Fracture network seepage and solute transport visual experiment device

Abstract

The utility model discloses a fissure network seepage and solute transport visualization experiment device, which belongs to the technical field of fissure medium seepage and solute transport and comprises a seepage test system, a data acquisition system and a light transmission imaging system. The seepage test system comprises a fracture network model and an injection assembly; the injection assembly is used for injecting a solution into the fracture network model; the data acquisition system is used for acquiring seepage image data and solution concentration data of the fracture network model; and the light transmission imaging system is used for making a seepage image of the fracture network model clear. The utility model discloses a fissure network seepage and solute transport visualization experiment device which can effectively solve the problems that in the prior art, due to the non-transparent characteristic of rock mass, the fissure medium seepage and solute transport process cannot be completely captured in real time.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of fissure medium seepage and solute migration, and particularly relates to a fissure network seepage and solute migration visualization experiment device. BACKGROUND

[0002] Fissure medium seepage and solute migration is an important process generally involved in the engineering application in the fields of water conservancy, environment and energy. In water conservancy and hydropower engineering, fissure rock mass seepage and solute migration is closely related to engineering geology and hydrogeological survey, dam foundation rock mass seepage prevention performance evaluation, reservoir slope stability evaluation, and groundwater pollution prevention and control. Therefore, in-depth exploration of the law and mechanism of fissure medium seepage and solute migration is of great significance to the construction and safe operation of water conservancy and hydropower engineering.

[0003] Due to the undulating surface topography characteristics and complex opening space distribution of natural rock fissures, the fluid motion and solute migration therein exhibit more complex behaviors. In particular, in the air gap, the fissure medium seepage behavior exhibits long-term non-steady and non-continuous flow characteristics, which make the solute migration process in the fissure exhibit significant non-Fickian transport characteristics, such as early peak arrival, tailing, double peaks and multiple peaks. Although scholars in the past have carried out some experiments to study fissure medium seepage, due to the opaque nature of rock mass, past fissure medium seepage experiments have been mostly limited to obtaining basic seepage parameters and permeability characteristics of fissures, and cannot completely and real-time capture the fissure medium seepage and solute migration process. Therefore, it is urgent to develop a visualization experiment device for the mechanism research of fissure medium seepage and solute migration. SUMMARY

[0004] In view of the problems existing in the prior art, the utility model provides a fissure network seepage and solute migration visualization experiment device, which aims to solve the problems in the prior art that the opaque nature of rock mass cannot completely and real-time capture the fissure medium seepage and solute migration process. To achieve the above purpose, the utility model provides the following technical scheme:

[0005] A fissure network seepage and solute migration visualization experiment device, comprising a seepage test system, a data acquisition system and a light transmission imaging system; the seepage test system comprises a fissure network model and an injection assembly; the injection assembly is used for injecting a solution into the fissure network model; the data acquisition system is used for acquiring seepage image data and solution concentration data of the fissure network model; and the light transmission imaging system is used for making the seepage image of the fissure network model clear.

[0006] Further, the light transmission imaging system comprises a base and an LED light source; the data acquisition system comprises a camera; the base is provided with a camera support rod and a model support rod assembly; the camera is fixed on the base through the camera support rod; the fracture network model is fixed on the base through the model support rod assembly; and the LED light source is directly fixed on the base.

[0007] Further, the camera, the fracture network model and the LED light source are arranged in sequence along the front-rear order, and the centers of the camera, the fracture network model and the LED light source are on the same straight line.

[0008] Further, the base is provided with a rotating shaft; the base can rotate around the rotating shaft to drive the camera, the fracture network model and the LED light source to rotate synchronously, and the centers of the camera, the fracture network model and the LED light source always remain on the same straight line during the rotation.

[0009] Further, the injection assembly comprises an injection pump, an injector and an injection tube; the injector communicates with the inlet of the fracture network model through the injection tube; and the injection pump is used to drive the injector to inject.

[0010] Further, the injector injects soluble dye and soluble conservative tracer into the fracture network model through the injection tube.

[0011] Further, the data acquisition system comprises an electronic balance; the electronic balance is provided with a first beaker located directly below the outlet of the fracture network model; and the electronic balance is used to obtain the mass of the solution flowing out of the outlet of the fracture network model collected in the first beaker.

[0012] Further, the data acquisition system comprises an electric conductivity meter, an electric conductivity probe and a second beaker; the electric conductivity meter is connected with the electric conductivity probe; the second beaker is used to dilute the solution at the outlet of the fracture network model to reach the minimum liquid depth required by the electric conductivity probe; and the electric conductivity probe is placed in the second beaker.

[0013] Further, the data acquisition system comprises a computer; the computer is connected with the electric conductivity meter and the camera through data lines respectively.

[0014] Further, the model support rod assembly comprises a model suspension rod, a first model support rod and a second model support rod; the first model support rod and the second model support rod are fixedly connected to the base; the two ends of the model suspension rod are connected to the top of the first model support rod and the second model support rod respectively; and the bottom of the model suspension rod is fixedly connected with the fracture network model.

[0015] The utility model discloses the beneficial effect is:

[0016] (1) by adopting transparent resin material to obtain the fissure network model of 3D printing, make fissure network model have higher light transmittance, and LED light source provides stable and continuous light source, and camera real -time record fissure network model's image, realized the real -time visualization observation of seepage behavior in fissure network.

[0017] (2) the conductivity meter is used to measure the conductivity value of the dyeing solution of different tracer concentration, obtains the calibration curve of solution concentration and solution conductivity, can calculate the concentration of fissure network model export solution by measuring the conductivity value of fissure network model export solution, and then obtains the solute breakthrough curve of fissure network export solution.

[0018] (3) the liquid in the syringe is dissolved with dyeing agent and conservative tracer, and the presence of the dyeing agent makes the gas phase and liquid phase in the experimental image can be clearly distinguished, and the presence of the tracer makes the solute transport process of the fissure network can be captured, simultaneously realizes the real -time visualization observation of fissure network seepage and the acquisition of the solute breakthrough curve of fissure network export solution.

[0019] (4) the base drives camera, fissure network model and LED light source along the rotation axis rotation fixed angle, guarantee under different rotation angle camera center and fissure model center always on the same straight line, realizes the observation of fissure network seepage behavior under different gravity effect and the acquisition of the solute breakthrough curve of fissure network export solution. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is the structure schematic drawing of the utility model;

[0021] Figure 2 It is the part moment fissure network seepage diagram of real -time record in the utility model seepage experiment;

[0022] Figure 3 It is the calibration curve diagram obtained by fitting the scatter diagram of dyeing solution concentration and conductivity of the utility model;

[0023] Figure 4 It is the solute breakthrough curve diagram of fissure network export solution when the inlet flow of the utility model seepage experiment is 3ml / min;

[0024] The reference signs are: 1, second beaker; 2, conductivity meter; 3, computer; 4, injection pump; 5, camera; 6, camera support rod; 7, first model support rod; 8, second model support rod; 9, fracture network model; 10, first beaker; 11, electronic balance; 12, LED light source; 13, rotating shaft; 14, base; 15, model suspension rod; 16, syringe; 17, injection tube; 18, conductivity probe; 19, camera data line; 20, conductivity meter data line. DETAILED DESCRIPTION

[0025] The utility model is further described in detail below in combination with the drawings and specific embodiments, but the utility model is not limited to the following examples.

[0026] In the description of the utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as a limitation on the utility model.

[0027] In the description of the utility model, "first feature" and "second feature" can include one or more features.

[0028] In the description of the utility model, "multiple" means two or more.

[0029] In the description of the utility model, "above" or "below" the first feature in the second feature can include that the first and second features are in direct contact, or can include that the first and second features are not in direct contact but are in contact through another feature between them.

[0030] In the description of the utility model, "above", "above" and "above" of the first feature in the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature.

[0031] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," and "some examples" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] Example

[0033] See attached Figures 1-4 This embodiment provides a visualization experimental device for seepage and solute transport in fractured networks, including a seepage experimental system, a light transmission imaging system, and a data acquisition system. The seepage experimental system includes a fractured network model and an injection component. The injection component is used to inject a solution into the fractured network model. The data acquisition system is used to acquire seepage image data and solution concentration data of the fractured network model. The light transmission imaging system is used to make the seepage image of the fractured network model clear. The light transmission imaging system includes a base 14 and an LED light source 12, with the LED light source 12 directly connected to the base 14. The data acquisition system includes a camera 5, an electronic balance 11, a conductivity meter 2, a conductivity probe 18, a dedicated computer 3, a first beaker 10, and a second beaker 1. The camera 5 is connected to the base 14 via a camera support rod 6. The injection assembly includes an injection pump 4, a syringe 16, and an injection tube 17. The syringe 16 is fixed to the injection pump 4 and connected to the fracture network model 9 via the injection tube 17. The fracture network model 9 is fixed to the base 14 via a model support rod assembly, which includes a model suspension rod 15, a first model support rod 7, and a second model support rod 8. Both the first model support rod 7 and the second model support rod 8 are fixedly connected to the base 14. The two ends of the model suspension rod 15 are respectively connected to the tops of the first model support rod 7 and the second model support rod 8, and the bottom of the model suspension rod 15 is fixedly connected to the fracture network model 9. The base 14 is equipped with a rotating shaft 13. Both ends of the rotating shaft 13 can be fixed in the laboratory used for experiments. The base 14 as a whole can rotate around the rotating shaft 13, thereby driving the camera 5, the rift network model 9 and the LED light source 12 on the base 14 to rotate synchronously.

[0034] In this embodiment, the liquid in syringe 16 contains two solutes: a soluble dye and a soluble conserved tracer. The syringe pump 4 injects the dye solution from syringe 16 into the fracture network model 9 via syringe tube 17 to conduct fracture network seepage and solute transport experiments. Under the illumination of LED light source 12, the gas phase and liquid phase can be distinguished in the image data acquired by camera 5, enabling visualization of the seepage.

[0035] In this embodiment, the camera 5 has a maximum acquisition speed of 10 FPS, is equipped with a wide-angle lens, and has a large field of view. It is positioned directly in front of the fracture network model 9 for recording. The camera 5 is connected to a dedicated computer 3 via a camera data cable 19. The continuously captured image data can be transmitted to the dedicated computer 3 in real time. The dedicated computer 3 can process the image data acquired by the camera 5. Based on the RGB values, it can extract the number of pixels of the dyed liquid in the image and the number of liquid pixels in the saturated state of the fracture network, and then calculate the saturation of the fracture network at the corresponding moment in the image, which is the ratio of the number of liquid pixels at that moment to the number of liquid pixels in the saturated state. The LED light source 12 is placed behind the fracture network model 9, with an illumination area of ​​25×25cm. It has high performance, does not flicker, and has stable light intensity, providing a stable and continuous light source for the experiment. The center of the camera 5, the center of the fracture network model 9, and the center of the LED light source 12 are always on the same straight line to ensure the stability and clarity of the images recorded by the camera 5.

[0036] In this embodiment, the rotating shaft 13 is connected to the base 14, and the camera 5, the fracture network model 9, and the LED light source 12 are directly or indirectly connected to the base 14. As the base 14 rotates along the rotating shaft 13, the camera 5, the fracture network model 9, and the LED light source 12 also rotate by the same angle. Furthermore, the center of the camera 5, the center of the fracture network model 9, and the center of the LED light source 12 are always on the same straight line, enabling the visualization and observation of the fracture network seepage behavior under different model tilt angles.

[0037] In this embodiment, the electronic balance 11 is placed directly below the fracture network model 9, and the first beaker 10 is placed on the electronic balance 11. This allows for the collection of the solution from the outlet of the fracture network model 9, with a measurement accuracy of 0.001g, enabling precise measurement of the weight of the outlet liquid. The conductivity meter has a sampling range of 0.000 μS / cm-1000 mS / cm and a minimum resolution of 0.001 μS / cm. The second beaker 1 is placed on the conductivity meter 2, which is connected to a conductivity probe 18. The conductivity probe 18 is placed in the second beaker 1 to measure the conductivity value of the liquid in the second beaker 1. The minimum depth requirement for the conductivity probe 18 to detect the liquid is 3cm. Therefore, the outlet solution of the fracture network model 9 is first collected in the first beaker 10, then transferred to the second beaker 1 for dilution. A certain amount of pure water is added to make the liquid level in the second beaker 1 reach more than 3cm. The conductivity value of the diluted solution is then measured using the conductivity meter 2. The conductivity meter 2 is connected to the dedicated computer 3 via the conductivity meter data cable 20, and the data collected by the conductivity meter 2 can be automatically transmitted to the dedicated computer 3.

[0038] In this embodiment, the syringe pump 4 is a Harvard Apparatus PhD Ultra 70-3007, with a stability accuracy of 0.25%, a repeatability accuracy of 0.05%, and a flow rate of 1 mL / min-100 mL / min. It is used to propel the syringe 16 to inject the staining solution into the fractured network model 9. The number of syringes 16 can be increased on the syringe pump 4 to enable simultaneous injection through multiple channels, allowing the staining liquid to permeate into the fractured network at all boundaries. The syringe 16 has a capacity of 50 mL, and the injection tube 17 has an inner diameter of 2.5 mm and an outer diameter of 3.5 mm. The staining solution is injected into the fractured network model 9 through the injection tube 17.

[0039] In this embodiment, the material of the fracture network model 9 is transparent resin. A random fracture network is generated by Monte Carlo simulation. An STL format drawing file of the fracture network model is generated in the drawing software. The model drawing file is 3D printed to obtain the fracture network model 9, which is 15cm×15cm in size, with a fracture aperture of 1mm and a fracture depth of 2mm.

[0040] In this embodiment, the staining solution in syringe 16 uses capsanthin as the staining agent, with a concentration of 0.5 g / L, and the conductivity of the stained water is 427 μS / cm. Sodium chloride is used as the tracer in the staining solution in syringe 16, with an initial concentration of 5 g / L. After staining, the transmittance of the gas phase and liquid phase in the fracture network model 9 is different. Under the illumination of LED light source 12, the aqueous phase and liquid phase can be distinguished in the image data acquired by camera 5. First, a capsanthin staining solution is prepared, then the solution is divided into multiple portions, and different amounts of sodium chloride are added to each portion to obtain solutions with different sodium chloride concentrations. The conductivity values ​​corresponding to different concentrations are measured using a conductivity meter 2. The corresponding data of the staining solution concentration and conductivity values ​​are shown in Table 1 below.

[0041] Table 1. Corresponding data on the concentration and conductivity of the paprika oleoresin staining solution.

[0042]

[0043] Based on the concentration and conductivity data of the staining solution, a scatter plot of solution concentration and conductivity was plotted, and a calibration curve of solution concentration and conductivity was obtained by fitting. Figure 3 The diagram illustrates a scatter plot of the concentration and conductivity of the staining solution, along with the fitted calibration curve. The formula for the calibration curve is shown below:

[0044] .

[0045] in The conductivity of the dyed sodium chloride solution is expressed in mS / cm. The concentration of the staining sodium chloride solution is expressed in mol / L.

[0046] Based on the calibration curve formula, the conductivity value of the diluted solution measured by conductivity meter 2 can be converted into a concentration value. Combined with the mass value measured by electronic balance 11, the concentration of the outlet solution of the fracture network model 9 can be calculated, thereby obtaining the solute breakthrough curve of the outlet solution of the fracture network. The calculation formula is shown below:

[0047] .

[0048] in The concentration of the pure water used for dilution is 0 here; The concentration of the diluted solution is expressed in mol / L and is calculated from the measured conductivity value. The concentration of the solution at the outlet of the fracture network is expressed in mol / L. The mass of the solution exiting the fracture network is expressed in grams and is measured by an electronic balance. The density of the solution at the outlet of the fracture network is expressed in g / cm³, and the measured value is 1.005 g / cm³. This represents the volume of pure water used to dilute the solution, expressed in liters (L).

[0049] When using the above-mentioned visualization experimental device for fractured network seepage and solute transport, the real-time observation method for fractured network seepage and solute transport is as follows:

[0050] Step 1: Set the relative positions of camera 5, slit network model 9, LED light source 12 and base 14, and rotate shaft 13 to adjust the slit network model to the required tilt angle (90°) for the experiment.

[0051] Step 2: Set the focal length, exposure intensity, shooting range, and shooting speed of camera 5;

[0052] Step 3: Connect the injection tube 17 to the inlet of the fracture network model 9, and set the injection flow rate (3ml / min) and injection volume (5ml) of the injection pump 4.

[0053] Step 4: Start the camera 5, then start the injection pump 4, and push the syringe 16 to inject the staining solution into the fracture network model 9 at a certain flow rate. At the same time, use the first beaker 10 to collect the outflowing solution at the outlet of the fracture network model 9. Replace the beaker at intervals to collect the newly outflowing solution.

[0054] Step 5: After injecting the staining solution, fill syringe 16 with pure water and inject pure water into the fracture network model 9 at the same flow rate (3 ml / min). Camera 5 and electronic balance 11 continuously record data.

[0055] Step 6: Pour a certain amount of pure water into the second beaker 1 to dilute the staining solution, and use a conductivity meter 2 to measure the conductivity value of the diluted solution;

[0056] Step 7: Based on the mass data collected by the electronic balance 11 and the conductivity data collected by the conductivity meter 2, the solution concentration data at the outlet of the fracture network model 9 is calculated. Simultaneously, the camera 5 records the seepage image of the fracture network model 9, thus realizing the observation of the fracture network seepage and the acquisition of the solute breakthrough curve of the solution at the fracture network outlet. Figure 2 The images of the fracture network seepage at 18 seconds and 64 seconds are shown respectively. Figure 4 The solute breakthrough curve of the outlet solution of the fracture network is illustrated when the inlet flow rate is 3 ml / min. C represents the concentration of the injected staining solution, and C represents the concentration of the solution at the outlet of the fracture network.

[0057] The above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model. Technologies, shapes, and structural parts not described in detail in this utility model are all known technologies.

Claims

1. A visualization experimental device for fracture network seepage and solute transport, characterized in that: The system includes a seepage test system, a data acquisition system, and a light transmission imaging system. The seepage test system includes a fracture network model (9) and an injection component. The injection component is used to inject a solution into the fracture network model (9). The data acquisition system is used to acquire seepage image data and solution concentration data of the fracture network model (9). The light transmission imaging system is used to make the seepage image of the fracture network model (9) clear.

2. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 1, characterized in that: The light transmission imaging system includes a base (14) and an LED light source (12); the data acquisition system includes a camera (5); the base (14) is provided with a camera support rod (6) and a model support rod assembly; the camera (5) is fixed on the base (14) by the camera support rod (6); the fracture network model (9) is fixed on the base (14) by the model support rod assembly; the LED light source (12) is directly fixed on the base (14).

3. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 2, characterized in that: The camera (5), the rift network model (9), and the LED light source (12) are arranged in a front-to-back sequence, and the centers of the camera (5), the rift network model (9), and the LED light source (12) are on the same straight line.

4. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 2, characterized in that: The base (14) is provided with a rotating shaft (13); the base (14) can rotate around the rotating shaft (13), driving the camera (5), the fracture network model (9) and the LED light source (12) to rotate synchronously, and during the rotation, the centers of the camera (5), the fracture network model (9) and the LED light source (12) always remain on the same straight line.

5. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 1, characterized in that: The injection assembly includes an injection pump (4), a syringe (16), and an injection tube (17); the syringe (16) is connected to the inlet of the fracture network model (9) through the injection tube (17); the injection pump (4) is used to push the syringe (16) to inject.

6. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 5, characterized in that: The syringe (16) injects a soluble staining agent and a soluble conservative tracer into the fracture network model (9) through the injection tube (17).

7. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 2, characterized in that: The data acquisition system includes an electronic balance (11); the electronic balance (11) is equipped with a first beaker (10) located directly below the outlet of the fracture network model (9); the electronic balance (11) is used to obtain the mass of the solution collected in the first beaker (10) flowing out of the outlet of the fracture network model (9).

8. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 7, characterized in that: The data acquisition system includes a conductivity meter (2), a conductivity probe (18), and a second beaker (1); the conductivity meter (2) and the conductivity probe (18) are connected; the second beaker (1) is used to dilute the solution at the outlet of the fracture network model (9) to achieve the minimum liquid depth required by the conductivity probe (18); the conductivity probe (18) is placed in the second beaker (1).

9. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 8, characterized in that: The data acquisition system includes a computer (3); the computer (3) is connected to the conductivity meter (2) and the camera (5) via data cables.

10. The experimental apparatus for visualizing fracture network seepage and solute transport according to claim 2, characterized in that: The model support rod assembly includes a model suspension rod (15), a first model support rod (7), and a second model support rod (8); the first model support rod (7) and the second model support rod (8) are both fixedly connected to the base (14); the two ends of the model suspension rod (15) are respectively connected to the top of the first model support rod (7) and the second model support rod (8); the bottom of the model suspension rod (15) is fixedly connected to the fracture network model (9).

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