Dam leakage plugging method based on electrogenerated plugging material

Abstract

The invention relates to a dam leakage blocking method based on an electrogenerated blocking material. The method comprises the steps that electromagnetic field applying equipment is arranged on a dam body of a dam; an electro-blocking material is put on the upstream face of the dam, and an electromagnetic field is applied to the dam body through the electromagnetic field applying equipment; wherein the electro-blocking material is magnetic nanoparticles modified by a stabilizer. According to the operation method, on the basis of the solubility and the electrogenerated response rapid crystallization and precipitation characteristic of the electrogenerated plugging material, self-pursuit and precipitation-free water level rapid plugging of the dam leakage channel are comprehensively achieved, and support is provided for low-cost rapid treatment of dam leakage diseases. The scheme is not only suitable for blocking treatment of existing leakage channels of dams, but also suitable for timely prevention of expansion of secondary leakage channel development caused by reservoir water level periodic rising and falling.

Description

Technical Field

[0001] The invention belongs to the field of water conservancy project disease control, and particularly relates to a dam leakage blocking method based on electrolytic blocking materials. Background Art

[0002] Dams are important water conservancy projects, serving multiple functions, including regulating water flow, flood control, water supply, power generation, and irrigation. They play a vital role in economic development, water resource utilization, and ecological protection. Earth-rockfill dams are the most widely used and fastest-growing type of dam in my country. However, leakage in earth-rockfill dams remains a key factor affecting their stability and safety. Leakage refers to channels within an earth-rockfill dam or in its foundation that allow water to flow. These channels can be caused by factors such as uneven fill material, construction quality control deficiencies, adverse geological conditions such as earthquakes, and long-term water erosion. Once formed, leakage channels accelerate erosion and damage to the dam. Long-term water flow within these channels can lead to loss of fill material within the dam, increasing the risk of collapse and landslides. Furthermore, leakage channels can cause seepage damage, leading to cracks and landslides, increasing the risk of sudden dam instability.

[0003] If leakage problems are left untreated for a long time, a minor problem can easily become a major disaster. Currently, there are three challenges in managing leakage problems: 1. Accurate detection is difficult: the leakage channels are hidden underwater, buried deep within the dam body, and have small cross-sectional dimensions. Detection and positioning cannot resolve the conflict between accuracy and depth. The taller the dam and the larger the reservoir, the more difficult it is to accurately locate them. 2. Efficient plugging is difficult. The commonly used plugging method is grouting, which generally requires lowering the reservoir water level to expose the entrance of the leakage channel to facilitate reliable grouting, or re-installing an anti-seepage curtain on the dam. This is not only labor-intensive and complex, but also often difficult to guarantee the effectiveness. 3. Root cause treatment is difficult. After the main leakage channel is cut off, the dam leakage improves. However, as the reservoir water level rises and falls with operation, the original minor leakage channel gradually expands into the main channel, causing the dam leakage to recur. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and provide a dam leakage blocking method based on electro-blocking materials.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A dam leakage plugging method based on electro-blocking materials, the method comprising: Install electromagnetic field application equipment on the dam body; placing electro-blocking materials on the water-facing side of the dam, and applying an electromagnetic field on the dam body by means of the electromagnetic field applying equipment; Wherein, the electroblocking material is magnetic nanoparticles modified by a stabilizer.

[0006] As a preferred embodiment, the electro-blocking material is ferrosoferric oxide nanoparticles modified with sodium citrate.

[0007] Furthermore, the electro-blocking material is prepared by: After the iron salt and sodium citrate are mixed and dissolved in an organic solvent, acetate is added, and the mixture is transferred to a reactor for reaction after magnetic stirring to obtain sodium citrate-modified ferrosoferric oxide nanoparticles.

[0008] As a preferred embodiment, the molar ratio of iron to sodium citrate in the electrosealing material is 1:0.35-0.5; the iron salt and sodium citrate are reacted in a reactor for 10-20 hours.

[0009] As a preferred embodiment, the electromagnetic field applying equipment comprises a signal transmitter and a transmitting electrode; the signal transmitter is connected to the transmitting electrode via a wire, and transmits an excitation signal to the dam body via the transmitting electrode.

[0010] Furthermore, the signal transmitter is arranged on the top of the dam, and the transmitting electrodes are arranged on both sides of the dam soil.

[0011] Furthermore, the signal transmitter is a pseudo-random signal generator with a wide current intensity and voltage range and an adjustable transmission frequency, which generates a pseudo-random signal as an excitation signal.

[0012] Furthermore, the method also includes applying a specific electromagnetic field to each section or region of the dam body by adjusting the position and arrangement of the emitting electrodes. This method facilitates controlling the precipitation range of the suspended phase plugging material. For example, if the leakage channel can be roughly determined within a certain area, the electromagnetic field can be applied to that specific area.

[0013] As a preferred embodiment, the electrosealing material is pre-placed into a water-containing container and then dispersed by ultrasonic waves before being placed into the water body in front of the dam.

[0014] As a preferred embodiment, the electromagnetic field applying equipment applies a vertical electromagnetic field on the dam body.

[0015] The principle of the present invention is that after the electro-blocking material is released into the water body in front of the dam (the water-facing surface of the dam), the electro-blocking material disperses in the reservoir water to form a suspended phase. The electro-blocking material in the suspended phase enters the leakage channel with the water flow. Then, a magnetic field perpendicular to the direction of the leakage channel is applied to the dam. The electro-blocking material in the suspended phase is affected by the electromagnetic field and crystallizes and precipitates in the leakage channel, completing the blocking of the leakage channel.

[0016] The present invention has the following beneficial effects: 1. For dams with seepage channel defects, especially when they are diffuse seepage channels, water will randomly diffuse and flow through countless tiny pores in the porous medium, thus forming multiple seepage paths, which are characterized by slow seepage speed, complex and unclear seepage paths. The electro-blocking material of the present invention is used for blocking. First, the blocking material is released in the water body in front of the dam to form the suspended phase. Then, the channel effect, permeability difference and hydraulic gradient changed by the presence of the seepage channel in the earth-rock dam are combined to make the blocking material of the suspended phase enter the seepage channel autonomously with the water flow. Then, the electromagnetic field application equipment of the dam body is combined to generate a specific induced electromagnetic field in the dam body and the seepage channel, so that the suspended phase blocking material moving with the seepage water flow can quickly respond to the electromagnetic field and quickly crystallize and precipitate in the seepage channel to generate a precipitated phase blocking material, thereby achieving the purpose of blocking the seepage channel without positioning and without lowering the water level.

[0017] 2. The electro-blocking material used for plugging leakage channels of the present invention is a hydrophilic material. The surface groups of the material are fully utilized to enable the material to attract water molecules and form a water film on its surface, thereby being soluble in water or suspended in water to form a suspended phase plugging material. The electro-blocking material used is non-toxic, harmless, and environmentally friendly.

[0018] 3. Existing research and applications of traditional earth-rock dam leakage plugging focus on prioritizing the diagnosis of the location and scope of the leakage channel, and then performing curtain grouting or high-pressure jet grouting. However, for early-stage, tiny leakage channels, they are mainly hidden in the upstream water body and buried deep inside the dam body. They are difficult to accurately detect and locate, making it difficult to use traditional grouting methods to plug them. The method of the present invention can plug such tiny leakage channels with complex structures, making up for the shortcomings of traditional grouting methods. In addition, compared with traditional dam grouting plugging technology, the method of the present invention has lower management costs and shorter management time, and the electro-blocking material has no effect on the operation of the reservoir and the water body in front of the dam.

[0019] 4. The present method leverages the solubility and electroresponsive rapid crystallization and precipitation properties of the electro-blocking material to achieve self-tracking of dam leakage channels and rapid plugging without requiring a water level drop, providing support for rapid, low-cost management of dam leakage problems. This solution is suitable for both plugging and managing existing dam leakage channels and preventing the development and expansion of secondary leakage channels caused by cyclical fluctuations in reservoir water levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the self-tracking electroprecipitation plugging technology for dam leakage without requiring water level reduction.

[0021] In the figure: 1. Dam; 2. Water body in front of the dam; 3. Signal transmitter; 4. Water storage line; 5. Leakage channel; 6.1. Suspended phase sealing material, 6.2. Precipitated phase sealing material; 7.1, 7.2, single-sided transmitting electrodes; 8. Conductor; 9. Conducted current; 10. Direction of magnetic induction intensity generated by the conducted current.

[0022] Figure 2 Schematic diagram of the scaled experiment, where (a) is a schematic diagram of the simulated leakage channel with pre-buried capillaries of different inner diameters; (b) is a model diagram of the earth-rock dam; and (c) is a schematic diagram of the upstream placement of plugging materials. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0024] The electro-blocking material described in the embodiment refers to a material that can precipitate and crystallize under the action of an electromagnetic field to block leakage channels.

[0025] Example 1 like Figure 1 As shown, the method of the present invention comprises the following steps: (1) A dam body electromagnetic field applying device is arranged on the dam body 1 to apply an electromagnetic field to the dam body 1. The electromagnetic field applying device comprises a signal transmitter 3, a transmitting electrode 7.1, a transmitting electrode 7.2 and a wire 8. The signal transmitter 3 is arranged on the top of the dam body and is connected to the transmitting electrodes 7.1 and 7.2 through the wire 8. The transmitting electrodes 7.1 and 7.2 are arranged on both sides of the soil in the dam body 1.

[0026] In this embodiment, the signal transmitter 3 uses a pseudo-random signal generator with a wide current intensity, voltage range and adjustable transmission frequency; the transmitting electrodes 7.1 and 7.2 are selected from materials with good conductivity, flexible and convenient electrode shapes and sizes, easy layout, and stable and reliable connections, meeting the technical requirements that the signal transmitter and the transmitting electrodes can work together.

[0027] (2) The electro-blocking material is released in the water body in front of the dam body 1, so that the electro-blocking material enters the water body. The electro-blocking material is a magnetic nanoparticle modified with a stabilizer. After entering the water body, it is in a suspended phase. Combined with the channel effect when there is a leakage channel 5 inside the dam body 1, the permeability difference and the hydraulic gradient changed by the existence of the leakage channel 5, the suspended phase plugging material 6.1 enters the leakage channel 5 autonomously along with the water flow.

[0028] (3) A pseudo-random signal is generated as an excitation signal by the signal transmitter 3. The excitation signal is supplied to the soil inside the dam body through the transmitting electrodes 7.1 and 7.2 on both sides via the conductor 8. The electromagnetic field generated by the conduction current 9 covers the leakage channel 5 and generates magnetic anomalies inside the leakage channel 5. The application of specific electromagnetic fields in each section and area of ​​the dam body 1 can be achieved by adjusting the position and layout of the transmitting electrodes 7.1 and 7.2. The direction of the magnetic induction intensity caused by the conduction current 9 is 10.

[0029] (4) The current is concentrated along the low-resistance path (leakage zone) in the soil. The suspended phase plugging material 6.1 in the leakage zone is affected by the electromagnetic field and crystallizes and precipitates in the leakage channel to form the precipitated phase plugging material 6.2, thus completing the plugging of the leakage zone.

[0030] Example 2 This example tests the effects of different electro-blocking materials.

[0031] In order to achieve dam sealing, the performance requirements for electro-sealing materials are as follows: soluble in water or suspended in water, with a sedimentation volume of less than 10% in still water within 6 hours; under the action of an excited electromagnetic field, the sedimentation volume in still water is greater than 70% within 5 minutes; when the dynamic water flow rate is less than 1m / s, the sedimentation volume is greater than 50% within 5 minutes; at the same time, under the action of a specific electromagnetic field 10, it can respond quickly and accelerate crystallization precipitation, and should be a non-toxic, harmless, green and environmentally friendly material.

[0032] Stabilizer-modified magnetic nanoparticles can disperse well when entering water and accelerate crystallization and precipitation when subjected to a magnetic field. In this example, sodium citrate-modified ferroferric oxide nanoparticles were selected as the plugging material for testing, and the experimental effects of sodium citrate-modified ferroferric oxide nanoparticles with different ratios were analyzed. The steps are as follows: (1) Measure 80 mL of ethylene glycol and add 2.7 g (0.01 mol) of FeCl₃·6H₂O and X g of sodium citrate. Stir alternately with ultrasonic and magnetic stirring for 30 min until the mixture is completely dissolved. (Make sure to cover the beaker with plastic wrap and seal it tightly.) (2) Add 4.1 g of sodium acetate (sodium acetate CH3COONa), stir magnetically for 30 min, and transfer to a 100 mL Teflon-lined stainless steel autoclave (100 mL volume) and react at 200 °C for Y h.

[0033] (3) After cooling to room temperature, the hydrothermal reactor is loose and can be opened. The product can be collected with a magnet and washed three times with ethanol / water alternatingly.

[0034] Taking different values ​​for X and Y, the product properties obtained are shown in Table 1: Table 1 Properties of sodium citrate modified ferroferric oxide nanoparticles

[0035] In this test, it can be seen from the experimental products No. 1, 5, 7 and 8 that when the mass of ferric chloride and sodium citrate raw materials is constant, the motion response of the material under the magnetic field gradually increases with the increase of reaction time until it reaches a threshold; the suspension property decreases with the increase of reaction time; we speculate that it may be that with the increase of reaction time, the particle size of the microscopic material gradually increases, the mass and specific surface area of ​​the individual particles change, and the number of H bonds between its surface functional groups and water will also change, thereby affecting the motion response and suspension property; from the experimental products No. 2-6, it can be seen that when the reaction time remains unchanged, as the amount of sodium citrate increases, its motion response gradually weakens and the suspension property gradually increases.

[0036] Intuitive observations reveal that suspension and kinematic response are mutually influenced by material properties. Based on practical application requirements (high kinematic response and suspension for more than 6 hours), sample 7 (X = 1g, Y = 20h) was tested to have a 5% sedimentation rate in still water within 6 hours; 95% sedimentation rate in still water within 5 minutes under an electromagnetic field; and 60% sedimentation rate within 5 minutes at a dynamic water velocity of less than 1m / s. This non-toxic, environmentally friendly material is an optimal choice for plugging. Sample 5 (X = 1g, Y = 10h) also meets the requirements for an electro-plugging material, but its sedimentation rate after application of a magnetic field is slower than that of sample 7. In addition to sodium citrate-modified Fe3O4 nanoparticles, we also tested Fe3O4 nanoparticles modified with a silane coupling agent as a plugging material. However, within the tested silane dosage and reaction time, these Fe3O4 nanoparticles sedimented rapidly and could not maintain suspension for an extended period, thus being excluded as a potential plugging material.

[0037] Example 3 This example tests the blocking effect of the solution of the present invention based on a scaled experiment.

[0038] The earth-rockfill dam model in this example considers a generalized model of a small homogeneous earth-rockfill dam with a dam height of 12m, a crest width of 4m, and an upstream-downstream slope ratio of 1:1.5. The model was designed at a scale of 1:100, with the dam model height being 12cm, the crest width being 4cm, and the embankment model length (along the dam axis) being 20cm. Furthermore, the water level in front of the dam was set at 80% of the model dam height, or 9.6cm.

[0039] The model box used in the experiment is 100 cm long, 40 cm high and 20 cm wide. From left to right, it contains the water inlet tank, experimental tank and water outlet tank. A water supply valve is arranged every 10 cm from bottom to top on the left side of the water inlet tank for head control. A turbine flowmeter is arranged at the bottom right of the water outlet tank to monitor the flow rate and flow velocity of the leaking water.

[0040] In this example, the earth-rockfill dam model itself was constructed with fine-grained yellow clay with a low permeability coefficient to ensure the dam's inherent anti-seepage properties. Silicone capillaries of varying inner diameters were used to simulate leakage channels, characterizing leakage channels of varying shapes and orientations. A plugging test was conducted using Sample No. 7, prepared in Example 2, and a vertical magnetic field was applied using an N52 NdFeB square strong magnet.

[0041] like Figure 2 As shown, after a vertical magnetic field is applied to the dam and plugging materials are placed, containers are used to collect downstream leakage water samples at different stages, and the plugging effect is qualitatively and quantitatively analyzed by monitoring and recording the total seepage within a fixed time interval. In this embodiment, four stages are selected for monitoring, namely 0-30 minutes after upstream water injection, 0-30 minutes after placement of a strong magnet, 30 minutes to 1 hour after placement of a strong magnet, and 1 hour to 1.5 hours after placement of a strong magnet, to illustrate the effect. The monitoring results show that the leakage amount is reduced after the application of the magnetic field, and as time goes by, about 45 minutes after the application of the magnetic field, no water seeps out of the downstream outlet, and the leakage water amount in this monitoring window is reduced by about 66.7% compared with the same time window before plugging, indicating that the nanoparticles in the silica gel capillary have accumulated to a certain extent, blocking the leakage water flow and successfully blocking the leakage channel.

[0042] The earth dam model was dismantled and the pre-buried silicone capillaries were removed. Results revealed that the interiors of the three inner diameter capillaries, located downstream of the dam and covered by the magnetic field, were filled with a large number of modified nanoparticles. This demonstrates that the plugging material can gradually accumulate within the seepage channels under the stimulation of a vertical magnetic field, thereby blocking the flow of seepage water. Given that early-stage, microscopic seepage channels in actual earth-rockfill dams often have complex geometries and nonlinearity, the accumulated nanoparticles offer a more effective barrier to seepage.

[0043] Existing research and application of leak plugging in earth-rock dams focuses on prioritizing the location and extent of leakage channels, followed by curtain grouting or high-pressure jet grouting. However, early-stage, small leakage channels are primarily hidden in upstream water bodies and buried deep within the dam body, making them difficult to accurately detect and locate, making them difficult to plug using traditional grouting methods. The method of the present invention can plug these complex, small leakage channels, addressing the shortcomings of traditional grouting methods.

Claims

1. A dam leakage blocking method based on electro-blocking materials, characterized in that: The method comprises: Install electromagnetic field application equipment on the dam body; placing electro-blocking materials on the water-facing side of the dam, and applying an electromagnetic field on the dam body by means of the electromagnetic field applying equipment; Wherein, the electroblocking material is magnetic nanoparticles modified by a stabilizer.

2. The method according to claim 1, characterized in that The electro-blocking material is ferrosoferric oxide nanoparticles modified by sodium citrate.

3. The method according to claim 2, characterized in that The preparation method of the electro-blocking material is as follows: After the iron salt and sodium citrate are mixed and dissolved in an organic solvent, acetate is added, and the mixture is transferred to a reactor for reaction after magnetic stirring to obtain sodium citrate-modified ferrosoferric oxide nanoparticles.

4. The method according to claim 2 or 3, characterized in that The molar ratio of iron to sodium citrate in the electrosealing material is 1:0.35-0.5; the iron salt and sodium citrate are reacted in a reactor for 10-20 hours.

5. The method according to claim 1, wherein The electromagnetic field applying equipment comprises a signal transmitter and a transmitting electrode; the signal transmitter is connected to the transmitting electrode via a wire, and transmits an excitation signal to the dam body via the transmitting electrode.

6. The method according to claim 5, characterized in that The signal transmitter is arranged on the top of the dam, and the transmitting electrodes are arranged on both sides of the dam soil.

7. The method according to claim 5, characterized in that The signal transmitter is a pseudo-random signal generator with a wide current intensity and voltage range and adjustable transmission frequency, which generates a pseudo-random signal as an excitation signal.

8. The method according to claim 5 or 7, characterized in that The method also includes applying a specific electromagnetic field to each section and area of ​​the dam body by adjusting the position and layout of the transmitting electrodes.

9. The method according to claim 1, characterized in that The electro-sealing material is put into a water-containing container in advance, dispersed by ultrasonic waves, and then put into the water body in front of the dam.

10. The method according to claim 1, characterized in that The electromagnetic field applying equipment applies a vertical electromagnetic field on the dam body.

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