A field composite erosion observation plot structure and its application method

Abstract

The present invention relates to a field composite erosion observation cell structure and an application method thereof. The observation cell is composed of three single-body runoff cells for soil and water loss monitoring arranged side by side; the freeze-thaw observation area is fully wrapped with a breathable and water-permeable layer; the freeze-thaw + wind erosion observation area is completely shielded by a rainproof cover plate; the freeze-thaw + wind erosion + water erosion observation area is fully exposed to ensure the free action of water, wind, and freeze-thaw. The field composite erosion observation cell of the present invention can be conveniently installed on slopes of various surface types, and can realize the synchronous observation of runoff cells under different erosion dynamics such as freeze-thaw, freeze-thaw + wind erosion, freeze-thaw + wind erosion + water erosion. When in use, a three-dimensional terrain scan is performed on the observation cell at different periods in a time period, and terrain point cloud data of different periods are obtained and a slope DEM is generated. Then, the point cloud data of different periods are compared to obtain the terrain change amount of the time period, and the erosion amount of the freeze-thaw cell, freeze-thaw + wind erosion cell, and freeze-thaw + wind erosion + water erosion is obtained through conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of soil and water loss monitoring, and in particular to a field composite erosion observation cell structure and an application method thereof. Background Art

[0002] In arid and semi-arid areas such as the wind-water interlaced zone of the Loess Plateau and the agricultural-pastoral interlaced zone in the north, soil erosion is driven by the alternation of water, wind, and freeze-thaw, and changes in seasonal cycles. In winter and spring, freeze-thaw and weathering are serious, and runoff accumulates at the foot of the slope to form a fan-shaped slope skirt; in summer and autumn, heavy rains and floods are frequent, forming heavy rain runoff rich in sediment, causing a large amount of coarse sediment accumulated in the early stage to move downward, resulting in a high-intensity erosion and sand production process. Water erosion, wind erosion, and freeze-thaw erosion are the result of the combined effects of water, wind, and temperature in nature. They are coupled with each other in terms of temporal and spatial distribution, energy supply, and material sources, forming a sediment erosion, transportation, and deposition process that is completely different from the single mechanism of water erosion or wind erosion.

[0003] At present, the monitoring of soil erosion is mainly based on single water erosion or wind erosion, that is, wind erosion and water erosion are measured as two independent processes.

[0004] For example, the utility model patent "Slope water erosion monitoring device" with authorization announcement number CN 205749231 U discloses a slope water erosion monitoring device that can improve the accuracy of measuring soil migration; the invention patent "A method for measuring soil wind erosion amount in a soil wind erosion circle" with publication number CN 106813892 A sets a soil wind erosion circle, then measures wind speed and direction, and finally calculates physical parameters related to soil wind erosion amount and soil wind erosion amount in the soil wind erosion circle.

[0005] However, water erosion has obvious boundaries, which can be obtained by measuring the runoff sediment at the outlet of the basin, while wind erosion has no obvious boundaries, and the wind erosion flux can only be measured by tracking the changes on the soil surface or analyzing the particles. At present, the commonly used methods for analyzing wind erosion and sand production include direct estimation method, sediment transport balance method, particle size analysis method, model method, isotope tracer method, etc. Among them, the first three methods are to calculate the amount of wind erosion through investigation and observation or experiment, using wind force, ground condition observation, sampling and survey data, but it is difficult to reflect the interaction between wind erosion and water erosion. The isotope tracer method is to use radioactive nuclides to 137 Cs, 7 Be analysis determines the spatial variation of sediment flux and shows certain advantages in measuring water erosion and wind erosion. However, the impact of wind erosion on water erosion is divided into two aspects: wind accumulation and weathering. The current wind erosion measurement methods are all quantitative observations of wind accumulation, while the impact of weathering cannot be quantified, which also increases the difficulty of studying wind-water interaction erosion. Summary of the invention

[0006] In order to solve the problem that the existing technology cannot realize the study of the temporal and spatial differentiation of slope erosion and sand production under different dynamic composite modes, the present invention provides a test plot structure for conducting in-situ slope erosion dynamic observation under field composite erosion conditions, which can monitor slope topography, sediment particle size distribution, erosion rate of different rock layers, and slope erosion and sand production process at different time periods. The observation cell structure has a simple structure, is easy to operate and maintain, and can monitor the slope erosion process under different dynamic composite effects such as water power, wind power, and freeze-thaw.

[0007] In order to solve the above problems, the present invention adopts the following technical solutions:

[0008] The present invention provides a field composite erosion observation area structure, wherein the observation area is composed of three parallel-arranged single-body runoff areas for soil and water loss monitoring, which are freeze-thaw observation area, freeze-thaw + wind erosion observation area, and freeze-thaw + wind erosion + water erosion observation area in sequence; the freeze-thaw observation area is fully wrapped with an air-permeable and water-permeable layer;

[0009] The freeze-thaw + wind erosion observation area is completely shielded by a rain cover;

[0010] The freeze-thaw + wind erosion + water erosion observation area is completely exposed to ensure the free action of water, wind and freeze-thaw.

[0011] As a preferred solution, the runoff cells are spaced 1 m apart.

[0012] As a preferred solution, each of the runoff cells is 5 m long and 1 m wide.

[0013] As a preferred solution, each of the runoff areas is surrounded by a retaining fence and a collecting trough, with retaining fences on three sides and a collecting trough at the bottom, the collecting trough is connected to a collecting barrel, the retaining fence includes an upper retaining fence and side retaining fences on both sides of the upper retaining fence, the upper retaining fence is arranged opposite to the collecting trough. As a preferred solution, a barrel cover is arranged above the barrel body of the collecting barrel, and a drainage valve is arranged below the barrel body.

[0014] As a preferred solution, the water-permeable and air-permeable layer is a layer structure made of spunbonded polypropylene macromolecular polymer material, and the water-permeable and air-permeable layer is fixed to the three-side retaining grilles and one-side collecting trough by means of wave-shaped spring clips.

[0015] As a preferred solution, the rain shield cover is a lighting curved surface endurance board made of PC solid material.

[0016] As a preferred solution, the rain shield cover is fixed to the retaining fence by four vertical poles, and the lowest point of the edge of the rain shield cover is 1.3m away from the slope surface.

[0017] The application method of the above-mentioned field composite erosion observation cell structure is as follows:

[0018] A three-dimensional terrain scan was conducted on the observation area at different periods in a time period to obtain the terrain point cloud data of different periods and generate the slope DEM. Then, by comparing the terrain point cloud data of different periods, the terrain change in the time period was obtained. After conversion, the erosion amount of the freeze-thaw area, freeze-thaw + wind erosion area and freeze-thaw + wind erosion + water erosion was obtained.

[0019] The present invention has the following beneficial effects:

[0020] (1) The field composite erosion observation plot of the present invention can be conveniently installed on slopes of various surface types, and can realize the synchronous observation of runoff plots under different erosion dynamics such as freeze-thaw, freeze-thaw + wind erosion, freeze-thaw + wind erosion + water erosion.

[0021] (2) The freeze-thaw erosion observation area is fully wrapped with a breathable and water-permeable layer, which can block wind and raindrops from directly hitting the slope surface, and allow rainwater to infiltrate freely, ensuring the consistency of soil moisture content, which is used to observe the erosion effect of freeze-thaw on the slope surface.

[0022] (3) A rain cover is installed at the top of the freeze-thaw + wind erosion observation area to effectively block rainfall above it and ensure air circulation, which is used to observe the erosion effects of freeze-thaw and wind on the slope.

[0023] (4) Based on the observation data obtained from the three plots of freeze-thaw, freeze-thaw + wind erosion, and freeze-thaw + wind erosion + water erosion, we can deduce the process of soil and water loss on the slope under different erosion dynamics and analyze the response law of soil and water loss process with the change of erosion dynamics. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structure of a field composite erosion observation cell structure of the present invention Figure 1 .

[0025] Figure 2 A schematic diagram of the structure of a field composite erosion observation cell structure of the present invention Figure 2 .

[0026] In the attached figure, 1 is freeze-thaw observation area, 2 is freeze-thaw + wind erosion observation area, 3 is freeze-thaw + wind erosion + water erosion observation area, 4 is water-permeable and breathable layer, 5 is vertical pole, 6 is rain shield cover, 7 is upper retaining fence, 8 is side retaining fence, 9 is collecting trough, 10 is connecting pipe, 11 is barrel cover, 12 is collecting barrel, 13 is drainage valve, 14 is spring clip. DETAILED DESCRIPTION

[0027] The present invention is described in detail below through specific embodiments, but the protection scope of the present invention is not limited to the following embodiments, and any technical solutions that can be thought of by any technician in the field based on the present invention and combined with the common knowledge in the field belong to the protection scope of the present invention.

[0028] Example 1

[0029] like Figures 1-2 As shown, a field composite erosion observation area of ​​the present embodiment is set on the slope, and the observation area is composed of three single-body runoff areas for soil and water loss monitoring arranged side by side, namely freeze-thaw observation area 1, freeze-thaw + wind erosion observation area 2, freeze-thaw + wind erosion + water erosion observation area 3. Each runoff area is 5m long and 1m wide, and there is a 1m interval between the areas to serve as measurement channels.

[0030] Each runoff area is enclosed by three retaining fences and one collecting trough 9, wherein the retaining fence includes an upper retaining fence 7 and side retaining fences 8 located on both sides of the upper retaining fence 7. A collecting trough 9 is provided at the bottom of the runoff area, opposite to the upper retaining fence 7. The runoff area is located on a slope, so the upper retaining fence 7 is located at the high part of the slope, and the collecting trough 9 is located at the low part of the slope.

[0031] The collecting trough 9 is connected to the collecting barrel 12 through a connecting pipe 10. The connecting pipe 10 is cylindrical with an outer diameter of 0.1 to 0.2 m and is used to divert runoff sediment. The collecting barrel 12 is connected to the end of the connecting pipe 10 and is used to collect runoff sediment. The barrel body specifications are designed according to local rainfall conditions. A barrel cover 11 is provided above the barrel body to block rainwater and debris. A drainage valve 13 is provided below the barrel body to facilitate cleaning of the collecting barrel.

[0032] In order to prevent water and wind erosion and only retain freeze-thaw erosion, the freeze-thaw observation area 1 is fully wrapped with a water-permeable and breathable layer 4 made of spunbond polypropylene polymer material. The spunbond polypropylene polymer material has the characteristics of air permeability, water permeability and non-heat insulation. It can not only block raindrop splashing, runoff erosion and wind action, but also allow rainwater to infiltrate freely to ensure that the soil moisture content and temperature of the freeze-thaw observation area 1 are consistent with the outside world and do not affect the freeze-thaw erosion. The water-permeable and breathable layer 4 is fixed to the three-side retaining fence and the one-side collecting trough 9 by a wavy spring clip 14 and is detachable.

[0033] In order to prevent hydraulic erosion and retain wind erosion and freeze-thaw erosion, a rain shield 6 is set above the freeze-thaw + wind erosion observation area 2 to block rainfall. The rain shield 6 is a lighting arc-shaped endurance plate made of PC solid material, which is fixed to the retaining fence through four vertical poles 5. The lowest point of the edge of the rain shield 6 is 1.3m away from the slope surface to ensure air circulation and lighting on the slope surface without affecting wind erosion and freeze-thaw erosion.

[0034] Freeze-thaw + wind erosion + water erosion observation area 3 is a full-factor erosion dynamics observation area, and the area is completely exposed to ensure the free action of water, wind, and freeze-thaw.

[0035] The construction method of the field composite erosion observation area is as follows:

[0036] First, three single-body runoff cells for soil and water loss monitoring are built: 0.3m deep trenches are dug on the three sides of the slope, the retaining fences are buried in the trenches, and the soil is backfilled to fix them, so as to enclose a rectangular single runoff cell; then a collecting trough 9 and a collecting barrel 12 are set at the bottom of the runoff cell, and the collecting trough 9 and the collecting barrel 12 are connected with a connecting pipe 10.

[0037] Then build three single-body runoff plots for soil and water loss monitoring: freeze-thaw observation area 1, freeze-thaw + wind erosion observation area 2, and freeze-thaw + wind erosion + water erosion observation area 3. Construction of freeze-thaw observation area 1: A water-permeable and breathable layer 4 made of spunbond polypropylene polymer material is fixed on the retaining fence and collecting trough 9 of the single-body runoff plot for soil and water loss monitoring through a wavy spring clip 14, so that the spunbond polypropylene polymer material completely wraps the observation plot to form freeze-thaw observation area 1. Construction of freeze-thaw + wind erosion observation area 2: A rainproof cover 6 is built above the single-body runoff plot for soil and water loss monitoring through four vertical poles 5 to form freeze-thaw + wind erosion observation area 2. The third single-body runoff plot for soil and water loss monitoring is freeze-thaw + wind erosion + water erosion observation area 3 without adding other structures.

[0038] Application method of the field composite erosion observation area:

[0039] A 3D laser terrain scanner was used to perform 3D terrain scanning on the observation area at different periods in a certain time period, and the terrain point cloud data of different periods were obtained and the slope DEM was generated. Then, by comparing the terrain point cloud data of different periods, the terrain change in that time period was obtained, and the erosion amount of the freeze-thaw area, freeze-thaw + wind erosion area and freeze-thaw + wind erosion + water erosion was obtained after conversion.

[0040] Example 2 Application Example

[0041] In order to monitor the process of soil and water loss on the slope in the field, three 5m long and 1m wide control test plots were set up on a typical slope in the Arsenic Sandstone area of ​​the Ordos Plateau in Inner Mongolia: freeze-thaw, freeze-thaw + wind erosion, freeze-thaw + wind erosion + water erosion. The three-dimensional terrain scans of the test plots were carried out three times on December 21, 2018, April 15, 2019, and August 26, 2019 using a three-dimensional laser terrain scanner. Three periods of terrain point cloud data (more than 300,000 points) were obtained and a slope DEM with a resolution of 1mm×1mm was generated. By comparing the point cloud data on December 21, 2018 and April 15, 2019, the terrain changes of the test plots from December 21, 2018 to April 15, 2019 were obtained: 0.048m in the freeze-thaw plot and 0.048m in the freeze-thaw plot. 3 , freeze-thaw + wind erosion area 0.065m 3 , freeze-thaw + wind erosion + water erosion 0.076m 3, after conversion, the erosion amount was 67.68kg for the freeze-thaw area, 91.36kg for the freeze-thaw + wind erosion area, and 106.44kg for the freeze-thaw + wind erosion + water erosion; by comparing the point cloud data on April 15, 2019 and August 26, 2019, the terrain change of the test area from April 15, 2019 to August 26, 2019 was obtained: 0.006m in the freeze-thaw area 3 , freeze-thaw + wind erosion area 0.02m 3 , freeze-thaw + wind erosion + water erosion 0.19m 3 After conversion, the erosion amount is 8.36kg for the freeze-thaw area, 27.48kg for the freeze-thaw + wind erosion area, and 265.97kg for the freeze-thaw + wind erosion + water erosion area. The process of soil and water loss on the slope under different erosion dynamics is obtained, as shown in Table 1.

[0042] Table 1 Soil and water loss process on slope under different erosion dynamics

[0043]

[0044] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made based on the structure, features and principles of the patent scope of the present invention should be included in the patent application scope of the present invention.

Claims

1. A field composite erosion observation cell structure, characterized in that: The observation area is composed of three single-type soil and water loss monitoring runoff areas arranged side by side, which are freeze-thaw observation area (1), freeze-thaw + wind erosion observation area (2), and freeze-thaw + wind erosion + water erosion observation area (3); The freeze-thaw observation area (1) is completely wrapped with a breathable and water-permeable layer (4), and the breathable and water-permeable layer (4) is a layer structure made of a spunbond polypropylene polymer material; The freeze-thaw + wind erosion observation area (2) is completely shielded from the rain cover (6), and the rain cover (6) is a light-collecting curved surface endurance plate made of PC solid material; The freeze-thaw + wind erosion + water erosion observation area (3) is completely exposed to ensure the free action of water, wind and freeze-thaw.

2. A field composite erosion observation cell structure according to claim 1, characterized in that: The runoff cells are spaced 1 m apart.

3. A field composite erosion observation cell structure according to claim 1, characterized in that: Each of the runoff cells is 5 m long and 1 m wide.

4. A field composite erosion observation cell structure according to claim 1, characterized in that: Each runoff area is formed by a barrier fence and a flow collecting trough (9), wherein the barrier fence is provided on three sides and a flow collecting trough (9) is provided at the bottom, wherein the flow collecting trough (9) is connected to a flow collecting barrel (12), wherein the barrier fence comprises an upper barrier fence (7) and side barrier fences (8) located on both sides of the upper barrier fence (7), wherein the upper barrier fence (7) is arranged opposite to the flow collecting trough (9).

5. The field composite erosion observation cell structure according to claim 1 is characterized in that: A barrel cover (11) is arranged above the barrel body of the collecting barrel (12), and a drainage valve (13) is arranged below the barrel body.

6. A field composite erosion observation cell structure according to claim 1, characterized in that: The water-permeable and air-permeable layer (4) is fixed to the three-side retaining fences and the one-side collecting trough (9) via wave-shaped spring clips (14).

7. A field composite erosion observation cell structure according to claim 1, characterized in that: The rain shield cover (6) is fixed to the barrier fence via four vertical poles (5), and the lowest point of the edge of the rain shield cover (6) is 1.3 m from the slope surface.

8. The application method of the field composite erosion observation cell structure according to claim 1 is characterized in that: A three-dimensional terrain scan was conducted on the observation area at different periods in a time period to obtain the terrain point cloud data of different periods and generate the slope DEM. Then, by comparing the terrain point cloud data of different periods, the terrain change in the time period was obtained. After conversion, the erosion amount of the freeze-thaw area, freeze-thaw + wind erosion area and freeze-thaw + wind erosion + water erosion was obtained.

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