A three-dimensional visual simulation device for a three-water formation process of rainfall runoff

Abstract

The application discloses a three-dimensional visual simulation device for rainfall runoff generation three-water formation process, and belongs to the technical field of hydrological process simulation and experimental teaching. The device comprises a transparent simulation cavity and a rainfall simulation system. The rainfall simulation system is arranged above the transparent simulation cavity. A non-homogeneous soil layered medium system comprises a water-bearing layer, a low-permeability barrier layer and a high-permeability layer which are sequentially filled in the transparent simulation cavity from the bottom to the opening end along the height direction. After the water-bearing layer, the low-permeability barrier layer and the high-permeability layer are stacked in the transparent simulation cavity to a preset height, a cavity exists above the high-permeability layer as a surface runoff space. The transparent simulation cavity is provided with a surface runoff collecting unit which is in communication and is located outside the surface runoff space at the junction of the high-permeability layer. The transparent simulation cavity is provided with soil-moisture flow collecting units which are in communication and are located outside the high-permeability layer and the low-permeability barrier layer. The transparent simulation cavity is provided with a ground water collecting unit which is in communication and is located outside the water-bearing layer. The device can cooperatively display the formation processes of surface runoff, soil-moisture flow and ground water in the same transparent simulation cavity.

Description

Technical Field

[0001] This invention relates to the field of hydrological process simulation and experimental teaching technology, specifically to a three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff. Background Technology

[0002] In the teaching and research of hydrology, soil physics, and environmental engineering, understanding how rainfall is transformed into surface runoff, interflow, and groundwater runoff (i.e., "three types of runoff") is a core component. Surface runoff is the water flow that flows along the surface slope after rainfall exceeds the soil's infiltration capacity or the soil becomes saturated, following the principles of over-infiltration runoff and saturation runoff. Interflow is the lateral seepage of water at the interface of heterogeneous soil layers due to capillary resistance, and is one of the key aspects of slope hydrological processes. Groundwater runoff is the water flow that penetrates the soil layer into the aquifer and steadily infiltrates under the influence of gravity, serving as the main source of groundwater recharge.

[0003] Currently, there is a relative lack of dedicated simulation and demonstration devices for the formation mechanisms of surface runoff, interflow, and groundwater runoff during rainfall generation. Related teaching often relies on theoretical explanations, image displays, or two-dimensional diagrams, which fail to intuitively reflect the infiltration, migration, and diversion processes of water within the soil. Furthermore, under natural conditions, the movement of water within the soil is often concealed, making it difficult to clearly identify the formation and evolution of interflow and groundwater runoff through direct observation. This results in students' insufficient understanding of the mechanisms of these three water transformations during teaching. Therefore, there is an urgent need for a demonstration device that can realistically simulate the movement of water within the soil under rainfall conditions and provide a direct visual demonstration of the formation processes of surface runoff, interflow, and groundwater runoff to meet the needs of teaching demonstrations and experimental learning.

[0004] Therefore, it is particularly important to develop a runoff transformation simulation device that conforms to hydraulic principles, can realistically simulate heterogeneous soil environments, and has intelligent monitoring functions. Summary of the Invention

[0005] This invention provides a three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff, which is used to collaboratively display the formation process of surface runoff, interflow and groundwater runoff in the same transparent simulation cavity under controlled rainfall and adjustable slope conditions.

[0006] The technical solution of this invention is:

[0007] A three-dimensional visualization simulation device for the formation process of three streams in rainfall runoff includes:

[0008] A transparent simulation cavity 2, wherein the transparent simulation cavity 2 is a transparent simulation structure with an opening at one end along the height direction;

[0009] Rainfall simulation system 3, which is disposed above the transparent simulation cavity 2, is used to simulate rainfall;

[0010] The heterogeneous soil stratified media system 4 includes an aquifer 43, a low-permeability barrier layer 42, and a high-permeability layer 41, which are sequentially filled in the transparent simulated cavity 2 from bottom to open end along the height direction. After the aquifer 43, low-permeability barrier layer 42, and high-permeability layer 41 are stacked inside the transparent simulated cavity 2 to a preset height, there is a cavity above the high-permeability layer 41 as a surface runoff space. The permeability coefficient K3 of the aquifer 43 is greater than the permeability coefficient K1 of the high-permeability layer 41 and the permeability coefficient K2 of the low-permeability barrier layer 42, so that lateral interflow is formed at the interface between the high-permeability layer 41 and the low-permeability barrier layer 42 during rainfall infiltration, and groundwater runoff is formed in the aquifer 43.

[0011] The three types of runoff separation and collection systems include: a transparent simulation cavity 2 located outside the surface runoff space at the junction with the high permeability layer 41 with a connected surface runoff collection unit 51; a transparent simulation cavity 2 located outside the junction of the high permeability layer 41 and the low permeability barrier layer 42 with a connected interflow collection unit 52; and a transparent simulation cavity 2 located outside the aquifer 43 with a connected underground runoff collection unit 53.

[0012] Furthermore, the three-dimensional visualization simulation device also includes a frame assembly 1, which is used to install the transparent simulation cavity 2 and the rainfall simulation system 3.

[0013] Furthermore, the frame assembly 1 includes a frame and a tilt adjustment mechanism; the tilt adjustment mechanism and a rainfall simulation system 3 are installed on the frame, and a transparent simulation cavity 2 is installed on the tilt adjustment mechanism to adjust the tilt angle of the transparent simulation cavity 2.

[0014] Furthermore, the tilt adjustment mechanism includes a hinge seat 12 and an electric push rod 11. One end of the transparent simulation cavity 2 away from the rainfall simulation system 3 is hinged to the support rod of the frame through the hinge seat 12. The other end of the transparent simulation cavity 2 away from the rainfall simulation system 3 is connected to the rod end of the electric push rod 11 through the hinge seat. The cylinder end of the electric push rod 11 is connected to the frame through the hinge seat.

[0015] Furthermore, we set K1 / K2≥100.

[0016] Furthermore, a porous isolation structure 21 is provided between the high-permeability layer 41 and the low-permeability barrier layer 42, and between the low-permeability barrier layer 42 and the aquifer 43.

[0017] Furthermore, the thickness of the high-permeability layer 41 is greater than the thickness of the low-permeability barrier layer 42; the thickness of the aquifer 43 is greater than or equal to the thickness of the high-permeability layer 41.

[0018] Furthermore, the thickness of the aquifer 43 is 1.2 to 2.0 times the thickness of the high-permeability layer 41; the thickness of the low-permeability barrier layer 42 is 3 cm to 5 cm.

[0019] Furthermore, the high-permeability layer 41 is filled with medium sand, the particle size of which ranges from 0.25 mm to 0.5 mm; the low-permeability barrier layer 42 is filled with silty clay medium, the silty clay being composed of clay particles, silt particles, and sand particles, wherein the clay particle content is 10% to 30%, the silt particle content is 40% to 70%, and the sand particle content is 10% to 30%; the aquifer 43 is filled with a gravel-sand mixture, the gravel-sand mixture being formed by uniformly mixing gravel and coarse sand in a mass ratio of 1:3 to 2:3, wherein the gravel particle size is 2 mm to 10 mm, and the coarse sand particle size is 0.5 mm to 2 mm.

[0020] Furthermore, a porous isolation structure 21 is provided at the connection between the surface runoff collection unit 51 and the transparent simulation cavity 2. The outlet end of the surface runoff collection unit 51 is connected to a transparent water storage structure I13-1 via a pipe to display the surface runoff collection and water level change process. A porous isolation structure 21 is provided at the connection between the interflow collection unit 52 and the transparent simulation cavity 2. The outlet end of the interflow collection unit 52 is connected to a transparent water storage structure II13-2 via a pipe to display the interflow collection and water level change process. A porous isolation structure 21 is provided at the connection between the underground runoff collection unit 53 and the transparent simulation cavity 2. The outlet end of the underground runoff collection unit 53 is connected to a transparent water storage structure III13-3 via a pipe to display the underground runoff collection and water level change process.

[0021] The beneficial effects of this invention are:

[0022] 1. It can collaboratively display the formation processes of surface runoff, interflow, and subsurface runoff within the same transparent simulation cavity, making the processes of rainfall infiltration, interface blockage, lateral transport, and subsurface confluence more intuitive.

[0023] 2. By setting a low-permeability barrier layer and ensuring K3 > K1 > K2, and K1 / K2 ≥ 100, interflow can be stably induced at the interface between the high-permeability layer and the low-permeability barrier layer, thus improving the problem of interflow being difficult to observe and quantitatively collect.

[0024] 3. The independent quantitative collection of surface runoff, interflow, and groundwater runoff through three types of runoff separation and collection systems is beneficial for analyzing the runoff conversion ratio under different rainfall and slope conditions.

[0025] 4. The transparent simulation cavity adopts an open top design, which reduces the impact of air resistance on the infiltration process without affecting the infiltration of rainfall, making the simulation results closer to the water movement process of the underlying surface of a natural slope.

[0026] 5. The slope adjustment mechanism works in conjunction with the layered medium system. When the layer is stable, there is no need to re-lay the medium every time the slope is adjusted. Only local repair or overall reconstruction is needed when the medium is disturbed, which helps to improve the repeatability and operational efficiency of comparative experiments. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention;

[0028] Figure 2 This is a schematic diagram of the heterogeneous layered medium distribution of the present invention;

[0029] Figure 3 This is a data transmission flowchart of the soil moisture monitoring system of the present invention.

[0030] The labels in the diagram are as follows: 1-Frame assembly, 11-Electric actuator, 12-Hinged shaft, 13-1-Transparent water storage structure I, 13-2-Transparent water storage structure II, 13-3-Transparent water storage structure III, 2-Transparent simulation cavity, 21-Porous isolation structure, 3-Rainfall simulation system, 4-Heterogeneous soil stratified media system, 41-High permeability layer, 42-Low permeability barrier layer, 43-Aquifer, 51-Surface runoff collection unit, 52-Interflow collection unit, 53-Subsurface runoff collection unit, 6-Soil moisture monitoring system, 7-External computer terminal. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0032] Example 1: As Figures 1-3 As shown, the present invention provides a three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff, comprising:

[0033] A transparent simulation cavity 2 is a transparent simulation structure with one end open along the height direction; exemplarily, it has a hexahedral configuration, with one end along the height direction being the open end and the other five sides being closed, and the opening is located at the upper end of the transparent simulation cavity 2 along the height direction.

[0034] Rainfall simulation system 3, which is disposed above the transparent simulation cavity 2, is used to simulate rainfall;

[0035] A heterogeneous soil stratified media system 4 includes an aquifer 43, a low-permeability barrier layer 42, and a high-permeability layer 41, which are sequentially filled from bottom to open end within a transparent simulated cavity 2. The aquifer 43, low-permeability barrier layer 42, and high-permeability layer 41 are stacked to a preset height inside the transparent simulated cavity 2, with a cavity above the high-permeability layer 41 serving as a surface runoff space. The permeability coefficient K3 of the aquifer 43 is greater than the permeability coefficient K1 of the high-permeability layer 41, which in turn is greater than the permeability coefficient K2 of the low-permeability barrier layer 42, so that during rainfall infiltration, a cavity forms at the interface between the high-permeability layer 41 and the low-permeability barrier layer 42. It forms a lateral interflow in the soil and creates underground runoff in aquifer 43; the three media form a continuous layered structure in space, and in terms of hydraulic action, it forms a continuous water flow path of "rainfall infiltration - interlayer hindrance - lateral confluence - deep confluence"; among them, the high-permeability layer 41 has a high infiltration capacity, which allows rainfall to enter the soil quickly; the permeability of the low-permeability hindrance layer 42 is significantly lower than that of the high-permeability layer 41, and a permeability abrupt change is formed at the junction of the two layers, which causes some infiltrated water to migrate laterally along the interlayer, forming interflow in the soil; the aquifer 43 has a strong water conduction and collection capacity, which is used to receive water passing through the low-permeability hindrance layer 42 and form a stable underground runoff.

[0036] The three-type runoff separation and collection system includes a transparent simulation cavity 2 located at the surface runoff space at the interface with the high-permeability layer 41, with a connected surface runoff collection unit 51; a transparent simulation cavity 2 located at the interface between the high-permeability layer 41 and the low-permeability retention layer 42, with a connected interflow collection unit 52; and a transparent simulation cavity 2 located outside the aquifer 43, with a connected underground runoff collection unit 53. In other words, by cleverly setting up the surface runoff collection unit 51 for collecting surface runoff, the interflow collection unit 52 located at the interface between the high-permeability layer and the low-permeability retention layer for collecting interflow, and the underground runoff collection unit 53 located outside the aquifer 43 for collecting underground runoff, the system achieves the separation and quantitative collection of surface runoff, interflow, and underground runoff.

[0037] Furthermore, the transparent simulation cavity 2 is made of transparent plexiglass, tempered glass or other transparent materials. It is a transparent cavity structure with an open top, which can be used by the rainfall simulation system 3 to simulate the flow of water formed by rainfall into the cavity. At the same time, it is also used to maintain the air pressure balance between the inside of the cavity and the outside, so as to eliminate the air resistance effect in the soil infiltration process.

[0038] Furthermore, the rainfall simulation system 3 includes a water supply pipeline, a multi-nozzle array, and a flow regulation unit; the water supply pipeline is equipped with a multi-nozzle array, and a flow regulation unit (such as a valve) is provided at the inlet of the water supply pipeline of each nozzle in the multi-nozzle array to regulate the flow of each nozzle; by adjusting the water supply flow and the number of nozzles, different rainfall intensities can be simulated.

[0039] Furthermore, a porous isolation structure 21 is provided between the high-permeability layer 41 and the low-permeability barrier layer 42, and between the low-permeability barrier layer 42 and the aquifer 43.

[0040] Furthermore, the porous isolation structure 21 can be made of permeable geotextile, screen, gravel cushion or other porous isolation materials, which allows water to pass through continuously while preventing the mixing of media with different particle sizes.

[0041] Furthermore, the three-dimensional visualization simulation device also includes a frame assembly 1, which is used to install the transparent simulation cavity 2 and the rainfall simulation system 3.

[0042] Furthermore, the frame assembly 1 includes a frame and a tilt adjustment mechanism; the tilt adjustment mechanism and a rainfall simulation system 3 are installed on the frame, and a transparent simulation cavity 2 is installed on the tilt adjustment mechanism to adjust the tilt angle of the transparent simulation cavity 2.

[0043] Furthermore, the tilt adjustment mechanism includes a hinge seat 12 and an electric push rod 11. One end of the transparent simulation cavity 2 away from the rainfall simulation system 3 is hinged to the support rod of the frame via the hinge seat 12. The other end of the transparent simulation cavity 2 away from the rainfall simulation system 3 is connected to the rod end of the electric push rod 11 via the hinge seat. The cylinder end of the electric push rod 11 is connected to the frame via the hinge seat. The tilt adjustment is achieved by extending and retracting the electric push rod 11 to rotate the transparent simulation cavity 2 around the hinge seat 12. Specifically, when the transparent simulation cavity 2 is in a horizontal initial state, the electric push rod 11 extends, pushing the end of the transparent simulation cavity 2 away from the hinge axis 12 upward, causing the transparent simulation cavity 2 to rotate upward around the hinge axis 12. The angle between the bottom surface of the transparent simulation cavity 2 and the horizontal plane gradually increases, achieving adjustment from a horizontal state to a sloped state. When the transparent simulation cavity 2 is at a certain tilt angle, the electric push rod 11 shortens, causing the end furthest from the hinge axis 12 to gradually descend under its own weight. The transparent simulation cavity 2 then rotates in the opposite direction around the hinge axis 12, gradually reducing the angle between it and the horizontal plane until it returns to a horizontal state. In this way, the tilt angle of the transparent simulation cavity 2 can be continuously adjusted within the range of 0° to 45°, where 0° represents a horizontal state and 45° represents the maximum simulated slope, thus meeting the simulation requirements for the formation processes of surface runoff, interflow, and subsurface runoff under different slope conditions.

[0044] During slope adjustment, the heterogeneous soil stratified media system 4 is not required to be re-laid or replaced with each slope change. Within the preset slope range, the transparent simulation cavity 2 rotates around the hinge seat 12 as a whole. The high-permeability layer 41, the low-permeability barrier layer 42, and the aquifer 43 remain stable relative to the transparent simulation cavity 2. Each layer of media maintains stratification stability through the constraints of the transparent simulation cavity sidewalls, end baffles, self-weight, and the porous isolation structure 21. As long as the interfaces of each layer are continuous, without significant slippage, cracking, collapse, or mixing, and the interflow collection unit 52 still corresponds to the interface position between the high-permeability layer 41 and the low-permeability barrier layer 42, it is generally not necessary to completely reprocess the heterogeneous soil stratified media system 4. To ensure the comparability of experimental results under different slope conditions, it is preferable to adjust the slope sequentially under the same component layer media and the same initial moisture content, and to perform short-term static setting, surface leveling, and interlayer interface inspection after each slope adjustment. During the adjustment of the transparent simulation cavity 2 from a horizontal state to the target slope, if the single tilt angle adjustment exceeds 10°, or the adjusted working tilt angle exceeds 30°, it can be considered a significant slope change. In this case, the interlayer continuity of the heterogeneous soil stratified media system 4 and the stability of the porous isolation structure 21 should be checked to ensure that the high-permeability layer 41, low-permeability blocking layer 42, and aquifer 43 have not experienced significant slippage, cracking, collapse, or mixing. If the interfaces of each layer remain continuous after adjustment, and there is no media slippage, cracking, collapse, mixing, or shift in the collection unit layer position, then there is no need to repave the heterogeneous soil stratified media system 4. When only local disturbance occurs, the disturbed area should be replenished, leveled, reset, or recompacted. When the disturbance range is large enough that the interlayer interfaces cannot be restored to a continuous state, the heterogeneous soil stratified media system 4 should be reconstructed.

[0045] Preferably, K1 / K2 is set to ≥100 to enhance the interlayer blocking effect and improve the formation and observation effect of interflow.

[0046] Furthermore, the thickness of the high-permeability layer 41 is greater than the thickness of the low-permeability barrier layer 42; the thickness of the aquifer 43 is greater than or equal to the thickness of the high-permeability layer 41, and more preferably, the thickness of the aquifer 43 is 1.2 to 2.0 times the thickness of the high-permeability layer 41. The thickness of the low-permeability barrier layer 42 is 3 cm to 5 cm. Under larger dip angles, the thickness of the high-permeability layer 41 can be appropriately increased, the continuity of the interlayer interface can be improved, or the single slope adjustment amplitude can be reduced, so as to ensure that the lateral transport process of the interflow along the interlayer interface can be fully displayed.

[0047] Furthermore, the high-permeability layer 41 is filled with medium sand, the particle size of which ranges from 0.25 mm to 0.5 mm, and the non-uniformity coefficient is controlled between 1.5 and 3.0, so that the particle size distribution of the medium remains relatively uniform, thereby ensuring that the layer has a stable pore structure and high permeability. For example, the particle size of the medium sand is 0.4 mm.

[0048] Furthermore, the low-permeability barrier layer 42 is filled with a silty clay medium, which is composed of clay particles, silt particles, and sand particles. The clay content is 10%–30%, the silt content is 40%–70%, and the sand content is 10%–30%, with a high proportion of fine particles smaller than 0.075 mm to ensure that the layer has low permeability and forms a capillary barrier effect at the interface with the high-permeability layer 41. For example, the clay content is 20%, the silt content is 60%, and the sand content is 20%.

[0049] Furthermore, the aquifer 43 is filled with a gravel-sand mixture, which is formed by uniformly mixing commercially available gravel and coarse sand in a mass ratio of 1:3 to 2:3, wherein the gravel particle size is 2 mm to 10 mm and the coarse sand particle size is 0.5 mm to 2 mm; to ensure that the aquifer has a large porosity and strong water conductivity. For example, the gravel particle size is 5 mm, the coarse sand particle size is 1 mm, and the gravel and coarse sand are mixed in a mass ratio of 1.5:3.

[0050] The above parameters can be combined arbitrarily within each value range to form a feasible solution.

[0051] Furthermore, a porous isolation structure 21 is provided at the connection between the surface runoff collection unit 51 and the transparent simulation cavity 2. The outlet end of the surface runoff collection unit 51 is connected to a transparent water storage structure I13-1 via a pipe to display the surface runoff collection and water level change process. A porous isolation structure 21 is provided at the connection between the interflow collection unit 52 and the transparent simulation cavity 2. The outlet end of the interflow collection unit 52 is connected to a transparent water storage structure II13-2 via a pipe to display the interflow collection and water level change process. A porous isolation structure 21 is provided at the connection between the underground runoff collection unit 53 and the transparent simulation cavity 2. The outlet end of the underground runoff collection unit 53 is connected to a transparent water storage structure III13-3 via a pipe to display the underground runoff collection and water level change process.

[0052] Furthermore, it also includes a soil moisture monitoring system 6, used to collect real-time moisture content data of the aquifer 43, the low-permeability barrier layer 42, and the high-permeability layer 41. The soil moisture monitoring system 6 is wirelessly connected to an external computer terminal 7 to realize the real-time transmission, storage, and display of soil moisture data.

[0053] To investigate the formation timing and proportional variations of surface runoff, interflow, and groundwater runoff under different rainfall intensities and durations, and to further verify the applicability of this device in demonstrating rainfall-runoff mechanisms, the following implementation process is described:

[0054] I. Equipment Preparation

[0055] The transparent simulation chamber 2 is installed on the frame assembly 1 with an adjustable slope of 10°. The open design at the top of the transparent simulation chamber 2 ensures air pressure balance and eliminates air resistance.

[0056] II. Construction of Layered Media Systems for Heterogeneous Soils

[0057] Within the transparent simulation cavity 2, a water-bearing layer 43, a low-permeability barrier layer 42, and a high-permeability layer 41 are laid vertically from bottom to top, forming a heterogeneous soil stratification structure with significant differences in permeability. Each layer is separated by a porous isolation structure. This porous isolation structure prevents the mixing of media with different particle sizes while allowing water to pass freely without affecting the hydraulic connection between layers.

[0058] The high-permeability layer 41 is filled with medium sand, with a thickness of 12 cm. The particle size of the medium sand ranges from 0.25 mm to 0.5 mm, the non-uniformity coefficient is controlled between 1.5 and 3.0, and the saturated permeability coefficient is approximately 1.0 × 10⁻⁶. -4 m / s. This layer, as the primary medium for rainfall, has a high porosity and infiltration capacity, allowing rainfall to move rapidly downwards and providing a continuous water source for interflow and groundwater runoff.

[0059] The low-permeability retaining layer 42 is located below the high-permeability layer 41. It is filled with silty clay and consists of clay particles, silt particles, and a small amount of sand particles. The thickness is 4 cm. The clay content (by mass) is 10%–30%, the silt content (by mass) is 40%–70%, and the sand content (by mass) is 10%–30%. The proportion of fine particles with a particle size of less than 0.075 mm is relatively high, and its saturated permeability coefficient is controlled at 1.0 × 10⁻⁶. -7 m / s ~ 1.0 × 10 -6 Within the range of m / s, the preferred value is 1.0 × 10⁻⁶ m / s. -6 The flow rate is set at m / s to make its permeability significantly lower than that of the high-permeability layer 41, and to create a capillary blocking effect at the interface between the two, thus promoting the formation of interflow.

[0060] Aquifer 43 is located below low-permeability retaining layer 42 and is filled with a gravel-sand mixture with a thickness of 18 cm. The gravel-sand mixture consists of gravel and coarse sand, with gravel particles ranging from 2 mm to 5 mm and coarse sand particles ranging from 0.5 mm to 2 mm. The gravel and coarse sand are uniformly mixed at a mass ratio of 1:3 to 2:3, and the saturated permeability coefficient is 1.0 × 10⁻⁶. -3 m / s. This layer has high porosity and water conductivity, which is used to receive water passing through the low-permeability barrier layer 42 and form groundwater runoff.

[0061] In this embodiment, the material parameters of each dielectric layer are shown in Table 1.

[0062] Table 1

[0063]

[0064] The three media layers satisfy the following permeability coefficient relationship: K3 > K1 > K2, and K1 / K2 ≥ 100. Regarding layer thickness, in this embodiment, the high-permeability layer 41 is thicker than the low-permeability retaining layer 42, and the aquifer 43 is approximately 1.5 times thicker than the high-permeability layer 41, providing sufficient space for underground runoff storage and confluence. The high-permeability layer 41 and the low-permeability retaining layer 42 form a functional interface for interflow generation, while the low-permeability retaining layer 42 and the aquifer 43 form a transitional interface for underground recharge. The three media layers are arranged continuously in space, forming a continuous flow path of "rainfall infiltration—interlayer retention—lateral confluence—deep infiltration" in hydraulic terms. This allows rainfall entering the transparent simulation cavity 2 to sequentially form surface runoff, interflow, and underground runoff, achieving simultaneous demonstration and independent collection of these three types of runoff. If the experimental tilt angle is adjusted to a larger range, the thickness of the high-permeability layer can be appropriately increased, the continuity of the interlayer interface strengthened, or the single slope adjustment amplitude reduced, depending on the observation needs.

[0065] III. Slope Adjustment and Medium Condition Inspection

[0066] When conducting comparative experiments with different slopes, it is preferable to use the same component layered medium and maintain the same initial moisture content. Before and after each slope adjustment, check whether the interlayer interfaces of the high-permeability layer 41, low-permeability barrier layer 42, and aquifer 43 are continuous; check whether the porous isolation structure 21 has shifted; check whether the interflow collection unit 52 still corresponds to the interface position between the high-permeability layer 41 and the low-permeability barrier layer 42; and check whether the sensor probes of the soil moisture monitoring system 6 are loose. When no obvious slippage, mixing, cracking, collapse, or layer misalignment occurs after the slope change, it is not necessary to repave the layers involved in the heterogeneous soil layered medium system. When local disturbance occurs, the disturbed area should be replenished, leveled, reset, or recompacted. When the disturbance range is large and the interlayer interfaces cannot be restored to continuity, the heterogeneous soil layered medium system 4 should be reconstructed.

[0067] IV. Grouping of Rainfall Conditions

[0068] Three sets of experiments with different rainfall intensities were set up, as shown in Table 2.

[0069] Table 2

[0070]

[0071] V. Experimental Procedure

[0072] After the rainfall simulation system is activated, the water in the soil undergoes the following evolution process:

[0073] ① Low-intensity rainfall stage: Rainfall is almost entirely infiltrated, surface runoff is basically not generated, interflow gradually forms and becomes dominant, and a small amount of water enters the lower layer to form groundwater runoff.

[0074] Characteristics: Primarily characterized by interflow within the soil.

[0075] ②Medium-intensity rainfall stage: Infiltration intensity gradually approaches infiltration capacity, surface runoff gradually occurs, interflow appears, and groundwater runoff gradually occurs.

[0076] Characteristics: All three types of runoff coexist.

[0077] ③ High-intensity rainfall stage: The rainfall intensity is much greater than the infiltration capacity, which quickly forms continuous surface runoff. Interflow appears earlier and has a stable flow rate, and groundwater runoff is generated stably.

[0078] Characteristics: Primarily driven by surface runoff.

[0079] Data collection and analysis:

[0080] The flow rate variation curves of surface runoff, interflow, and groundwater runoff were recorded using three runoff separation and collection systems; changes in water content at different depths were recorded using a soil moisture monitoring system. The analysis included the time difference initiation of the three types of runoff, the change in the proportion of each runoff over time, the influence of rainfall intensity on the runoff generation mechanism, and the influence of slope change on the lateral transport velocity of interflow and the proportion of groundwater runoff. This embodiment demonstrates that the present invention can be used to visually illustrate the formation sequence of the three types of runoff under different rainfall and slope conditions, the key role of interflow in rainfall runoff generation, the critical transition process from no surface runoff to runoff, and the dynamic distribution relationship among the three types of runoff. This embodiment verifies the effectiveness, stability, and repeatability of this device in teaching and experimental research on rainfall runoff generation mechanisms.

[0081] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff, characterized in that, include: A transparent simulation cavity (2) is a transparent simulation structure with an opening at one end along the height direction; A rainfall simulation system (3) is disposed above the transparent simulation cavity (2) for simulating rainfall; The heterogeneous soil stratified media system (4) includes an aquifer (43), a low-permeability barrier layer (42) and a high-permeability layer (41) that are sequentially filled in the transparent simulated cavity (2) from bottom to open end along the height direction. The aquifer (43), the low-permeability barrier layer (42) and the high-permeability layer (41) are stacked inside the transparent simulated cavity (2) to a preset height. There is a cavity above the high-permeability layer (41) as a surface runoff space. The permeability coefficient K3 of the aquifer (43) is greater than the permeability coefficient K1 of the high-permeability layer (41) and the permeability coefficient K2 of the low-permeability barrier layer (42) so that lateral interflow is formed at the interface between the high-permeability layer (41) and the low-permeability barrier layer (42) during rainfall infiltration, and groundwater runoff is formed in the aquifer (43). The three types of runoff separation and collection systems include a transparent simulation cavity (2) located outside the surface runoff space at the junction with the high permeability layer (41) with a connected surface runoff collection unit (51); a transparent simulation cavity (2) located outside the junction of the high permeability layer (41) and the low permeability barrier layer (42) with a connected interflow collection unit (52); and a transparent simulation cavity (2) located outside the aquifer (43) with a connected underground runoff collection unit (53).

2. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 1, characterized in that, The three-dimensional visualization simulation device also includes a rack assembly (1) for mounting a transparent simulation cavity (2) and a rainfall simulation system (3).

3. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 2, characterized in that, The frame assembly (1) includes a frame and a tilt adjustment mechanism; the tilt adjustment mechanism and a rainfall simulation system (3) are installed on the frame, and a transparent simulation cavity (2) is installed on the tilt adjustment mechanism to adjust the tilt angle of the transparent simulation cavity (2).

4. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 3, characterized in that, The tilt adjustment mechanism includes a hinge seat (12) and an electric push rod (11). One end of the transparent simulation cavity (2) away from the rainfall simulation system (3) is hinged to the support rod of the frame through the hinge seat (12). The other end of the transparent simulation cavity (2) away from the rainfall simulation system (3) is connected to the rod end of the electric push rod (11) through the hinge seat. The cylinder end of the electric push rod (11) is connected to the frame through the hinge seat.

5. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 1, characterized in that, Set K1 / K2≥100.

6. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 1, characterized in that, A porous isolation structure (21) is provided between the high-permeability layer (41) and the low-permeability barrier layer (42), and between the low-permeability barrier layer (42) and the aquifer (43).

7. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 1, characterized in that, The thickness of the high-permeability layer (41) is greater than the thickness of the low-permeability barrier layer (42); the thickness of the aquifer (43) is greater than or equal to the thickness of the high-permeability layer (41).

8. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 7, characterized in that, The thickness of the aquifer (43) is 1.2 to 2.0 times the thickness of the high-permeability layer (41); the thickness of the low-permeability barrier layer (42) is 3 cm to 5 cm.

9. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 1, characterized in that, The high-permeability layer (41) is filled with medium sand, the particle size of which ranges from 0.25 mm to 2 mm; The low-permeability barrier layer (42) is filled with silty clay medium, which is composed of clay particles, silt particles and sand particles, wherein the clay particle content is 10% to 30%, the silt particle content is 40% to 70%, and the sand particle content is 10% to 30%. The aquifer (43) is filled with a gravel-sand mixture, which is formed by uniformly mixing gravel and coarse sand in a mass ratio of 1:3 to 2:3, wherein the gravel particle size is 2 mm to 10 mm and the coarse sand particle size is 0.5 mm to 2 mm.

10. The three-dimensional visualization simulation device for the formation process of three waters in rainfall runoff according to claim 1, characterized in that, A porous isolation structure (21) is provided at the connection between the surface runoff collection unit (51) and the transparent simulation cavity (2). The outlet end of the surface runoff collection unit (51) is connected to a transparent water storage structure I (13-1) via a pipe, which is used to display the surface runoff collection and water level change process. A porous isolation structure (21) is provided at the connection between the soil flow collection unit (52) and the transparent simulation cavity (2). The outlet end of the soil flow collection unit (52) is connected to a transparent water storage structure II (13-2) via a pipe to display the soil flow collection and water level change process. A porous isolation structure (21) is provided at the connection between the underground runoff collection unit (53) and the transparent simulation cavity (2). The outlet end of the underground runoff collection unit (53) is connected to a transparent water storage structure III (13-3) via a pipe, which is used to display the underground runoff collection and water level change process.

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