Device for rapidly and accurately measuring surface roughness of soil

Abstract

The utility model discloses a device for rapidly and accurately measuring the surface roughness of soil, and belongs to the technical field of field measuring equipment. The device comprises four length-adjustable metal rods, a top thin plastic plate, a middle thick plastic plate, a plurality of fixed metal rods, a probe unit, a resistance wire and two metal rolling shafts, the four length-adjustable metal rods are arranged in a rectangular mode, the top thin plastic plate and the middle thick plastic plate are horizontally installed on the four metal rods, and the fixed metal rods are fixed to the middle thick plastic plate, penetrate out of the top thin plastic plate and are arranged among the length-adjustable metal rods in a rectangular mode at equal intervals. The probe units penetrate through the middle thick plastic plate and are arranged between the fixed metal rods in parallel at equal intervals in a chessboard manner; the metal rolling shaft is installed on the middle thick plastic plate, one end of the resistance wire is welded to the fixed metal rod, and the other end of the resistance wire penetrates through the probe unit and the fixed metal rod and then is wound on a rolling wheel of the metal rolling shaft. According to the utility model, the soil surface roughness is measured by using the voltage change, and the measurement is rapid and accurate.

Description

Technical Field

[0001] The utility model belongs to the technical field of field measurement equipment and relates to a device for quickly and accurately measuring the surface roughness of two-dimensional soil. Background Art

[0002] Soil surface roughness, a key component of field surveys, is a crucial indicator influencing surface runoff and erosion. Surface roughness is typically the result of factors such as crop cultivation and management practices, human activities, and soil erosion. It is a primary physical property of the ground and a key factor controlling land surface processes such as rainfall infiltration, surface runoff, wind erosion, and water erosion. Soil surface roughness reflects the surface microtopography and is an essential parameter for modeling and predicting soil and water loss processes and the migration and transformation of pollutants.

[0003] Currently, commonly used methods for measuring soil surface roughness can be generally categorized into two types: non-contact and contact measurement. Non-contact measurement techniques offer higher accuracy and automation, primarily including image analysis and remote sensing technologies. For example, image analysis involves capturing images of the soil surface, analyzing them using image processing software, and extracting surface contour information, thereby determining soil roughness. Remote sensing, on the other hand, involves acquiring surface images using platforms such as remote sensing satellites or drones, and extracting surface roughness information through remote sensing image processing and analysis. Contact measurement methods, on the other hand, primarily include the chain method and the stylus method, which typically utilize simple, inexpensive instruments. The chain method involves placing a fixed-length chain on the surface and measuring the relationship between the chain's horizontal length and its actual length to measure surface roughness. The stylus method, on the other hand, utilizes a row of equally spaced, movable styluses of equal length. The stylus tips are placed in contact with the surface, and the position of the stylus tips is recorded to map the surface profile and calculate surface roughness.

[0004] While both the aforementioned non-contact and contact measurement techniques can be used to measure soil surface roughness, non-contact measurement equipment is bulky, cumbersome, and expensive. Furthermore, it is subject to various factors and requires specialized image processing software and technical support, making it unsuitable for rapid field surveys. Compared to non-contact measurement techniques, contact measurement instruments offer simpler structures, lower costs, and portability, making them more suitable for rapid field surveys. However, existing methods are relatively complex to operate, their measurement process is significantly influenced by human experience, and they can only measure linear surface roughness. For complex terrain and large areas, multiple measurements and splicing of the results are required, which is not only time-consuming and labor-intensive but also prone to errors. In summary, while research on soil surface roughness measurement has been conducted, the development of equipment capable of accurately and rapidly measuring two-dimensional surface roughness in the field remains insufficient. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings of the above-mentioned existing technologies and provide a device that can quickly and accurately measure the roughness of the soil surface, providing technical support for surface erosion, runoff and eco-hydrological processes.

[0006] The purpose of this utility model is achieved through the following technical solutions:

[0007] A device for quickly and accurately measuring soil surface roughness comprises four adjustable metal rods, a top thin plastic plate, a middle thick plastic plate, multiple fixed metal rods, multiple probe units, multiple resistance wires serving as measurement references, and two metal rollers. The four metal rods are arranged in a rectangular shape, with the top thin plastic plate and the middle thick plastic plate mounted horizontally on the four metal rods. The multiple fixed metal rods are fixed to the middle thick plastic plate and extend through the top thin plastic plate to be arranged in a rectangular, equidistant pattern between the adjustable metal rods. The multiple probe units are plastic needles of equal length. The middle thick plastic plate is also provided with holes for the probe units to pass through, allowing them to slide up and down. The multiple probe units extend through the middle thick plastic plate and are arranged in parallel, equidistantly, in a checkerboard pattern between the fixed metal rods. Threading holes for the resistance wires are provided on the upper portions of the probe units. The two metal rollers are mounted on adjacent sides of the central thick plastic plate, facing the same direction as the fixed metal rod with the threading hole. Multiple rollers are evenly spaced on the metal rollers, with the same number and spacing as the fixed metal rod on the same side. One end of the resistance wire is welded to the other two fixed metal rods, while the other end passes through the stylus unit and the fixed metal rod with the threading hole, then winds around the rollers on the metal rollers. The length of the resistance wire can be adjusted by rotating the rollers 13.

[0008] The adjustable length metal rod can be adjusted in height according to the actual surface conditions, and the bottom is preferably a conical needle structure, which is easy to install and fix on the surface to be measured. A preferred size of the adjustable length metal rod is: 15.0 cm high and 0.5 cm in diameter.

[0009] The top thin plastic plate, middle thick plastic plate, and roller are preferably made of polyvinyl chloride. The top thin plastic plate is used to support the stylus unit to prevent it from falling out and serves as a reference for the parallelism of the stylus tip. The middle thick plastic plate is used to secure the stylus unit. It has a smooth, perforated interior, with each hole corresponding to the number of stylus units. Preferred dimensions for the top thin plastic plate and middle thick plastic plate are: 13.0 cm long, 13.0 cm wide, and 0.5 cm thick for the top thin plastic plate; 13.0 cm long, 13.0 cm wide, and 4.0 cm thick for the middle thick plastic plate.

[0010] The diameter of the fixed metal rod is preferably 0.3 cm, the height of the portion exposed from the top thin plastic plate 2 is preferably 2.0 cm, and the distance between the fixed metal rods is preferably 0.4 cm.

[0011] The stylus unit is preferably a black polyvinyl chloride plastic needle. Preferred dimensions are: 10.0 cm long, 0.1 cm in diameter, and 0.4 cm between each needle. A rubber pad is provided at the bottom of the stylus unit to prevent it from digging into the soil and causing measurement errors. Preferred dimensions are: 0.3 cm long, 0.1 cm wide.

[0012] The resistance wire is preferably made of nickel-chromium alloy with a smooth surface, and is preferably fixed to the fixed metal rod by welding. A preferred size of the resistance wire is: 0.05 cm in diameter.

[0013] A preferred size for the metal roller is 11.0 cm long and 0.2 cm in diameter. The distance between the rollers on the metal roller is preferably 0.4 cm. The roller is used to wind and electrically adjust the length of the resistance wire. Once all stylus units are fixed in place, the resistance wire can be straightened by rotating the roller, returning all stylus units to their original positions.

[0014] The application of the device for measuring soil surface roughness in measuring soil surface roughness. The soil surface is a two-dimensional plane soil surface.

[0015] The method for measuring soil surface roughness using the above-mentioned device for measuring soil surface roughness includes the following steps: inserting four metal rods of adjustable length into the soil so that the device is horizontal and the highest position of the surface protrusion contacts the probe unit; rotating a roller to straighten the resistance wire so that all the probe units are located at the same horizontal position and are parallel and equidistant from the top thin plastic plate, connecting the top of the fixed metal rod to a power supply device and a data collector via an electric wire, and measuring the voltage value V1 across each resistance wire at this time through the data collector; then, loosening the roller to release the resistance wire so that the rubber support at the bottom of each probe unit is in close contact with the soil surface, tightening the roller so that the resistance wire can be consistent with the contour line shape of the top position of the probe unit, and measuring the voltage value V2 across each resistance wire at this time through the data collector;

[0016] According to Ohm's law Apply the same current I and calculate the resistance of the resistance wire R1 and R2;

[0017] According to the law of resistance Where ρ is the resistivity, S is the cross-sectional area, and the lengths of the resistance wire L1 and L2 before and after the measurement are calculated;

[0018] The linear surface roughness Cr of each row and column of the measured sample is calculated through the relationship equation Cr = (1-L1 / L2) × 100;

[0019] Through the equation Determine the roughness of two-dimensional surface soil Wherein n is the number of resistance wires in the device.

[0020] Advantages and benefits of this utility model: By measuring the voltage across a resistance wire, the utility model obtains the resistance value of the resistance wire during the initial and measurement phases, infers the change in the resistance wire length, and ultimately determines the soil surface roughness. This utility model uses voltage changes to measure soil surface roughness, providing fast and accurate measurements, easy operation, and portability, making it suitable for rapid field soil surface roughness measurements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of the surface roughness measuring device of the utility model;

[0022] Figure 2 This is a schematic diagram of the top view of the surface roughness measuring device of the present invention; the top thin plastic plate is omitted in this schematic diagram to facilitate the display of other structures;

[0023] Figure 3 This is a schematic diagram of the structure of a single measuring unit of the surface roughness measuring device of the utility model;

[0024] Figure 4 This is a schematic structural diagram of a probe unit of a surface roughness measuring device of the present invention;

[0025] Figure 5 The results of measuring surface roughness using the surface roughness measuring device of the utility model are compared with those using the traditional chain method.

[0026] In the figure: 1-metal rod with adjustable length, 2-top thin plastic plate, 3-middle thick plastic plate, 4-fixed metal rod, 5-fixed metal rod, 6-fixed metal rod, 7-fixed metal rod, 8-probe unit, 9-rubber support, 10-resistance wire, 11-roller, 12-roller, 13-roller, 14-electric wire. DETAILED DESCRIPTION

[0027] The structure of the device of the present invention and the principle and method of measuring soil surface roughness are further described in detail below with reference to the embodiments and drawings.

[0028] Example 1

[0029] The utility model provides a device for quickly and accurately measuring the roughness of soil surface. Figure 1-4As shown, the system comprises four adjustable metal rods 1, a top thin plastic plate 2, a middle thick plastic plate 3, multiple fixed metal rods 4, 5, 6, and 7 (one representative on each side), multiple stylus units 8, a rubber support 9, multiple resistance wires 10 serving as a reference for measurement, and two metal rollers (rollers 11 and 12). The four metal rods 1 are arranged in a rectangular shape, with the top thin plastic plate 2 and middle thick plastic plate 3 mounted horizontally on the four metal rods 1. The bottoms of the metal rods 1 are tapered, needle-like structures, making them easy to attach to the surface being measured. The multiple fixed metal rods are fixed to the middle thick plastic plate 3 and extend through the top thin plastic plate 2, arranged equidistantly between the metal rods 1 in a rectangular pattern. The multiple stylus units 8 are plastic needles of equal length. The middle thick plastic plate 3 also has holes for the stylus units 8 to pass through, allowing them to slide up and down. The multiple stylus units 8 are arranged equidistantly and parallelly through the middle thick plastic plate 3, forming a checkerboard pattern, between the fixed metal rods. The adjacent fixed metal rods (6 and 7) are provided with threading holes for the resistance wire 10 to pass through. The upper portion of the stylus unit 8 is provided with a threading hole for the resistance wire 10 to pass through, and the lower end of the stylus unit 8 is mounted with a rubber support 9. The two metal rollers (11 and 12) are mounted on the adjacent sides of the middle thick plastic plate 3 in the same direction as the fixed metal rods (6 and 7) with threading holes. Multiple rollers 13 are equidistantly mounted on the metal rollers, and the number and spacing of rollers 13 are consistent with those of the fixed metal rods on the same side. One end of the resistance wire 10 is welded to the other two fixed metal rods (4 and 5). The other end passes through the stylus unit 8 and the fixed metal rods (6 and 7) with threading holes, and is then wound around the roller 13 of the metal roller. The length of the resistance wire 10 is adjusted by rotating the roller 13. The top of the fixed metal rod is connected to an electric wire 14, which can be connected to an external power supply device and a data acquisition device.

[0030] A preferred dimension of the device for quickly and accurately measuring soil surface roughness is as follows: the adjustable metal rod is 15.0 cm high and 0.5 cm in diameter, and its height can be adjusted according to the actual surface conditions. The top thin plastic plate 2, the middle thick plastic plate 3, and the multiple rollers 13 are made of polyvinyl chloride. The top thin plastic plate is 13.0 cm long, 13.0 cm wide, and 0.5 cm thick; the middle thick plastic plate is 13.0 cm long, 13.0 cm wide, and 4.0 cm thick. The fixed metal rod has a diameter of 0.3 cm and a height of 2.0 cm above the top thin plastic plate 2. The distance between the fixed metal rods is 0.4 cm. The measuring probe unit 8 consists of multiple black polyvinyl chloride plastic needles of equal length, each 10.0 cm long and 0.1 cm in diameter, with the distance between each needle being 0.4 cm. The rubber support 9 is 0.3 cm long and 0.1 cm in diameter. The resistance wire 10 is made of a smooth nickel-chromium alloy with a diameter of 0.05 cm. A preferred size of the metal roller is 11.0 cm in length and 0.2 cm in diameter, and the distance between the rollers 13 on the metal roller is 0.4 cm.

[0031] This device calculates the difference in voltage between the resistance wire and the resistance wire before and during measurement, and then calculates the difference in resistance wire length change. The soil surface roughness is then calculated using the equation that relates the resistance wire length change to the surface roughness. The method for using this device and the soil surface roughness calculation process are as follows.

[0032] Adjust the length of the metal rod 1 according to the actual surface roughness to ensure the measuring device is at an appropriate height. Insert the tapered needle-shaped metal rods at the bottom vertically into the surface to be measured, ensuring that all four rods are inserted into the soil and the device is level. The device should not be too high, which would cause excessive deformation of the resistance wire during the downward movement of the stylus unit 8. It should also not be too low, which would cause a large amount of the rubber support 9 at the bottom of the stylus unit 8 to contact the surface before measurement, causing errors. Ensure that the highest point of the surface protrusion contacts the stylus unit.

[0033] Next, check that the resistance wire 10 passes through the threading holes in the upper portion of the stylus unit 8. This example uses a 625-stylus unit (25×25) setup. The stylus unit 8 consists of 625 black plastic needles of equal length, 10.0 cm long and 0.1 cm in diameter, with the distance between adjacent needles being 0.4 cm. Ensure that the 625 stylus units can move vertically on the middle thick plastic plate 3. The upper end of the stylus unit 8 is positioned outside the top of the middle thick plastic plate 3 and does not contact the thin, short plastic plate 2 at the top. The lower end passes through the bottom of the middle thick plastic plate 3 and rests on the surface to be measured. After checking that everything is correct, adjust the corresponding resistance wire 10 by rotating the roller 13 in sequence until the resistance wire 10 is straightened and the 625 measuring probe units are restored to their original positions, so that all measuring probe units 8 are located at the same horizontal position and are parallel and equidistant from the top thin plastic plate 2. The top ends of the fixed metal rods 3, 4, 5, and 6 are connected to the power supply device and the data collector through the wires 14, and the voltage value V1 at both ends of each resistance wire at this time is measured by the data collector.

[0034] Afterwards, loosen roller 13 to release resistance wire 10, allowing the rubber support 9 at the bottom of each probe unit 8 to rest against the soil surface. After all 625 probe units 8 have fully contacted the surface to be measured, slightly tighten roller 13 so that the resistance wire 10 is aligned with the contour line at the top of the probe unit 8. The voltage V2 across each resistance wire is then measured using a data logger. According to Ohm's law (1), when the same current I is applied, the resistance R1 and R2 of each resistance wire can be calculated.

[0035]

[0036] According to the resistance law (2), the lengths L1 and L2 of each resistance wire before and after the measurement are calculated. And according to the relationship equation (3) between the change in the length of each resistance wire and the soil roughness, the linear surface roughness Cr of each row and column of the measured sample is calculated. Finally, according to equation (4), the roughness of the two-dimensional surface soil can be quickly and accurately measured.

[0037]

[0038] Wherein ρ is the resistivity and S is the cross-sectional area, both of which are related to the material of the resistance wire used. The resistance wire used in the present invention is made of nickel-chromium alloy with a smooth surface and a diameter of 0.05 cm.

[0039] Cr=(1-L1 / L2)×100 (3)

[0040]

[0041] In this embodiment, n is 50, which can be adjusted according to the size of the sample plot.

[0042] In summary, the present invention provides a device for quickly and accurately measuring soil surface roughness. The device primarily comprises an adjustable metal rod 1, fixed metal rods 4, 5, 6, and 7, a probe unit 8, a resistance wire 10, two plastic plates 2 and 3, rollers 11 and 12, and a wheel 13. The metal rod 1 can be fixed vertically to the surface to be measured to secure the device. Multiple probe units 8 are arranged parallel and equidistantly in a rectangular pattern between the four adjustable metal rods 1. Each resistance wire 10 sequentially passes through the probe units, simulating the true contour of the surface to be measured. The resistance wire 10 and probe unit 8 can measure the surface roughness of the surface to be measured using both the chain method and the probe method. Simultaneously, by measuring the voltage difference between the front and rear ends of the resistance wire, the resistance value and length change of the resistance wire are calculated. The linear surface roughness is calculated based on the equation relating the resistance wire length difference to the surface roughness. Finally, by taking the average value, the two-dimensional planar soil surface roughness can be quickly and accurately measured.

[0043] Example 2

[0044] In September 2024, five sample plots (each sample plot was repeated five times, and the distance between sample plots was greater than 10.0 m) were selected from typical aeolian sandy soils in the northern Loess Plateau of China, and the soil surface roughness was measured using the traditional chain method and the device of this utility model.

[0045] (1) Preliminary preparation: Before measurement, ensure that the roller on the roller is in a state where the resistance wire is completely stretched. Clear the dead branches and leaves on the selected soil surface. Adjust the four adjustable length metal rods according to the actual surface conditions. Then, straighten the soil surface roughness measuring device and slowly place it on the surface to be measured. Insert the lower ends of the four metal rods into the soil to ensure that the device is stable during the measurement process.

[0046] (2) Formal measurement: First, use a CR3000 data logger (Campbell Scientific, Inc., USA) to record the voltage across the resistance wire (25×2) in its initial state. Then, adjust the roller (25) on one side of the roller to relax the resistance wire. Slowly adjust the roller (25) on the other side according to the actual surface roughness, and slowly loosen the tight resistance wire so that the rubber drag at the bottom of the probe unit touches the ground until all 25 probe units on the resistance wire are in close contact with the surface to be measured. Immediately stop adjusting the roller. Repeat the above operation. After adjusting all the rollers on one side of the measuring device, start adjusting the length of the resistance wire on the side that was initially relaxed. Slightly tighten the resistance wire so that it can be consistent with the connection position of the top position of the probe unit. After repeating the above operation, use the data logger to record the voltage across all the resistance wires at this time.

[0047] (3) Data processing: The voltage difference between the two ends of the resistance wire before and after the measurement is obtained by the data acquisition device, and the resistance difference of the resistance wire before and after the measurement is obtained, which is then converted into the change value of the resistance wire length. Finally, 50 (25×2) values ​​of the soil surface roughness of this two-dimensional plane are calculated, and the final roughness of the soil surface is obtained by taking the average value.

[0048] In addition, the surface roughness was measured using the traditional chain method (silver, 20.0 cm long, 0.1 cm in diameter) at the same plot. The results of the measurement using the traditional chain method and the device of the utility model ( Figure 5 ) shows that for roughness measurements of the same plot, the traditional chain method may be subject to large human reading errors (at most one decimal place can be estimated), while the device of the present invention can accurately measure the change in resistance based on the resistance wire's conformity to the surface undulations, thereby deriving the surface roughness (the measurement result can be accurate to three decimal places). This is reflected in the specific results. For example, in plot 1, the maximum value measured by the traditional chain method was 6.0, while the minimum value was 4.3, with a difference of 1.7; while the maximum value measured by the device of the present invention was 5.455, and the minimum value was 4.460, with a difference of only 0.995. For example, in sample site 3, the maximum value measured by the traditional chain method is 6.4, and the minimum value is 4.2, with a difference of 2.2 between the maximum and minimum values; while the maximum value measured by the device of the present invention is 6.230, and the minimum value is 4.993, with a difference of only 1.237 between the maximum and minimum values. In addition, the median and average values ​​measured by the device of the present invention are relatively close, which further confirms the applicability of the device of the present invention.

[0049] The above embodiments are provided for the purpose of illustration and description in order to better illustrate the principles and practical applications of the present invention. However, the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for the purpose of illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, and these changes and improvements shall fall within the scope of the present invention to be protected.

Claims

1. A device for quickly and accurately measuring soil surface roughness, characterized by: It includes four metal rods with adjustable lengths, a thin plastic plate on the top, a thick plastic plate in the middle, multiple fixed metal rods, multiple measuring needle units, multiple resistance wires, and two metal rollers; The four adjustable length metal rods are arranged in a rectangular shape, and the top thin plastic plate and the middle thick plastic plate are horizontally installed on the four metal rods; the multiple fixed metal rods are fixed to the middle thick plastic plate and pass through the top thin plastic plate and are arranged in a rectangular shape with equal distances between the adjustable length metal rods; The multiple measuring needle units are multiple plastic needles of equal length; the middle thick plastic plate is provided with holes for the measuring needle units to pass through, and the multiple measuring needle units pass through the middle thick plastic plate and are equidistantly and parallelly arranged in a checkerboard pattern between the fixed metal rods; the fixed metal rods on the adjacent two sides are provided with threading holes for the resistance wire to pass through, and the upper part of the measuring needle unit is provided with a threading hole for the resistance wire to pass through; the two metal rollers are installed on the adjacent two sides of the middle thick plastic plate in the same direction as the fixed metal rod with the threading holes, and multiple rollers are equidistantly installed on the metal roller, and the number and spacing of the rollers are consistent with the fixed metal rod on the same side; one end of the resistance wire is welded to the fixed metal rods on the other two sides, and the other end passes through the measuring needle unit and the fixed metal rod with the threading holes and then is wrapped around the roller of the metal roller.

2. The device for quickly and accurately measuring soil surface roughness according to claim 1, characterized in that: The bottom of the length-adjustable metal rod is a conical needle-shaped structure.

3. The device for quickly and accurately measuring soil surface roughness according to claim 1, characterized in that: The top thin plastic plate, the middle thick plastic plate, the measuring needle unit and the roller are made of polyvinyl chloride.

4. The device for quickly and accurately measuring soil surface roughness according to claim 1, characterized in that: A rubber support is provided at the bottom of the measuring needle unit.

5. The device for quickly and accurately measuring soil surface roughness according to claim 1, characterized in that: The resistance wire is made of nickel-chromium alloy.

6. The device for quickly and accurately measuring soil surface roughness according to any one of claims 1 to 5, characterized in that: The adjustable length metal rod is 15.0 cm and has a diameter of 0.5 cm. The fixed metal rod has a diameter of 0.3 cm, and the portion exposed from the top thin plastic plate is 2.0 cm high. The measuring needle unit is 10.0 cm long and has a diameter of 0.1 cm.

7. The device for quickly and accurately measuring soil surface roughness according to claim 4, characterized in that: The rubber tray is 0.3 cm long and 0.1 cm wide.

8. The device for quickly and accurately measuring soil surface roughness according to any one of claims 1 to 5, characterized in that: The resistance wire has a diameter of 0.05 cm.

9. The device for quickly and accurately measuring soil surface roughness according to any one of claims 1 to 5, characterized in that: The top thin plastic plate is 13.0 cm long, 13.0 cm wide and 0.5 cm thick; the middle thick plastic plate is 13.0 cm long, 13.0 cm wide and 4.0 cm thick; the metal roller is 11.0 cm long and 0.2 cm in diameter.

10. The device for quickly and accurately measuring soil surface roughness according to any one of claims 1 to 5, characterized in that: The distance between the fixed metal rods is 0.4 cm; the distance between the measuring needle units is 0.4 cm; and the distance between the rollers is 0.4 cm.

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