Device and method for measuring sediment characteristics of dredged soil based on illumination

Abstract

The invention relates to a dredged soil precipitation characteristic measuring device based on illumination. Comprising a light-proof camera obscura, the right side of the light-proof camera obscura is open, an LED lighting source is installed on the left portion of an inner cavity of the light-proof camera obscura, and a plurality of light-proof partition plates which are longitudinally arranged at equal intervals are arranged on the right portion of the inner cavity of the light-proof camera obscura from top to bottom; a cuboid-shaped glass measuring cylinder with an opening in the top is placed in front of the light-proof dark box, light-proof films are arranged on the front wall and the rear wall of the glass measuring cylinder, light-transmitting cloth is arranged on the right side wall of the glass measuring cylinder, a plurality of dividing lines are arranged on the light-transmitting cloth from top to bottom, and the dividing lines transversely face the light-proof partition plates; the device further comprises a light-proof top plate assembly, the light-proof top plate assembly comprises a top plate, and the top plate is flush with the upper edge of the light-proof pasting film when placed in the inner cavity of the glass measuring cylinder. And an illuminometer is also included. The invention further relates to a measuring method. The sediment characteristic index of the dredged soil can be conveniently and effectively measured, and a basis is provided for effectively predicting the loading production efficiency of the trailing suction dredger.

Description

Technical Field

[0001] This invention belongs to the field of dredging engineering technology, and particularly relates to a device and method for measuring the sedimentation characteristics of dredged soil based on illumination. Background Technology

[0002] During dredging operations, trailing suction hopper dredgers use a rake to excavate and mix underwater soil to form slurry. This slurry is then pumped into a slurry tank via a slurry pump and pipelines for sedimentation. The sedimentation characteristics of the soil particles in the slurry directly affect the dredging efficiency of the dredging hopper dredger: if the soil particles in the slurry are coarse, the sedimentation performance is good, resulting in high loading efficiency and a shorter loading time; conversely, coarse particles result in low loading efficiency and a longer loading time. The slurry is generally composed of a mixture of various dredged soils, with complex soil types and a wide range of particle sizes. Existing geotechnical testing methods cannot determine the overall settling performance of the soil particles in the slurry, nor can they measure the sedimentation coefficient, an index that measures the overall settling characteristics of the soil particles in the slurry. Therefore, it is impossible to effectively predict the dredging efficiency of the dredging hopper dredger, nor can it provide a reference for adjusting the loading time.

[0003] In summary, it is necessary to develop and design a device for measuring the sedimentation characteristics of dredged soil in order to solve the aforementioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a light-based device for measuring the sedimentation characteristics of dredged soil, which can conveniently and effectively measure the sedimentation characteristics of dredged soil, providing a basis for effectively predicting the production efficiency of trailing suction hopper dredgers and a reference for adjusting the loading time.

[0005] The technical solution adopted in this invention is as follows: a light-based device for measuring the sedimentation characteristics of dredged soil, comprising an opaque dark box with an open right side; a rectangular, planar LED lighting source installed in the left part of the inner cavity of the dark box; multiple longitudinally spaced, opaque partitions arranged vertically in the right part of the inner cavity of the dark box; and a rectangular, open-topped glass measuring cylinder placed in front of the dark box, with opaque partitions on the front and rear walls. The device includes a light-transmitting film and a light-transmitting cloth on the right side wall. The height of the light-transmitting cloth is the same as the height of the opaque dark box, and the upper edge of the light-transmitting cloth is at the same height as the upper edge of the opaque film. Multiple dividing lines are provided on the light-transmitting cloth from top to bottom, and each dividing line is horizontally aligned with each opaque partition. It also includes an opaque top plate assembly, which includes a top plate with the same outline shape as the cross-sectional outline shape of the inner cavity of the glass measuring cylinder. When the top plate is inserted into the inner cavity of the glass measuring cylinder, it is flush with the upper edge of the opaque film. It also includes an illuminance meter.

[0006] Preferably, the opaque top plate assembly also includes a T-shaped bracket, the lower end of the vertical rod of the T-shaped bracket is fixedly connected to the center of the top plate, and when the top plate is placed into the inner cavity of the glass measuring cylinder, the end of the horizontal rod of the T-shaped bracket overlaps the cylinder wall at the mouth of the glass measuring cylinder.

[0007] Preferably, it also includes a horizontal support base plate, and the bottom of the opaque dark box is fixed on the support base plate; a graduated cylinder position marking area is also marked on the support base plate in front of the opaque dark box, and the glass graduated cylinder is placed in the graduated cylinder position marking area.

[0008] Preferably, the illuminance meter has a cylindrical photosensitive probe, the radial dimension of which is smaller than the distance between adjacent dividing lines on the light-transmitting cloth.

[0009] This invention also relates to a measurement method for a light-based device for measuring the sedimentation characteristics of dredged soil, comprising the following steps: Step S1, Preparation before measurement: Pour clean water into the glass graduated cylinder until the water level is flush with the top edge of the opaque film and the transparent cloth; place the glass graduated cylinder on the graduated cylinder position marking area on the support base plate, so that the transparent surface of the glass graduated cylinder is in close contact with the open opening of the opaque dark box; slowly lower the opaque top plate assembly until the T-shaped bracket rests on the cylinder opening wall, at which point the top plate just touches the liquid surface inside the cylinder; Turn on the LED lighting source and turn off all other indoor light sources. Place the illuminance meter's photosensitive probe against the surface of the translucent cloth. Measure and record the illuminance values ​​in the area between adjacent dividing lines, from top to bottom. When the range of all illuminance data is less than 3% of the average, record the average illuminance meter reading, h. w If the range of all illuminance data is greater than or equal to 3% of the average value, the cause should be investigated and the device adjusted. After adjustment, repeat the above operation until the range of all illuminance data is less than 3% of the average value. Remove the opaque top plate assembly, pour out the water from the glass graduated cylinder, wipe the water off the inner wall of the glass graduated cylinder with a paper towel, and place the glass graduated cylinder back into the graduated cylinder position marking area so that the light-transmitting surface of the glass graduated cylinder is tightly fitted with the open opening of the opaque dark box. Step S2, Measurement: Collect mud at the hatch of the trailing suction hopper, bring the mud back to the room, stir it thoroughly, and then pour it into a glass measuring cylinder until the surface of the mud is level with the top edge of the translucent cloth. Stir the slurry in the glass graduated cylinder thoroughly. After the liquid surface returns to calm, place the opaque top plate assembly until the T-shaped bracket rests on the cylinder wall. At this point, the top plate will just touch the liquid surface inside the cylinder. Turn on the LED lighting source and turn off all other indoor light sources. Start a stopwatch and record the time as 0. Place the illuminance meter's photosensitive probe against the surface of the translucent cloth and measure the illuminance value from top to bottom in the area between adjacent dividing lines. Record the illuminance data h. 0,j Where j is the number of the light-transmitting fabric partition and j = 1, 2, 3, ..., n; When the stopwatch reaches 5 min, 15 min, 30 min, 90 min, and 180 min, the illuminance value is measured again following the aforementioned procedure, and the illuminance meter reading h is recorded respectively. 5,j h 15,j h 30,j h 90,j and h 180,j Where j is the number of the light-transmitting fabric partition and j = 1, 2, 3, ..., n; Step S3, Calculation of sedimentation characteristic indicators: First, calculate the sum of the illuminance meter readings for each zone at time 0, using the following formula: ; Secondly, calculate the absolute value of the difference between the illuminance meter readings of each zone at time t and the readings at time 0, using the following formula: ; Next, the sum of the differences in illuminance meter readings for each zone at time t is calculated using the following formula: ; Finally, the mud settling coefficient at time t is defined and calculated using the following formula: .

[0010] The advantages and positive effects of this invention are: This invention provides a light-based device and method for measuring the sedimentation characteristics of dredged soil, enabling convenient and effective measurement of sedimentation properties. During measurement, the sampled slurry is thoroughly stirred and allowed to settle and stratify within a glass graduated cylinder. Light from a planar LED light source passes laterally through an opaque partition and enters the graduated cylinder. Different layers of the sedimented slurry exhibit varying light transmittance. An illuminance meter is used to detect and record the illuminance layer by layer, and the sedimentation characteristics of the dredged soil are calculated using the illuminance values. Therefore, this sedimentation characteristic measurement device provides a light-based measurement method that is convenient to operate and effectively obtains sedimentation characteristics, i.e., the sedimentation coefficient. This provides a basis for effectively predicting the production efficiency of trailing suction hopper dredgers, and thus offers a reference for adjusting and optimizing the loading time of trailing suction hopper dredgers. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of the present invention, in the state before measurement; Figure 2 This is a schematic diagram of the structure of the present invention, showing the state during measurement; Figure 3 This is a structural schematic diagram of the main body of the present invention. The dotted line in the diagram indicates the placement position of the glass measuring cylinder.

[0012] In the picture: 1. Support base plate; 2. LED lighting source; 3. Opaque partition; 4. Opaque dark box; 5. Glass measuring cylinder; 6. Opaque film; 7. Opaque top plate assembly; 8. Translucent cloth; 9. Mud; 10. Illuminance meter. Detailed Implementation

[0013] To further understand the invention's content, features, and effects, the following embodiments are provided for detailed explanation.

[0014] Please see Figure 1 , Figure 2 and Figure 3 The light-based dredged soil sedimentation characteristic measuring device of the present invention includes an opaque dark box 4 with an open right side. A rectangular, planar LED lighting source 2 is installed in the left part of the inner cavity of the opaque dark box 4. Multiple longitudinally spaced opaque partitions 3 are arranged from top to bottom in the right part of the inner cavity of the opaque dark box 4.

[0015] The opaque dark box 4 is open on the right side, and closed at the top, bottom, front, rear, and bottom. It is constructed entirely of opaque panels, and the opaque partition 3 uses the same panel as the opaque dark box 4. As shown in the figure, the LED lighting source 2 includes a cuboid-shaped housing. A rectangular, flat lampshade is installed on the right side of the housing. The height of the housing and lampshade is equal to the height of the inner cavity of the opaque dark box 4. An array of LED beads is installed inside the housing. The LED lighting source 2 produces uniform illumination and shines towards the right. The power cord of the LED lighting source 2 passes through the side wall of the opaque dark box 4 and is connected to the power supply.

[0016] As shown in the figure, all the opaque partitions 3 are the same size, the left edges of all the opaque partitions 3 are aligned vertically, and the right edges of all the opaque partitions 3 are aligned vertically and flush with the right opening of the opaque dark box 4. The uniform illumination light generated by the LED lighting source 2 passes laterally through the space between the opaque partitions 3.

[0017] A rectangular glass graduated cylinder 5 with an open top is placed in front of the opaque dark box 4, as shown in the figure. The height of the glass graduated cylinder 5 is greater than the height of the opaque dark box 4. Opaque films 6 are applied to the front and rear walls of the glass graduated cylinder 5, and a translucent cloth 8 is applied to the right side wall. Therefore, the front and rear walls of the glass graduated cylinder 5 are opaque, the right side wall is translucent, and the left side wall is untreated and thus translucent. The height of the translucent cloth 8 is the same as the height of the opaque dark box 4, and the upper edge of the translucent cloth 8 is at the same height as the upper edge of the opaque film 6.

[0018] Multiple dividing lines are provided on the translucent cloth 8 from top to bottom, and each dividing line is horizontally aligned with each opaque partition 3. Therefore, the illumination light passing through the space between the opaque partitions 3 passes horizontally through the mud 9 inside the glass measuring cylinder 5 and then illuminates the right side wall of the glass measuring cylinder 5. The illumination light of each layer corresponds to the area between a set of adjacent dividing lines on the translucent cloth 8. Due to the layering effect produced after the mud settles, the light intensity received by the area defined by each dividing line on the translucent cloth 8 is different, that is, the illuminance is different.

[0019] It also includes an opaque top plate assembly 7, which includes a top plate with the same outline shape as the cross-sectional outline shape of the inner cavity of the glass measuring cylinder 5. When the top plate is placed into the inner cavity of the glass measuring cylinder 5, it is flush with the upper edge of the opaque film 6 and also flush with the upper edge of the light-transmitting cloth 8.

[0020] In this embodiment, the opaque top plate assembly 7 also includes a T-shaped bracket. The lower end of the vertical rod of the T-shaped bracket is fixedly connected to the center of the top plate. When the top plate is placed into the inner cavity of the glass measuring cylinder 5, the end of the horizontal rod of the T-shaped bracket overlaps the cylinder wall of the glass measuring cylinder 5. By setting the T-shaped bracket, the ease of operation of placing the top plate into the glass measuring cylinder 5 and taking it out of the glass measuring cylinder 5 is improved. At the same time, the T-shaped bracket serves as a limiting bracket for the top plate, so that when the top plate is placed into the glass measuring cylinder 5, it is flush with the upper edge of the opaque film 6 and the light-transmitting cloth 8.

[0021] In this embodiment, a horizontal support base plate 1 is also included, and the bottom of the opaque dark box 4 is fixed on the support base plate 1; a graduated cylinder position marking area is also marked on the support base plate 1 and in front of the opaque dark box 4. Figure 3 (as shown in the dashed box), the glass graduated cylinder 5 is placed in the graduated cylinder position marking area.

[0022] It also includes a lux meter 10, which is used to measure the illuminance in the area between two adjacent dividing lines on the light-transmitting fabric 8. In this embodiment, the lux meter 10 has a cylindrical photosensitive probe, the radial dimension of which is smaller than the distance between adjacent dividing lines on the light-transmitting fabric 8. The lux meter 10 is currently widely used in various industries, such as lighting engineering, architectural design, plant growth, and indoor and outdoor lighting environment assessment. It is acquired through purchase, and its structure and function will not be described in detail.

[0023] Measurement operation method: Step S1, Preparation before measurement: Pour clean water into the glass graduated cylinder 5 until the water level is flush with the upper edge of the opaque film 6 and the light-transmitting cloth 8; place the glass graduated cylinder 5 in the graduated cylinder position marking area on the support base plate 1, so that the light-transmitting surface (i.e., the left side wall) of the glass graduated cylinder 5 is in close contact with the open opening (i.e., the right side) of the opaque dark box 4; slowly lower the opaque top plate assembly 7 until the T-shaped bracket falls on the cylinder opening wall of the glass graduated cylinder 5, at which point the top plate just touches the liquid surface inside the cylinder; Turn on LED lighting source 2 and turn off all other indoor light sources. Attach the photosensitive probe of illuminance meter 10 to the surface of the light-transmitting cloth 8. Measure and record the illuminance values ​​in the area between adjacent dividing lines from top to bottom. When the range of all illuminance data is less than 3% of the average value, record the average value h of the illuminance meter 10 readings. w If the range of all illuminance data is greater than or equal to 3% of the average value, the cause should be investigated and the device adjusted. After adjustment, repeat the above operation until the range of all illuminance data is less than 3% of the average value. Remove the opaque top plate assembly 7, pour out the water from the glass measuring cylinder 5, wipe the water off the inner wall of the glass measuring cylinder 5 with a paper towel, and place the glass measuring cylinder 5 back on the measuring cylinder position marking area on the support base plate 1 so that the light-transmitting surface of the glass measuring cylinder 5 is tightly fitted with the open opening of the opaque dark box 4.

[0024] Step S2, Measurement: Collect mud slurry 9 at the hatch of the trailing suction hopper, bring the mud slurry 9 back to the room, stir it thoroughly, and then pour it into the glass measuring cylinder 5 until the liquid level of the mud slurry 9 is level with the upper edge of the light-transmitting cloth 8. Stir the mud 9 in the glass graduated cylinder 5 thoroughly. After the liquid surface returns to calm, place the opaque top plate assembly 7 until the T-shaped bracket falls on the cylinder wall of the glass graduated cylinder 5. At this time, the top plate just touches the liquid surface inside the cylinder. Turn on LED lighting source 2, turn off all other indoor light sources, start a stopwatch and record the time as 0, attach the photosensitive probe of illuminance meter 10 to the surface of the light-transmitting cloth 8, and measure the illuminance value from top to bottom in the area between adjacent dividing lines, recording the illuminance data h. 0,j Where j is the number of the light-transmitting fabric partition and j = 1, 2, 3, ..., n; When the stopwatch reaches 5 min, 15 min, 30 min, 90 min, and 180 min, the illuminance value is measured again following the aforementioned procedure, and the illuminance meter reading h is recorded respectively. 5,j h 15,j h 30,j h 90,j and h 180,j , where j is the number of the light-transmitting fabric partition and j=1,2,3....n.

[0025] Step S3, Calculation of sedimentation characteristic indicators: First, calculate the sum of the illuminance meter readings for each zone at time 0, using the following formula: ; Secondly, calculate the absolute value of the difference between the illuminance meter readings of each zone at time t and the readings at time 0, using the following formula: ; Next, the sum of the differences in illuminance meter readings for each zone at time t is calculated using the following formula: ; Finally, the mud settling coefficient at time t is defined and calculated using the following formula: .

[0026] The following example illustrates the calculation method for the precipitation coefficient, a specific indicator of precipitation characteristics.

[0027] The glass measuring cylinder 5 has dimensions of 15×15×40cm. The light-transmitting cloth 8 has a width of 14cm and a height of 30cm. The light-transmitting cloth 8 is divided into 10 layers by dividing lines, and the height of each layer is 3cm. The diameter of the photosensitive probe of the illuminance meter 10 is 2.5cm.

[0028] The sedimentation test data of the dredged silt, clay and fine sand by a 20,000 cubic meter (referring to the mud tank size) trailing suction hopper vessel, measured according to the above method, are recorded in Table 1 below: Table 1 Record of sedimentation test data for dredged soil serial number <![CDATA[h w ]]> <![CDATA[h 0,j ]]> <![CDATA[h 5,j ]]> <![CDATA[h 15,j ]]> <![CDATA[h 30,j ]]> <![CDATA[h 90,j ]]> <![CDATA[h 180,j ]]> 1 267 88 185 263 265 267 267 2 264 86 144 230 257 263 265 3 266 85 112 177 221 256 261 4 265 85 104 121 178 213 244 5 263 84 88 99 143 178 190 6 262 85 83 75 89 112 133 7 263 84 77 52 32 23 20 8 264 83 65 43 26 16 9 9 264 82 53 32 17 6 4 10 265 82 43 20 7 3 3 Summation 2643 844 954 1112 1235 1337 1396 The calculated value is H0 = 844.

[0029] The calculation of precipitation test data at each time point is shown in Table 2 below: Table 2 Data Calculation Table for Each Time Point serial number <![CDATA[Δh 5,j ]]> <![CDATA[Δh 15,j ]]> <![CDATA[Δh 30,j ]]> <![CDATA[Δh 90,j ]]> <![CDATA[Δh 180,j ]]> 1 97 175 177 179 179 2 58 144 171 177 179 3 27 92 136 171 176 4 19 36 93 128 159 5 4 15 59 94 106 6 2 10 4 27 48 7 7 32 52 61 64 8 18 40 57 67 74 9 29 50 65 76 78 10 39 62 75 79 79 <![CDATA[Sum ΔH t > 300 656 889 1059 1142 <![CDATA[Precipitation system F t > 0.36 0.78 1.05 1.25 1.35 Measurement conclusion: The sedimentation coefficient F5 at 5 min was 0.36; the sedimentation coefficient F at 15 min was... 15 =0.78; 30min sedimentation coefficient F 30 =1.06; 90min sedimentation coefficient F 90 =1.25; 180min sedimentation coefficient F 180 =1.35. Correspondingly, actual measurements from the project show that the loading capacity of a 20,000 cubic meter trailing suction hopper dredger is 500 cubic meters in 5 minutes, 2,000 cubic meters in 15 minutes, 4,500 cubic meters in 30 minutes, 6,000 cubic meters in 90 minutes, and 8,000 cubic meters in 180 minutes.

[0030] The above data will be recorded in the database for predicting the production efficiency of the trailing suction hopper in subsequent projects, and the loading time of the trailing suction hopper will be adjusted and optimized accordingly.

[0031] Specifically, in the aforementioned experiments, a relationship curve between the sedimentation coefficient and the loading capacity can be established based on the data. The trailing suction hopper (LTH) production efficiency = loading capacity / LDH construction cycle. The LDH construction cycle = loading time + travel time to the dumping site + dumping time + return time to the loading site. Therefore, this relationship curve can also be converted into the relationship between the LDH production efficiency and the sedimentation coefficient. For short-distance dumping scenarios (e.g., 1 km), there is an optimal solution for the LDH production efficiency based on the loading capacity. In other words, for short-distance dumping scenarios, a suitable loading capacity will maximize the aforementioned LDH production efficiency.

[0032] In subsequent project construction, the sedimentation characteristics measuring device of this dredged soil was used to measure the sedimentation coefficient of the collected mud samples. The obtained sedimentation coefficients were substituted into the aforementioned relationship curve to obtain multiple trailing suction hopper production efficiency values. For the project, the production efficiency of the trailing suction hopper should be maximized. Therefore, the loading volume corresponding to the sedimentation coefficient that maximizes the production efficiency value of the trailing suction hopper should be selected. Since loading time = loading volume / loading flow rate, it can provide guidance for the optimal loading time of the current project, making the construction process more reasonable.

Claims

1. A device for measuring the sedimentation characteristics of dredged soil based on illumination, characterized in that: The device includes an opaque dark box (4), with an open right side. A rectangular, planar LED lighting source (2) is installed on the left side of the inner cavity of the opaque dark box (4). Multiple longitudinally spaced opaque partitions (3) are arranged vertically on the right side of the inner cavity of the opaque dark box (4). A rectangular, open-topped glass measuring cylinder (5) is placed in front of the opaque dark box (4). Opaque films (6) are installed on the front and back walls of the glass measuring cylinder (5), and a light-transmitting cloth (8) is installed on the right side wall. (8) has the same height as the opaque dark box (4). The upper edge of the light-transmitting cloth (8) is at the same height as the upper edge of the opaque film (6). Multiple dividing lines are provided on the light-transmitting cloth (8) from top to bottom, and each dividing line is horizontally aligned with each opaque partition (3). It also includes an opaque top plate assembly (7), which includes a top plate with the same outline shape as the cross-sectional outline shape of the inner cavity of the glass measuring cylinder (5). When the top plate is placed into the inner cavity of the glass measuring cylinder (5), it is flush with the upper edge of the opaque film (6). It also includes a lux meter (10).

2. The light-based dredged soil sedimentation characteristic measuring device as described in claim 1, characterized in that: The opaque top plate assembly (7) also includes a T-shaped bracket. The lower end of the vertical rod of the T-shaped bracket is fixedly connected to the center of the top plate. When the top plate is placed into the inner cavity of the glass measuring cylinder (5), the end of the horizontal rod of the T-shaped bracket overlaps the cylinder wall of the glass measuring cylinder (5).

3. The light-based dredged soil sedimentation characteristic measuring device as described in claim 2, characterized in that: It also includes a horizontal support base plate (1), and the bottom of the opaque dark box (4) is fixed on the support base plate (1); On the supporting base plate (1), in front of the opaque dark box (4), there is a graduated cylinder position marking area, and the glass graduated cylinder (5) is placed in the graduated cylinder position marking area.

4. The light-based dredged soil sedimentation characteristic measuring device as described in claim 3, characterized in that: The illuminance meter (10) has a cylindrical photosensitive probe, the radial dimension of which is smaller than the distance between adjacent dividing lines on the light-transmitting cloth (8).

5. The measurement method of the illumination-based dredged soil sedimentation characteristic measuring device as described in any one of claims 1 to 4, characterized in that: Including the following step, Step S1, Preparation before measurement: Pour clean water into the glass graduated cylinder (5) until the water level is flush with the upper edge of the opaque film (6) and the transparent cloth (8); place the glass graduated cylinder (5) on the graduated cylinder position marking area on the support base plate (1) so that the transparent surface of the glass graduated cylinder (5) is in close contact with the open opening of the opaque dark box (4); slowly lower the opaque top plate assembly (7) until the T-shaped bracket falls on the cylinder wall of the glass graduated cylinder (5), at which point the top plate just touches the liquid surface inside the cylinder; Turn on the LED lighting source (2), turn off all other indoor light sources, attach the photosensitive probe of the illuminance meter (10) to the surface of the light-transmitting cloth (8), measure and record the illuminance values ​​in the area between adjacent dividing lines from top to bottom, and record the average value h of the illuminance meter (10) readings when the range of all illuminance data is less than 3% of the average value. w If the range of all illuminance data is greater than or equal to 3% of the average value, the cause should be investigated and the device adjusted. After adjustment, repeat the above operation until the range of all illuminance data is less than 3% of the average value. Take out the opaque top plate assembly (7), pour out the water in the glass measuring cylinder (5), wipe the water off the inner wall of the glass measuring cylinder (5) with a paper towel, and place the glass measuring cylinder (5) back in the measuring cylinder position marking area so that the light-transmitting surface of the glass measuring cylinder (5) is tightly fitted with the open opening of the opaque dark box (4). Step S2, Measurement: Collect mud (9) at the hatch of the trailing suction hopper, bring the mud (9) back to the room, stir it thoroughly and pour it into the glass measuring cylinder (5) until the surface of the mud (9) is level with the upper edge of the light-transmitting cloth (8); Stir the mud (9) in the glass graduated cylinder (5) thoroughly. After the liquid surface returns to calm, place the opaque top plate assembly (7) until the T-shaped bracket falls on the cylinder wall of the glass graduated cylinder (5). At this time, the top plate just touches the liquid surface inside the cylinder. Turn on the LED lighting source (2), turn off all other indoor light sources, start the stopwatch to record the time as 0, attach the photosensitive probe of the illuminance meter (10) to the surface of the light-transmitting cloth (8), measure the illuminance value from top to bottom in the area between adjacent dividing lines, and record the illuminance data h. 0,j Where j is the number of the light-transmitting fabric partition and j = 1, 2, 3, ..., n; When the stopwatch reaches 5 min, 15 min, 30 min, 90 min, and 180 min, the illuminance value is measured again following the aforementioned procedure, and the illuminance meter reading h is recorded respectively. 5,j h 15,j h 30,j h 90,j and h 180,j Where j is the number of the light-transmitting fabric partition and j = 1, 2, 3, ..., n; Step S3, Calculation of sedimentation characteristic indicators: First, calculate the sum of the illuminance meter readings for each zone at time 0, using the following formula: ； Secondly, calculate the absolute value of the difference between the illuminance meter readings of each zone at time t and the readings at time 0, using the following formula: ； Next, the sum of the differences in illuminance meter readings for each zone at time t is calculated using the following formula: ； Finally, the mud settling coefficient at time t is defined and calculated using the following formula: 。

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