Experimental device for simulating influence of seawater upstream on percolation of canal transparent soil slope

Abstract

The experimental device comprises a water tank, a gate, a transparent soil slope, a first collecting water tank, a second collecting water tank, a first water suction pump and a second water suction pump, the gate is mounted in the water tank and divides the water tank into a fresh water area and a saline water area, the transparent soil slope is stacked on one side of the fresh water area, the fresh water tank is arranged on one side of the water tank, and the saline water tank is arranged on the other side of the water tank. A seawater tank is arranged on the other side of the water tank, a salt water area water pump is arranged in the salt water area and connected with the seawater tank, a first collecting water tank and a second collecting water tank are arranged on the outer side of the water tank, and the first collecting water tank is connected with the fresh water area through a first water suction pump. The second collecting water tank is connected with the salt water area through a second water suction pump. The device provided by the utility model can simulate the process of seawater upstream and salty water and fresh water alternation, and has the advantages of low cost, simple experimental operation, visual experimental process and easy acquisition of experimental data.

Description

Technical Field

[0001] The utility model belongs to the technical field of geotechnical engineering and hydrogeological engineering, and specifically relates to an experimental device for simulating the influence of seawater upstream on the seepage of a canal transparent soil slope. Background Art

[0002] The tidal section of the canal is located at the intersection of the river and the ocean, and the hydrogeological conditions are relatively complex. Due to excessive groundwater exploitation or due to factors such as the drop in canal water level and the reduction in canal water flow speed, there is a head difference between salt and fresh water. Under the action of tidal force, seawater moves upstream along the river channel and mixes with fresh water. The process of alternating salt and fresh water mixing is not static. Once seawater moves upstream, the salt and fresh water transition zone formed at the intersection also fluctuates with the action of the tide, the salt and fresh water mixing process is enhanced, and the range of seawater moving upstream is also expanded. Such problems affect the lives of people in the area and also have a certain impact on the bank slope soil of the tidal section of the canal. At present, there are more studies on the impact of seawater moving upstream on groundwater pollution, and less research on the impact on the seepage field in the bank slope soil. Therefore, it is of great significance to study the impact of seawater moving upstream on the seepage field of the bank slope of the tidal section of the canal and the impact of seawater moving upstream on the long-term stability of the bank slope soil. Utility Model Content

[0003] In view of the problems existing in the above-mentioned prior art, the utility model provides an experimental device for simulating the influence of seawater upstream on the seepage of the transparent soil slope of the canal, with the purpose of revealing the process of salt-fresh water soil alternation in the canal and the morphology, position and development evolution law of the salt-fresh water interface, and studying the influence of salt-fresh water alternation on the seepage field and stability of the transparent soil slope in the tidal section of the canal.

[0004] In order to achieve the above purpose, the specific scheme of the utility model is as follows:

[0005] The invention discloses an experimental device for simulating the influence of seawater upstream on the seepage of transparent soil slope of a canal, comprising a water tank, a gate, a transparent soil slope, a collecting water tank 1, a collecting water tank 2, a pump 1 and a pump 2, wherein the gate is installed in the water tank to divide the water tank into a fresh water area and a salt water area, a transparent soil slope is piled on one side of the fresh water area, a fresh water tank is arranged on one side of the water tank, a fresh water area pump is arranged in the fresh water area and connected to the fresh water tank, a sea water tank is arranged on the other side of the water tank, a salt water area pump is arranged in the salt water area and connected to the sea water tank, the collecting water tank 1 and the collecting water tank 2 are respectively arranged on the outside of the water tank, the collecting water tank 1 is connected to the fresh water area through the pump 1, and the collecting water tank 2 is connected to the salt water area through the pump 2.

[0006] Furthermore, it also includes salt concentration sensors, moisture sensors, pore water pressure sensors, cameras, high-speed cameras and three-dimensional laser scanners and other image acquisition equipment. The salt concentration sensor, moisture sensor, pore water pressure sensor, camera, and high-speed camera are respectively connected to computers. Multiple pore water pressure sensors and moisture sensors are respectively arranged in the transparent soil slope, multiple cameras are arranged on the top of the fresh water area, multiple high-speed cameras and three-dimensional laser scanners are respectively arranged on the outside of the water tank and facing the fresh water area, and multiple salt concentration sensors are respectively arranged in the length and height directions of the side wall of the water tank.

[0007] Furthermore, a flow meter and a water level scale are provided in the fresh water area and the salt water area respectively.

[0008] Furthermore, the length of the freshwater area is greater than that of the saltwater area, a tracer flows into the transparent soil slope, and a dye is injected into the seawater tank.

[0009] Furthermore, the water tank, the fresh water tank and the sea water tank are all connected by a steel frame and organic glass to form a tank body.

[0010] Advantages of the utility model

[0011] The experimental device for simulating the effect of seawater upstream on the seepage of a canal transparent soil slope of the utility model injects tracer particles into the transparent soil slope. After the experiment begins, a high-speed camera is used to record the flow trajectory of the tracer particles in the cross section and profile of the transparent soil slope in real time, and the changes in water content, pore water pressure and salt concentration are recorded by sensors at the same time, and then the flow changes of the tracer particles are obtained during the process of seawater upstream (i.e., the alternating mixing of salty and fresh water), reflecting the seepage process of water in the soil body during the upstream process. The experimental device can simulate the process of seawater upstream and the alternation of salty and fresh water, the experimental device has a low cost, the experimental operation is simple, and the experimental data is easy to collect; transparent soil materials are used to replace general soil for experiments, and non-embedded observation of the transparent soil slope is performed in combination with technical methods such as particle image velocimetry system, so that the experimental process is visualized and convenient for observation of the experimental process; by changing the flow rate of the water pump, multiple groups of comparative experiments at different water levels or different flow rates can be carried out to obtain general rules. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a three-dimensional structural schematic diagram of the utility model of the simulated seawater upstream experimental device.

[0013] In the figure:

[0014] 1: Steel frame water tank; 2: Transparent soil slope; 3: Fresh water area; 4: Salt water area; 5: Gate; 6: Fresh water area water pump; 7: Salt water area water pump; 8: Suction pump; 9: Suction pump; 10: Collection tank; 11: Collection tank; 12: Fresh water tank; 13: Sea water tank; 14: Water sensor; 15: Pore water pressure sensor; 16: Salt concentration sensor; 17: 3D laser scanner; 18: Camera; 19: High-speed camera; 20: Water level scale; 21: Flow meter. DETAILED DESCRIPTION

[0015] The present invention is further explained below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that this specific embodiment is not intended to limit the scope of rights of the present invention.

[0016] like Figure 1 As shown, the experimental device for simulating the influence of seawater upstream on the seepage of the transparent soil slope of the canal provided in this specific embodiment includes a steel frame water tank 1, a gate 5, a transparent soil slope 2, a collecting water tank 10, a collecting water tank 2 11, a pump 1 8, a pump 2 9, a salt concentration sensor 16, a moisture sensor 14, a pore water pressure sensor 15, a camera 18, a high-speed camera 19, a three-dimensional laser scanner 17 and a computer.

[0017] The steel frame water tank 1, the fresh water tank 12 and the sea water tank 13 are all connected by a steel frame and organic glass to form a tank body. The size of the steel frame water tank 1 is 4.5m×0.8m×0.6m. A gate 5 with an automatic lifting switch is embedded in the steel frame water tank 1 to separate the steel frame water tank 1 into a fresh water area 3 and a salt water area 4. The length of the fresh water area 3 is greater than that of the salt water area 4. The length of the fresh water area 3 in this specific embodiment is 3m, and the length of the salt water area 4 is 1.5m, simulating the tidal section of the canal. The mixing and alternation of salt and fresh water in the steel frame water tank 1 is controlled by the gate 5 and the salt water area water pump 7. The opening and closing of the gate 5 corresponds to the start and end of the experiment to accurately record the time of the experiment. When the gate 5 is closed, the airtightness of both sides of the steel frame water tank 1 is ensured, and the fresh water area 3 and the salt water area 4 on both sides of the steel frame water tank 1 do not affect each other; when the gate 5 is opened, under the action of the water pump in the salt water area 4, seawater invades the fresh water area 3 upstream in the opposite direction of the fresh water flow.

[0018] The freshwater area 3 and the saltwater area 4 are respectively provided with a flow meter 21 and a water level scale 20 to monitor the flow velocity and water level of the freshwater area 3 and the saltwater area 4 before the experiment. A transparent soil slope 2 is piled up at different angles on one side of the freshwater area 3 to simulate the bank slope of the tidal section of the canal, for example: the slope is 20° and the slope height is 0.30m. Transparent soil materials are used to replace ordinary soil. The transparent soil materials used are the same as the original graded soil of the canal bank slope and meet the physical and mechanical properties of the soil required by the experiment. The preparation and stacking process are not described here. Moisture sensors 14 and pore water pressure sensors 15 are buried in the transparent soil slope 2 at intervals of 15cm to 20cm in the length direction, and multiple salt concentration sensors 16 are buried at intervals of 15cm to 20cm in the side wall of the steel frame water tank 1 at intervals of 15cm to 20cm in the length direction and 15cm in the height direction to monitor the changes in water content, pore water pressure, and salt concentration during the experiment. The salt concentration sensor 16, the moisture sensor 14, the pore water pressure sensor 15, the camera 18, the high-speed camera 19 and the three-dimensional laser scanner 17 are connected to the computer respectively. A tracer is injected into the transparent soil slope 2, a dye is added into the seawater tank 13, and image acquisition equipment such as a three-dimensional laser scanner 17, a high-speed camera 19 and a camera 18 are arranged outside the steel frame water tank 1. The particle image velocimetry system (PIV) technology is used to visualize the process of seawater upstream mixing with fresh water and the seepage field in the soil slope.

[0019] A freshwater tank 12 is provided on one side of the steel frame water tank 1, and a freshwater area water pump 6 is provided in the freshwater area and connected to the freshwater tank 12. A collecting water tank 10 and a collecting water tank 2 11 are respectively arranged outside the steel frame water tank 1, and the collecting water tank 10 is connected to the freshwater area 3 through a pumping pump 8. Specifically, the freshwater tank 12 is connected and separated from the freshwater area 3 by a piece of organic glass, and a hole for installing the freshwater area water pump 6 is reserved on the glass. When the freshwater area water pump 6 is turned on, the fresh water in the freshwater tank 12 is sent to the freshwater area 3, and the change of the water level is monitored by the water level scale 20. When the water level in the freshwater area 3 is about to rise to the preset value of the experiment, the pumping pump 8 is turned on. The flow rate in the freshwater area 3 is calculated by the flow meter 21 and the change of the water level in the collecting water tank 10 per unit time. According to the preset requirements of the experiment, the pumping pump 8 and the freshwater area water pump 6 are adjusted to the same set flow rate at the same time, so that the flow rate in the freshwater area 3 is constant and the water level reaches the preset value, effectively simulating the flow of river water in the tidal section of the canal; when the water level reaches the preset requirements, the freshwater area water pump 6 and the pumping pump 8 can also be closed to simulate the working condition where the river water flow rate is 0.

[0020] A seawater tank 13 is provided on the other side of the steel frame water tank 1, a saltwater area water pump 7 is provided in the saltwater area 4 and connected to the seawater tank 13, and a collecting water tank 11 is connected to the saltwater area 4 through a pumping pump 9. Specifically, the seawater tank 13 is connected and separated from the saltwater area 4 by a piece of organic glass, and a hole for installing the saltwater area water pump 7 is reserved on the glass. When the saltwater area water pump 7 is turned on, the seawater in the seawater tank 13 is sent into the saltwater area 4, and the change of the water level is monitored by the water level scale 20. When the water level of the saltwater area 4 is about to rise to the preset value of the experiment, the pumping pump 9 is turned on. The flow rate in the saltwater area 3 is calculated by the flow meter 21 and the change of the water level in the collecting water tank 11 per unit time. According to the preset requirements of the experiment, the pumping pump 9 and the saltwater area water pump 7 are adjusted to the same set flow rate at the same time, so that the flow rate in the saltwater area 4 is constant, and the water level reaches the preset value to simulate the flow of seawater.

[0021] By adjusting the flow rates of the freshwater area pump 6 and the pumping pump 1 8, and the saltwater area pump 7 and the pumping pump 2 9, the water level and water flow rate in the freshwater area 3 and the saltwater area 4 are controlled to meet the preset requirements of the experiment. After the gate 5 is opened, the set flow rates of the freshwater area pump 6 and the pumping pump 1 8 are kept unchanged, and the pumping pump 2 9 is adjusted to make it the same as the flow rates of the two, and the set flow rate of the saltwater area pump 7 is kept unchanged. Under the action of the saltwater area pump 7, seawater is alternately mixed with fresh water to simulate the water flow state when seawater is upstream in the tidal section of the canal.

[0022] The above experimental device uses multiple cameras 18 to record in real time the distance and time of seawater with dyes going upstream along the river channel and mixing with fresh water, and uses a high-speed camera 19 to record in real time the change process of the flow of tracer particles in the transparent soil slope 2. Through multiple moisture sensors 14, pore water pressure sensors 15 and salt concentration sensors 16, the changes in the water content, pore water pressure and salt concentration in the soil slope at different positions at the same time and at different times at the same position are recorded and studied respectively, and the law of changes in the time and distance of seawater going upstream is analyzed to analyze the changes in the seepage field in the soil slope after seawater goes upstream.

[0023] Working principle:

[0024] Under the two working conditions that the initial freshwater level is lower than the saltwater level, or the initial freshwater flow rate is lower than the seawater flow rate, multiple groups of control experiments with different water levels or flow rates are carried out according to the experimental plan. By repeating the experimental analysis and comparing the experimental results under different conditions, the law of the influence of seawater upstream on the seepage field of the transparent soil slope in the tidal section of the canal can be obtained.

[0025] Before the experiment, after the water flow stabilizes, a tracer is injected into the transparent soil slope 2 to mark the seepage path, and a dye is added to the seawater tank 13 to distinguish the color of fresh water; at the beginning of the experiment, the gate 5 is turned on and the flow rate of the pump 2 9 is adjusted to be the same as the flow rate of the freshwater area pump 6 and the pump 1 8. The saltwater area pump 7 pumps the seawater with dye into the freshwater area 3 to simulate the process of seawater upstream and mixing with fresh water; during the experiment, the moisture sensor 14, the pore water pressure sensor 15, and the salt concentration sensor 16 respectively record the changes in water content, pore water pressure, and salt concentration at different positions in the transparent soil at the same time and at different times at the same position; multiple cameras 18 record the distance and time of the seawater with dye upstream; multiple high-speed cameras 19 record the changes in the seepage field marked by the tracer in the transparent soil. After the experiment, the gate 5 is closed and the above three experimental data are analyzed.

[0026] According to the experimental requirements of different flow rates and water levels in the plan, the flow rates of the freshwater area pump 6, the saltwater area pump 7, the pumping pump 1 8, and the pumping pump 2 9 are adjusted, and the above steps are repeated to obtain multiple sets of experimental data to simulate the seawater upstreaming under the conditions where the freshwater flow rate is less than the seawater flow rate and the freshwater water level is lower than the seawater level, and the results are compared and analyzed to obtain general rules.

[0027] During the experiment, multiple cameras 18 were used to capture real-time motion images of the upward movement of tracer-carrying seawater and the mixing of fresh water. Particle image velocimetry system technology was used to capture real-time changes in the seepage field in the transparent soil slope through multiple high-speed cameras 19. The relationship between changes in water content, pore water pressure and salt concentration and the processes of seawater upward movement and fresh water alternation was studied. The interaction process of salt-fresh water and soil on the canal bank slope and the morphology, position and development evolution of the salt-fresh water interface were revealed, and the laws of the influence of salt-fresh water alternation on the seepage field of the canal bank slope were obtained.

Claims

1. An experimental device for simulating the effect of seawater upstream on the seepage of transparent soil slopes in a canal, characterized in that: The utility model comprises a water trough, a gate, a transparent earth slope, a first collecting water tank, a second collecting water tank, a first pump and a second pump. The gate is installed in the water trough to divide the water trough into a fresh water area and a salt water area. A transparent earth slope is piled on one side of the fresh water area. A fresh water tank is arranged on one side of the water trough. A fresh water area pump is arranged in the fresh water area and connected to the fresh water tank. A sea water tank is arranged on the other side of the water trough. A salt water area pump is arranged in the salt water area and connected to the sea water tank. The first collecting water tank and the second collecting water tank are respectively arranged on the outside of the water trough. The first collecting water tank is connected to the fresh water area through the first pump, and the second collecting water tank is connected to the salt water area through the second pump.

2. The experimental device for simulating the effect of seawater upstream on the seepage of transparent soil slopes in a canal according to claim 1 is characterized in that: It also includes a salt concentration sensor, a moisture sensor, a pore water pressure sensor, a camera, a high-speed camera, a three-dimensional laser scanner and a computer. The salt concentration sensor, moisture sensor, pore water pressure sensor, camera, high-speed camera and three-dimensional laser scanner are respectively connected to the computer. Multiple pore water pressure sensors and moisture sensors are respectively arranged in the transparent soil slope, multiple cameras are arranged on the top of the fresh water area, multiple high-speed cameras and three-dimensional laser scanners are respectively arranged on the outside of the water tank and facing the fresh water area, and multiple salt concentration sensors are respectively arranged in the length and height directions of the side wall of the water tank.

3. The experimental device for simulating the effect of seawater upstream on the seepage of transparent soil slope in a canal according to claim 1 is characterized in that: The fresh water area and the salt water area are respectively provided with a flow meter and a water level scale.

4. The experimental device for simulating the effect of seawater upstream on the seepage of transparent soil slopes in a canal according to claim 1, characterized in that: The length of the freshwater area is greater than that of the saltwater area, a tracer is added into the transparent soil slope, and a dye is injected into the seawater tank.

5. The experimental device for simulating the effect of seawater upstream on the seepage of transparent soil slopes in a canal according to claim 1 is characterized in that: The water tank, the fresh water tank and the sea water tank are all connected by a steel frame and organic glass to form a tank body.

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