CN108535454A - A kind of soil erosion test system and method - Google Patents

Abstract

The present invention provides a kind of soil erosion test system comprising the gradient for being configured to adjust sink in the bottom of sink is arranged in sink, sediment transport equipment, mixing plant, gradient regulating mechanism, the first pond and the second pond, gradient regulating mechanism；First pond is arranged in the lower section of sink outlet, second pond is arranged near the first pond and is connect by communicating pipe with the first pond, mixing plant is arranged in the top of sink, sink is connected with water inlet pipe, the other end of water inlet pipe connects the second pond, second pond is internally provided with muddy water pump, and muddy water pump is provided with the flow control valve for adjusting water flow.The system structure is simple, floor space is small, it can provide condition for analysis overland flow River Sediment Carrying Capacity and sedimentation, analyse in depth overland flow River Sediment Carrying Capacity and sedimentation process under different condition, understand that soil erosion process provides experimental condition to be deep.

Description

A soil erosion testing system and method

technical field

The invention relates to the field of soil erosion, in particular to a soil erosion testing system and method.

Background technique

Slope soil erosion is the main source of non-point source pollution. The study of soil erosion process can provide key technologies for the development of soil erosion models and an important basis for soil erosion control. The flume test is an important means to study the law of soil erosion on the slope. Existing tank tests often use a funnel above the tank for sand supply. This sand supply method is not only laborious and poor in stability, but also has potential safety hazards. Therefore, changing the sand supply mode of the tank is of great significance to ensure the safety and stability of the test. For this reason, sand transport equipment based on ground sand transport has been developed, which is effectively combined with the water tank, which improves the safety factor of the water tank test and also provides a guarantee for stable sand supply.

Contents of the invention

In order to overcome the defects of the prior art, the present invention provides a test system and method for soil erosion experiments, which has a simple structure and a small footprint, and can provide conditions for soil erosion, sand transport and sediment deposition tests to deeply explore the soil erosion process It provides services for the research and development of soil erosion models and soil erosion control.

Specifically, the present invention provides a soil erosion experiment testing system, which includes a water tank, sand transport equipment, stirring equipment, a slope adjustment mechanism, a first pool and a second pool, the slope adjustment mechanism is arranged at the bottom of the water tank, configured to adjust the slope of the trough;

The first water pool is arranged below the water outlet of the water tank, the second water pool is arranged near the first water pool and connected to the first water pool through a communication pipe,

The stirring device is arranged above the water tank, the water tank is connected with a water inlet pipe, the other end of the water inlet pipe is connected with a second pool, and a muddy water pump is arranged at a suitable position inside the second pool, and the muddy water pump is provided with a useful A flow regulating valve for regulating the flow of water,

The bottom of the water tank is provided with a field rough simulation layer, the outlet of the water tank is provided with a V-shaped opening for collecting muddy water samples, and the top of the water tank is provided with a third pool connected to the inlet. water pipe,

The stirring device is arranged inside the third pool, the stirring device includes a control panel, a base and a stirring shaft, the end of the stirring shaft is provided with a plurality of helical blades, and the control panel is provided with a Gear adjustment switch for stirring equipment speed,

The gradient adjustment mechanism includes a lifting mechanism, a fixed pulley and a chain, and the chain is arranged at the bottom of the water tank and passes through the fixed pulley to connect the lifting mechanism,

The sand conveying equipment includes a sand conveying hopper, a motor, a controller and a sand conveying pipeline, the first end of the sand conveying pipeline is connected to the sand conveying hopper, and the second end of the sand conveying pipeline is arranged on the third Above the pool, the second end of the sand conveying pipeline is provided with an adjustable opening, the motor is arranged on the top of the sand conveying pipeline and is connected with the controller through a wire and controlled by the controller, The controller can adjust the frequency of the motor to adjust the sand delivery rate of the sand delivery equipment, and the inside of the sand delivery pipeline is provided with helical blades.

Preferably, the helical blades are arranged in a staggered manner inside the sand conveying pipeline.

Preferably, the height of the second end of the sand delivery pipeline from the ground is controlled by a hydraulic jack.

Preferably, the sand transport hopper is funnel-shaped, the bottom of the sand transport hopper is connected to the first end of the sand transport pipeline, the sand transport hopper is connected to the sand pool through a pipeline, and the sand transport hopper is internally provided with A pumping device, the pumping device is connected to the controller by means of a data line, and the opening is arranged at the bottom of the sand transport hopper.

Preferably, the size-adjustable opening includes a plurality of rotatable blades and a blade rotation driving mechanism, and the blades can rotate under the action of the blade rotation driving mechanism to form an opening and adjust the size of the opening according to the rotation angle. The blade rotation driving mechanism is in communication connection with the controller and is controlled by the controller.

Preferably, the blade rotation drive mechanism is provided with a blade angle rotation scale.

Preferably, the adjustment range of the slope of the water tank is 0-60%.

Preferably, the water flow rate is less than 6×10 ^-3 m ² /s.

Preferably, the lifting mechanism is a manual crank or an electric crank.

Preferably, the present invention also provides a method for testing water and soil loss, which comprises the following steps:

S1. Adjust the slope of the water tank, adjust the flow rate through the valve, make the test conditions reach the target conditions, and turn on the switch of the stirring equipment;

S2, close and open the feed port opening of the sand delivery equipment, and fill the sand delivery hopper with the test soil;

S3. Turn on the power supply of the controller, adjust the frequency of the controller to the frequency required by the designed sand delivery rate, and turn on the switch of the controller;

S4. Adjust the size-adjustable opening of the sand delivery equipment to the required size of the target sand delivery rate, and the test soil enters the third pool of the water tank through the sand delivery pipeline;

S5. Judging whether the amount of sediment transport meets the needs of the test. If the amount of sediment transport is insufficient, increase the opening to increase the amount of sediment transport. If it still cannot meet the needs of the test, increase the frequency of the controller until the amount of sediment transport meets the needs of the test; If the amount is too large, reduce the opening to reduce the amount of sand transported, if it still cannot meet the needs, reduce the frequency of the controller to meet the test needs;

S6. After the test is over, first close the feed port opening of the sand conveying equipment, then close the controller switch, disconnect the controller power supply, and close the stirring equipment switch.

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

The invention provides a soil and water loss testing system and method, which can provide stable sand supply, save labor, be efficient, safe, have a simple structure, and occupy a small area, which can provide conditions for the exploration of soil erosion mechanisms.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the plan view of tank and pool of the present invention;

Fig. 3 is a structural schematic block diagram of the present invention;

Fig. 4 is the structural representation of mixing equipment of the present invention;

Fig. 5 is a schematic structural view of the size-adjustable opening of the present invention;

Fig. 6 is the relationship between the water flow sand-carrying force and the flow velocity of the cinnamon soil of the embodiment of the present invention;

Fig. 7 is the relationship between the predicted value of the sand-carrying force and the measured value of the embodiment of the present invention;

Fig. 8 is the relationship between the water flow sand-carrying force and the shear force of the cinnamon soil of the embodiment of the present invention;

Fig. 9 is the relationship between the predicted value and the measured value of the sand-carrying force of the cinnamon soil of the embodiment of the present invention;

Fig. 10 is the relationship between the water flow sand-carrying force and water flow power of the cinnamon soil of the embodiment of the present invention;

Fig. 11 is the relationship between the predicted value and the measured value of the sand-carrying force of the cinnamon soil of the embodiment of the present invention;

Fig. 12 is the relationship between the sand-carrying force of water flow and the power of unit water flow in an embodiment of the present invention;

Fig. 13 is the relationship between the water flow sand-carrying force and the flow rate of the cinnamon soil of the embodiment of the present invention;

Fig. 14 is the relationship between the predicted value and the measured value of the water flow sand-carrying force of the cinnamon soil according to the embodiment of the present invention.

Detailed ways

Exemplary embodiments, features, and performance aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numbers in the figures indicate functionally identical or similar elements. While various aspects of the embodiments are shown in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The present invention provides a water and soil loss testing system, as shown in Figures 1 to 3, which includes a water tank 1, sand transport equipment 2, stirring equipment 3, slope adjustment mechanism 4, a first pool 11 and a second pool 12, the slope adjustment The mechanism 4 is arranged at the bottom of the water tank 1, and is configured to adjust the slope of the water tank 1, and the adjustment range of the slope of the water tank is 0-60%.

The first pool 11 is arranged below the water outlet of the water tank 1, the second pool 12 is arranged near the first pool 11 and is connected with the first pool 11 through the connecting pipe 13, and the first pool 11 and the second pool 12 are connected with each other. The connecting pipe 13 is connected to ensure water recycling and stable water supply.

A stirring device 3 is arranged above the water tank 1, and the water tank 1 is connected with a water inlet pipe 14, and the other end of the water inlet pipe 14 is connected with the second pool 12, and a muddy water pump 15 is arranged at a suitable position inside the second pool 12, and the muddy water pump 15 is provided with a device for adjusting the water flow. Flow regulating valve for flow.

The bottom of the water tank 1 is provided with a field rough simulation layer, the outlet of the water tank 1 is provided with a V-shaped opening 16 for collecting muddy water samples, and the top of the water tank 1 is provided with a third pool 17 connected to the water inlet pipe 14. By means of the muddy water sample V-shaped opening 16, muddy water samples can be manually collected for experiments.

As shown in Figure 4, the stirring device 3 is arranged inside the third pool 17, the stirring device 3 includes a control panel, a base 31 and a stirring shaft 32, the end of the stirring shaft 32 is provided with a plurality of helical blades 33, and the control panel is provided with There is a gear adjustment switch for adjusting the speed of the stirring device, and multiple gears of the stirring device 3 can be adjusted by means of adjusting the gear adjustment switch.

The slope adjustment mechanism includes a lifting mechanism, a fixed pulley and a chain. The chain is arranged at the bottom of the water tank and passes through the fixed pulley to connect the lifting mechanism. The lifting mechanism is a manual crank or an electric crank.

The sand conveying equipment 2 is provided with a sand conveying hopper 21, a sand conveying pipeline 22, a motor 101 and a controller 10, the first end of the sand conveying pipeline 22 is connected to the sand conveying hopper 21, and the second end of the sand conveying pipeline 22 is arranged in the third pool 17 above, the second end of the sand delivery pipeline 22, that is, the sand discharge part 23, is provided with an adjustable opening 105, and the motor 101 is arranged on the top of the sand delivery pipeline 22 and is connected with the controller 10 by wires and is controlled by the controller 10. , the controller 10 can adjust the frequency of the motor 101 to adjust the sand delivery rate of the sand delivery equipment, and the inside of the sand delivery pipeline 22 is provided with helical blades. The helical blades 33 are arranged in a staggered manner inside the sand conveying pipeline 22 .

Preferably, the height of the second end of the sand delivery pipeline 22 from the ground is controlled by a hydraulic jack.

Preferably, the sand transport hopper 21 is funnel-shaped, the bottom of the sand transport hopper 21 is connected to the first end of the sand transport pipeline 22, the sand transport hopper 21 is connected to the sand pool through the pipeline, and a pumping device is arranged inside the sand transport hopper, pumping The device is connected to the controller 10 by means of data lines.

Preferably, as shown in FIG. 5 , the size-adjustable opening 105 includes a plurality of rotatable blades 1051 and a blade rotation drive mechanism 1052. A drive motor is arranged inside the blade rotation drive mechanism 1052, and the configuration of the drive motor is used to drive the blades to rotate. The drive mechanism 1052 rotates to drive the blades to rotate. The blade rotation drive mechanism 1052 is provided with a blade angle rotation scale. Under the control of the controller 10, the drive motor drives the blade rotation drive mechanism to rotate according to the blade angle rotation scale to drive the blades to rotate to adjust the size of the opening. . The blade 1051 can rotate under the action of the blade rotation driving mechanism to form an opening and adjust the size of the opening 1053 according to the rotation angle scale. The blade rotation driving mechanism 1052 is connected with the controller 10 and controlled by the controller 10 .

The scale range of feed opening size is 4-18mm. The sand discharge part 23 is provided with a sand delivery amount detection sensor 231 for detecting the sand delivery amount.

The output end of the sand delivery detection sensor 231 is connected to the input end of the controller 10, and the output end of the controller 10 is connected to the input end of the motor 101 and the opening size adjustment mechanism 105, and the sand delivery detection sensor 231 sends the sand delivery amount to the controller 10. , the controller 10 is internally provided with a minimum threshold of the amount of sediment transported and a maximum threshold of the amount of sediment transported.

When the amount of sand conveyed detected by the sand conveyance detection sensor 231 is lower than the minimum threshold of sand conveyance, the controller 10 sends a signal to the opening size adjustment mechanism to increase the opening to increase the sand conveyance, such as when the opening is adjusted to the maximum The amount of sand transported is still lower than the minimum threshold of the amount of sand transported, then the controller 10 increases the frequency of the motor 101 to increase the amount of sand transported by the pumping device 103 until the amount of sand transported reaches the minimum threshold of the amount of sand transported;

When the amount of sediment detected by the detection sensor 231 is higher than the highest threshold of the amount of sediment, the controller sends a signal to the opening size adjustment mechanism 105 to reduce the opening to reduce the amount of sediment, such as when the opening is adjusted to the minimum If the amount of sediment is still higher than the maximum threshold of the amount of sediment, the controller will reduce the frequency of the controller until the amount of sediment reaches the maximum threshold of the amount of sediment.

Preferably, a water flow sensor 104 is provided at the end of the water inlet pipe connected to the water tank, and the water flow sensor 104 is connected in communication with the controller 10 and is controlled by the controller 10 .

Preferably, the sand delivery hopper 21 is connected to the sand tank through a pipeline, and a pumping device 103 is arranged inside the sand delivery hopper 21, and the pumping device 103 is connected to the controller 10 by means of a data line, and the opening 105 is arranged at the bottom of the sand delivery hopper.

Preferably, the adjustment range of the slope of the tank is 0-60%.

Preferably, the water flow rate is less than 6×10 ^-3 m ² /s.

This system can be used to simulate soil erosion of different soils, provide conditions for analyzing the influence of different soil properties on the sand-carrying force of slope water flow, and simulate actual soil erosion. It can use soil as a test material and combine the soil erosion characteristics of steep slopes in my country , taking into account the characteristics of soil texture, in-depth analysis of the impact of different soil properties on the sediment-carrying force of slope flow.

The present invention also provides a method for testing water and soil loss, which comprises the following steps:

S1. Adjust the slope of the water tank, adjust the flow rate through the valve, make the test conditions reach the target conditions, and turn on the switch of the stirring equipment;

S2, open the feed port opening of the sand delivery equipment, and fill the sand delivery hopper with the test soil;

S3. Turn on the power supply of the controller, adjust the frequency of the controller to the frequency required by the designed sand delivery rate, and turn on the switch of the controller;

S4. Adjust the size-adjustable opening of the sand delivery equipment to the required size of the target sand delivery rate, and the test soil enters the third pool of the water tank through the sand delivery pipeline;

S5. Judging whether the amount of sediment transport meets the needs of the test. If the amount of sediment transport is insufficient, increase the opening to increase the amount of sediment transport. If it still cannot meet the needs of the test, increase the frequency of the controller until the amount of sediment transport meets the needs of the test; If the amount is too large, reduce the opening to reduce the amount of sand transported, if it still cannot meet the needs, reduce the frequency of the controller to meet the test needs;

S6. After the test is over, first close the feed port opening of the sand conveying equipment, then close the controller switch, disconnect the controller power supply, and close the stirring equipment switch.

Among them, the sand delivery frequency of cinnamon soil and the sand delivery rate of the sand conveyor after the feed opening of the feeding part is adjusted are shown in Table 1 below:

Table 1

Among them, the sand delivery frequency and the sand delivery rate of the sand delivery device after the feed opening of the feeding part are adjusted are shown in Table 2 below:

Table 2

specific embodiment

Soil Erosion Test Method for Cinnamon Soil

S1. Adjust the slope of the water tank to the slope value used in the experiment, adjust the flow rate of the water flow to the flow rate used in the experiment with a solenoid valve, and perform flow measurement. After the flow measurement, turn on the switch of the mixing device, start the sand delivery equipment, and adjust the frequency and opening size of the sand delivery equipment. The soil supply rate is continuously increased until the sediment cannot be completely taken away by the water flow, and when slight deposition occurs, the measurement of the sand-carrying force of the water flow is started, and water and sand samples are collected by means of water and sand standard sample collection equipment.

S2. Calculation of water flow velocity, water shear force, water flow power and unit water flow power:

Among them: the calculation formula of water depth is as follows:

In the formula, V is the water velocity (m/s), Q is the flow rate (m ³ /s), B is the width of the tank (m), and H is the water depth (m);

The formula for calculating the shear force of water flow is as follows:

τ=ρgHS

In the formula, τ is the shear force of water flow (Pa), ρ is the density of water (kg/m ³ ), and S is the slope of the tank (m/m);

The formula for calculating water flow power is as follows:

ω=τV

Where ω is water flow power (kg/m ³ );

The calculation formula of unit water flow power is as follows:

P=VS

In the formula, P is the unit water flow power (m/s);

S3, carry out data processing and chart making to the hydrodynamic parameters of measurement and the water flow sand-carrying force of the test soil, obtain the relationship between the test soil water flow sand-carrying force and different hydrodynamic parameters;

S4. For cinnamon soil, select different combinations of slope and flow rate, repeat steps S1-S3, conduct 30 sets of experiments, and record the relevant parameters of each experiment.

Preferably, step S3 specifically includes the following steps:

S31, fitting the relationship between the sand-carrying force of the water flow and the flow velocity, and making a relationship curve;

S32, fitting the relationship between the sand-carrying force of the water flow and the shear force of the water flow, and making a relationship curve;

S33, fitting the relationship between the sand-carrying force of the water flow and the power of the water flow, and making a relationship curve;

S34. Fitting the relationship between the sand-carrying force of the water flow and the slope and flow, and making a relationship curve.

Among them, the fitting formula of sand-carrying force and flow velocity on the slope surface of cinnamon soil is shown below, and the coefficient of determination is 0.92. Figure 5 shows the relationship curve between the sand-carrying force of water flow and the flow velocity of cinnamon soil;

T _{brown soil} = 6.878V ^2.571 R ² = 0.92 (1)

The relationship between the sand-carrying force of the slope flow and the velocity of the cinnamon soil can be well expressed by a power function, and the sediment-carrying force of the water flow increases with the increase of the velocity. The influence of the sediment-carrying force of the slope flow increases accordingly.

It can be seen from Figure 6 that the predicted and measured values of sand-carrying force of cinnamon soil calculated by the above formula are basically distributed near the 1:1 line, indicating that the above formula can better predict the sand-carrying force of cinnamon soil on slopes.

The fitting method of the relationship between the sand-carrying force of the water flow and the shear force of the water flow is as follows:

Tcinnamon _soil ＝0.275τ ^1.445 R ² ＝0.80 (2)

The sand-carrying force of the slope flow on the cinnamon soil increases with the increase of the shear force of the water flow. The relationship between the sand-carrying force of the water flow and the shear force of the water flow can be expressed by a power function. The correlation is shown in the above formula. The coefficient of determination is 0.80. The relationship between the two is shown in Figure 5.

As shown in Figure 7, the predicted value and the measured value of the sand-carrying force of cinnamon soil calculated by the formula are generally distributed near the 1:1 line, and some predicted values are smaller than the measured value.

The fitting formula of the relationship between the sediment-carrying force of the water flow and the power of the water flow is as follows:

T _{brown soil} = 0.901ω ^0.969

R2 = 0.83 (3)

The sand-carrying force of slope flow on cinnamon soil increases with the increase of water flow power. The relationship between the sand-carrying force of slope flow on cinnamon soil and water flow power can be expressed by a power function. The fitting formula is Equation 3, and the coefficient of determination is 0.83, and the relationship curve between the two is shown in Figure 8.

It can be seen from Figure 9 that the predicted and measured values of sand-carrying force of cinnamon soil calculated by formula 3 are roughly distributed around the 1:1 line, and some predicted values are smaller than the measured values.

Relationship between sand-carrying force of water flow and unit flow power

As shown in Figure 10, the coefficient of determination of the obtained fitting formula is only 0.28, which shows that the sand-carrying force of cinnamon soil and the unit flow power A good fit cannot be made between them.

The relationship between sand-carrying force of water flow and flow rate

Under different slope conditions, the overland flow sediment-carrying force of cinnamon soil increases with the increase of flow rate. The simulated relationship between the overland flow sediment-carrying force and flow rate of cinnamon soil is shown in Table 3. Figure 11 shows different slopes The relationship curve between the overland flow sand-carrying force and flow rate of cinnamon soil under the same conditions.

Table 3 Relationship between sand-carrying force of water flow and flow rate (cinnamon soil)

It can be seen from Table 3 that under different slope conditions, there is a good power function relationship between the sand-carrying force of the cinnamon soil and the single-width discharge, and the determination coefficients are all above 0.98. It can be seen from Figure 12 that under the same flow rate and different slope conditions, the difference in the sand-carrying force of the water flow is small, indicating that the slope has little effect on the sand-carrying force of the slope flow on the cinnamon soil.

Relationship between sand-carrying force of water flow and slope

Under different discharge conditions, the sand-carrying force of the slope flow on the cinnamon soil increases with the increase of the slope. The relationship curve between the sand-carrying force of the slope flow and the slope of the soil. It can be seen from Table 4 that, under different discharge conditions, there is a good power function relationship between the sediment-carrying force of overland flow and slope of cinnamon soil, and the determination coefficients are all above 0.92.

Table 4 Relationship between sand-carrying force of water flow and slope (cinnamon soil)

It can be seen from Figure 12 that as the slope increases, the sediment-carrying force of overland flow with different flows increases. As the slope increases, the difference in sediment-carrying force of overland flow under different discharge conditions also increases. When the flow rate increases above 1.5L/s, the slope of cinnamon soil

The sand-carrying force of surface flow has increased obviously. It shows that the discharge has a great influence on the sand-carrying force of the slope flow on the cinnamon soil.

The relationship between the sand-carrying force of water flow and slope and flow

R2 = 0.96 (4)

After a comprehensive analysis of 27 sets of test data of the cinnamon soil test, it is found that the sand-carrying force of the slope flow on the cinnamon soil has a power function relationship with the slope and flow, and the coefficient of determination is 0.96. Its fitting formula is formula (4). It can be seen from Figure 13 that the predicted and measured values of the overland flow sediment-carrying force of cinnamon soil calculated by formula (4) are basically distributed near the 1:1 line, indicating that formula (4) can better predict the water flow of cinnamon soil Carry sand force.

The sand-carrying force of the slope flow on the cinnamon soil is mainly affected by the discharge. The slope item in the formula (4) is deleted, and the 27 sets of data of the cinnamon soil test are comprehensively analyzed, and the following formula can be obtained.

R2 = 0.89 (5)

Compared with formula (4), the coefficient of determination of formula (5) has decreased by 7%, which is 0.89. However, it can be seen from Figure 14 that the predicted and measured values of the sand-carrying force of cinnamon soil calculated by formula (5) are basically distributed near the 1:1 line, which shows that formula (5) predicts the sand-carrying force of slope water flow on cinnamon soil The force effect is better.

Finally, it should be noted that: the above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand : It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements to some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention range.

Claims (10)

1. A soil erosion testing system, characterized in that: it comprises a water tank, a sand delivery device, a stirring device, a slope adjustment mechanism, a first pool and a second water pool, and the slope adjustment mechanism is arranged at the bottom of the water tank, its configured to adjust the slope of the tank; The first water pool is arranged below the water outlet of the water tank, the second water pool is arranged near the first water pool and connected to the first water pool through a communication pipe, The stirring device is arranged above the water tank, the water tank is connected with a water inlet pipe, the other end of the water inlet pipe is connected with a second pool, and a muddy water pump is arranged at a suitable position inside the second pool, and the muddy water pump is provided with a useful A flow regulating valve for regulating the flow of water, The bottom of the water tank is provided with a field rough simulation layer, the outlet of the water tank is provided with a V-shaped opening for collecting muddy water samples, and the top of the water tank is provided with a third pool connected to the inlet. water pipe, The stirring device is arranged inside the third pool, the stirring device includes a control panel, a base and a stirring shaft, the end of the stirring shaft is provided with a plurality of helical blades, and the control panel is provided with a Gear adjustment switch for stirring equipment speed, The gradient adjustment mechanism includes a lifting mechanism, a fixed pulley and a chain, and the chain is arranged at the bottom of the water tank and passes through the fixed pulley to connect the lifting mechanism, The sand conveying equipment includes a sand conveying hopper, a motor, a controller and a sand conveying pipeline, the first end of the sand conveying pipeline is connected to the sand conveying hopper, and the second end of the sand conveying pipeline is arranged on the third Above the pool, the second end of the sand conveying pipeline is provided with an adjustable opening, the motor is arranged on the top of the sand conveying pipeline and is connected with the controller through a wire and controlled by the controller, The controller can adjust the frequency of the motor to adjust the sand delivery rate of the sand delivery equipment, and the inside of the sand delivery pipeline is provided with helical blades. 2 . The soil erosion testing system according to claim 1 , wherein the helical blades are arranged in a staggered manner inside the sand conveying pipeline. 3 . 3. The soil erosion testing system according to claim 1, characterized in that: the height of the second end of the sand delivery pipeline from the ground is controlled by a hydraulic jack. 4. The soil erosion testing system according to claim 1, characterized in that: the sand transport hopper is funnel-shaped, the bottom of the sand transport hopper is connected to the first end of the sand transport pipeline, and the sand transport hopper The sand tank is connected through a pipeline, and a pumping device is arranged inside the sand delivery hopper, and the pumping device is connected with the controller by means of a data line, and the opening is arranged at the bottom of the sand delivery hopper. 5. The soil erosion testing system according to claim 1, wherein the size-adjustable opening includes a plurality of rotatable blades and a blade rotation drive mechanism, and the blades can be rotated under the action of the blade rotation drive mechanism. Rotate to form an opening and adjust the size of the opening according to the rotation angle. The blade rotation driving mechanism is connected with and controlled by the controller in communication. 6. The water and soil loss testing system according to claim 5, characterized in that: the blade rotation driving mechanism is provided with a blade angle rotation scale. 7. The water and soil loss testing system according to claim 1, characterized in that: the adjustment range of the slope of the water tank is 0-60 degrees. 8. ^{The soil erosion testing system according to claim 3, characterized in that: the flow rate of said water flow is less than 6×10 −3 m 2} /s. 9. The soil erosion testing system according to claim 3, characterized in that: the lifting mechanism is a manual crank or an electric crank. 10. A method for testing according to the soil erosion testing system according to claim 1, characterized in that: It includes the following steps: S1. Adjust the slope of the water tank, adjust the flow rate through the valve, make the test conditions reach the target conditions, and turn on the switch of the stirring equipment; S2, close and open the feed port opening of the sand delivery equipment, and fill the sand delivery hopper with the test soil; S3. Turn on the power supply of the controller, adjust the frequency of the controller to the frequency required by the designed sand delivery rate, and turn on the switch of the controller; S4. Adjust the size-adjustable opening of the sand delivery equipment to the required size of the target sand delivery rate, and the test soil enters the third pool of the water tank through the sand delivery pipeline; S5. Judging whether the amount of sediment transport meets the needs of the test. If the amount of sediment transport is insufficient, increase the opening to increase the amount of sediment transport. If it still cannot meet the needs of the test, increase the frequency of the controller until the amount of sediment transport meets the needs of the test; If the amount is too large, reduce the opening to reduce the amount of sand transported, if it still cannot meet the needs, reduce the frequency of the controller to meet the test needs; S6. After the test is over, first close the feed port opening of the sand conveying equipment, then close the controller switch, disconnect the controller power supply, and close the stirring equipment switch.