Non-contact monitoring method suitable for seepage flow of long-distance large-flow causeway drainage ditch

Abstract

The invention belongs to the field of large seepage flow monitoring, and particularly provides a long-distance large-flow causeway drainage ditch seepage flow non-contact monitoring method which comprises the steps that drainage ditch seepage flow monitoring section size and elevation are rechecked, and accurate monitoring section size and elevation data are obtained; a flow velocity meter method is adopted to measure the flow velocity of each monitoring section of the drainage ditch, and the roughness of the Manning formula at each monitoring section is calibrated; the unmanned aerial vehicle flies to collect a water gauge high-definition image of each monitoring section of the drainage ditch, and the water depth of each monitoring section is identified through the image; calculating the hydraulic radius of each monitoring section according to the water depth of each monitoring section, and calculating the flow velocity of each monitoring section by combining with a calibrated Manning formula; and calculating to obtain the seepage flow of each monitoring section. According to the method, the problems of time and labor consumption and high cost of the current common flow velocity meter method are solved.

Description

Technical Field

[0001] The invention belongs to the field of seepage monitoring, and in particular relates to a non-contact monitoring method for seepage in a drainage ditch with a long distance and a large flow rate. Background Art

[0002] After the water retaining structures of the reservoir are filled with water, seepage will inevitably occur. When the seepage is in a stable state, its seepage volume will maintain a stable response change with the size of the water head. A significant increase or decrease in the seepage volume under the same water head means the destruction of the stability of the seepage. A significant increase in the seepage volume may cause pipe bursts or concentrated leakage channels in the dam body or dam foundation; a significant decrease in the seepage volume may be a reflection of the blockage of the drainage pump. Therefore, monitoring the seepage volume is of great significance for judging whether the seepage is stable and understanding whether the anti-seepage and drainage facilities are working normally.

[0003] At present, the main methods for monitoring seepage flow are volumetric method, water weir method and flow velocity method. The volumetric method is suitable for the case where the seepage flow is less than 1 L / s; the water weir method is suitable for the case where the seepage flow is 1~300 L / s; when the seepage flow is greater than 300 L / s, the flow velocity method is often used. The following methods are currently used to monitor the seepage flow of large-flow embankment drainage ditches: (1) Use the buoy method to monitor the surface flow velocity through the buoy v , and then combined with the monitoring cross-sectional area A and the surface velocity coefficient K , calculate the seepage volume of the monitoring section Q = KvA ; (2) Using the conventional flow meter method, the velocity at the typical position of the monitoring section is measured, and then the seepage of the monitoring section is calculated; (3) Using the Doppler flow meter method, the Doppler flow meter system is installed in the monitoring section to monitor the seepage of the section in real time. Obviously, when monitoring the seepage of multiple monitoring sections of long-distance and large-flow embankment drainage ditches, there are the following problems: (1) When using the buoy method and conventional flow meter method for monitoring, the workload is large, time-consuming and labor-intensive; (2) When using the Doppler flow meter method for monitoring, the cost is high and it is difficult for general projects to afford it. Therefore, it is urgent to invent a fast and economical monitoring method for the seepage of long-distance and large-flow embankment drainage ditches. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a non-contact monitoring method for seepage volume of a drainage ditch around a long-distance and large-flow dike, which solves the problem that the current commonly used flow meter method is time-consuming, labor-intensive and expensive.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a non-contact monitoring method for seepage volume of a long-distance and large-flow embankment drainage ditch, comprising the following steps: S1. Review the monitoring section size and elevation of the drainage ditch seepage flow to obtain accurate monitoring section size and elevation data; S2. Use the velocity meter method to measure the flow velocity of each monitoring section of the drainage ditch and calibrate the roughness of the Manning formula at each monitoring section; S3. During the operation and maintenance period, drones are used to collect high-definition images of the water level at each monitoring section of the drainage ditch, and the water depth of each monitoring section is identified through images; S4. Calculate the hydraulic radius of each monitoring section based on the water depth of each monitoring section, and calculate the flow velocity of each monitoring section using the calibrated Manning formula; S5. Calculate and obtain the seepage volume of each monitoring section.

[0006] In a preferred embodiment, step S1 includes the following steps: S101, selecting leveling base points and working base points for each monitoring section in turn, and performing elevation calibration; S102, measuring the elevations of the starting point, the end point, and the turning point of the drainage ditch in sequence; S103. Accurately measure the width, depth, bottom and slope of the key sections of the drainage ditch. i The bottom width of the drainage ditch measured at the monitoring section of the drainage ditch is b i The right slope is m 1i , the left slope is m 2i ; S104. Obtain the area below the water surface of each monitoring section A i With water depth The exact relationship is expressed as: (1).

[0007] In a preferred embodiment, in step S2, i The flow rate at the monitoring section of the drainage ditch is measured by a flow meter at a water depth of 0.5 times the water depth. v 0.5i , use a ruler to measure the water depth at the center of the monitoring section , repeatedly measure the flow rate v 0.5i , calculate the mean and variance of the velocity at the 0.5 times water depth measuring point, and then use the classic statistical test method KS method to perform a statistical test on the velocity to obtain the probability density function f ( v ), select the upper limit value corresponding to the set guarantee rate as the standard value of the flow velocity of the monitoring section [ v 0.5i], using the measured velocity standard value of 0.5 times the water depth of the monitoring section [ v 0.5i ] and the average flow velocity of the cross section v i The relationship v i = 0.83[ v 0.5i ], calibrate the roughness of Manning's formula n i , the operation is as follows: Manning's formula is: v i = R i 2 / 3 S i 1 / 2 / n i (2); Get the roughness n i The calibration formula is: n i = R i 2 / 3 S i 1 / 2 / (0.83[ v 0.5 ])(3); R i = A i / x i (4); (5); In the formula, S i For the i The slope of the monitoring section of each drainage ditch; R i For the i The hydraulic radius of the monitoring section of a drainage ditch, A i For the i The area below the water surface of the drainage ditch monitoring section is calculated according to formula (1), χ i For the i The wet perimeter of a drainage ditch monitoring section.

[0008] In a preferred embodiment, step S3 includes the following steps: S301, the remote-controlled drone steadily flies to the top of the water gauge of the slope of the seepage monitoring section, collects multiple infrared images and visible light images, and then flies to the top of the water gauge of the next drainage ditch monitoring section, repeats the operation, and collects infrared images and visible light images of the water gauges corresponding to multiple drainage ditch monitoring sections; S302, water depth identification of monitoring section: combining the water gauge scale and the collected infrared image and visible light image of the water gauge, analyzing and identifying the water gauge length under the water surface of each monitoring section at the time of collection l i , calculate the water depth at each monitoring section h i , the calculation formula is as follows: h i = l i / m 1i (6); Where: m 1i For the i The right slope rate measured in the monitoring section of the drainage ditch is m 1i .

[0009] In a preferred embodiment, in step S4, i The water depth of the monitoring section measured in step S3 is h i , according to formula (1), the area below the water surface of the monitoring section is calculated A i , the wetted perimeter of the monitored section is calculated by formula (5) χ i , and then the hydraulic radius of each monitoring section is calculated by formula (4) R i , then combined with i The slope of the monitoring section S i and the calibrated roughness n i , according to the calibrated Manning formula v i = R i 2 / 3 S i 1 / 2 / n i Calculate the first i The average flow velocity of the monitoring section v i .

[0010] In the preferred solution, in step S5, i The average flow velocity of the monitoring section v i and the area below the water surface of the monitoring section A i , calculate the seepage volume of each monitoring section, the calculation formula is: Q i = v i A i (7); In the formula, Q i It is the seepage volume of each monitoring section.

[0011] The present invention provides a non-contact monitoring method for seepage flow in a long-distance and large-flow embankment drainage ditch, which has the following beneficial effects: 1. In view of the problem that manual measurement is time-consuming and labor-intensive when monitoring long-distance and large-flow embankment drainage ditches due to complex on-site conditions, and manual measurement is dangerous in the face of deeper drainage ditches, it is proposed that only flow meters and rulers need to be used to measure flow velocity and water depth during calibration, and then the seepage volume is calculated, and then the roughness of the Manning formula is calibrated. During the operation and maintenance period, drones are used to collect high-definition photos of the water level of each monitoring section of the drainage ditch, which solves the problem of time-consuming and labor-intensive manual measurement.

[0012] 2. When monitoring the seepage volume of multiple monitoring sections of long-distance and large-flow embankment drainage ditches, there are problems such as large workload, time-consuming and labor-intensive use of conventional flow meters, and high cost of Doppler flow meters. A fast and economical monitoring method for seepage volume of long-distance and large-flow embankment drainage ditches based on the Manning formula is proposed, which solves the problem of time-consuming, labor-intensive and high cost of the currently commonly used flow meter method. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a technical roadmap of non-contact monitoring of seepage volume of long-distance and large-flow embankment drainage ditch of the present invention; Figure 2 Provide a flow chart for reviewing the cross-section dimensions and elevations for drainage ditch seepage monitoring; Figure 3 This is a comparison diagram of the original and verified cross-section dimensions of a typical monitoring section on the right bank; Figure 4 Take water gauge images for drones; Figure 5 Flowchart for drone flight monitoring. DETAILED DESCRIPTION

[0014] The total length of the earth-rock dam of a water conservancy hub in Central China is 18.6 kilometers, including the Gucheng earth-rock dam (4759 meters long), the main riverbed earth-rock dam (1251 meters long), the left bank dike of the old river channel (6184 meters long) and the right bank dike of the old river channel (6440 meters long). Drainage ditches are set up at the slopes of the earth-rock dam and the dike to collect the infiltration water of the reservoir through the dike and the foundation. To this end, one seepage flow monitoring section is set up in the drainage ditch of the Gucheng earth-rock dam, and seven seepage flow monitoring sections are set up in the drainage ditches of the left and right dikes. The measured values ​​show that the measured seepage flow values ​​of the monitoring sections of the drainage ditches of the left and right dikes are basically greater than 300L / s. The traditional buoy method is used for monitoring, which is labor-intensive; if the Doppler current meter method is used for monitoring, the cost is high.

[0015] Therefore, a non-contact monitoring method for seepage flow in long-distance and large-flow embankment drainage ditches is provided. Figure 1 As shown, the following steps are included: S1. Review the drainage ditch seepage monitoring section size and elevation to obtain accurate monitoring section size and elevation data, including the following steps: S101, selecting leveling base points and working base points for each monitoring section in turn, and performing elevation calibration; S102, measuring the elevations of the starting point, the end point, and the turning point of the drainage ditch in sequence; S103. Accurately measure the width, depth, bottom and slope of the key sections of the drainage ditch. i The bottom width of the drainage ditch measured at the monitoring section of the drainage ditch is b i The right slope is m 1i , the left slope is m 2i ; S104. Obtain the area below the water surface of each monitoring section A i With water depth The exact relationship is expressed as: (1).

[0016] In this embodiment, combined with the engineering design drawings and the actual situation on site, the cross-sectional dimensions and elevations of the typical monitoring sections of the right bank embankment drainage ditch at right 1+625 and right 2+300 were reviewed using tools such as a total station and a tape measure, and the bottom width of the drainage ditch monitoring section was measured. b The right slope is m 1, the left slope is m 2. Organize and record. The implementation steps are as follows Figure 2 shown.

[0017] The review results of two typical monitoring sections of the right bank embankment drainage ditch are shown in Table 1 and Appendix. Figure 3 .

[0018]

[0019] S2. Use the flow meter method to measure the flow velocity of each monitoring section of the drainage ditch and calibrate the roughness of the Manning formula at each monitoring section.

[0020] Specifically, for i The flow rate at the monitoring section of the drainage ditch is measured by a flow meter at a water depth of 0.5 times the water depth. v 0.5i , use a ruler to measure the water depth at the center of the monitoring section h , repeatedly measure the flow rate v 0.5i , calculate the mean and variance of the velocity at the 0.5 times water depth measuring point, and then use the classic statistical test method KS method to perform a statistical test on the velocity to obtain the probability density function f ( v ), select the upper limit value corresponding to the set guarantee rate as the standard value of the flow velocity of the monitoring section [ v 0.5i ] Specifically, the flow velocity at 0.5 times the water depth of the monitoring section is measured by the one-line-one-point method, that is, the survey line is arranged on a vertical line at the center of the drainage ditch, and one measuring point is arranged on this survey line, which is called the one-line-one-point method.

[0021] Using the measured velocity standard value of 0.5 times the water depth of the monitoring section [ v 0.5i ] and the average flow velocity of the cross section v i The relationship v i = 0.83[ v 0.5i ], calibrate the roughness of Manning's formula n i , the operation is as follows: Manning's formula is: v i = R i 2 / 3 S i 1 / 2 / n i (2); Get the roughness n i The calibration formula is: n i= R i 2 / 3 S i 1 / 2 / (0.83[ v 0.5 ])(3); R i = A i / x i (4); (5); In the formula, S i For the i The slope of the monitoring section of each drainage ditch; R i For the i The hydraulic radius of the monitoring section of a drainage ditch, A i For the i The area below the water surface of the drainage ditch monitoring section is calculated according to formula (1), χ i For the i The wet perimeter of a drainage ditch monitoring section.

[0022] In this embodiment, the conventional flow meter method is used to conduct on-site testing on the typical monitoring sections of the drainage ditch, right 1+625 and right 2+300, and the flow velocity at the two seepage flow monitoring sections at 0.5 times the water depth is measured. v 0.5i Eight measurements were carried out and the water depth at the center of the monitoring section was measured with a ruler. Based on the classic statistical test method KS method, the probability density function is obtained by statistical test of flow velocity f ( v ), see Table 2.

[0023] The KS method is a classic statistical test method and a commonly used method in statistics. The formula of the KS method is as follows: (6); Where: D for F ( x )and F 0( x ), F ( x ) is the empirical distribution function of the sample; F 0( x ) is the theoretical distribution function of the sample; i The sample number.

[0024] After using formula (6) to calculate the D value, D ( n , α ) for comparison, D ( n , α ) is the Kolmogorov critical value, n is the number of samples, α is the significance level, and the Kolmogorov critical value can be obtained by looking up the table. D > D ( n , α ) is considered that the sample distribution satisfies F 0( x ),when D < D ( n , α ) is considered that the sample distribution does not satisfy F 0( x ), we need to re-assume the sample distribution type.

[0025] In this embodiment, the flow velocities of two typical monitoring sections conform to the normal distribution and the extreme value type I distribution, respectively, as shown in Table 2.

[0026]

[0027] According to the probability distribution of flow velocity in the monitoring section, the upper limit corresponding to the 80% guarantee rate is calculated, and the standard flow velocity values ​​of the monitoring section right 1+625 and right 2+300 are obtained [ v 0.5i ] are 0.495 m / s and 0.367 m / s respectively. h , the cross-section size verification value is calculated to obtain the monitoring cross-section hydraulic radius, and the calculation result is substituted into the formula n i = R i 2 / 3 S i 1 / 2 / (0.83[ v 0.5 ]) to obtain the calibrated roughness of each monitoring section. The calculation results are shown in Table 3.

[0028]

[0029] S3, using drones to collect high-definition images of water gauges at each monitoring section of the drainage ditch, and identifying the water depth of each monitoring section through the images, including the following steps: S301, the remote-controlled drone steadily flies to the top of the water gauge of the slope of the seepage monitoring section, collects multiple infrared images and visible light images, and then flies to the top of the water gauge of the next drainage ditch monitoring section, repeats the operation, and collects infrared images and visible light images of the water gauges corresponding to multiple drainage ditch monitoring sections; S302, water depth identification of monitoring section: combining the water gauge scale and the collected infrared image and visible light image of the water gauge, analyzing and identifying the water gauge length under the water surface of each monitoring section at the time of collection l i , calculate the water depth at each monitoring section h i , the calculation formula is as follows: h i = l i / m 1i (6); Where: m 1i For the i The right slope rate measured in the monitoring section of the drainage ditch is m 1i .

[0030] In this embodiment, if Figure 5 As shown, the implementation process is as follows: 1) Formulate UAV flight monitoring tasks and submit them to the leaders of the hydraulic sub-plant for review and approval.

[0031] 2) Preparation for UAV flight: After the operator arrives at the first drainage ditch seepage monitoring section with the UAV, he / she will look for an undisturbed flat open space nearby to check the condition of the UAV equipment, ensure the equipment's stable and safe operation, and record the detection period and related environmental factors (temperature, atmospheric humidity, wind speed, solar radiation, etc.) during that period. The DJI Mavic 3T Dual-Light Industry Edition UAV was used for this flight.

[0032] 3) Start the flight mission. After completing the relevant preparations, start the UAV equipment and start the flight mission. The remote-controlled UAV will fly steadily to the point just above the water gauge on the slope of the seepage monitoring section. After hovering for 1 minute, multiple high-definition infrared images and visible light images will be collected. Then the UAV will fly to the point just above the water gauge of the next drainage ditch monitoring section. Following the same operation, multiple high-definition infrared images and visible light images will be collected.

[0033] 4) End the flight mission. When the remote-controlled drone has collected high-definition infrared images and visible light images of the water level of all monitoring sections of the long-distance drainage ditch, the flight mission is ended and the drone equipment is landed smoothly on the open ground. During the landing process, ensure the safety of the environment and avoid pedestrians or vehicles.

[0034] The high-resolution images of the water level on the slope of a typical drainage ditch monitoring section are shown in the attached figure. Figure 4 shown.

[0035] (5) Water depth identification of the monitoring section. Five prefabricated blocks with a side length of 50 cm are laid in each row on the right bank of the drainage ditch around the embankment. Each block of the red and white water gauge is 10 cm wide. The infrared and visible light water gauge photos collected are identified by using a picture ruler and naked eye observation. The water gauge length under the water surface of the right 1+625 and right 2+300 of the monitoring section is obtained by comprehensive judgment. l 1.03m, 1.00m respectively, depending on the water depth h Length to water gauge l , right bank slope m 1 The relationship between h = l / m 1 The calculated water depths of the monitoring sections right 1+625 and right 2+300 are 0.68 m and 0.66 m respectively.

[0036] S4. Calculate the hydraulic radius of each monitoring section based on the water depth of each monitoring section, and calculate the flow velocity of each monitoring section using the calibrated Manning formula.

[0037] Specifically, for i The water depth of the monitoring section measured in step S3 is h i , according to formula (1), the area below the water surface of the monitoring section is calculated A i , the wetted perimeter of the monitored section is calculated by formula (5) χ i , and then the hydraulic radius of each monitoring section is calculated by formula (4) R i , then combined with i The slope of the monitoring section S i and the calibrated roughness n i , according to Manning's formula v i = R i 2 / 3 S i 1 / 2 / n i Calculate the first i The average flow velocity of the monitoring section v i , the calculation results are shown in Table 4.

[0038]

[0039] S5. Calculate and obtain the seepage volume of each monitoring section.

[0040] In step S5, i The average flow velocity of the monitoring section v i and the area below the water surface of the monitoring section A i , calculate the seepage volume of each monitoring section, the calculation formula is: Q i = v i A i (7).

[0041] In the formula, Q i It is the seepage volume of each monitoring section.

[0042] In this embodiment, the seepage volume at the right 1+625 of the monitoring section is calculated. Q 1= v 1 A 1 = 1.385 × 0.456 = 0.631 m 3 / s, seepage volume at the right 2+300 of the monitoring section Q 2= v 2 A 2 = 1.316 × 0.328 = 0.431 m 3 / s.

[0043] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A non-contact monitoring method for seepage in long-distance and large-flow embankment drainage ditches, characterized in that: The following steps are involved: S1. Review the monitoring section size and elevation of the drainage ditch seepage flow to obtain accurate monitoring section size and elevation data; S2. Use the velocity meter method to measure the flow velocity of each monitoring section of the drainage ditch and calibrate the roughness of the Manning formula at each monitoring section; S3. During the operation and maintenance period, drones are used to collect high-definition images of the water level at each monitoring section of the drainage ditch, and the water depth of each monitoring section is identified through images; S4. Calculate the hydraulic radius of each monitoring section based on the water depth of each monitoring section, and calculate the flow velocity of each monitoring section using the calibrated Manning formula; S5. Calculate and obtain the seepage volume of each monitoring section.

2. According to claim 1, a non-contact monitoring method for seepage in long-distance and large-flow embankment drainage ditches is characterized in that: The step S1 includes the following steps: S101, selecting leveling base points and working base points for each monitoring section in turn, and performing elevation calibration; S102, measuring the elevations of the starting point, the end point, and the turning point of the drainage ditch in sequence; S103. Accurately measure the width, depth, bottom and slope of the key sections of the drainage ditch. i The bottom width of the drainage ditch measured at the monitoring section of the drainage ditch is b i The right slope is m 1i , the left slope is m 2i ; S104. Obtain the area below the water surface of each monitoring section A i With water depth The exact relationship is expressed as: （1）。 3. According to claim 2, a non-contact monitoring method for seepage in long-distance and large-flow embankment drainage ditches is characterized in that: In step S2, i The flow rate at the monitoring section of the drainage ditch is measured by a flow meter at a water depth of 0.5 times the water depth. v 0.5i , use a ruler to measure the water depth at the center of the monitoring section , repeatedly measure the flow rate v 0.5i , calculate the mean and variance of the velocity at the 0.5 times water depth measuring point, and then use the classic statistical test method KS method to perform a statistical test on the velocity to obtain the probability density function f ( v ), select the upper limit value corresponding to the set guarantee rate as the standard value of the flow velocity of the monitoring section [ v 0.5i ], using the measured velocity standard value of 0.5 times the water depth of the monitoring section [ v 0.5i ] and the average flow velocity of the cross section v i The relationship v i = 0.83[ v 0.5i ], calibrate the roughness of Manning's formula n i , the operation is as follows: Manning's formula is: v i = R i 2 / 3 S i 1 / 2 / n i （2）； Get the roughness n i The calibration formula is: n i = R i 2 / 3 S i 1 / 2 / (0.83[ v 0.5 ])（3）； R i = A i / h i (4); （5）； In the formula, S i For the i The slope of the monitoring section of each drainage ditch; R i For the i The hydraulic radius of the monitoring section of a drainage ditch, A i For the i The area below the water surface of the drainage ditch monitoring section is calculated according to formula (1), χ i For the i The wet perimeter of a drainage ditch monitoring section.

4. According to claim 3, a non-contact monitoring method for seepage in a long-distance and large-flow embankment drainage ditch is characterized in that: The step S3 includes the following steps: S301, the remote-controlled drone steadily flies to the top of the water gauge of the slope of the seepage monitoring section, collects multiple infrared images and visible light images, and then flies to the top of the water gauge of the next drainage ditch monitoring section, repeats the operation, and collects infrared images and visible light images of the water gauges corresponding to multiple drainage ditch monitoring sections; S302, water depth identification of monitoring section: combining the water gauge scale and the collected infrared image and visible light image of the water gauge, analyzing and identifying the water gauge length under the water surface of each monitoring section at the time of collection l i , calculate the water depth at each monitoring section h i , the calculation formula is as follows: h i = l i / m 1i （6）； Where: m 1i For the i The right slope rate measured in the monitoring section of the drainage ditch is m 1i .

5. According to claim 4, a non-contact monitoring method for seepage in long-distance and large-flow embankment drainage ditches is characterized in that: In step S4, i The water depth of the monitoring section measured in step S3 is h i , according to formula (1), the area below the water surface of the monitoring section is calculated A i , the wetted perimeter of the monitored section is calculated by formula (5) χ i , and then the hydraulic radius of each monitoring section is calculated by formula (4) R i , then combined with i The slope of the monitoring section S i and the calibrated roughness n i , according to the calibrated Manning formula v i = R i 2 / 3 S i 1 / 2 / n i Calculate the first i The average flow velocity of the monitoring section v i .

6. According to claim 1, a non-contact monitoring method for seepage in a long-distance and large-flow embankment drainage ditch is characterized in that: In step S5, i The average flow velocity of the monitoring section v i and the area below the water surface of the monitoring section A i , calculate the seepage volume of each monitoring section, the calculation formula is: Q i = v i A i （7）； In the formula, Q i It is the seepage volume of each monitoring section.

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