A visual soil-rock mixture bank slope seepage erosion monitoring system and method

Abstract

A visualized soil-rock mixture reservoir bank slope seepage erosion monitoring system and method, a landslide simulation device is provided with a soil-rock mixture interlayer inside, a nozzle is provided above the soil-rock mixture interlayer, a permeable concrete cover layer is arranged on the upper part of the soil-rock mixture interlayer, a slide bed is arranged at the lower part of the soil-rock mixture interlayer, and a guide pipe is provided at the lowest part of the soil-rock mixture interlayer; a weighing device is connected to the guide pipe of the landslide simulation device through a tightening ring, a support frame is placed on a weighing sensor, a filter bag is arranged below the tightening ring, and a water storage bucket is arranged outside the filter bag. The weighing sensor is connected to a recording and display system. A high-speed camera shoots and records in real time. The visualized soil-rock mixture reservoir bank slope seepage erosion monitoring system and method of the present invention can effectively monitor the seepage erosion in real time from the internal cross section of the bank slope; it also integrates monitoring and evaluation, and is suitable for indoor laboratory environments.

Description

Technical Field

[0001] The present invention relates to the technical field of simulated landslide erosion monitoring, and in particular to a visualized soil-rock mixture bank slope seepage erosion monitoring system and method. Background Art

[0002] Since the Three Gorges Project began to store water, landslides have occurred frequently on the reservoir banks. These landslides can be divided into rock landslides and soil landslides according to the materials used. Among them, soil-rock mixed landslides are a special type of soil landslides and are widely found in the Three Gorges Reservoir area. Figure 1 As shown in the figure, soil-rock mixture is a loose rock medium composed of boulders of different sizes and clay, with typical heterogeneity, non-uniformity and discontinuity. The clay filling between the boulders is crucial to the deformation stability of the soil-rock mixture. On the one hand, it bonds boulders of different sizes together, and on the other hand, it can play a role in preventing seepage.

[0003] After the completion of the Three Gorges Project, the reservoir water level rose by more than 100 meters. In addition, according to the flood control operation and scheduling requirements, the reservoir water level fluctuates periodically between the flood control level of 145m and the water storage and power generation level of 175m, and is often accompanied by heavy rain and extreme rain. Under the influence of these complex factors, soil-rock mixtures are prone to erosion, such as Figure 2 As shown in the figure, a large amount of clay particles filling between the boulders are lost, resulting in the deterioration of the physical and mechanical properties of the soil-rock mixture, which in turn directly affects the deformation stability of the soil-rock mixture slope.

[0004] In order to simulate and analyze the deformation stability evolution law of reservoir bank slope under complex conditions, the researchers designed relevant test equipment, but mainly used the landslide model test method to simulate the deformation and destruction process of the landslide. During the test, the deformation, stress, pore water pressure and other parameters of the slope were monitored and analyzed. The erosion monitoring equipment and quantitative evaluation indicators of the relevant soil-rock mixture have not been reported. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a visualized soil-rock mixture reservoir bank slope seepage erosion monitoring system and method, which can effectively monitor the seepage erosion from the internal cross-section of the slope in real time; at the same time, it integrates monitoring and evaluation, and is suitable for indoor laboratory environments.

[0006] The technical solution adopted by the present invention is:

[0007] A visualized soil-rock mixture bank slope seepage erosion monitoring system, the system comprising:

[0008] Landslide simulation device, weighing device, recording and display system;

[0009] The landslide simulation device has a soil-rock mixture interlayer inside, a sprinkler is arranged above one side of the soil-rock mixture interlayer, a permeable concrete cover layer is arranged on the upper part of the soil-rock mixture interlayer, a slide bed is arranged at the lower part of the soil-rock mixture interlayer, and a diversion pipe is arranged at the lowest part of the soil-rock mixture interlayer;

[0010] The weighing device includes a support and a water storage bucket; the weighing device is connected to the guide pipe of the landslide simulation device through a tightening ring arranged on the support frame, the support frame is placed on the weighing sensor, a filter bag is arranged below the tightening ring, a water storage bucket is arranged outside the filter bag, and the water storage bucket is placed on the support.

[0011] The weighing sensor is connected to the recording and display system, which is used to record the pore development process in the interlayer of the soil-rock mixture and use the global threshold Otsu method to perform image binarization processing.

[0012] The system also includes a high-speed camera, which is used to monitor the surface of the soil-rock mixture interlayer in the landslide simulation device.

[0013] The landslide simulation device comprises an observation wall made of transparent material, and the landslide simulation device is placed on a frame with running wheels.

[0014] The nozzle is arranged in an open water tank whose bottom is made of permeable stone.

[0015] The nozzle is connected to a spray system, and the spray system can control the switch of the nozzle and the flow rate and flow velocity of water in the nozzle, and the height position can be adjusted manually.

[0016] There are multiple guide pipes, and the guide pipes are supported by support rods arranged on the outer wall of the landslide simulation device.

[0017] The water storage barrel is provided with a drain pipe.

[0018] The present invention provides a visualized soil-rock mixture bank slope seepage erosion monitoring system and method, and the technical effects are as follows:

[0019] (1): Seepage erosion often occurs inside the bank slope. In order to visualize it and monitor the pore development process throughout, transparent materials such as plexiglass are used as observation walls, so that the internal seepage erosion can be better monitored and the study of pore evolution can be visualized. In addition, the thickness and material of the overlying material of the soil-rock mixture interlayer can be changed, which can simulate the influence of different overlying rock stress on the seepage erosion evolution law of the soil-rock mixture interlayer; the position of the nozzle can be adjusted, and the water flow and flow rate can be controlled, which can simulate more complex situations, such as seepage erosion under different overlying rock stress, seepage erosion under the coupling of rainfall and water level rise and fall, etc.

[0020] Therefore, the system of the present invention can well simulate the erosion process of soil-rock mixture under the single factor or multiple factor coupling effects such as groundwater level change, reservoir water level rise and fall, rainfall and overlying rock stress.

[0021] (2): The present invention uses a weighing sensor and a recording and display system to monitor the entire seepage erosion process. The real-time clay mass transmitted by the weighing sensor is used to calculate the mass loss rate of the clay.

[0022] (4) The present invention sets a high-speed camera and uses the global threshold Otsu method image processing technology to perform binarization processing on the microstructure image of the soil-rock mixture, so as to facilitate the observation and monitoring of the pore evolution law and the subsequent calculation of the erosion rate.

[0023] (5) The present invention combines a weighing sensor, a recording and display system, and a global threshold Otsu method image processing system to achieve macroscopic clay mass loss and microscopic soil erosion monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a diagram of the soil-rock mixture before erosion.

[0025] Figure 2 It is a mixture of soil and rock after erosion.

[0026] Figure 3(a) is a grayscale image of the soil-rock mixture before erosion;

[0027] Figure 3(b) is the binarized image of Figure 3(a).

[0028] Figure 4(a) is a grayscale image of the soil-rock mixture after erosion;

[0029] Figure 4(b) is the binarized image of Figure 4(a).

[0030] Figure 5 It is an overall schematic diagram of the seepage erosion monitoring system of the present invention;

[0031] Figure 6 It is an enlarged schematic diagram of the sprinkler head and the soil-rock mixture interlayer of the system of the present invention.

[0032] Figure 7 It is a schematic diagram of water level rise and fall erosion monitoring of the system of the present invention.

[0033] Figure 8 This is a schematic diagram of the water level rise and fall erosion monitoring area of ​​the system of the present invention.

[0034] Fig. 9 It is a schematic diagram of slope rainfall erosion monitoring of the system of the present invention.

[0035] Fig.10 It is a schematic diagram of the weighing device in the present invention. DETAILED DESCRIPTION

[0036] like Figure 5 As shown, a visualized soil-rock mixture bank slope seepage erosion monitoring system includes a landslide simulation device 1, a weighing device 2, a recording and display system 4, and a high-speed camera 5. The weighing device 2 is connected to a weighing sensor 3, and the weighing sensor 3 is connected to the recording and display system 4.

[0037] The weighing sensor 3 can adopt the Spato sensor. The original output signal of the sensor is about 0-2mv / v. Normally, a transmitter or display is required to convert this millivolt signal into a digital communication signal RS232, RS485, and then connect it to the computer via USB.

[0038] The recording and display system 4 can use software developed by Sparto Corporation to connect to a computer to collect data. It can be used by connecting to a computer via USB, or it can send data to a computer via WiFi or Bluetooth to collect data.

[0039] The landslide simulation device 1 includes an observation wall 6 made of transparent material, such as organic glass, and the landslide simulation device 1 is placed on a frame 7 with running wheels. A regular soil-rock mixture interlayer 8 is arranged in the landslide simulation device 1, and a nozzle 9 is arranged at the upper left entrance position of the soil-rock mixture interlayer 8. By controlling the flow rate and flow rate of water in the nozzle 9, the change of groundwater level is simulated. The nozzle 9 is placed in an open water tank 11 with a permeable stone 10 at the bottom. The open water tank 11 can store water, and the permeable stone 10 has good permeability. Due to the change of its own gravity, the water continuously seeps downward freely through the permeable stone 10 at the bottom, thereby simulating the change of groundwater level in the natural state.

[0040] A slide bed 12 made of concrete or other materials with a corresponding angle is arranged below the soil-rock mixture interlayer 8, and a permeable concrete cover layer 13 is arranged above the soil-rock mixture interlayer 8. A plurality of guide pipes 14 are arranged on the lowest observation wall of the soil-rock mixture interlayer 8, and the guide pipes 14 are supported by support rods 15 arranged on the outer wall of the landslide simulation device 1, and the support rods 15 are used to prevent the weight of the guide pipes 14 from pressing on the support frame 16 of the weighing device 2 to affect the weighing accuracy. The soil-rock mixture interlayer 8 of the entire bank slope is monitored.

[0041] The weighing device 2 is connected to the guide pipe 14 of the landslide simulation device 1 through the tightening ring 17 on the support frame 16. The tightening ring 17 can fix the filter bag 18 firmly and conveniently.

[0042] The support frame 16 is placed on the weighing sensor 3; a filter bag 18 is arranged below the tightening ring 17, a water storage bucket 19 is arranged outside the filter bag 18, the water storage bucket 19 is placed on the support 20, and a drain pipe 21 is arranged at 4 / 5 of the height of the water storage bucket 19, so that water above the 4 / 5 water level line can be discharged in time.

[0043] The filter bag 18 is used to collect clay particles flowing out of the guide tube 14, and water can flow freely inside and outside.

[0044] The water storage barrel 19 is used to hold water at a certain water level, and a drainage pipe 21 is provided at the water level, so that the water storage barrel 19 can discharge water above the water level in time, so that the water quality in the barrel is maintained within a certain range, that is, the buoyancy of the water is basically maintained unchanged, reducing the impact on the weighing of the clay quality.

[0045] The weight borne by the weighing sensor 3 is the weight of the support frame 16, the tightening ring 17 and the filter bag 18. The weight can be reset before use to obtain the mass of the clay. The drainage pipe 21 can ensure that the water level in the water storage bucket 19 is maintained at 4 / 5 of the bucket height, reducing the influence of the buoyancy of the water on the quality of the clay.

[0046] The high-speed camera 5 is an i-SPEED726 high-speed camera with a maximum shooting frequency of 1,000,000 times / s. The high-speed camera 5 is used to monitor the observation surface of the soil-rock mixture interlayer 8 in the device.

[0047] The switch of the nozzle 9 and the flow rate and flow rate of the water in the nozzle can be controlled by the spray system, and the height position can be adjusted manually.

[0048] When simulating groundwater level changes, Figure 5 As shown, the flow rate can be set from 0L / s to 0.1L / s.

[0049] like Figure 7 As shown, a sprinkler 9 is arranged below the water level line H1 at the lower right of the soil-rock mixture interlayer 8, and the flow rate and velocity of the water in the sprinkler 9 are controlled. When simulating the rise and fall of the reservoir water level, a sprinkler is first lowered to the H1 water level line. The actual situation is that the reservoir water level rises at a rate of 0.8 m / d for about 30 days, and then the reservoir water level runs at a high water level of 175 m for about 90 days; the reservoir water level slowly drops at a rate of 0.13 m / d for about 60 days, and then the reservoir water level runs at a water level of 165 m for about 30 days; the reservoir water level drops rapidly at a rate of 0.6 m / d for about 30 days, and then the reservoir water level maintains a low water level of 145 m for 120 days.

[0050] like Figure 8 As shown, the locations where the soil-rock mixture on the bank slope is affected by the changes in water level are selected for monitoring.

[0051] like Fig. 9As shown in , a soil-rock mixture interlayer 8 is arranged in the landslide simulation device 1, and a row of nozzles 9 are arranged at the movable frame position above the soil-rock mixture interlayer 8. By controlling the flow rate and flow rate of water in the nozzles 9, rainfall is simulated to monitor the soil-rock mixture of the entire slope. When simulating the rise and fall of reservoir water level, simulation can be carried out according to one's own test plan. When simulating rainfall, the actual rainfall intensity ranges from light rain 10mm / d to heavy rain 125.56mm / d once in 10 years. During the test, simulation can be carried out according to one's own test plan, for example: spraying water evenly on the surface of the soil-rock mixture slope at an intensity of 70mm / d for 2h to simulate heavy rain. When simulating the stress of the overlying rock strata: the stress magnitude of different overlying rock strata is simulated by changing the thickness of the overlying rock strata, i.e., the permeable concrete cover 13.

[0052] A real-time monitoring method for seepage erosion of a soil-rock mixture is disclosed. When making a model, the mass of dry clay is first weighed, and then clay and block stones are mixed in a certain ratio (6:4-7:3) and evenly arranged on a slide bed 12, and a permeable concrete cover layer 13 of corresponding thickness is arranged according to different stress conditions.

[0053] When seepage erosion occurs in the landslide simulation device 1, the weighing device 2 can obtain the mass of clay lost due to erosion of the soil-rock mixture interlayer 8. The mass of clay measured by the weighing sensor 3 is transmitted to the recording and display system 4 through the data line 22. The mass loss of clay particles is judged by the mass of soil appearing in the recording and display system 4.

[0054] The mass loss rate is used to evaluate the mass loss degree of clay:

[0055]

[0056] Where: M t is the clay mass loss rate at time t, m s is the mass of clay particles before erosion, is the mass of soil in water at time t after erosion, that is, the real-time data during the erosion process after the weighing sensor 3 is reset.

[0057] When the landslide simulation device 1 simulates the erosion process of the soil-rock mixture under the coupling of single factors or multiple factors such as groundwater level changes, reservoir water level changes, rainfall and overlying rock stress, the high-speed camera 5 can capture and record the pore development process in the interlayer 8 of the soil-rock mixture, and use the global threshold Otsu method to perform image binarization processing.

[0058] Using erosion rate N t Evaluation of soil erosion:

[0059]

[0060]

[0061] N t =n t -n0;

[0062] Where: n0 is the initial porosity, is the original pore area of ​​the sample, S is the original surface area of ​​the sample; n t is the porosity at time t, is the area of ​​the pore at time t, N t is the erosion rate at time t. In actual operation, the image taken by the high-speed camera at time t is imported into Matlab software for processing. Through image monitoring and analysis, the erosion evolution law of different areas of soil-rock mixture under different test conditions and at different times can be obtained.

[0063] Global Threshold Otsu Method:

[0064] The Otsu method (maximum inter-class variance method) is an adaptive threshold determination method. It uses the idea of ​​clustering, divides the grayscale of the image into two parts according to the grayscale level, so that the grayscale value difference between the two parts is the largest, and the grayscale difference between each part is the smallest, and finds a suitable grayscale level for division by calculating the variance. Therefore, the Otsu algorithm can be used to automatically select the threshold for binarization during binarization. The Otsu algorithm is considered to be the best algorithm for threshold selection in image segmentation. It is simple to calculate and is not affected by image brightness and contrast. Therefore, the segmentation that maximizes the inter-class variance means the minimum probability of misclassification.

[0065] Import the original image into Matlab and use the rgb2gray() function to convert the image into a grayscale image to facilitate subsequent calculations and processing. Then use the graythresh() function in Matlab to find the appropriate threshold level for the image. This threshold is in the range of [0,1] and can be passed to im2bw to complete the conversion of the grayscale image into a binary image. This threshold is usually better than the manually set threshold to convert a grayscale image into a binary image. As shown in Figure 3(a) and Figure 3(b), the grayscale image of the soil-rock mixture is converted into a binary image, where the white area is soil and stone blocks, and the black area is pores. According to the method described above, the porosity is calculated to be 9.31%.

[0066] FIG4(a) and FIG4(b) are typical photos of soil-rock mixture after erosion. The calculated porosity is 16.13%. Assuming that the porosity before erosion is 0%, the corresponding erosion rate is 16.13%-0%=16.13%.

[0067] Implementation steps:

[0068] First, install the landslide simulation device 1;

[0069] When seepage erosion occurs in the landslide simulation device 1, the weighing device 2 arranged outside can obtain the mass of soil lost due to erosion of the soil-rock mixture interlayer 8. The mass of clay measured by the weighing sensor 3 is transmitted to the recording and display system 4 through the data line 22. The mass of the soil appearing in the recording and display system 4 is used to judge the mass loss of the clay.

[0070] A high-speed camera 5 is arranged outside the landslide simulation device 1 , and the high-speed camera 5 is used to monitor the observation surface of the soil-rock mixture interlayer 8 in the landslide simulation device 1 .

[0071] When the landslide simulation device 1 simulates the erosion process of the soil-rock mixture under the coupling of single factors or multiple factors such as groundwater level changes, reservoir water level changes, rainfall and overlying rock stress, the high-speed camera 5 can capture and record the pore development process in the interlayer of the soil-rock mixture, and use the global threshold Otsu method to perform image binarization processing to facilitate subsequent calculations and evaluations.

[0072] Combining the landslide simulation device 1, the weighing device 2, and the high-speed camera 5, it is possible to better simulate the seepage erosion of the bank slope under various complex conditions, and at the same time more intuitively monitor the seepage erosion process inside the bank slope, and evaluate the seepage erosion process through image processing and calculation, so as to achieve the purpose of real-time monitoring.

Claims

1. A visual soil-rock mixture bank slope seepage erosion monitoring system, characterized in that The system includes: Landslide simulation device (1), weighing device (2), recording and display system (4); The landslide simulation device (1) is provided with a soil-rock mixture interlayer (8) inside, a nozzle (9) is provided above one side of the soil-rock mixture interlayer (8), a permeable concrete covering layer (13) is arranged above the soil-rock mixture interlayer (8), a slide bed (12) is arranged below the soil-rock mixture interlayer (8), and a guide pipe (14) is provided at the lowest point of the soil-rock mixture interlayer (8); The weighing device (2) comprises a support (20) and a water storage bucket (19); The weighing device (2) is connected to the guide pipe (14) of the landslide simulation device (1) through a tightening ring (17) arranged on a support frame (16); the support frame (16) is placed on the weighing sensor (3); a filter bag (18) is arranged below the tightening ring (17); a water storage bucket (19) is arranged outside the filter bag (18); and the water storage bucket (19) is placed on a support (20); The weighing sensor (3) is connected to a recording and display system (4), and the recording and display system (4) is used to record the pore development process in the soil-rock mixture interlayer (8); The mass loss rate is used to evaluate the mass loss degree of clay: Where: M t is the clay mass loss rate at time t, m s is the mass of clay particles before erosion, is the mass of soil in water at time t after erosion, i.e., the real-time data during the erosion process after the weighing sensor (3) is reset; Using erosion rate N t Evaluation of soil erosion: A t =n t -n0; Where: n0 is the initial porosity, is the original pore area of ​​the sample, S is the original surface area of ​​the sample; n t is the porosity at time t, is the area of ​​the pore at time t, N t is the erosion rate at time t.

2. According to claim 1, a visualized soil-rock mixture bank slope seepage erosion monitoring system is characterized by: The system also includes a high-speed camera (5), which is used to monitor the surface of the soil-rock mixture interlayer (8) in the landslide simulation device (1).

3. According to claim 1, a visualized soil-rock mixture bank slope seepage erosion monitoring system is characterized by: The landslide simulation device (1) comprises an observation wall (6) made of a transparent material. The landslide simulation device (1) is placed on a frame (7) with running wheels.

4. According to claim 1, a visualized soil-rock mixture bank slope seepage erosion monitoring system is characterized by: The nozzle (9) is arranged in an open water tank (11) whose bottom is a permeable stone (10).

5. According to claim 4, a visualized soil-rock mixture bank slope seepage erosion monitoring system is characterized by: The spray head (9) is connected to a spray system, and the spray system can control the switch of the spray head (9) and the flow rate and flow velocity of water in the spray head.

6. According to claim 1, a visualized soil-rock mixture bank slope seepage erosion monitoring system is characterized by: There are a plurality of guide pipes (14), and the guide pipes (14) are supported by support rods (15) arranged on the outer wall of the landslide simulation device (1).

7. According to claim 1, a visualized soil-rock mixture bank slope seepage erosion monitoring system is characterized by: The water storage barrel (19) is provided with a drainage pipe (21).

8. A real-time monitoring method for seepage erosion of soil-rock mixture using a monitoring system according to any one of claims 1 to 7, characterized in that: First, the mass of dry clay is weighed, and then the clay and stone blocks are mixed and evenly arranged on the slide bed (12), and a permeable concrete cover layer (13) of corresponding thickness is arranged according to different stress conditions; When seepage erosion occurs in the landslide simulation device (1), the weighing device (2) can obtain the mass of clay lost due to erosion of the soil-rock mixture interlayer (8). The mass of clay measured by the weighing sensor (3) is transmitted to the recording and display system (4). The mass loss of clay particles is determined by the mass of soil appearing in the recording and display system (4).

9. A real-time monitoring method for seepage erosion of soil-rock mixture using a monitoring system as claimed in any one of claims 1 to 7, characterized in that: When the landslide simulation device (1) simulates the erosion process of the soil-rock mixture under the single factor or multiple factors of the coupling effect of the change of groundwater level, the rise and fall of reservoir water level, rainfall and the stress of the overlying rock layer, the high-speed camera (5) shoots and records the pore development process in the interlayer (8) of the soil-rock mixture, and uses the global threshold Otsu method to perform image binarization processing; Using erosion rate N t To evaluate the soil erosion situation, in actual operation, the pictures taken by the high-speed camera at time t can be imported into Matlab software for processing; through image monitoring and analysis, the erosion evolution laws of different areas of the soil-rock mixture under different test conditions and at different times can be obtained.

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