional or three-dimensional image data of the slurry diffusion process captured in real time by the image acquisition device using image processing technology; analyze the trends of temperature, pressure, and flow rate changes over time to extract data features at a set time point or stage. And by analyzing data on changes in the geometry of the cracks, we determined their impact on slurry diffusion; S3. Construct a slurry diffusion effect prediction model: Use machine learning algorithms to train the model; adjust hyperparameters, find the optimal model configuration through cross-validation, and evaluate and optimize the model; S4. Prediction and evaluation of grout diffusion effect: The optimized model is used to predict the effect of grout diffusion, and the grouting parameters are optimized based on the collected data.

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