Grouting simulation test system and method for high-temperature water-rich filled fractures

Abstract

A grouting simulation test system and method for high-temperature water-rich filled fractures. The grouting simulation test system comprises: a water head intelligent sensing and adjusting module, a fracture medium intelligent simulation module, a double-liquid grouting module, a data analysis module, and an intelligent control module. The fracture medium intelligent simulation module comprises a water bath circulation temperature control unit, a fracture model (11), and an opening degree adjustment unit. The water bath circulation temperature control unit is arranged on upper and lower sides of the fracture model (11). Circulating water is provided in the water bath circulation temperature control unit, and the temperature of the circulating water is controllable. The fracture model (11) is formed by combining a plurality of model units. The opening degree adjustment unit is connected to the water bath circulation temperature control unit above the fracture model (11) and is capable of raising and lowering the water bath circulation temperature control unit. The present test system can achieve the study of a grouting diffusion mechanism under the coupling action of two or more factors such as different slurry properties, dynamic water flow velocity, dynamic water temperature, fracture medium multivariate factors, medium temperature, and filling conditions.

Description

High-temperature water-rich filling fracture grouting simulation test system and method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present invention claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on December 11, 2023, with application number 202311705940.6 and invention name “High-temperature water-rich filling fracture grouting simulation test system and method”, the entire contents of which are incorporated by reference into the present invention and constitute a part of the present invention for all purposes. Technical Field

[0003] The present invention relates to the technical field of grouting simulation test, and in particular to a high-temperature water-rich fissure-filling grouting simulation test system and method. Background Art

[0004] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0005] Fractured media are ubiquitous in various rock types in the Earth's crust. The distribution, size, shape, direction, and connectivity of fractures vary greatly in space and are typically highly heterogeneous and discontinuous. The presence of fractures is one of the key factors leading to problems such as reduced mechanical properties of tunnel surrounding rock, the opening of sudden seepage channels connecting to groundwater systems, and increased uncertainty in geological predictions.

[0006] Grouting technology involves injecting slurry into fractures and other media through grouting boreholes or grouting pipes, achieving reinforcement and water blocking through phase change. It has been widely used in civil engineering, mining, water conservancy, and other fields. After grouting is completed in fractured media, the filling of the medium can lead to uneven slurry diffusion. Furthermore, the presence of multiple microcracks within the fractures, the varying roughness of the fractured rock walls, the inclination and dip of the fractures, and the type and distribution of the filling material all have a direct impact on the curing and reinforcement of the grouting material.

[0007] Medium temperature changes are also a complex and critical issue. The increase in medium ambient temperature may accelerate the curing process of the grouting material, but when a certain high temperature is reached, the grouting material may fail. In addition, temperature changes will also affect the thermal expansion and contraction of the fractured medium, thereby changing the opening and distribution of the fractures, thereby affecting the distribution of the grouting material and the final reinforcement effect.

[0008] Grouting simulation tests can more realistically reproduce the slurry diffusion behavior in the cracks during the actual grouting process, and are an important means of studying grouting theory. However, existing grouting simulation tests do not consider the impact of the temperature environment of the slurry on the grouting process, nor do they consider the influence of the distribution of microcracks on the main cracks and the influence of the roughness of the main cracks on the slurry diffusion mechanism under the coupling of ambient temperature and other factors. It is also difficult to monitor and capture the flow field during the grouting process of the fractured medium. In addition, existing grouting simulation experiments require the production of corresponding fracture models based on the fracture conditions in the actual environment. Since the production of the fracture model takes a certain amount of time, this will affect the efficiency of the grouting simulation to a certain extent. Summary of the Invention

[0009] In order to solve the above problems, the present invention proposes a high-temperature, water-rich filling fracture grouting simulation test system and method, which can realize the regulation of different dynamic water flow rates and different dynamic water temperatures of fracture media, and at the same time can realize intelligent visual simulation of different fracture medium ambient temperatures, different types of filling media, different filling degrees and different fracture openings, and the micro-crack distribution and roughness of the fracture medium.

[0010] In some embodiments, the following technical solutions are adopted:

[0011] A high-temperature water-rich filling fracture grouting simulation test system, comprising:

[0012] The intelligent water head sensing and regulation module includes a temperature-controlled water tank for providing running water of a set temperature to the simulated fractured medium, and a water head control device for automatically adjusting the water head height; the water head control device is connected to the temperature-controlled water tank through a water inlet and is used to transport water from the temperature-controlled water tank to the intelligent fractured medium simulation module;

[0013] The intelligent fracture medium simulation module includes a water bath circulation temperature control unit, a fracture model, and an opening adjustment unit. The water bath circulation temperature control unit is arranged on the upper and lower sides of the fracture model. The water bath circulation temperature control unit is provided with circulating water with controllable temperature to provide the required ambient temperature for the fracture model. The fracture model is composed of multiple model units. The opening adjustment unit is connected to the water bath circulation temperature control unit above the fracture model and can lift the water bath circulation temperature control unit up and down.

[0014] Dual-liquid grouting module, used for grouting into the fracture model;

[0015] A data analysis module is used to obtain dynamic water temperature, grouting pressure, water bath ambient temperature and grouting process image information during the grouting process, and analyze the information to obtain the law of slurry diffusion mechanism under different grouting conditions during the grouting process;

[0016] The intelligent control module is used to intelligently control the temperature in the temperature-controlled water tank, the adjustment height of the head control device, the lifting height of the opening adjustment unit, and the temperature of the circulating water in the water bath circulation temperature control unit based on the received dynamic water temperature, head water level, crack opening and ambient temperature data.

[0017] In other embodiments, the following technical solutions are adopted:

[0018] An experimental method for a high-temperature, water-rich filling fracture grouting simulation test system, comprising:

[0019] Determine the slurry ratio, water head height, flowing water temperature, filling material properties, fracture environment temperature, inclination angle, filling degree and fracture aperture;

[0020] Based on the crack distribution and roughness of the actual grouting site, model units with matching crack distribution and roughness are selected for assembly and combination to obtain a crack model that matches the actual grouting site.

[0021] Respectively control the water temperature in the temperature-controlled water tank, the adjustment height of the water head control device, the temperature of the circulating water in the water bath circulation temperature control unit, and the lifting height of the opening adjustment unit to achieve the set requirements;

[0022] Start grouting, collect temperature and pressure data in real time during the grouting process, and visualize the changes in temperature and pressure fields during the grouting process;

[0023] After the grouting is completed, the slurry plugging rules and mechanisms under the coupling of different grouting conditions are obtained through data analysis.

[0024] In addition, according to the simulation test results, the fluid domain grid is constructed, the initial boundary conditions are set, and the momentum prediction equation is established based on the dynamic water velocity, grouting pressure, phase fraction and slurry viscosity. The discretized momentum prediction equation is:

[0025] The continuity equation of slurry water is:

[0026] The discretized momentum prediction equation is coupled with the discretized slurry water continuity equation to calculate the grouting pressure and dynamic water velocity at the current time step;

[0027] The slurry water heat transfer equation is established according to the dynamic water velocity v of the current time step: Q=-ΔH rxn r

[0028] The discretized slurry water heat transfer equation is:

[0029] The discretized slurry water heat transfer equation is coupled with the discretized momentum prediction equation to calculate the dynamic water temperature and dynamic water velocity at the current time step;

[0030] Compare the calculated grouting pressure, dynamic water temperature and dynamic water velocity data of the current time step with the data obtained from the grouting simulation test to verify the accuracy of the grouting simulation test results;

[0031] Where ρ is density, p is pressure, μ is viscosity, g is acceleration due to gravity, and F st is the surface tension, ρ n+1 v n+1 and ρ n v n are the density and velocity products of the new and old time steps, V CV is the volume of the control volume, S face The area vector of the control volume surface, p n is the pressure at the current time step, is the viscous stress at the current time step, g is the acceleration due to gravity, is the surface tension, Δt is the time step, T is the temperature, c p is the specific heat capacity of the fluid, k is the thermal conductivity of the porous medium, Q represents the heat generated and released during the solidification phase change of the slurry, ΔH rxn is the heat released per mole of reaction, which can be an empirical value, r is the rate of chemical reaction, which can be an empirical value, and v is the fluid velocity vector.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention realizes the regulation of different dynamic water flow rates and different dynamic water temperatures of the fracture medium through the intelligent head sensing and regulation system, and realizes the intelligent visual simulation of grouting conditions such as different fracture medium ambient temperatures, different types of filling media, different filling degrees, different fracture openings, micro-crack distribution and roughness of the fracture medium through intelligent simulation of the fracture medium. In conjunction with the dual-liquid grouting module and the information acquisition and analysis system, the grouting diffusion mechanism under the coupling action of two or more factors such as different slurry properties, dynamic water flow rates, dynamic water temperatures, multi-factors of fracture media, medium temperature, filling conditions, etc. is finally realized.

[0034] (2) The high-temperature water-rich filling fracture grouting simulation test system of the present invention prefabricates fluorescent blocks with different microcrack distributions and roughness distributions into fracture plate units, and performs modular assembly according to engineering and test requirements, thereby achieving convenient, environmentally friendly and rapid simulation of complex microcracks and roughness distributions of the main fracture plate.

[0035] (3) The present invention captures the changes in the dynamic water temperature, grouting velocity, pressure and other fields in the fracture medium, combines the coupling of the heat transfer equation and the momentum equation to establish the relationship between the temperature field and the dynamic water velocity field, and realizes the evolution tracking of the velocity field and the accurate characterization and representation of the plugging effect.

[0036] Other features and advantages of additional aspects of the present invention will be given in part in the following description and in part will become obvious from the following description or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a diagram of a high-temperature water-rich fracture filling grouting simulation test system according to an embodiment of the present invention;

[0038] 2 is a diagram showing the arrangement of sensors in a high-temperature, water-rich filling fracture grouting simulation test system according to an embodiment of the present invention;

[0039] 3 is a flow chart of a high-temperature water-rich fracture filling grouting simulation test method according to an embodiment of the present invention;

[0040] FIG4 is a schematic diagram of modular assembly of micro-crack fluorescent blocks in a high-temperature, water-rich filling crack grouting model according to an embodiment of the present invention;

[0041] 5 is a schematic diagram of modular assembly of roughness fluorescent blocks of a high-temperature, water-rich filling fracture grouting model according to an embodiment of the present invention;

[0042] Among them, 1. Water storage tank; 2. Water injection port; 3. Head regulating box; 4. Lifting unit; 5. Water pipeline; 6. Duckbill water injection channel; 7. Image acquisition device; 8. Dual-liquid grouting module; 9. Opening adjustment device; 10. Water bath box; 11. Fracture model; 12. Heating device; 13. Telescopic device; 14. Waste liquid collection module; 15. Temperature sensor layout hole; 16. Pressure sensor layout hole; 17. Grouting port; 18. First model unit; 19. Nylon groove; 20. Second model unit. DETAILED DESCRIPTION

[0043] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0044] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0045] Example 1

[0046] In one or more embodiments, a high-temperature water-rich filling fracture grouting simulation test system is disclosed, which, in conjunction with FIG1 , specifically includes:

[0047] (1) Water head intelligent sensing and regulating module, including: temperature-controlled water storage tank 1 and water head regulating device;

[0048] Among them, the temperature-controlled water tank 1 provides a dynamic water source of set temperature when simulating the dynamic water flow process in the fracture medium; the water tank is provided with a heating device 12 and a heat preservation device to achieve the regulation and constant control of the water source temperature.

[0049] The water head control device includes a water head regulating box 3 and a lifting unit 4. The water head regulating box 3 adopts a semi-open type, and the lower end of the opening is flush with the water outlet pipe; the water head regulating box 3 has a hole in the side wall close to the temperature-controlled water storage tank 1 as a water inlet 2, which is connected to the temperature-controlled water storage tank 1 through a hose to achieve continuous water supply to the water head regulating box 3 and ensure water overflow when adjusting the water head; the lifting unit 4 is placed at the lower part of the water head regulating box 3, and automatically lifts and starts and stops according to the received lifting instructions to reach the specified water level.

[0050] The water head regulating box 3 is connected to the intelligent simulation module of the fracture medium through the dynamic water pipe 5. The dynamic water pipe 5 includes a pipeline between the water head regulating box 3 and the intelligent simulation module of the fracture medium and a duckbill water injection channel 6 connected to the pipeline. The pipeline adopts a retractable hose. Connecting the duckbill water injection channel facilitates the adjustment of the water head height and is conducive to the uniform injection of dynamic water in the hose into the fracture model 11.

[0051] Furthermore, a temperature sensor is provided in the temperature-controlled water tank 1 for obtaining the water source temperature in the temperature-controlled water tank 1 in real time; a water level monitoring element is provided in the water head regulating box 3 for obtaining the water level height in the water head regulating box 3 in real time.

[0052] (2) Fracture medium intelligent simulation module, including: water bath circulation temperature control unit, fracture model 11 and opening adjustment unit;

[0053] Among them, the water bath circulation temperature control unit is set on the upper and lower sides of the fracture model 11. The water bath circulation temperature control unit is provided with circulating water, and the temperature of the circulating water is controllable to provide the required ambient temperature for the fracture model 11. Specifically, the water bath circulation temperature control unit includes a water bath box 10. The water bath box 10 is provided with a circulation pump inside to ensure the uniformity of the temperature inside the water bath device. The interior is provided with a heating device 12 to achieve autonomous adjustment of the water temperature. The four corners of the bottom of the water bath circulation temperature control unit set on the lower side of the fracture model 11 are respectively provided with a telescopic device 13, which together with the opening adjustment unit realizes the intelligent adjustment of the inclination angle of the fracture model 11. The adjustment process of the inclination angle of the entire model is as follows: first adjust the lower water bath box, then fix the fracture plate on the lower water bath box to achieve the adjustment of the fracture plate, and finally adjust the upper water bath box. The telescopic device 13 can be extended and retracted up and down. The height of the four telescopic devices 13 at the bottom of the lower water bath can be adjusted according to different inclination angles to adjust the inclination angle of the lower water bath, thereby adjusting the inclination angle of the fracture model 11. The telescopic device 13 can be implemented using an existing structure, such as a folding structure, and the height of the four corners can be adjusted by adjusting the tension.

[0054] The water bath 10 is also equipped with a temperature sensor for real-time acquisition of the water temperature within the water bath. The heater 12 maintains the temperature within the water bath at a stable set value. The fracture model 11 comprises an upper fracture plate and a lower fracture plate, which are sealed by a sealing device. Each fracture plate is composed of a plurality of different model units.

[0055] Specifically, in combination with Figures 4 and 5, this embodiment respectively sets up a micro-crack plate group and a roughness plate group. The micro-crack plate group includes a plurality of first model units 18 prefabricated with different micro-crack distributions; the roughness plate group includes a plurality of second model units 20 prefabricated with different roughnesses; the roughness plate group achieves the prefabrication of different roughnesses by prefabricating hair tips of different heights, different sharpnesses, and different sizes; the first model unit 18 and the second model unit 20 are made of different fluorescent color materials, and the shape of each unit is a square of a set size.

[0056] The microcrack distribution and roughness of the upper and lower fracture plates are determined based on actual engineering data, including fracture aperture, fracture inclination angle, microcrack distribution, and roughness. A suitable first model unit 18 is selected from the microcrack plate set, and a suitable second model unit 20 is selected from the roughness plate set for assembly. During assembly, each unit is fixed and spliced ​​by being embedded in a prefabricated nylon groove 19, forming upper and lower fracture plates that are compatible with the actual project. The upper and lower fracture plates are combined to form a fracture grouting medium with the desired fracture roughness and microcrack distribution.

[0057] The upper and lower fracture plates are arranged between the two water bath boxes 10. Grouting holes are opened on the lower fracture plate. The internal filling medium type and filling degree distribution can be changed according to research needs to realize the exploration of fracture filling grouting mechanism with different roughness and micro-crack distribution.

[0058] The opening adjustment unit includes a pulling device, a beam and an adjusting device. The pulling device is fixed to the surface of the upper water bath box 10, and the upper part of the pulling device is connected to the beam; the beam is used to place the image acquisition device 7 and provide tension for the pulling device; the adjusting device is used to set the height of the beam and realize the rotation and angle adjustment of the pulling device, thereby changing the position of the pulling device to change the opening of the fracture medium, thereby realizing convenient adjustment of the fracture opening and adjustment of the inclination angle.

[0059] 2 , a plurality of temperature sensor layout holes 15 and pressure sensor layout holes 16 are provided on the upper portion of the fracture model 11, which are used to respectively layout temperature data acquisition elements and pressure data acquisition elements; the temperature data acquisition element determines the monitoring position according to the monitoring requirements, and is used to obtain the internal temperature of the medium and the temperature change inside the medium during the grouting process; the position of the pressure data acquisition element is determined according to the monitoring requirements, wherein a pressure sensor is provided directly above the grouting port 17 for monitoring the grouting pressure, and pressure sensors at other positions are used to obtain data on the internal pressure during the grouting process.

[0060] (3) A dual-liquid grouting module 8 is used to inject grout into the fracture model 11; the dual-liquid grouting module 8 includes a slurry storage tank, a cylinder, and a grouting pipeline; the slurry storage tank is used to store the prepared slurry, is placed under the cylinder, and is connected to the cylinder; the cylinder provides power for slurry injection to ensure that the slurry is smoothly injected into the medium model; the grouting pipeline uses a transparent hose to ensure a certain pressure bearing capacity and visibility.

[0061] (4) Data analysis module, which is used to obtain the dynamic water temperature, grouting pressure, water bath environment temperature and grouting process image information during the grouting process, and analyze this information to obtain the law of slurry diffusion mechanism under different grouting conditions during the grouting process.

[0062] In this embodiment, the temperature sensor in the temperature-controlled water storage tank 1, the water level monitoring element in the head regulating tank 3, the temperature acquisition element in the water bath 10, the temperature and pressure data acquisition elements on the upper portion of the fracture model 11, and the image acquisition device 7 on the lifting device are each connected to the data analysis module. Each of these elements converts the collected data into a unified format and transmits it to the data analysis module. The image acquisition device 7 is used to capture the slurry diffusion pattern during the grouting process, capturing the slurry-water-fill material interface, and transmitting this data to the data analysis module.

[0063] The data analysis module can describe the temperature field changes during the grouting process based on the temperature data; the data analysis module can monitor the pressure changes during the grouting process based on the pressure data, and is used to analyze the grouting pressure changes under different conditions; the data analysis module can analyze and compare the laws of the slurry diffusion mechanism under different medium filling, different dynamic water flow rates and other conditions during the grouting process based on the image information transmitted by the image acquisition device 7.

[0064] (5) An intelligent control module, which is used to intelligently control the temperature in the temperature-controlled water tank 1, the adjustment height of the water head control device, the lifting height of the opening adjustment unit, and the temperature of the circulating water in the water bath circulation temperature control unit based on the received dynamic water temperature, water head water level, crack opening and ambient temperature data.

[0065] In this embodiment, the temperature sensor in the temperature-controlled water tank 1, the water level monitoring element in the head regulating box 3, the temperature acquisition element in the water bath box 10, the temperature data acquisition element and the pressure data acquisition element on the upper part of the fracture model 11, the image acquisition device 7 on the pulling device, etc. are respectively connected to the intelligent control module.

[0066] The intelligent control module can realize intelligent regulation of the entire system. It can intelligently control the water temperature in the water tank 1 according to the temperature data transmitted from the temperature-controlled water tank 1. When the water temperature reaches the set temperature, the internal temperature control is realized by starting and stopping the heating device 12; according to the water level data transmitted from the head control device, it can realize intelligent control of the head height in the head regulating device, automatically detect the water level in the head regulating box 3 and adjust the lifting unit 4 under the water tank to achieve the specified water level height to control the dynamic water flow rate; realize intelligent rotation control of the opening regulating device 9, control of the telescopic device 13 set at the four corners of the bottom of the water bath box 10, and intelligent opening regulation control.

[0067] (6) The waste liquid collection module 14 includes a waste liquid filtering device, a waste liquid storage tank and a waste liquid drainage device. The waste liquid filtering device uses a filter bag made of PP material to achieve solid-liquid separation and collection.

[0068] (7) The visualization module is connected to the data analysis module to receive the analysis data from the data analysis module and realize the visualization of the slurry diffusion law and the temperature field and pressure field during the grouting process.

[0069] Specifically, the visualization module can realize a slurry diffusion visualization unit, a temperature field visualization unit, and a pressure field visualization unit;

[0070] The slurry diffusion visualization unit receives data from the information acquisition and analysis system to realize the interface capture and dynamic display of the slurry diffusion path; the temperature field visualization unit and the pressure field visualization unit realize the dynamic display of the temperature field and pressure field respectively.

[0071] Example 2

[0072] In one or more embodiments, an experimental method for a high-temperature water-rich filling fracture grouting simulation test system is disclosed, which specifically includes:

[0073] S101: According to the research purpose, determine the slurry ratio, head height, dynamic water temperature, filling material properties, fracture medium temperature, inclination angle, filling degree and fracture opening; prepare slurry according to the slurry ratio and inject it into the slurry storage tank. The slurry can be single-liquid or double-liquid slurry. The material can be selected as cement slurry or specified materials such as water glass and new materials according to needs. When using the double-liquid slurry grouting method, the mixing position of the double slurry should be close to the grouting port 17 to prevent the mixing path from being too long and causing the double liquid to solidify and block the pipeline; adjust the head control device according to the head height, open the water outlet, and inject the water from the water storage tank 1 into the head regulating tank 3 until the water overflows, and adjust the head height according to the set head height by adjusting the lifting device; adjust the water temperature of the water storage tank 1 according to the set dynamic water temperature; lift the upper water bath to a certain height through the lifting device in the opening adjustment unit, and adjust the inclination angle of the lower water bath by adjusting the telescopic device 13 set at the four corners of the bottom of the lower water bath.

[0074] S102: Based on the crack distribution and roughness of the actual grouting site, model units with matching crack distribution and roughness are selected for assembly and combination to obtain a crack model 11 matching the actual grouting site;

[0075] Specifically, the microcrack distribution and roughness of the upper and lower crack plates are identified according to the engineering data, and the model units divided in the microcrack plate group and the rough plate group are combined and assembled. The lower crack plate that is assembled to restore the engineering distribution is placed on the lower water bath box 10, and sealing gaskets are placed around it. The medium is filled according to the properties and filling degree of the filling material. The upper crack plate that is assembled to restore the engineering distribution is attached to the bottom of the upper water bath box 10, and the upper crack plate and the upper water bath are placed parallel to each other through a lifting device on the upper part of the sealing gasket above the lower crack plate, so as to realize the setting and simulation of the crack opening, crack inclination angle, microcrack distribution and roughness of the test model.

[0076] S103: Arrange data monitoring components according to the test purpose, connect the components to the data acquisition device, turn on the image acquisition device 7, and prepare for grouting;

[0077] S104: According to the test requirements, different cylinder pressures are set according to different grouting rate ratios. After the settings are completed, grouting begins. The temperature, pressure and other monitoring data are tracked and recorded in real time during the injection process.

[0078] S105: While collecting and transmitting data, the collected data is analyzed, and the temperature field change description of the grouting process is realized based on the temperature data.

[0079] In this embodiment, a fluid domain grid is constructed according to the test model, and initial boundary conditions are set. The initial boundary conditions include grouting velocity, grouting pressure, slurry temperature, dynamic water velocity, and slurry viscosity. A momentum prediction equation is constructed based on the dynamic water velocity, grouting pressure, phase fraction, and slurry viscosity, and the dynamic water velocity is predicted by solving the momentum.

[0080] The momentum equation is:

[0081] Where ρ is density, p is pressure, μ is the existing viscosity function characterized by time t and slurry temperature T, which can be obtained through experiments, g is the acceleration of gravity, F st is the surface tension.

[0082] The momentum prediction equation after discretization is solved to predict the dynamic water velocity:

[0083] Among them, ρ n+1 v n+1 and ρ n v n are the density and velocity products of the new and old time steps, V CV is the volume of the control volume, S face The area vector of the control volume surface, p n is the pressure at the current time step, is the viscous stress at the current time step, is a mathematical operator; g is the acceleration due to gravity, is the surface tension and Δt is the time step.

[0084] Furthermore, the slurry water continuity equation is:

[0085] Where v is the fluid velocity vector.

[0086] The slurry water continuity equation is discretized and coupled with the discretized momentum prediction equation (Equation (2)) to achieve repeated solution and iteration of slurry pressure, dynamic water velocity and grouting speed until the number of iterations is reached. The grouting pressure and dynamic water velocity obtained are the grouting pressure and dynamic water velocity v of the current time step.

[0087] Furthermore, the slurry water heat transfer equation is established according to the dynamic water velocity v of the current time step: Q=-ΔH rxn r (5)

[0088] Where T is temperature, c p is the specific heat capacity of the fluid, k is the thermal conductivity of the porous medium, Q represents the heat generated and released during the solidification phase change of the slurry, ΔH rxn is the heat released per mole of reaction, which can be an empirical value, r is the rate of chemical reaction, which can be an empirical value, and v is the fluid velocity vector.

[0089] The discretized slurry water heat transfer equation is solved to predict the dynamic water temperature:

[0090] Among them, T new With T old are the temperatures of the old and new time steps respectively, Δt is the time step length, V CV is the volume of the control volume, S face is the area vector of the control volume face, pointing normal to the face and outward.

[0091] The discrete slurry heat transfer equation (Equation (6)) is coupled with the discrete momentum prediction equation (Equation (2)) to achieve repeated solution and iteration of the dynamic water temperature and dynamic water velocity until the number of iterations is reached. The dynamic water temperature and dynamic water velocity v, Σ faces represents the sum of the values ​​on all faces, is a mathematical operator.

[0092] After the simulation is completed, the temperature field data and grouting pressure data of the current time step are compared with the actual test data. If the temperature field data and grouting pressure data are consistent with the test data, the dynamic water velocity field is accurately simulated and the test plugging effect is characterized.

[0093] The pressure data is used to monitor the pressure changes during the grouting process. Based on the image information transmitted by the image acquisition and transmission module, the laws of the slurry diffusion mechanism under different medium filling and different dynamic water flow rates during the grouting process are analyzed and compared.

[0094] S106: After the grouting is completed, the data analysis results are used to obtain the slurry plugging rules and mechanisms under single variable conditions or multi-condition coupling conditions such as different medium temperatures, different filling effects, different dynamic water flow rates, and different dynamic water temperatures. By monitoring the temperature field, the relationship between the temperature field and the dynamic water flow rate field is established to capture the flow rate during the plugging process and characterize the plugging effect.

[0095] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A high-temperature water-rich filling fracture grouting simulation test system, characterized in that: include: The water head intelligent sensing and regulating module includes a temperature-controlled water storage tank for providing moving water of a set temperature in the simulated fracture medium, and a water head regulating device for automatically adjusting the water head height; the water head regulating device is connected to the temperature-controlled water storage tank and is used to transport the water source in the temperature-controlled water storage tank to the fracture medium intelligent simulation module; The intelligent simulation module of fracture medium comprises a water bath circulation temperature control unit, a fracture model and an opening adjustment unit; the water bath circulation temperature control unit is arranged on the upper and lower sides of the fracture model, and circulating water is arranged in the water bath circulation temperature control unit, and the temperature of the circulating water is controllable, and is used to provide the required ambient temperature for the fracture model; the fracture model is composed of a plurality of model units; the fracture model comprises an upper fracture plate and a lower fracture plate, and the two are sealed by a sealing device; the upper fracture plate and the lower fracture plate are respectively composed of a plurality of different model units; The microcrack plate group includes a plurality of prefabricated first model units with different microcrack distributions; the roughness plate group includes a plurality of prefabricated second model units with different roughnesses; the microcrack distribution and roughness of the upper and lower crack plates are judged according to actual engineering data, and a suitable first model unit is selected from the microcrack plate group, and a suitable second model unit is selected from the roughness plate group for assembly to form upper and lower crack plates adapted to the actual project; The opening adjustment unit is connected to the water bath circulation temperature control unit above the crack model, and the water bath circulation temperature control unit can be pulled up and down to achieve convenient adjustment of the crack opening and the adjustment of the inclination angle; Dual-liquid grouting module, used for grouting into the fracture model; A data analysis module is used to obtain the dynamic water temperature, grouting pressure, water bath environment temperature and grouting process image information during the grouting process, and analyze the information to obtain the law of slurry diffusion mechanism under different grouting conditions during the grouting process; The intelligent control module is used to intelligently control the temperature in the temperature-controlled water tank, the adjustment height of the head control device, the lifting height of the opening adjustment unit, and the temperature of the circulating water in the water bath circulation temperature control unit based on the received dynamic water temperature, water head water level, crack opening and ambient temperature data.

2. A high-temperature water-rich filling fracture grouting simulation test system as claimed in claim 1, characterized in that: The water head control device includes a water head regulating box and a lifting unit; the water head regulating box has a hole in the side wall close to the temperature-controlled water tank and is connected to the temperature-controlled water tank through a hose to achieve continuous water supply to the water head regulating box; the lifting unit is arranged at the lower part of the water head regulating box and automatically controls the water head regulating box to a set height according to the received control instructions.

3. A high temperature water-rich filling fracture grouting simulation test system as claimed in claim 1, characterized in that: The water head regulating device is connected to the fracture medium intelligent simulation module through a pipeline and a duckbill water injection channel connected to the pipeline.

4. A high-temperature water-rich filling fracture grouting simulation test system as claimed in claim 1, characterized in that: A temperature sensor is provided in the temperature-controlled water tank, and a water level monitoring element is provided in the water head regulating device; data collected by the temperature sensor and the water level monitoring element are transmitted to the data analysis module and the intelligent control module respectively.

5. A high temperature water-rich filling fracture grouting simulation test system as claimed in claim 1, characterized in that: The water bath circulation temperature control unit comprises a water bath box, in which a circulation pump, a temperature collection element and a heating device are arranged; the data collected by the temperature collection element are transmitted to the data analysis module and the intelligent control module respectively; The four bottom corners of the water bath circulation temperature control unit arranged at the lower side of the fracture model are respectively provided with telescopic devices, which together with the opening adjustment unit realize the intelligent adjustment of the inclination angle of the fracture model.

6. A high temperature water-rich filling fracture grouting simulation test system as claimed in claim 1, characterized in that: The fracture model is provided with a temperature sensor for collecting slurry temperature and a pressure sensor for obtaining grouting pressure. The data collected by the temperature sensor and the pressure sensor are transmitted to the data analysis module and the intelligent control module respectively.

7. A high temperature water-rich filling fracture grouting simulation test system as claimed in claim 1, characterized in that: Also includes: A waste liquid collection module, used to filter and collect waste liquid during the grouting process; The visualization module is used to visualize the slurry diffusion law and the temperature and pressure fields during the grouting process.

8. An experimental method of a high-temperature water-rich filling fracture grouting simulation test system, using a high-temperature water-rich filling fracture grouting simulation test system as claimed in any one of claims 1 to 7, characterized in that: include: Determine the slurry ratio, water head height, dynamic water temperature, filling material properties, fracture environment temperature, inclination angle, filling degree and fracture opening; Based on the crack distribution and roughness of the actual grouting site, model units with matching crack distribution and roughness are selected for assembly and combination to obtain a crack model matching the actual grouting site. Respectively control the water temperature in the temperature-controlled water tank, the adjustment height of the water head control device, the temperature of the circulating water in the water bath circulation temperature control unit, and the lifting height of the opening adjustment unit to achieve the set requirements; Start grouting, collect temperature and pressure data in real time during the grouting process, and visualize the changes in temperature and pressure fields during the grouting process; After the grouting is completed, the slurry plugging law and mechanism under the coupling of different grouting conditions are obtained through data analysis.

9. The experimental method of a high-temperature water-rich filling fracture grouting simulation test system as claimed in claim 8, characterized in that: Also includes: According to the simulation test, the fluid domain grid is constructed, the initial boundary conditions are set, and the momentum prediction equation is established according to the dynamic water velocity, grouting pressure, phase fraction and slurry viscosity. The discretized momentum prediction equation is: The continuity equation of slurry water is: The discretized momentum prediction equation is coupled with the discretized slurry water continuity equation to calculate the grouting pressure and dynamic water velocity at the current time step; The slurry water heat transfer equation is established according to the dynamic water velocity v of the current time step: Q=-ΔH rxn r The discretized slurry water heat transfer equation is: The discrete slurry water heat transfer equation is coupled with the discrete momentum prediction equation to calculate the dynamic water temperature and dynamic water velocity at the current time step; The calculated grouting pressure, dynamic water temperature and dynamic water velocity data of the current time step are compared with the data obtained from the grouting simulation test to verify the accuracy of the grouting simulation test results; Among them, ρ is density, p is pressure, μ is viscosity, g is gravitational acceleration, ρ n+1 v n+1 and ρ n v n are the product of density and velocity at the new and old time steps, V CV is the volume of the control volume, S face The area vector of the control volume face, p n is the pressure at the current time step, is the viscous stress at the current time step, g is the gravitational acceleration, is the surface tension at the nth time step, Δt is the time step, T is the temperature, c p is the specific heat capacity of the fluid, k is the thermal conductivity of the porous medium, Q represents the heat generated and released during the solidification phase change of the slurry; ΔH rxn is the heat released per mole of reaction, using empirical values; r is the rate of chemical reaction, using empirical values; v is the fluid velocity vector, T new With T old are the temperatures of the new and old time steps, Σ faces Represents the sum of the values ​​on all faces.

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