An experimental device and method for simulating the influence of rainfall under different cover conditions

Abstract

The application discloses an experimental device and method for simulating the influence of rainfall under different cover conditions, and belongs to the technical field of rainfall simulation experiments, and comprises an isolation frame, a top of the isolation frame is provided with a simulated rainfall device; a soil simulation box, the soil simulation box comprises a soil box body, a permeable plate is detachably installed at the bottom of the soil box body, experimental soil layers are filled in the permeable plate, and a cover simulation plate is detachably installed at the top of the soil box body. The technical key points are as follows: through cooperation of the simulated rainfall device and the cover simulation plate, different rainfall parameters (particle size, intensity and duration) and various cover types (realized by filling different cover fillers) can be freely combined, and the soil slope can be adjusted, so that the complex experimental requirements of multiple factors are met, the application has a flexible structure and is simple to operate, the action mechanism of rainfall on soil runoff, infiltration and erosion under different cover conditions can be systematically studied, and reliable experimental support is provided for water and soil conservation and ecological restoration.

Description

Technical Field

[0001] This invention relates to the field of rainfall simulation experiment technology, specifically an experimental apparatus and method for simulating the effects of rainfall under different cover conditions. Background Technology

[0002] In fields such as soil erosion, hydrological cycle, and ecological research, understanding the interaction between land cover factors and rainfall is crucial. The cover condition, type, and density of land cover significantly influence the direct impact of rainfall on the soil, thereby affecting the dynamic processes of soil particle stripping, transport, and deposition. This is of great significance for accurately assessing soil erosion and developing scientifically effective soil and water conservation measures. Currently, some rainfall simulation devices can control parameters such as rainfall intensity and duration, but most can only conduct experiments on bare soil or single-cover conditions. They struggle to flexibly simulate multiple cover types (such as cover layers of different thicknesses and materials) and the coupling effects between cover and rainfall parameters. Furthermore, existing devices have limitations in adjusting soil slope, simulating different soil layer structures, and facilitating rapid cover replacement, restricting the efficient implementation of multi-factor, multi-scenario experiments.

[0003] For example, the prior art document with publication number CN102034001A discloses a distributed hydrological model design method using grids as simulation units. Based on mathematical statistics, stochastic simulation and weak stability theory, it uses a meteorological generator to calculate the stochastic solution set of five types of meteorological parameters, namely rainfall, temperature, solar radiation, relative humidity and average wind speed. It is used to fill in the gaps when meteorological data at stations is incomplete, to simulate when meteorological data is missing, and to predict future meteorological parameters.

[0004] In existing studies on the impact of rainfall simulation on soil, researchers have largely focused on improving the uniformity of rainfall simulations and accurately controlling key indicators such as rainfall amount, while neglecting the influence of soil surface cover. Due to differences in topography, climate, and ecological environment in different regions, soil surfaces are often covered by different types of cover, and the cover thickness varies. Some areas have sparse and thin cover, while others have dense and thick cover. This diversity in cover type and thickness alters the distribution and infiltration of rainfall on the soil surface, resulting in significant differences between actual measured rainfall-related data, such as soil moisture content and runoff formation time, and the results expected by simulations based on ideal conditions. This poses a serious challenge to the accuracy and reliability of rainfall simulations. Furthermore, soils with different slopes are affected differently by rainfall erosion. In summary, existing rainfall simulation devices cannot accurately simulate different rainfall environments while flexibly adjusting cover type, cover thickness, and soil slope to achieve a systematic study of soil response patterns under different rainfall and cover conditions. Therefore, there is an urgent need to propose an experimental device and method that can overcome the above-mentioned shortcomings and realize the synergistic simulation of rainfall and cover. Summary of the Invention

[0005] To address the technical problem that it is difficult to add a flexibly adjustable cover simulation component to the existing rainfall simulation device to adjust the experimental slope and complete simulation experiments under different combined conditions, the present invention provides an experimental device and method for simulating the effects of rainfall under different cover conditions.

[0006] The technical solution adopted by the embodiments of this application to solve its technical problem is:

[0007] An experimental apparatus for simulating the effects of rainfall under different cover conditions includes an isolation frame with a simulated rainfall device mounted on top. The isolation frame is covered with a transparent waterproof membrane, and a support platform is mounted on the bottom of the isolation frame. A soil simulation box is mounted on the support platform and includes a soil box body with a bottom plate. A permeable plate is detachably installed at the bottom of the soil box body, forming a bottom runoff channel between the permeable plate and the bottom plate. The permeable plate is filled with an experimental soil layer. A cover simulation plate is detachably installed on the top of the soil box body, which is in contact with the experimental soil layer. In addition, several sets of moisture detection mechanisms in contact with the experimental soil layer are installed on the side of the soil box body.

[0008] In one possible implementation, the covering simulation board includes a lower frame and an upper frame, both of which have completely identical structures and are U-shaped. A constraint net is fixedly installed on both the lower frame and the upper frame, and the space between the lower frame and the upper frame is filled with covering filler. Several opening barrier wires are provided at the openings of both the lower frame and the upper frame.

[0009] In one possible implementation, a plurality of connecting screws are fixedly arranged on the lower plate frame, and the upper plate frame has through holes corresponding to the connecting screws one by one. The connecting screws are equipped with locking nuts. In addition, symmetrically arranged handles are fixedly arranged on the upper plate frame.

[0010] In one possible implementation, the permeation plate includes a frame on which a handle is fixedly mounted, and bolted leak-proof mesh plates are installed at its upper and lower ends. The space formed by the frame and the leak-proof mesh plates is filled with a permeation medium.

[0011] In one possible implementation, the permeable plate further includes a support mesh plate for supporting the frame and the leak-proof mesh plate, wherein geotextile is laid on both the support mesh plate and the leak-proof mesh plate located on the upper side.

[0012] In one possible implementation, an inner support platform is fixedly installed inside the soil box, and an outer support platform is formed on the top of the soil box. The projected area of ​​the outer contour of the outer support platform is larger than the projected area of ​​the outer contour of the inner support platform. The frame overlaps on the inner support platform, and the lower plate frame overlaps on the outer support platform.

[0013] In one possible implementation, the front end of the soil box is fixedly provided with two layers of water guide plates. The upper surface of the upper water guide plate is flush with the outer support platform, and the upper surface of the lower water guide plate is flush with the bottom of the bottom flow channel. Both water guide plates are provided with drainage outlets at their ends, and the water guide plates are machined to form a guide slope towards the drainage outlets.

[0014] Each drain outlet has a graduated collection container placed below it. A tray is attached to the lower water guide plate, with the collection container for the upper drain outlet placed on the tray and the collection container for the lower drain outlet placed on the support frame.

[0015] In one possible implementation, the moisture detection mechanism includes several sealing sleeves fixedly disposed on the side of a soil tank, wherein a through monitoring hole is provided on the soil tank, and a soil moisture sensor is inserted into the sealing sleeve, with its probe inserted into the experimental soil layer through the monitoring hole.

[0016] In one possible implementation, the support frame includes a base plate on which a plurality of support beams are mounted, wherein a plurality of anti-slip strips are fixedly provided on the lower end face of the base plate and engage with the support beams.

[0017] An experimental method for simulating the effects of rainfall under different cover conditions includes: preparing experimental soil layer raw materials, cover simulation plates, and permeable plates; setting up multiple sets of control soil simulation boxes, in which permeable plates are installed sequentially, experimental soil layers are filled, and then cover simulation plates with different parameters are installed according to different conditions, and a moisture detection mechanism is installed to monitor the initial soil moisture; starting the simulated rainfall device to simulate rainfall, and adjusting the parameters according to the experimental design; after the simulated rainfall ends, recording the parameters of the corresponding simulated rainfall device, the amount of rainwater collected by the collection containers corresponding to surface runoff and bottom runoff, the data of the moisture detection mechanism, and the damage (erosion degree) of the experimental soil layer.

[0018] In summary, the present invention has the following beneficial technical effects:

[0019] By using a simulated rainfall device and a cover simulation board, different rainfall conditions and cover conditions can be combined to meet various complex experimental needs. The simulated rainfall device can precisely control parameters such as rainfall particle size, intensity, and duration, simulating various natural rainfall conditions and providing accurate experimental input for studying the impact of cover on soil under different rainfall conditions. The cover simulation board adopts a detachable and replaceable design, and by filling it with different cover fillers, it can simulate various different cover types, such as vegetation cover, mulch film cover, and litter cover, thereby simulating the corresponding actual outdoor soil scenarios. The above flexible simulation method provides convenience for studying the mechanism of rainfall on soil under different cover conditions, and helps to deepen the understanding of the important role of cover in soil erosion control and water management.

[0020] The water guide plate, collection container, and moisture detection mechanism in the experimental setup can accurately measure surface runoff, bottom runoff, and moisture changes in the experimental soil layer. The guide slope design of the water guide plate ensures smooth discharge of runoff and avoids accumulation and backflow of runoff at the front of the soil box. The graduated collection container can accurately measure the runoff volume, providing quantitative data for analyzing the impact of rainfall on soil runoff. The soil moisture sensor can monitor changes in soil moisture in real time, providing detailed data support for studying the dynamic process of soil moisture.

[0021] Furthermore, by adjusting the height of the support beams within the support frame, the tilt angle of the soil simulation box placed on it can be flexibly changed, thereby simulating different slope conditions. When it is necessary to increase the tilt angle of the soil simulation box, the height of the support beam on one side can be appropriately increased, raising that side of the soil simulation box and thus forming a larger tilt angle. Conversely, when it is necessary to decrease the tilt angle, the height of the corresponding support beam can be lowered. This height adjustment method is simple to operate and can quickly and accurately simulate different slopes, providing diverse conditions for experiments.

[0022] The entire experimental setup has a reasonable structural design and the connections between the components are firm, ensuring stability during the experiment. The isolation frame, support platform, soil simulation box and other components are easy to install and disassemble, facilitating pre-experiment preparation and post-experiment cleanup. The detachable design of the permeation plate and the covering simulation plate allows for flexible replacement of different components according to experimental needs, improving the efficiency and flexibility of the experiment. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the soil simulation box structure of the present invention;

[0026] Figure 3 This is a cross-sectional view of the soil simulation box of the present invention;

[0027] Figure 4 This is a partial structural diagram of the soil simulation box of the present invention;

[0028] Figure 5 This is a schematic diagram of the runoff collection structure of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the cover simulation plate of the present invention. Figure 1 ;

[0030] Figure 7 This is a schematic diagram of the structure of the cover simulation plate of the present invention. Figure 2 ;

[0031] Figure 8 This is a schematic diagram of the permeation plate structure of the present invention;

[0032] Figure 9 This is a schematic diagram of the support frame structure of the present invention;

[0033] Figure 10 This is a schematic diagram of the moisture detection mechanism of the present invention.

[0034] In the diagram: 1. Isolation frame; 2. Simulated rain generator; 3. Support platform; 31. Plate base; 32. Support beam; 4. Soil simulation box; 41. Soil box body; 411. Inner support platform; 412. Outer support platform; 42. Base plate; 421. Anti-slip strip; 43. Bottom flow channel; 44. Water guide plate; 441. Drainage outlet; 45. Collection container; 46. Support plate; 5. Permeable plate; 51. Frame; 52. Leak-proof mesh plate; 53. Handle one; 54. Geotextile; 55. Supporting mesh plate; 6. Covering simulation plate; 61. Lower frame; 62. Upper frame; 63. Restraint net; 64. Connecting screw; 65. Locking nut; 66. Opening barrier wire; 67. Handle two; 7. Moisture detection mechanism; 71. Sealing sleeve; 72. Soil moisture sensor. Detailed Implementation

[0035] This application organically combines rainfall simulation with cover simulation. By precisely controlling parameters such as rainfall particle size, intensity, and duration, it can simulate various natural rainfall conditions, providing accurate experimental input for studying the impact of cover on soil under different rainfall conditions. It can also simulate various different cover types, such as cover cover, mulch film cover, and litter cover, which helps to deepen the understanding of the important role of cover in soil erosion control and water management.

[0036] Example 1

[0037] To organically combine rainfall simulation and cover simulation, the overall approach of this embodiment is as follows:

[0038] This embodiment provides an experimental device for simulating the impact of rainfall under different cover conditions. It mainly consists of three parts: a rainfall simulation part, a soil simulation part, and a cover simulation part. The structure and working principle of these three parts are described in detail below.

[0039] The rainfall simulation section mainly consists of an isolation frame 1 and a simulated rainfall device 2, such as... Figure 1 As shown, the isolation frame 1, which serves as the basic support structure for the entire experimental setup, is equipped with a simulated rain device 2 on its top. To facilitate observation of the experimental process and prevent interference from external moisture, the isolation frame 1 is covered with a transparent waterproof membrane. Meanwhile, the bottom of the isolation frame 1 is equipped with a support platform 3, which provides stable support for the entire soil simulation section.

[0040] The simulated rain device 2 is used to simulate rainfall of different particle sizes and intensities. By precisely controlling the parameters of the simulated rain device 2, such as rainfall height, nozzle orifice diameter, and water pressure, various natural rainfall conditions can be simulated, providing accurate rainfall input for experiments. The implementation principle and adjustment method of the above-mentioned technical effects are mature existing solutions, and will not be elaborated further here. The simulated rain device 2 can be a particle size-based simulated rainfall device, which can precisely adjust the range of rainfall particle sizes and set different rainfall intensities to ensure that rainfall is evenly distributed in the experimental area to meet the needs of different experimental conditions; it can also be a needle-type rainfall simulator, which uses a fine needle array to simulate rainfall. By controlling parameters such as needle density, height, and water pressure, the intensity and particle size of rainfall can be adjusted; or a disc-type rainfall simulator can be used, which simulates rainfall by spraying water through small holes on a rotating disc. Adjusting the disc rotation speed, the size and number of water holes, and the water supply pressure can change the intensity and particle size distribution of rainfall.

[0041] like Figure 2-3 As shown, the main structure of the soil simulation part is a soil box 41. A bottom plate 42 is provided at the bottom of the soil box 41. A permeable plate 5 is detachably installed at the bottom of the soil box 41. A bottom runoff channel 43 is formed between the permeable plate 5 and the bottom plate 42 to collect water that has seeped down from the soil and form bottom runoff. An experimental soil layer is filled on the permeable plate 5 to simulate the actual soil environment.

[0042] To achieve the collection of bottom runoff and surface runoff, such as Figure 5 As shown, the front end of the soil box 41 is fixedly equipped with two layers of water guide plates 44. The upper surface of the upper water guide plate 44 is flush with the outer support platform 412, and the upper surface of the lower water guide plate 44 is flush with the bottom of the bottom runoff channel 43. Both water guide plates 44 are provided with drainage outlets 441 at their ends, and the water guide plates 44 are machined to form a slope towards the drainage outlets 441 to ensure that surface runoff and bottom runoff can be discharged smoothly through the drainage outlets 441. In addition, a graduated collection container 45 is placed below each drainage outlet 441 for accurate collection and measurement of runoff. The lower water guide plate 44 is supported by a support plate 46, the collection container 45 of the upper drainage outlet 441 is placed on the support plate 46, and the collection container 45 of the lower drainage outlet 441 is placed on the support frame 3. This layered placement design avoids mutual interference between different runoffs and improves the accuracy of measurement data.

[0043] The cover simulation mainly consists of the cover material placed on the surface of the experimental soil layer, providing a certain degree of protection. It adheres closely to the soil layer to simulate various cover conditions: First, it simulates different coverage levels of the same type of cover, including no cover, partial cover, and full cover, such as using straw to cover different areas; second, it simulates different cover thicknesses of the same type of cover, such as controlling the stacking of straw to 200cm, 180cm, and 150cm; third, it simulates different types of cover, using not only common straw cover but also different surface cover materials such as plastic film, gravel, and different types of cover such as turf and leaves. These simulation schemes can be combined, but careful control of variables is necessary during the experiment.

[0044] In addition, in order to monitor the changes in the moisture content of the experimental soil layer in real time during rainfall, such as Figure 2 As shown, the side of the soil chamber 41 is also equipped with several sets of moisture detection mechanisms 7 that are in contact with the experimental soil layer to monitor the changes in moisture content of the experimental soil layer in real time. Specifically, as shown... Figure 10 As shown, it includes several sealing sleeves 71 fixedly installed on the side of the soil tank 41. A through monitoring hole is provided on the soil tank 41. A soil moisture sensor 72 is inserted and installed in each sealing sleeve 71. Its probe is inserted into the experimental soil layer through the monitoring hole. The soil moisture sensor 72 can monitor the moisture content of the experimental soil layer in real time and transmit the data to an external data acquisition system, providing accurate data support for experimental analysis. It is important to note that before the experiment begins, the moisture content of the experimental soil layers in different groups needs to be measured using the soil moisture sensor 72 to avoid significant differences in moisture content between different groups.

[0045] During the experiment, to ensure rainwater could flow out smoothly and be collected, and also to simulate the impact of rainfall at different angles on the covered slope, such as... Figure 9 As shown, the support frame 3 includes a base 31 on which several support beams 32 are installed. The support frame 3 not only provides a stable support platform for the soil simulation box 4, but also ensures the stability of the center of gravity of the entire device through reasonable design. By adjusting the height of the support beams 32, the tilt angle of the soil simulation box 4 placed on it can be adjusted to simulate different slope conditions. Among them, several anti-slip strips 421 are fixedly installed on the lower end face of the base plate 42 and engage with the support beams 32. This engagement design can effectively prevent the soil simulation box 4 from sliding during the experiment, especially the stability of the soil simulation box 4 when it is tilted, ensuring the accuracy of the experiment.

[0046] The aforementioned height adjustment operation is as follows: by adjusting the height of the support beam 32, the tilt angle of the soil simulation box 4 placed on it can be flexibly changed, thereby simulating different slope conditions. When it is necessary to increase the tilt angle of the soil simulation box 4, the height of one or more support beams 32 can be appropriately increased, raising that side of the soil simulation box 4 and thus forming a larger tilt angle. Conversely, when it is necessary to decrease the tilt angle, the height of the corresponding support beam 32 is lowered. This height adjustment method is simple to operate, can quickly and accurately simulate different slopes, and provides diverse conditions for experiments.

[0047] In an experiment using a support platform 3 to simulate different slopes and study the impact of rainfall on covered slopes, the required height of the support beam 32 at a specific inclination angle can be accurately calculated using only trigonometric functions. Once the slope angle θ to be simulated is determined, the soil simulation box 4 is considered as the hypotenuse of a right triangle, its length of which can be considered a fixed value L (e.g., the length of the soil simulation box 4 is known). The required height change h of the support beam 32 is equivalent to the right-angled side opposite angle θ in this right triangle. According to the definition of the tangent function in trigonometric functions, tanθ = h / L, after a simple transformation, we can obtain h = L×tanθ. Thus, by simply substituting the known length values ​​of the soil simulation box 4 and the target inclination angle into this formula, the height that the support beam 32 should be adjusted can be quickly and accurately calculated, providing a convenient and reliable calculation method for accurately simulating different slopes in experiments.

[0048] Example 2

[0049] When conducting experiments based on the above-mentioned Example 1, it was found that the simulated cover part required on-site stacking during the experiment, which not only affected the efficiency of the experiment, but also made it very difficult to control the quality of the cover due to temporary on-site stacking. It was also very easy for the various parameters of the cover to deviate significantly from the experimental design. Furthermore, the cleaning of the cover after the experiment was also very tedious. In addition, the permeable plate 5 was placed at the bottom of the experimental soil layer, which was very easy to be blocked by soil infiltration and needed to be cleaned frequently. Moreover, when conducting experiments on the effects of different permeable layers on the soil, permeable plates 5 with different parameters were also required.

[0050] Therefore, in this embodiment, the simulated covering part is fabricated as an integral simulated covering plate 6, such as... Figure 2-3 As shown, both the covered simulation plate 6 and the permeation plate 5 are designed to be detachable. The design also allows for the replacement of internal packing materials for both the covered simulation plate 6 and the permeation plate 5, improving the convenience of use and operation, and enabling the entire device to flexibly adjust experimental parameters.

[0051] Specifically, such as Figure 6-7As shown, the cover simulation board 6 includes a lower frame 61 and an upper frame 62, both of which have identical structures and are U-shaped. A restraint net 63 is fixedly installed on both the lower frame 61 and the upper frame 62, and the space between the lower frame 61 and the upper frame 62 is filled with cover filler, such as cover debris or mulch film fragments, to simulate different cover types. The mesh size of the restraint net 63 is selected according to the cover filler. The U-shaped structure of the lower frame 61 and the upper frame 62 has an opening at the front end, which will not obstruct the runoff on the cover surface and the runoff on the surface of the experimental soil layer, thus improving the realism of the experiment. As a complement, several opening barrier wires 66 are provided at the openings of the lower frame 61 and the upper frame 62 to prevent the cover filler from scattering during the experiment.

[0052] The lower frame 61 is fixedly provided with several connecting screws 64 arranged in a row, and the upper frame 62 is provided with through holes corresponding to the connecting screws 64. The connecting screws 64 are equipped with locking nuts 65. Through this connection method, the lower frame 61 and the upper frame 62 can be firmly connected together to form an integral covering simulation board 6. In addition, the upper frame 62 is fixedly provided with symmetrically arranged handles 67 to facilitate the installation and disassembly of the covering simulation board 6.

[0053] It should be noted that when preparing simulated plates 6 with different thicknesses of coating, the support height dimensions of the lower frame 61 and the upper frame 62 also need to be changed synchronously. That is, when connected by the connecting screw 64, the applied compressive force is mainly borne by the lower frame 61 and the upper frame 62 to avoid excessive pressure causing the coating filler to be compressed, thus making it inconsistent with the stacking situation under the natural state simulated in the experimental design.

[0054] like Figure 8 As shown, the permeable plate 5 includes a frame 51, on which a handle 53 is fixedly installed for easy installation and disassembly. The upper and lower ends of the permeable plate 5 are fitted with bolted anti-leakage mesh plates 52. The space formed by the frame 51 and the anti-leakage mesh plates 52 is filled with a permeable medium, such as sand, gravel, ceramsite, or plastic granules, to simulate the soil infiltration process. In addition, the permeable plate 5 includes a support mesh plate 55, which supports the frame 51 and the anti-leakage mesh plates 52 to ensure the structural stability of the permeable plate 5. Geotextile 54 is laid on both the support mesh plate 55 and the upper anti-leakage mesh plate 52. The geotextile 54 prevents the loss of the permeable medium while ensuring smooth water infiltration.

[0055] As a supplement, such as Figure 4As shown, an inner support platform 411 is fixedly installed inside the soil box 41, and an outer support platform 412 is machined on the top of the soil box 41. The outer contour projection area of ​​the outer support platform 412 is larger than that of the inner support platform 411. The frame 51 overlaps the inner support platform 411, and the lower plate frame 61 overlaps the outer support platform 412. This design makes the installation of the permeation plate 5 and the covering simulation plate 6 more stable, and also facilitates disassembly and replacement, making it convenient to conduct experiments under different conditions.

[0056] Finally, the use of this device and experimental methods are explained as follows:

[0057] I. Assembly of the Experimental Apparatus

[0058] First, place the support frame 3 on a level ground to ensure its stability; then, connect the bottom plate 42 of the soil simulation box 4 to the support beam 32 of the support frame 3 using anti-slip strips 421, and install the soil box 41 of the soil simulation box 4.

[0059] Install the permeation plate 5 on the inner support platform 411 at the bottom of the soil box 41, and overlap the frame 51 on the inner support platform 411 to ensure that the permeation plate 5 is installed firmly; fill the permeation plate 5 with the experimental soil layer, control the soil texture according to the experimental requirements, and scrape the soil surface to make it flush with the outer support platform 412.

[0060] Fill the space between the lower frame 61 and the upper frame 62 of the cover simulation board 6 with cover filler, and then connect the upper frame 62 and the lower frame 61 firmly with the connecting screw 64 and the locking nut 65. Lift the cover simulation board 6 and put it into the soil box 41, so that the lower frame 61 overlaps on the outer support platform 412 at the top of the soil box 41.

[0061] A soil moisture sensor 72 is inserted and installed in the sealing sleeve 71 on the side of the soil box 41, so that its probe is inserted into the experimental soil layer through the monitoring hole, and the soil moisture sensor 72 is connected to the external data acquisition system.

[0062] Place a graduated collection container 45 below the drain outlet 441 of the water guide plate 44 at the front end of the soil box 41. Place the collection container 45 of the upper drain outlet 441 on the tray 46 and the collection container 45 of the lower drain outlet 441 on the support frame 3.

[0063] II. Experimental Methods

[0064] Experimental preparation: Prepare experimental soil layer raw materials, select appropriate soil types according to experimental requirements, and perform screening, mixing and other treatments to ensure soil uniformity and consistency; prepare cover simulation board 6, and select appropriate cover filler to fill between the lower board frame 61 and the upper board frame 62 according to different cover conditions designed in the experiment; prepare permeable board 5, select appropriate permeable medium to fill the space formed by the frame 51 and the leak-proof net board 52, and lay geotextile 54 on the supporting net board 55 and the leak-proof net board 52 located on the upper side.

[0065] Set up a control experiment: Set up multiple control soil simulation boxes 4, install permeable plates 5 in them in sequence, and fill them with experimental soil layers to ensure that the experimental soil layer conditions in each group of soil simulation boxes 4 are consistent; according to different experimental conditions, install cover simulation plates 6 with different parameters on each group of soil simulation boxes 4, such as different cover types and cover thicknesses; install a moisture detection mechanism 7 to monitor the initial soil moisture in the experimental soil layer of each group of soil simulation boxes 4 and record the initial data.

[0066] Simulated rainfall experiment: Start the simulated rainfall device 2 to simulate rainfall. Adjust the parameters of the simulated rainfall device 2 according to the experimental design, such as rainfall height, nozzle orifice diameter, and water pressure, to simulate different rainfall conditions. During the simulated rainfall, observe the experimental phenomena in real time and record the generation of surface runoff and bottom runoff.

[0067] Data Recording and Analysis: Immediately after the simulated rainfall ends, record the parameters of the corresponding simulated rainfall device 2, such as rainfall intensity and duration; measure and record the amount of rainwater collected by the collection containers 45 corresponding to surface runoff and bottom runoff; read the data from the moisture detection device 7 to obtain the changes in moisture content of the experimental soil layer at different depths and locations; observe the damage to the experimental soil layer, such as the degree of soil erosion and changes in soil structure, and record the relevant phenomena; analyze the recorded data to study the effects of particle size rainfall under different cover conditions on soil runoff, water infiltration, and soil erosion, and draw experimental conclusions.

[0068] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An experimental apparatus for simulating the effects of rainfall under different cover conditions, characterized in that, include: An isolation frame (1) is equipped with a simulated rain device (2) on its top. The isolation frame (1) is covered with a transparent waterproof membrane, and a support frame (3) is installed at the bottom of the isolation frame (1). Soil simulation box (4), which is mounted on a support frame (3), includes a soil box body (41), and a bottom plate (42) is provided at the bottom of the soil box body (41). The soil box (41) is detachably installed with a permeable plate (5) at the bottom, and a bottom runoff channel (43) is formed between the permeable plate (42) and the bottom plate (42). The permeable plate (5) is filled with an experimental soil layer, and the top of the soil box (41) is detachably installed with a cover simulation plate (6) that is in contact with the experimental soil layer. In addition, several sets of moisture detection mechanisms (7) that are in contact with the experimental soil layer are installed on the side of the soil box (41).

2. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 1, characterized in that: The covering simulation plate (6) includes a lower plate frame (61) and an upper plate frame (62), both of which have the same structure and are U-shaped. A constraint net (63) is fixedly installed on both the lower plate frame (61) and the upper plate frame (62), and the space between the lower plate frame (61) and the upper plate frame (62) is filled with covering filler. Several opening barrier wires (66) are provided at the openings of both the lower plate frame (61) and the upper plate frame (62).

3. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 2, characterized in that: The lower plate frame (61) is fixedly provided with a number of connecting screws (64) arranged in a row. The upper plate frame (62) is provided with through holes corresponding to the connecting screws (64) one by one, and the connecting screws (64) are equipped with locking nuts (65). In addition, the upper plate frame (62) is fixedly provided with symmetrically arranged handles (67).

4. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 2, characterized in that: The permeation plate (5) includes a frame (51), on which a handle (53) is fixedly installed, and at its upper and lower ends are bolted leak-proof mesh plates (52). The space formed by the frame (51) and the leak-proof mesh plates (52) is filled with a permeation medium.

5. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 4, characterized in that: The permeable plate (5) also includes a support mesh plate (55) for supporting the frame (51) and the leak-proof mesh plate (52), wherein geotextile (54) is laid on both the support mesh plate (55) and the leak-proof mesh plate (52) located on the upper side.

6. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 4, characterized in that: An inner support platform (411) is fixedly installed inside the soil box (41). An outer support platform (412) is formed on the top of the soil box (41). The outer contour projection area of ​​the outer support platform (412) is larger than the outer contour projection area of ​​the inner support platform (411). The frame (51) overlaps the inner support platform (411), and the lower plate frame (61) overlaps the outer support platform (412).

7. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 1, characterized in that: The front end of the soil box (41) is fixedly provided with two layers of water guide plates (44). The upper end face of the upper water guide plate (44) is flush with the outer expansion support (412), and the upper end face of the lower water guide plate (44) is flush with the bottom of the bottom flow channel (43). Both water guide plates (44) are provided with drainage outlets (441) at their ends, and the water guide plates (44) are machined to form a slope towards the drainage outlets (441). Each drain outlet (441) has a graduated collection container (45) placed below it. A tray (46) is attached to the lower water guide plate (44). The collection container (45) of the upper drain outlet (441) is placed on the tray (46), and the collection container (45) of the lower drain outlet (441) is placed on the support frame (3).

8. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 1, characterized in that: The moisture detection mechanism (7) includes several sealing sleeves (71) fixedly installed on the side of the soil box (41). The soil box (41) has a through monitoring hole. A soil moisture sensor (72) is inserted into the sealing sleeve (71) and its probe is inserted into the experimental soil layer through the monitoring hole.

9. The experimental apparatus for simulating the effects of rainfall under different cover conditions according to claim 1, characterized in that: The support frame (3) includes a plate base (31) on which several support beams (32) are installed. The bottom plate (42) has several anti-slip strips (421) fixedly installed on its lower end surface to engage with the support beams (32).

10. An experimental method for simulating the effects of rainfall under different cover conditions, using the experimental apparatus for simulating the effects of rainfall under different cover conditions as described in any one of claims 1-9, characterized in that, The experimental method includes: Prepare experimental soil layer raw materials, cover simulation board (6) and permeable board (5); Set up multiple control soil simulation boxes (4), install infiltration plates (5) in sequence, fill the experimental soil layer, and then install cover simulation plates (6) with different parameters according to different conditions, and install a moisture detection mechanism (7) to monitor the initial soil moisture; Start the simulated rainfall device (2) to simulate rainfall, and adjust the parameters according to the experimental design; After the simulated rainfall ends, the parameters of the corresponding simulated rainfall device (2), the amount of rainwater collected by the collection container (45) corresponding to the surface runoff and bottom runoff, the data of the moisture detection device (7), and the damage status of the experimental soil layer are recorded.

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