Temperature control fracture network grouting experiment device and method

Abstract

The invention relates to the field of crack grouting, in particular to a temperature-control crack network grouting experimental device, which comprises a transparent crack model, which is formed by vertically attaching an upper covering surface and a crack network, the upper covering surface is provided with grouting holes, and the peripheries of the upper covering surface and the crack network are provided with water stop structures; the array distributed slice pressure sensor is arranged below the fracture network and is used for monitoring the seepage pressure change of each position in the fracture of the transparent fracture model; the double-liquid grouting system is connected with an inlet of the transparent fracture model and used for injecting grout into fractures of the transparent fracture model; the camera is arranged above the transparent crack model; the constant-pressure dynamic water injection system is connected with the transparent fracture model; and the temperature control system is arranged on the outer side of the transparent fracture model. According to the invention, a brand new solution is provided for optimal design and scientific evaluation of a rock mass grouting technology by systematically integrating a multifunctional device and an innovative test method.

Description

Technical Field

[0001] The invention relates to the field of crack grouting, and in particular to a temperature-controlled crack network grouting experimental device and method. Background Art

[0002] Grouting reinforcement technology for rock mass fissures is an important reinforcement and anti-seepage measure in geotechnical engineering, and is widely used in engineering practice, such as groundwater sealing, tunnel support, dam reinforcement of water conservancy and hydropower projects, and mine leakage prevention. In actual engineering, the geometric structure of the fracture network is complex and changeable, and the engineering environment is often accompanied by extreme temperature conditions, such as deep tunnel construction in high temperature areas or groundwater treatment in cold areas. These environmental factors have an important influence on the performance and plugging effect of grouting materials. For example, low temperature conditions will significantly reduce the fluidity of the slurry and the hydration rate of cement, thereby affecting the diffusion range, filling effect and plugging quality of the slurry. However, the current experimental research on grouting behavior under complex fracture networks and extreme environmental conditions is still relatively weak, especially the lack of precise experimental equipment and monitoring technology.

[0003] The existing grouting experimental device is mainly used for simple fractures, and a single-point pressure sensor is used to monitor the pressure changes during the grouting process. However, in a complex fracture network, the pressure changes have obvious randomness and uneven distribution characteristics, and single-point monitoring cannot fully reflect the grouting behavior of the fracture network. At the same time, the existing device has poor adaptability to extreme temperature conditions, and it is difficult to systematically evaluate the impact of temperature on the grouting effect. In addition, the monitoring of the grouting plugging effect mainly relies on indirect methods, lacking dynamic and quantitative analysis of the permeability evolution and anti-scouring ability of the plugging area. Summary of the invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a temperature-controlled fracture network grouting experimental device and a dynamic monitoring method of its plugging effect, which can realize sensitive capture of multi-point pressure distribution in the fracture network, simulation of extreme temperature conditions, and quasi-three-dimensional visualization and dynamic quantitative evaluation of the plugging effect.

[0005] According to one aspect of the present invention, a temperature-controlled fracture network grouting experimental device is provided, comprising:

[0006] The transparent fracture model is formed by laminating an upper covering surface and a fracture network, wherein the upper covering surface is provided with grouting holes, and a water-stopping structure is provided around the upper covering surface and the fracture network;

[0007] An array of distributed thin-sheet pressure sensors is arranged below the fracture network to monitor the changes in the permeability pressure at each location within the fracture of the transparent fracture model;

[0008] A double-liquid grouting system is connected to the inlet of the transparent fracture model and is used to inject grout into the fractures of the transparent fracture model;

[0009] A camera is arranged above the transparent fracture model and is used to monitor the grouting process of the transparent fracture model;

[0010] A constant pressure dynamic water injection system is connected to the transparent fracture model and is used to inject water into the transparent fracture model at a constant pressure;

[0011] The temperature control system is set outside the transparent fracture model to simulate the grouting environment in high temperature or cold areas.

[0012] As a further technical solution, the water-stopping structure includes an inlet cavity jointly arranged on one side of the upper covering surface and the crack network, and an outlet cavity jointly arranged on the other side of the upper covering surface and the crack network, and left acrylic side strips and right acrylic side strips are respectively arranged on both sides of the upper covering surface and the crack network, and upper acrylic splints, lower acrylic splints, front acrylic splints, rear acrylic splints, left acrylic splints, and right acrylic splints are respectively arranged on the outer sides of the upper covering surface and the crack network.

[0013] As a further technical solution, the dual-liquid grouting system includes a plunger pump A, a plunger pump B, a three-way valve and a static mixer. The plunger pump A and the plunger pump B are connected to the three-way valve through a grouting pipeline, the three-way valve is connected to the static mixer through a grouting pipeline, the static mixer is connected to the grouting hole of the transparent fracture model through the grouting pipeline, and a pressure sensor is arranged on the grouting pipeline between the static mixer and the fracture grouting hole.

[0014] As a further technical solution, the experimental device also includes a flat light source 1 and a flat light source 2 arranged above the transparent crack model, which are used to illuminate the transparent crack model.

[0015] As a further technical solution, the experimental device also includes a support system, which includes a stage, on which vertical support rod 1 and vertical support rod 2 are fixed, and vertical support rod 1 and vertical support rod 2 are jointly provided with fixed block 1 and fixed block 2, and fixed block 1 is provided with transverse support rod 1, the camera is installed on transverse support rod 1, and transverse support rod 2 and transverse support rod 3 are provided on fixed block 2, and flat-panel light source 1 and flat-panel light source 2 are respectively installed on transverse support rod 2 and transverse support rod 3.

[0016] As a further technical solution, the constant pressure dynamic water injection system includes a Marg flask, a lifting platform and a mass flow sensor. The Marg flask is placed on the lifting platform. The Marg flask is connected to the grouting hole of the transparent fracture model through a pipeline. A mass flow sensor is arranged on the pipeline between the Marg flask and the grouting hole. The outlet of the transparent fracture model is connected to a waste liquid bottle through a pipeline. The waste liquid bottle is placed above a high-precision electronic scale.

[0017] As a further technical solution, the temperature control system includes a circulating water pipe arranged around and below the cracks in the transparent crack model, and a high and low temperature circulating pump connected to the inlet and outlet of the circulating water pipe.

[0018] As a further technical solution, the experimental device also includes a waste liquid recovery bottle and an analysis system. The waste liquid recovery bottle and the analysis system include a test tube and a liquid chromatograph, which are used to take an appropriate amount of waste liquid through the test tube and use the liquid chromatograph to analyze the slurry components.

[0019] According to one aspect of the present invention, a temperature-controlled fracture network grouting experimental method is provided, comprising the following steps:

[0020] Turn on the high and low temperature circulation pump to make the temperature around the crack of the transparent crack model reach the set temperature and become uniform and stable. Then open the valve of the Malchnitz flask. The fluid will flow out of the Malchnitz flask and flow into the waste liquid bottle after passing through the transparent crack model.

[0021] When the fluid passes through the transparent fracture model, the permeability pressure change at each location in the fracture is obtained through the array distributed thin-sheet pressure sensor, and the mass flow rate of the fluid is recorded through the mass flow sensor and the high-precision electronic scale;

[0022] After the transparent fracture model is saturated and the liquid flow is stable, the camera, flat light source 1 and flat light source 2 are turned on to record the slurry diffusion process in real time, and the grouting pressure change is recorded through the pressure sensor. Then, the two solutions are respectively injected at the set flow rate by turning on the plunger pump A and the plunger pump B. After the two solutions are mixed in the static mixer, they are injected into the transparent fracture model through the grouting hole. After the injection reaches the set pressure or flow rate, the plunger pump A and the plunger pump B are turned off;

[0023] Replace the new waste liquid bottle, take a proper amount of waste liquid from the new waste liquid bottle with a test tube regularly, analyze the slurry composition with a liquid chromatograph, and quantify the mass of the solid washed off;

[0024] After flushing to the set time, turn off each instrument and the test ends.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention has significant advantages over the existing technology by constructing a fracture network structure and combining advanced sensing technology with visualization technology. The design of the fracture network is not only more in line with the complex fracture distribution in real projects, but also effectively improves the representativeness and reliability of the experimental results. The array distributed thin-film pressure sensor is used to dynamically capture the seepage pressure distribution and its changing law at each position in the fracture network, which significantly improves the monitoring accuracy and timeliness.

[0027] 2. In addition, the device integrates a high-resolution camera and an adjustable fill light device, which not only realizes the intuitive observation of the slurry diffusion range, but also can quantitatively evaluate the slurry thickness distribution and diffusion morphology, providing quasi-three-dimensional visualization results.

[0028] 3. At the same time, by arranging circulating water pipes around the cracks and connecting high and low temperature circulating pumps, the influence of different temperature environments on slurry performance and plugging effect was successfully simulated, providing important data support for grouting optimization design under complex working conditions.

[0029] 4. The built-in Martens flask constant pressure water injection system and mass flow sensor can also accurately reflect the dynamic changes of permeability in real time. Combined with the quality of the outlet waste liquid and the slurry composition analysis, the amount of slurry falling off during the flushing process can be quantified, thereby evaluating the anti-scouring ability and long-term stability of the plugging area.

[0030] 5. In addition, the device adopts a modular design, supports rapid assembly and flexible test settings, reduces maintenance and operating costs, and significantly improves test efficiency and applicability. The innovative design of the fracture network and the integration of the overall system provide more practical technical support for the development and engineering application of grouting technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings used in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of a temperature-controlled fracture network grouting experimental device provided in an embodiment of the present invention.

[0033] Figure 2 A schematic diagram of a transparent fracture model, a pressure sensor, a circulating water pipe and a water-stopping structure of a temperature-controlled fracture network grouting experimental device provided in an embodiment of the present invention.

[0034] Figure 3 A layout diagram of cracks, pressure sensors, circulating water pipes and fixtures of a temperature-controlled crack network grouting experimental device provided in an embodiment of the present invention.

[0035] Figure 4 A top view of the fracture network of the temperature-controlled fracture network grouting experimental device provided in an embodiment of the present invention.

[0036] In the figure: 1. Transparent crack model; 101. Upper covering surface; 102. Crack network; 103. Grouting hole; 104. Inlet cavity; 105. Outlet cavity; 106. Left acrylic side strip; 107. Right acrylic side strip; 108. Upper acrylic splint; 109. Lower acrylic splint; 110. Front acrylic splint; 111. Rear acrylic splint; 112. Left acrylic splint; 113. Right acrylic splint; 2. Array distributed sheet pressure sensor; 3. Plunger pump A; 4. Plunger pump B; 5. Three-way valve; 6. Static mixer; 7. Pressure sensor; 8. Stage; 9. Vertical support rod one; 10. Vertical support rod two; 11. Horizontal support rod one; 12. Horizontal support rod one; 13. Horizontal support rod three; 14. Fixed block one; 15. Fixed block two; 16. Camera; 17. Flat light source one; 18. Flat light source two; 19. Martens flask; 20. Lifting platform; 21. Mass flow sensor; 22. Waste liquid bottle; 23. High-precision electronic scale; 24. Test tube; 25. Liquid chromatograph; 26. Circulating water pipe; 27. High and low temperature circulating pump; 28. Computer. DETAILED DESCRIPTION

[0037] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions, for example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to the steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention are arbitrarily combined with each other to form a new technical solution. This combination is not restricted by the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that this combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] In actual projects, the evaluation and control of grouting effects not only rely on the analysis of the slurry diffusion range and the osmotic pressure distribution, but are also significantly affected by environmental conditions such as temperature and flow rate. However, the existing technology has obvious deficiencies in the following aspects:

[0040] (1) Lack of accurate monitoring of complex flow characteristics in fracture networks: Traditional experimental devices are usually based on a single fracture model, which makes it difficult to effectively simulate the multi-directional seepage behavior in complex fracture networks. In particular, the dynamic change characteristics of the interaction between fractures have not been fully studied.

[0041] (2) The influence of ambient temperature on the grouting process is not fully considered: In actual projects, high or low temperature environments will significantly affect the fluidity, diffusion range and plugging effect of the slurry. However, the existing test methods cannot achieve effective simulation and observation under different temperature conditions, and cannot reveal the influence of temperature on the grouting effect and the key factors.

[0042] (3) Lack of real-time and accurate reflection of the plugging effect and evaluation of the anti-scouring ability: The current test equipment focuses on observing the diffusion behavior of the slurry, but lacks real-time quantitative analysis of the plugging effect. In particular, the anti-scouring performance and long-term stability after the fissure plugging is completed are difficult to be comprehensively evaluated by existing means.

[0043] (4) Insufficient accuracy and depth of visual observation: Although existing devices support visual observation of slurry diffusion, the image quality and observation accuracy are limited, and cannot clearly reflect the thickness of slurry filling, the scouring conditions of the diffusion edge, and the dynamic distribution characteristics in three-dimensional space.

[0044] In order to solve the above problems, the present invention proposes a temperature-controlled fracture network grouting test device, such as Figure 1-4 As shown, it includes a transparent fracture model 1, an array distributed thin-film pressure sensor 2, a dual-liquid grouting system, a support system, a camera 16, a constant-pressure dynamic water injection system, a waste liquid recovery bottle and analysis system, a temperature control system and a computer 28.

[0045] In this embodiment, the transparent fracture model 1 is formed by laminating an upper covering surface 101 made of transparent flat glass and an epoxy resin fracture network 102. A grouting hole 103 is carved on the upper covering surface 101 near the entrance end, and a water-stopping structure is arranged around the upper covering surface 101 and the fracture network 102.

[0046] Among them, the water-stopping structure includes an inlet cavity 104 jointly arranged on one side of the upper covering surface 101 and the crack network 102, and an outlet cavity 105 jointly arranged on the other side of the upper covering surface 101 and the crack network 102. The left acrylic side strip 106 and the right acrylic side strip 107 are respectively arranged on both sides of the upper covering surface 101 and the crack network 102, and the outer sides of the upper covering surface 101 and the crack network 102 are respectively provided with an upper acrylic splint 108, a lower acrylic splint 109, a front acrylic splint 110, a rear acrylic splint 111 and a left acrylic splint 112, and a right acrylic splint 113.

[0047] The water-stopping effect of the transparent crack model 1 is improved by arranging the left acrylic side strip 106 and the right acrylic side strip 107, the upper acrylic splint 108, the lower acrylic splint 109, the front acrylic splint 110, the rear acrylic splint 111 and the left acrylic splint 112 and the right acrylic splint 113, and a slurry inlet is arranged at the position corresponding to the grouting hole 103 on the upper acrylic splint 108, and the slurry can enter the crack through the slurry inlet and the grouting hole 103.

[0048] The array distributed thin-sheet pressure sensor 2 is placed under the epoxy resin fracture network 102, and its size is adapted to the size of the fracture network 102. The number of sites can be set as needed. The denser the site, the more accurately it can reflect the changes in the permeability pressure at each location in the fracture. The pressure signal is transmitted to the computer 28 via Bluetooth.

[0049] By changing the rough network into a crack network 102, the existing pressure sensor at a single direct insertion point is very difficult to arrange, and the pressure change point is very random. The present application combines the crack network 102 with a dot matrix thin film sensor to more sensitively capture the pressure changes at each point.

[0050] In this embodiment, the dual-liquid grouting system is connected to the inlet of the transparent fracture model 1 and is used to inject slurry into the fractures of the transparent fracture model 1 .

[0051] Specifically, the dual-liquid grouting system includes a plunger pump A3, a plunger pump B4, a three-way valve 5 and a static mixer 6. The plunger pump A3 and the plunger pump B4 are both ISCO plunger pumps. The plunger pump A3 and the plunger pump B4 are connected to the three-way valve 5 through a grouting pipeline. The three-way valve 5 is connected to the static mixer 6 through a grouting pipeline. The static mixer 6 is connected to the grouting hole 103 of the transparent fracture model 1 through the grouting pipeline. At the same time, a pressure sensor 7 is arranged on the grouting pipeline between the static mixer 6 and the fracture grouting hole 103 to monitor the grouting pressure data.

[0052] When in use, the two components of the slurry are injected by plunger pump A3 and plunger pump B4 respectively. The plunger pump can accurately control the grouting flow rate and pressure to make the experimental results more accurate and reliable. The two slurries enter the static mixer 6 through the three-way valve 5 for sufficient mixing, and then are injected into the fracture through the fracture grouting hole 103. The pressure sensor 7 arranged on the grouting pipeline between the static mixer 6 and the fracture grouting hole 103 can be used to monitor the grouting pressure data.

[0053] In this embodiment, the experimental device further includes a flat light source 17 and a flat light source 18 disposed above the transparent crack model 1 , which are used to illuminate the transparent crack model 1 and improve the imaging quality of the camera 16 .

[0054] The present application sets a camera 16, combined with an adjustable flat light source 17 and a flat light source 2 18, which can not only observe the diffusion range but also determine the thickness of the slurry filling, thereby visualizing the plugging effect.

[0055] In this embodiment, the experimental device further includes a support system for providing installation positions for the camera 16 , the flat light source 1 17 and the flat light source 2 18 .

[0056] Specifically, the supporting system includes a stage 8, on which a vertical support rod 1 9 and a vertical support rod 2 10 are fixed, and a fixing block 14 and a fixing block 2 15 are commonly provided on the vertical support rod 1 9 and the vertical support rod 2 10, a transverse support rod 1 11 is provided on the fixing block 14, a camera 16 is installed on the transverse support rod 1 11, a transverse support rod 2 12 and a transverse support rod 3 13 are provided on the fixing block 2 15, and a flat light source 17 and a flat light source 2 18 are respectively installed on the transverse support rod 2 12 and the transverse support rod 3 13.

[0057] When in use, the camera 16 is fixed on the transparent crack model 1 through the fixing block 14 and the horizontal support rod 11, and the height, left and right position and front and back angle of the camera 16 can be adjusted by bolts. The flat light source 1 17 and the flat light source 2 18 used for fill light are fixed by the fixing block 2 15 and the horizontal support rod 2 12 and the horizontal support rod 3 13 respectively. The height, left and right position and front and back angle of the flat light source 1 17 and the flat light source 2 18 can be adjusted by bolts, and the light intensity of the flat light source 1 17 and the flat light source 2 18 can also be adjusted to obtain the best image quality. How to adjust by bolts is a known technology and will not be described in detail here.

[0058] In this embodiment, the constant pressure dynamic water injection system is connected to the transparent fracture model 1 and is used to inject water into the transparent fracture model 1 at a constant pressure.

[0059] Specifically, the constant pressure dynamic water injection system includes a Martens flask 19, a lifting platform 20 and a mass flow sensor 21. The Martens flask 19 is placed on the lifting platform 20. The Martens flask 19 is connected to the grouting hole 103 of the transparent fracture model 1 through a pipeline. The mass flow sensor 21 is arranged on the pipeline between the Martens flask 19 and the grouting hole 103. The outlet of the transparent fracture model 1 is connected to the waste liquid bottle 22 through a pipeline. The waste liquid bottle 22 is placed above the high-precision electronic scale 23.

[0060] When in use, constant pressure injection is achieved through the Marsh flask 19, the lifting platform 20 can be adjusted to a set water head height, the mass flow sensor 21 can measure flow changes, reflect the permeability changes in the cracks, and judge the blocking effect, while the liquid flowing out of the transparent crack model 1 can flow into the waste liquid bottle 22, and the high-precision electronic scale 23 is used to weigh the changes in the mass of the waste liquid at the outlet.

[0061] The water flows through the Martens flask 19, passes through the mass flow sensor 21 and is injected into the inlet cavity 104, then flows into the cracks of the transparent crack model 1, and the outlet is connected to the waste liquid bottle 22, and the high-precision electronic scale 23 is used to weigh the change in the mass of the waste liquid at the outlet, which further supplements the reflection of the plugging effect. The Martens flask 19 realizes constant pressure water injection, and combined with the mass flow sensor 21, it can realize real-time and accurate reflection of the plugging effect.

[0062] In this embodiment, the temperature control system is arranged outside the transparent fracture model 1 to simulate the grouting environment in high temperature or cold areas, and successfully simulates the influence of different temperature environments on the slurry performance and the plugging effect.

[0063] Specifically, the temperature control system includes a circulating water pipe 26 arranged around and below the cracks in the transparent crack model 1, and a high and low temperature circulating pump 27 connected thereto, which can create a constant temperature environment for the crack device by circulating constant temperature water flow to simulate the grouting environment in high temperature or cold areas.

[0064] Since low-temperature grouting is unavoidable in actual projects, and low temperature will affect the cement hydration process and slurry fluidity, and then affect the plugging effect, a low-temperature environment is created through the circulating water pipe 26, and the plugging effect is compared with that of a normal temperature environment under the same working conditions, the impact of low temperature and the analysis of influencing factors can be obtained.

[0065] In addition, the waste liquid recovery bottle and analysis system can also use the test tube 24 to take a proper amount of waste liquid at regular intervals to analyze the slurry composition using the liquid chromatograph 25 to quantify the quality of flushing and shedding.

[0066] This application tests the anti-scouring ability of the plugged area under high flow rate conditions after plugging is completed, quantifies the quality of scouring and shedding through changes in outlet waste liquid quality and slurry composition analysis, and evaluates the long-term stability of the plugging effect based on changes in permeability and pressure before and after scouring.

[0067] All sensors and high-precision electronic scales 23 in the device can connect signals to the computer 28 to read and save data.

[0068] Before the experiment begins, a transparent fracture model 1 is first prepared and the assembly of various instruments is completed, which specifically includes the following steps:

[0069] Cut the transparent flat glass into a set size as the transparent upper cover 101, and carve the threaded grouting holes 103; design the fracture network model, and make the epoxy resin fracture network 102 by pouring and curing;

[0070] The transparent upper cover 101 and the epoxy resin crack network 102 are assembled together, the left acrylic side strip 106, the right acrylic side strip 107, the inlet cavity 104, and the outlet cavity 105 are assembled around the cracks, and then the upper acrylic clamp 108, the lower acrylic clamp 109, the front acrylic clamp 110, the rear acrylic clamp 111, the left acrylic clamp 112, and the right acrylic clamp 113 are anchored with bolts to obtain the assembly. Figure 3 Transparent crack model in 1.

[0071] In order to enhance the water-stopping effect, a flexible epoxy resin strip or rubber strip may be added between the left acrylic side strip 106, the right acrylic side strip 107 and the inlet cavity 104, the outlet cavity 105 and the crack.

[0072] In addition, during the assembly process, the array distributed thin-film pressure sensor 2 can be placed between the epoxy resin crack network 102 and the circulating water pipe 26, and then the circulating water pipe 26 can be placed on the lower acrylic clamp 109, and the inlet and outlet of the circulating water pipe 26 must correspond to the pipe opening reserved on the right acrylic clamp 113.

[0073] Pipeline connection: first connect the outlets of plunger pump A3 and plunger pump B4 to the two inlets of three-way valve 5 respectively, the outlet of three-way valve 5 is connected to static mixer 6, static mixer 6 is connected to grouting hole 103 through grouting pipe, and a pressure sensor 7 is connected to the pipeline between static mixer 6 and grouting hole 103 to measure grouting pressure.

[0074] At the same time, after injecting water to a suitable height in the Marg flask 19, place it on the lifting platform 20, adjust the lifting platform 20 to a suitable height H, and then connect the water outlet of the Marg flask 19 to the inlet of the mass flow sensor 21, connect the outlet of the mass flow sensor 21 to the inlet cavity 104 of the transparent fracture model 1, and connect the outlet cavity 105 of the transparent fracture model 1 to the waste liquid bottle 22 placed on the high-precision electronic scale 23 through a pipeline.

[0075] Finally, the inlet and outlet of the circulating water pipe 26 are connected to the high and low temperature circulating pump 27, thus completing the connection of the pipeline.

[0076] Adjustment of imaging quality: connect computer 28 and camera 16, turn on flat light source 1 17 and flat light source 2 18, and adjust the height, left and right position, front and back angle and light intensity of camera 16 and flat light source 1 17 and flat light source 2 18 by adjusting transverse support rod 1 11, transverse support rod 2 12, transverse support rod 3 13 and fixing block 1 14 and fixing block 2 15 to obtain the best image quality.

[0077] Slurry preparation: Cement-water glass double liquid grouting requires the preparation of cement slurry and water glass solution. The cement slurry and water glass solution are prepared according to the water-cement ratio and Baume degree set in the experiment, and are loaded into the plunger pump A3 and the plunger pump B4 respectively.

[0078] After completing the above assembly work, the dynamic water grouting visualization experiment of rock fracture network can be carried out to monitor the global seepage pressure at different temperatures.

[0079] A temperature-controlled fracture network grouting test method comprises the following steps:

[0080] S1. First start the high and low temperature circulation pump 27, measure the temperature around the crack of the transparent crack model 1 with a thermometer, and when the temperature reaches the set temperature and is uniform and stable, turn on the Bluetooth of the array distributed thin film pressure sensor 2 to receive the pressure signal, then turn on the mass flow sensor 21 and the high-precision electronic scale 23 to record the mass flow, and open the valve of the Malchnitz flask 19 at the same time. The fluid will flow out of the Malchnitz flask 19 and flow into the waste liquid bottle 22 after passing through the transparent crack model 1.

[0081] S2, when the fluid passes through the transparent fracture model 1, the permeation pressure change at each location in the fracture is obtained through the array distributed thin-sheet pressure sensor 2, and the mass flow rate of the fluid is recorded through the mass flow sensor 21 and the high-precision electronic scale 23;

[0082] S3. After the transparent fracture model 1 is saturated and the liquid flow is stable, turn on the camera 16 to record the slurry diffusion process in real time, and turn on the pressure sensor 7 to record the grouting pressure change, then turn on the plunger pump A3 and the plunger pump B4 to inject cement and water glass solution at a set flow rate. After the two are mixed in the static mixer 6, they are injected into the transparent fracture model 1 through the grouting hole 103. After the injection reaches the set pressure or flow, turn off the plunger pump A3 and the plunger pump B4.

[0083] S4, replace the new waste liquid bottle 22, take a proper amount of waste liquid from the new waste liquid bottle 22 with a test tube 24 at regular intervals, and use a liquid chromatograph 25 to analyze the slurry composition to quantify the mass of the solid washed off;

[0084] S5. After flushing to the set time, close the valve of the Martens flask 19, turn off the camera 16 and the high-precision electronic scale 23, turn off the pressure sensor 7, the array distributed thin-sheet pressure sensor 2 and the mass flow sensor 21, turn off the high and low temperature circulation pump 27, the experiment is completed, disassemble and clean the transparent fracture model 1, and wait for the next experiment.

[0085] In summary, the device can realize accurate simulation and analysis of slurry diffusion behavior and plugging effect in complex fracture networks. This technology can be widely used in underground engineering, tunnel reinforcement, reservoir dam reinforcement, rock leakage control, mine tunnel support and other fields. The present invention provides a new solution for the optimization design and scientific evaluation of rock grouting technology through system integration of multifunctional devices and innovative test methods. The present invention accurately grasps the flow characteristics under complex fracture environments by dynamically monitoring the seepage pressure and slurry diffusion behavior at various positions in the fracture network. The present invention reveals the influence of temperature on slurry performance and plugging effect by simulating the grouting process under different temperature conditions. The present invention converts the real-time evolution process of the permeability of the fracture network through the monitoring of the flow rate by the mass flow sensor 21, thereby realizing real-time and accurate response to the plugging effect. The present invention improves the observation accuracy by using a high-resolution camera 16 and an adjustable light source to obtain a quasi-three-dimensional image of the diffusion of slurry in the fracture. The present invention tests the anti-scouring ability of the plugging area under high flow rate conditions after plugging is completed, quantifies the mass of scouring and shedding through the change in outlet waste liquid mass and slurry composition analysis, and evaluates the long-term stability of the plugging effect based on the permeability and pressure changes before and after scouring.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A temperature-controlled fracture network grouting experimental device, characterized in that: include: The transparent fracture model (1) is formed by laminating an upper covering surface (101) and a fracture network (102) together, wherein a grouting hole (103) is provided on the upper covering surface (101), and a water-stopping structure is provided around the upper covering surface (101) and the fracture network (102); An array of distributed thin-sheet pressure sensors (2) is disposed below the fracture network (102) and is used to monitor changes in permeability pressure at each location within the fracture of the transparent fracture model (1); A dual-liquid grouting system connected to the inlet of the transparent fracture model (1) and used for injecting grout into the fractures of the transparent fracture model (1); A camera (16) is arranged above the transparent fracture model (1) and is used to monitor the grouting process of the transparent fracture model (1); A constant pressure dynamic water injection system connected to the transparent fracture model (1) and used to inject water into the transparent fracture model (1) at a constant pressure; The temperature control system is arranged outside the transparent fracture model (1) and is used to simulate the grouting environment in high temperature or cold areas.

2. A temperature-controlled fracture network grouting experimental device according to claim 1, characterized in that: The water-stop structure comprises an inlet cavity (104) arranged on one side of an upper covering surface (101) and a crack network (102), and an outlet cavity (105) arranged on the other side of the upper covering surface (101) and the crack network (102); a left acrylic side strip (106) and a right acrylic side strip (107) are arranged on both sides of the upper covering surface (101) and the crack network (102); and an upper acrylic splint (108), a lower acrylic splint (109), a front acrylic splint (110), a rear acrylic splint (111), a left acrylic splint (112), and a right acrylic splint (113) are arranged on the outer sides of the upper covering surface (101) and the crack network (102).

3. A temperature-controlled fracture network grouting experimental device according to claim 1, characterized in that: The dual-liquid grouting system comprises a plunger pump A (3), a plunger pump B (4), a three-way valve (5) and a static mixer (6); the plunger pump A (3) and the plunger pump B (4) are connected to the three-way valve (5) via a grouting pipeline; the three-way valve (5) is connected to the static mixer (6) via a grouting pipeline; the static mixer (6) is connected to a grouting hole (103) of a transparent fracture model (1) via a grouting pipeline; a pressure sensor (7) is arranged on the grouting pipeline between the static mixer (6) and the fracture grouting hole (103).

4. A temperature-controlled fracture network grouting experimental device according to claim 1, characterized in that: The experimental device also includes a flat light source 1 (17) and a flat light source 2 (18) arranged above the transparent crack model (1) and used to illuminate the transparent crack model (1).

5. A temperature-controlled fracture network grouting experimental device according to claim 4, characterized in that: The experimental device also includes a support system, which includes a stage (8), on which a vertical support rod 1 (9) and a vertical support rod 2 (10) are fixed, and a fixing block 1 (14) and a fixing block 2 (15) are provided on the vertical support rod 1 (9) and the vertical support rod 2 (10), and a transverse support rod 1 (11) is provided on the fixing block 1 (14), and the camera (16) is installed on the transverse support rod 1 (11), and a transverse support rod 2 (12) and a transverse support rod 3 (13) are provided on the fixing block 2 (15), and the flat light source 1 (17) and the flat light source 2 (18) are installed on the transverse support rod 2 (12) and the transverse support rod 3 (13) respectively.

6. A temperature-controlled fracture network grouting experimental device according to claim 1, characterized in that: The constant pressure dynamic water injection system comprises a Martens flask (19), a lifting platform (20) and a mass flow sensor (21); the Martens flask (19) is placed on the lifting platform (20); the Martens flask (19) is connected to a grouting hole (103) of a transparent fracture model (1) via a pipeline; a mass flow sensor (21) is provided on the pipeline between the Martens flask (19) and the grouting hole (103); an outlet of the transparent fracture model (1) is connected to a waste liquid bottle (22) via a pipeline; and the waste liquid bottle (22) is placed above a high-precision electronic scale (23).

7. A temperature-controlled fracture network grouting experimental device according to claim 1, characterized in that: The temperature control system comprises a circulating water pipe (26) arranged around and below the cracks in the transparent crack model (1), and a high and low temperature circulating pump (27) connected to the inlet and outlet of the circulating water pipe (26).

8. A temperature-controlled fracture network grouting experimental device according to claim 1, characterized in that: The experimental device also includes a waste liquid recovery bottle and an analysis system. The waste liquid recovery bottle and the analysis system include a test tube (24) and a liquid chromatograph (25) for taking an appropriate amount of waste liquid through the test tube (24) and performing slurry component analysis using the liquid chromatograph (25).

9. A temperature-controlled fracture network grouting experimental method, characterized in that: The following steps are involved: Turn on the high and low temperature circulation pump (27) to make the temperature around the crack of the transparent crack model (1) reach the set temperature and become uniform and stable, then open the valve of the Malvern flask (19), and the fluid will flow out of the Malvern flask (19), pass through the transparent crack model (1) and flow into the waste liquid bottle (22); When the fluid passes through the transparent fracture model (1), the permeation pressure change at each location in the fracture is obtained through the array distributed thin-sheet pressure sensor (2), and the mass flow rate of the fluid is recorded through the mass flow sensor (21) and the high-precision electronic scale (23); After the transparent fracture model (1) is saturated and the liquid flow is stable, the camera (16), the flat light source 1 (17) and the flat light source 2 (18) are turned on to record the slurry diffusion process in real time, and the grouting pressure change is recorded through the pressure sensor (7). Then, the plunger pump A (3) and the plunger pump B (4) are turned on to inject the two solutions at a set flow rate. After the two solutions are mixed in the static mixer (6), they are injected into the transparent fracture model (1) through the grouting hole (103). After the injection reaches the set pressure or flow rate, the plunger pump A (3) and the plunger pump B (4) are turned off. Replace the new waste liquid bottle (22), take a proper amount of waste liquid from the new waste liquid bottle (22) with a test tube (24) at regular intervals, and use a liquid chromatograph (25) to analyze the slurry composition to quantify the mass of the solids washed off; After flushing to the set time, turn off each instrument and the test ends.

Images