A method and device for observing the underwater topography and flow structure in a lagoon

Abstract

The present application provides a kind of underwater topography and water flow structure prototype observation method and device in nest pond, including field preparation, determining measurement range and reference point, and demarcating survey line;Field measurement, arrange ADCP instrument, collect the water depth in measurement range, flow velocity vector and the horizontal position of instrument in water flow;Data processing, obtain complete underwater three-dimensional topographic data in nest area, consider the flow rate exceeding normal range as abnormal data, interpolate flow rate according to water depth, generate three-dimensional flow field diagram in nest measurement range;Dangerous area judgment, repeat monitoring several times, when emergency occurs, monitoring frequency should be increased in time, the area with larger flow rate, larger turbulence intensity and larger river bank topographic change is regarded as key attention area, the present application can determine the position of nest pond prone to scour after preliminary discovery of nest collapse, judge nest collapse dangerous area, facilitate timely rescue.

Description

Technical Field

[0001] This invention relates to the field of bank collapse monitoring technology, and in particular to a prototype observation method and device for underwater topography and water flow structure in ponds. Background Technology

[0002] Bank collapses are an important component of alluvial riverbed evolution, and can be classified into three types based on their morphology and characteristics: strip collapses, wash collapses, and crater collapses. Crater collapses, in particular, involve large-scale bank erosion occurring within a short period, with considerable length and width, ranging from tens to hundreds of meters. Their formation is closely related to uneven distribution of riverbank soil and specific water flow structures (circulation, crossflow, or oblique flow, etc.), and is the main form of bank collapse in the lower reaches of the Yangtze River. Crater collapses are characterized by rapid development and strong destructive power, posing a significant threat to flood control safety along the river, potentially causing major adjustments to the river's course, increasing the difficulty of river management, and in some cases, directly endangering the lives of the public.

[0003] Riverbed collapses are influenced by a variety of factors, including river morphology, near-shore currents, bank soil conditions, and human activities, resulting in complex formation. Current research on collapse development primarily relies on indoor generalized flume experiments to reveal the characteristics of flow and riverbed morphology changes at different development stages. However, limited field observation data leads to insufficient understanding of the collapse mechanism. Regarding field monitoring methods, traditional, periodically conducted measurements of water level, flow rate, and semi-river topography cannot meet the needs of continuous emergency monitoring of sudden bank collapses in localized river sections. While GNSS, displacement gauges, and pressure gauges can provide real-time monitoring, their installation, maintenance, and monitoring point placement remain challenging due to limitations in field conditions, thus limiting their application in actual bank collapse observation and monitoring. Furthermore, collapses are sudden and random, making it difficult to determine their timing and location. Therefore, field bank collapse observations typically begin after initial discovery of a collapse. At the long-distance river scale, the installation intervals of existing monitoring equipment are too large, and existing measurement methods cannot meet the required accuracy for emergency monitoring of collapses. Therefore, developing a prototype observation method and device for underwater topography and flow structure within riverbed collapses has significant application value. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a prototype observation method and device for underwater topography and water flow structure in ponds.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A prototype observation method for underwater topography and water flow structure in a pond includes the following steps:

[0007] Step 1: On-site preparation, determine the measurement range and benchmark points, and delineate multiple survey lines;

[0008] Step 2: On-site measurement. Deploy the ADCP instrument, ensuring the underwater transducer of the ADCP travels along the measurement line from one side of the Wotang River to the other, and collect water depth data within the measurement range. h Water flow velocity vector And the horizontal position of the instrument in the water flow. Water flow velocity vector Including instantaneous flow velocity components in the X, Y, and Z directions, respectively , , Until multiple survey lines are completed, data is collected and stored along each survey line;

[0009] Step 3: Data processing. Obtain complete underwater three-dimensional topographic data of the pond area. Treat flow velocities that exceed the normal range as abnormal data. Interpolate the flow velocities according to the water depth to generate a three-dimensional flow field map within the pond measurement range.

[0010] Step 4: Identify dangerous areas. Repeat steps 2-3 for multiple monitoring sessions. In case of emergency, increase the number of monitoring sessions promptly. Areas with high water flow velocity, high turbulence intensity, and significant changes in riverbank topography should be considered as key areas of concern.

[0011] Furthermore, in step 1, guide rails are set on both sides of the pond, and multiple survey lines parallel to the pond shoreline are set between the two guide rails to ensure that the number of survey line profiles is not less than 10 and the overlap of the coverage area of ​​adjacent survey lines is at least 60%.

[0012] Furthermore, in step 2, multiple measurements are taken and the average value is calculated. At least two measurements are taken back and forth along the same survey line, and the average value of the multiple measurements is used as the final value. For areas near the shore or those that are collapsing, multiple coverage scans are required to improve measurement accuracy.

[0013] Furthermore, in step 3, the riverbed elevation is obtained. z :

[0014] (1)

[0015] in, For the cross-sectional water depth, The depth of immersion. This refers to the water surface elevation.

[0016] According to the riverbed elevation z And the horizontal position of the instrument in the water flow Obtain complete underwater 3D topographic data for the Wotang area.

[0017] Furthermore, the power function vertical velocity distribution formula (2) is used for interpolation based on water depth. The components in each direction are calculated first, and then synthesized:

[0018] (2)

[0019] In the formula, u This represents the velocity component at the measuring point, in m / s. The maximum flow velocity along the vertical line is expressed in m / s. The distance from the measuring point to the riverbed is in meters (m). Water depth, in meters (m). The coefficients were obtained through linear regression fitting.

[0020] Furthermore, in step 3, the flow velocity distribution map of each survey line cross section is first generated using ADCP data processing software. Based on the data processing of multiple cross sections, the flow velocity distribution map of different cross sections with different water depths is then analyzed. Flow rate data below The flow velocity distribution map of the horizontal cross section is combined, and the flow velocity interpolation of the horizontal cross section is performed by an interpolation algorithm based on radial basis functions. Finally, image processing software is used to generate a three-dimensional flow field map of the monitoring pond area.

[0021] Further, in step 4, based on the three-dimensional flow field map obtained in step 3, the maximum flow velocity and the location of the larger flow velocity gradient in the crater zone are determined, and the turbulence intensity in the crater zone is obtained according to equations (3)-(5).

[0022] The expressions for the instantaneous velocity, time-averaged velocity, and turbulence intensity in the x, y, and z directions are as follows:

[0023] , , (3)

[0024] , , (4)

[0025] , , (5)

[0026] In the formula: , , The instantaneous flow velocity is expressed in m / s along the x, y, and z directions. , , The average flow velocity is expressed in m / s. , , The velocity is the pulsating flow rate, expressed in m / s. , , The turbulence intensity is expressed in m / s.

[0027] Furthermore, the turbulence intensity in the non-survey line plane area is processed using linear interpolation to generate a turbulence intensity plane distribution map.

[0028] A prototype observation device for underwater topography and water flow structure in a pond includes:

[0029] Two guide rails, perpendicular to the direction of water flow, are fixed to the two riverbanks on either side of the measurement area and extend a certain distance upstream and downstream.

[0030] Two remote-controlled cable rewinding and unwinding devices are slidably connected to two guide rails, each equipped with an adjustment mechanism;

[0031] The test line has two ends respectively set in the two remote-controlled wire take-up and release devices, and the wire is taken up or released by the adjustment structure respectively.

[0032] ADCP, fixed to the survey line, moves across the water surface via the survey line to collect water depth data within the measurement range. h Water flow velocity vector And the horizontal position of the instrument in the water flow. ;

[0033] RTK positioning device is used to locate ADCP and remote cable rewinding device and store data.

[0034] Furthermore, the adjustment structure includes a slider, a fixed bracket, a reel, a steel rope, a rotating shaft, a first bevel gear, a second bevel gear, an electric rotating wheel, a remote control host, and a remote control. The slider is slidably connected to the guide rail, the fixed bracket is fixed to the slider, the reel is rotatably connected to the fixed bracket, the steel rope is wound around the reel, one end of the rotating shaft is fixedly connected to the reel, and the other end is fixed with a first bevel gear, which meshes with the first bevel gear. The electric rotating wheel is fixed to the fixed bracket and connected to a second bevel gear that meshes with the first bevel gear. The remote control host is connected to a power supply device via a wire. The remote control of the reel-and-drop device transmits a take-up / drop signal to the remote control host. After receiving the signal, the remote control host drives the electric rotating wheel to rotate clockwise / counterclockwise, which in turn drives the rotating shaft to rotate via the second bevel gear. The rotating shaft then further drives the reel to rotate to complete the take-up or drop-off of the line.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] (1) The present invention provides a method and device for prototype observation of underwater topography and flow structure in ponds, which is time-saving, highly accurate and easy to operate. The ADCP can quickly perform three-dimensional measurement of topography and flow velocity, and has less disturbance to the flow field than traditional current meters. At the same time, the fixed guide rails at both ends enhance the stability during observation, ensuring that the ship travels in a straight line and the measurement trajectory is consistent in both directions, which enhances the convenience and accuracy of continuous observation. It is suitable for prototype observation of ponds under complex flow conditions and can be used for emergency monitoring of actual river channel collapses.

[0037] (2) The present invention provides a prototype observation method and device for underwater topography and water flow structure in ponds, which has high scientific research value. After the device is applied to field measurement, it can obtain rich field measurement data, which helps to deepen the research on the mechanism of pond collapse and further understand the evolution law of alluvial riverbed.

[0038] (3) The present invention provides a prototype observation method and device for underwater topography and water flow structure in a swamp, which has strong engineering applicability. The real-time monitoring data after timely processing can be used to determine the most dangerous area in the swamp area, provide guidance for the emergency management of swamps in the river channel, and accumulate practical experience to provide a scientific basis for the management of the middle and lower reaches of the Yangtze River and flood control and disaster reduction. Attached Figure Description

[0039] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0040] Figure 1 This is a flowchart illustrating a prototype observation method for underwater topography and water flow structure within a pond, provided in an embodiment of the present invention.

[0041] Figure 2 A schematic diagram (top view) of a prototype observation device for underwater topography and water flow structure in a pond, provided in an embodiment of the present invention.

[0042] Figure 3 This is a schematic diagram (side view) of a prototype observation device for underwater topography and water flow structure in a pond, provided as an embodiment of the present invention. Figure 2 Take the AA section as an example.

[0043] Figure 4 The present invention provides a remote-controlled cable rewinding and unwinding device.

[0044] Figure 5 A schematic diagram of the guide rail and its fixing method provided by the present invention.

[0045] In the diagram: 1. Guide rail; 1-1. Planar frame; 1-2. Positioning bolt hole; 1-3. Locking assembly; 1-4. Slider; 2. Cable take-up and unwinding device; 2-1. Fixed bracket; 2-2. Cable reel; 2-3. Steel rope; 2-4. Shaft; 2-5. First bevel gear; 2-6. Second bevel gear; 2-7. Electric rotary wheel; 2-8. Remote control host; 2-9. Remote control; 3. ADCP; 4. Riverbank; 5. River channel; 6. Pond area; 7. Survey line; 8. Water surface line; 9. RTK positioning device. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0048] This invention provides a prototype observation method for underwater topography and water flow structure within a pond, such as... Figure 1 As shown, it includes the following steps:

[0049] Step 1: On-site preparation, determine the measurement range and benchmark points, and draw multiple survey lines 7;

[0050] Step 2: On-site measurement. Deploy the ADCP3 instrument, ensuring the underwater transducer of the ADCP3 travels along measurement line 7 from one side of the Wotang River bank 4 to the other, and collect water depth data within the measurement range. h Water flow velocity vector And the horizontal position of the instrument in the water flow. Water flow velocity vector Including instantaneous flow velocity components in the X, Y, and Z directions, respectively , , Until all measurements of multiple survey lines 7 are completed, data are collected and stored along each survey line 7.

[0051] Step 3: Data processing. Obtain complete underwater three-dimensional topographic data of the Wotang area. Treat flow velocities that exceed the normal range as abnormal data. Interpolate the flow velocities according to the water depth to generate a three-dimensional flow field map within the Wotang measurement range.

[0052] Step 4: Identify dangerous areas. Repeat steps 2-3 for multiple monitoring sessions. In case of emergency, increase the number of monitoring sessions promptly. Areas with high water flow velocity, high turbulence intensity, and significant changes in riverbank topography should be considered as key areas of concern.

[0053] This invention provides a prototype observation method for underwater topography and flow structure in ponds, which is time-saving, highly accurate, and simple to operate. The ADCP3 can quickly perform three-dimensional measurements of topography and flow velocity, causing less disturbance to the flow field than traditional current meters. At the same time, the fixed guide rails 1 at both ends enhance the stability during observation, ensuring that the vessel travels in a straight line and that the measurement trajectory is consistent in both directions. This enhances the convenience and accuracy of continuous observation, and is suitable for prototype observation of ponds under complex flow conditions. It can also be used for emergency monitoring of collapse in actual river channels.

[0054] This invention provides a prototype observation method for underwater topography and flow structure within alluvial ponds, which has high scientific research value. When applied to field measurements, the device can obtain abundant on-site measurement data, contributing to in-depth research on the mechanism of alluvial collapse and further understanding of the evolution patterns of alluvial riverbeds.

[0055] This invention provides a prototype observation method for underwater topography and water flow structure within a landslide-prone area, which has strong engineering applicability. Real-time monitoring data, after timely processing, can be used to determine the most dangerous area within the landslide zone, providing guidance for landslide emergency management in river channel 5. It can also accumulate practical experience to provide a scientific basis for river management and flood control in the middle and lower reaches of the Yangtze River.

[0056] In this invention, ADCP3 is an acoustic Doppler velocity profiler.

[0057] In this invention, step 1 specifically includes:

[0058] Step 1.1: Determine the measurement range. The longitudinal range of the measurement area includes the landslide area and the affected areas upstream and downstream; the lateral range includes the above-water and underwater parts of the landslide area. The monitoring range can be determined according to actual needs, but it should at least cover the entire landslide area.

[0059] Step 1.2: Determine the benchmark point. Throughout the monitoring of the entire Wotang development process, a unified elevation system should be used. RTK positioning equipment (GNSS RTK, Real-time kinematic) should be used to collect positioning parameters, obtaining the plane coordinates and elevation as the benchmark station. Zero-point elevation measurements should be conducted using water gauges. After network establishment, nearby benchmark stations should be used to re-measure the benchmark station to determine if there is any displacement and ensure the accuracy of the benchmark station's coordinates. The datum surface should preferably be the frozen datum surface of a nearby hydrological station. If no hydrological station is available, the current national elevation system or the commonly used local elevation system can be used. For leveling points, priority should be given to using nearby national, hydrological, or other industry leveling points for reference.

[0060] Step 1.3: Draw survey lines 7. Several survey lines 7 are perpendicular to the guide rails 1 on both sides and roughly parallel to the riverbank 4 shoreline. The survey lines 7 need to be kept as straight as possible. The spacing between survey lines 7 is generally 3-5 m. If the pond is small in scale (width less than 50 m), the spacing can be increased as appropriate to ensure that the overlap of the coverage area of ​​adjacent survey lines 7 is at least 60%.

[0061] In this invention, step 2 specifically includes:

[0062] Step 2.1: Configure the ADCP3 (mobile acoustic Doppler current profiler) instrument. Select the general acquisition mode and follow the operation wizard to set the number of water layer units, water layer thickness, etc. Determine the maximum range based on the development stage and size of the sinkhole, generally about 20m. The thickness of the depth unit can be set to 0.1-0.5m.

[0063] Step 2.2: Connect the take-up and release device 2. Tie one end of two long, thick steel ropes 2-3 to ADCP3, and connect the other ends of the ropes to the take-up and release device 2 by passing them over the reels 2-2 on both sides.

[0064] Step 2.3: Determine the position of survey line 7, fix the positions of the wire take-up and release devices 2 on both sides on the guide rail 1, and input their coordinates into the GPS rover handbook to establish a survey line 7 based on the positions of the wire take-up and release devices 2 at both ends.

[0065] Step 2.4: Vertically lower the ADCP3 underwater transducer into the water and record the immersion depth. The starting position at the water's edge was precisely located using GPS, and the distance from the transducer to the water's edge and the water's elevation were recorded. Instrument observation results can be compared with manual observation results; when the error exceeds the limit, manual observation results should be used for calibration.

[0066] Step 2.5: Measure the flow field and topography along survey line 7. Pull the underwater transducer from one side to the other along the survey guideline by releasing and retracting steel cables 2-3, adjusting the course as needed based on the offset distance. Upon reaching the other side, use GPS to precisely locate the endpoint at the water's edge and record the distance from the transducer to the edge and the water surface elevation. Simultaneously, use ADCP3 to collect data including water depth. Water flow velocity vector (The instantaneous velocity components in the x, y, and z directions are respectively) , , The instrument's horizontal position P(x, y) in the water flow is continuously and in real time acquired, recorded, and stored by a computer via wireless transmission under the control of system software.

[0067] Step 2.6: Take multiple measurements and average the result. Measure back and forth along the same measuring traverse at least twice, and use the average of the multiple measurements as the final value. For key areas (near the shore or areas that are collapsing), multiple coverage scans are required to improve measurement accuracy.

[0068] Step 2.7: Collect and store data along each survey line 7. Repeat steps 2.3 to 2.6 along different survey lines 7 to measure the internal topography and flow velocity of the pond.

[0069] Step 3 specifically includes:

[0070] Step 3.1: Export flow velocity and terrain data using post-processing software. Use WinRiver post-processing software to export the ADCP3 measurement data ( , , (The position of ADCP3 needs to be accurately located using an RTK positioning device.)

[0071] Step 3.2: Process water depth data and determine underwater topographic coordinates. First, calculate the actual water depth and riverbed elevation z, and then collect the cross-sectional water depth data. Add water depth The actual water depth is then used to determine the water surface elevation. Subtract the actual water depth to get the riverbed elevation z Then, the topographic map was edited using CASS 7.1 drawing software based on AutoCAD, which can automatically generate contour lines to complete the calculations and draw cross-sectional topographic maps. Based on the starting and ending coordinates of the water's edge, the topographic coordinates between adjacent survey lines 7 were interpolated by straight lines, and the blank areas were densified by equidistant straight line interpolation to obtain complete underwater three-dimensional topographic data for the Wotang area 6. ;

[0072] Step 3.3: Treat flow velocities that exceed the normal range as abnormal data, and use the power function vertical velocity distribution formula to interpolate according to the water depth. First calculate the components in each direction, and then synthesize them.

[0073] Step 3.4: Generate the three-dimensional flow field. First, use ADCP data processing software to generate velocity distribution maps (xz plane) for each cross section of survey line 7. Based on the data processing of multiple cross sections, then further process the data at different depths... h Flow rate data below The flow velocity distribution map of the horizontal cross section (xy plane) is combined, and finally the three-dimensional flow field map of the monitoring pond area 6 is generated using image processing software;

[0074] Specifically, in step 3.2, the riverbed elevation is obtained. z :

[0075] (1)

[0076] in, For the cross-sectional water depth, The depth of immersion. This refers to the water surface elevation.

[0077] According to the riverbed elevation z And the horizontal position of the instrument in the water flow Obtain complete underwater 3D topographic data for the Wotang area.

[0078] In step 3.3, the power function vertical velocity distribution formula (2) is used to interpolate according to the water depth. The components in each direction are calculated first and then synthesized.

[0079] (2)

[0080] In the formula, u This represents the velocity component at the measuring point, in m / s. The maximum flow velocity along the vertical line is expressed in m / s. The distance from the measuring point to the riverbed is in meters (m). Water depth, in meters (m). The coefficients were obtained through linear regression fitting.

[0081] In summary, in step 3, the flow velocity distribution maps for each cross section of survey line 7 are first generated using ADCP data processing software. Based on the data processing of multiple cross sections, the flow velocity distribution maps for different cross sections with different water depths are then analyzed. Flow rate data below The flow velocity distribution map of the horizontal cross section is combined, and the flow velocity interpolation of the horizontal cross section is performed by an interpolation algorithm based on radial basis functions. Finally, the three-dimensional flow field map of the monitoring pond area 6 is generated using image processing software.

[0082] Step 4 specifically includes:

[0083] Step 4.1: Repeat steps 2-3 multiple times, determining the measurement frequency based on the duration of each measurement. When landslides accelerate, the landslide area continues to expand, or in the event of heavy rain, earthquakes, or thawing, the number of measurements should be increased promptly. It is recommended that 3-5 measurements be completed for emergency monitoring of landslide embankments.

[0084] Step 4.2: Identify areas with strong water scouring capacity, i.e., areas with high water flow velocity, velocity gradient, and turbulence intensity;

[0085] Step 4.3: Determine the areas of riverbank 4 with weaker erosion resistance based on the topographic changes of riverbank 4;

[0086] Step 4.4: Comprehensive analysis and report on the erosion-prone areas of riverbank 4, namely, areas with high flow velocity, high turbulence intensity, and significant topographic changes on riverbank 4, to guide the key areas to focus on in subsequent landslide emergency management. For example, larger boulders should be placed as reinforcement for erosion-prone areas.

[0087] In step 4.2, based on the three-dimensional flow field map obtained in step 3, the maximum flow velocity and the location of the larger flow velocity gradient in the crater zone are determined, and the turbulence intensity in the crater zone is obtained according to equations (3)-(5).

[0088] The expressions for the instantaneous velocity, time-averaged velocity, and turbulence intensity in the x, y, and z directions are as follows:

[0089] , , (3)

[0090] , , (4)

[0091] , , (5)

[0092] In the formula: , , The instantaneous flow velocity is expressed in m / s along the x, y, and z directions. , , The average flow velocity is expressed in m / s. , , The velocity is the pulsating flow rate, expressed in m / s. , , Turbulence intensity, in m / s;

[0093] The turbulence intensity in the plane region not located on survey line 7 is processed using linear interpolation to generate a turbulence intensity plane distribution map.

[0094] A prototype observation device for underwater topography and water flow structure in a pond, such as Figure 2 and Figure 3 As shown, it includes:

[0095] Two guide rails 1, perpendicular to the direction of water flow, are fixed to the two riverbanks 4 on either side of the measurement area and extend a certain distance upstream and downstream.

[0096] Two take-up and unwind devices 2 are slidably connected to two guide rails 1, and are equipped with adjustment structures.

[0097] The measuring line 7 has two ends respectively set in the two wire take-up and release devices 2 and is respectively taken up or released by the adjustment structure;

[0098] ADCP3, fixed on measuring line 7, moves across the water surface via measuring line 7 to collect water depth h and water flow velocity vector within the measurement range. And the horizontal position of the instrument in the water flow. ;

[0099] The RTK positioning device 9 is used to locate ADCP3 and remote control cable rewinding device 2 and store data.

[0100] like Figure 4 As shown, the adjustment structure includes a slider 1-4, a fixed bracket 2-1, a reel 2-2, a steel rope 2-3, a rotating shaft 2-4, a first bevel gear 2-5, a second bevel gear 2-6, an electric rotating wheel 2-7, a remote control host 2-8, and a remote control 2-9. The slider 1-4 is slidably connected to the guide rail 1. The fixed bracket 2-1 is fixed to the slider 1-4. The reel 2-2 is rotatably connected to the fixed bracket 2-1. The steel rope 2-3 is wound around the reel 2-2. One end of the rotating shaft 2-4 is fixedly connected to the reel 2-2, and the other end is fixed with the first bevel gear 2-5. The first bevel gear 2-5 is engaged, the electric rotating wheel 2-7 is fixed on the fixed bracket 2-1 and connected to a second bevel gear 2-6 that is engaged with the first bevel gear 2-5, the remote control host 2-8 is connected to the power supply device through a wire, and the remote control 2-9 of the take-up and release device 2 sends a take-up / release signal to the remote control host 2-8. After receiving the signal, the remote control host 2-8 drives the electric rotating wheel 2-7 to rotate clockwise / counterclockwise, and then drives the rotating shaft 2-4 to rotate through the second bevel gear 2-6. The rotating shaft 2-4 further drives the line wheel 2-2 to rotate to complete the take-up or release of line.

[0101] The ADCP3 can obtain the water flow velocity in the vertical profile using a vector synthesis method. Select the general acquisition mode and set the number of water layer units and water layer thickness according to the operation wizard. Determine the maximum range based on the development stage and size of the sinkhole, generally about 20m, and the thickness of the depth unit can be set to 0.1-0.5m.

[0102] like Figure 5 As shown, the guide rail 1 is made of steel and is formed by bolting together shorter sections of steel guide rail 1. Two guide rails 1 are perpendicular to the water flow direction and are mounted on a planar frame 1-1, respectively fixed to the riverbank 4 extending approximately 10m upstream and downstream from the measurement area. Length markings are made every 1m on the guide rails 1, and positioning bolt holes 1-2 are pre-drilled. The reel 2-2 is fixed to the slider 1-4 via a fixed bracket 2-1, allowing the slider 1-4 to move along the guide rail 1. Simultaneously, locking components 1-3 are installed at both ends of the slider 1-4, allowing the locking screws to be tightened at the positions reached by the slider 1-4.

[0103] The direction of the measuring line 7 should be perpendicular to the two guide rails 1 and roughly parallel to the riverbank 4. The spacing between measuring lines 7 is generally 5m. If the pond is small (width less than 50m), the spacing can be increased as needed to ensure that the number of measuring lines 7 is not less than 10 and the overlap of the coverage of adjacent measuring lines 7 is at least 60%.

[0104] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A prototype observation method for underwater topography and water flow structure in a pond, characterized in that, Includes the following steps: Step 1: On-site preparation, determine the measurement range and benchmark points, and delineate multiple measurement lines; set up guide rails on both sides of the pond, and set up multiple measurement lines parallel to the pond shoreline between the two guide rails to ensure that the number of measurement line profiles is not less than 10 and the overlap of the coverage area of ​​adjacent measurement lines is at least 60%. Step 2: On-site measurement. Deploy the ADCP instrument, ensuring the underwater transducer of the ADCP travels along the measurement line from one side of the Wotang River to the other, and collect water depth data within the measurement range. h Water flow velocity vector And the horizontal position of the instrument in the water flow. Water flow velocity vector Including instantaneous flow velocity components in the X, Y, and Z directions, respectively , , Until multiple survey lines are completed, data are collected and stored along each survey line; the same survey line is measured back and forth at least twice, and the average value of multiple measurements is taken as the final value. Multiple coverage scans are performed on areas near the shore or in the process of collapse. Step 3: Data processing. Obtain complete underwater three-dimensional topographic data of the Wotang area. Treat flow velocities that exceed the normal range as abnormal data. Use the power function vertical velocity distribution formula (2) to interpolate according to the water depth. First calculate the components in each direction, and then synthesize them. （2） In the formula, u The velocity component at the measuring point is expressed in m / s. The maximum flow velocity along the vertical line is expressed in m / s. The distance from the measuring point to the riverbed is in meters (m). Water depth, in meters (m). The coefficients were obtained through linear regression fitting; The flow velocity distribution map of each measurement line cross section was generated using ADCP data processing software. Then, the flow velocity data at different water depths h in different sections were combined into a horizontal cross section flow velocity distribution map. The horizontal cross section flow velocity interpolation was performed using an interpolation algorithm based on radial basis functions. Finally, a three-dimensional flow field map of the pond measurement range was generated. Step 4: Identify dangerous areas. Repeat steps 2-3 for multiple monitoring sessions. In case of emergency, increase the number of monitoring sessions promptly. Areas with high water flow velocity, high turbulence intensity, and significant changes in riverbank topography should be considered as key areas of concern.

2. The method for prototype observation of underwater topography and water flow structure in a pond according to claim 1, characterized in that: In step 3, the riverbed elevation is obtained. z : （1） in, For the cross-sectional water depth, The depth of immersion. This refers to the water surface elevation. According to the riverbed elevation z And the horizontal position of the instrument in the water flow Obtain complete underwater 3D topographic data for the Wotang area.

3. The method for prototype observation of underwater topography and water flow structure in a pond according to claim 1, characterized in that: In step 3, the flow velocity distribution map of each survey line cross section is first generated using ADCP data processing software. Based on the data processing of multiple cross sections, the flow velocity distribution map of different cross sections with different water depths is then analyzed. Flow rate data below The flow velocity distribution map of the horizontal cross section is combined, and the flow velocity interpolation of the horizontal cross section is performed by an interpolation algorithm based on radial basis functions. Finally, image processing software is used to generate a three-dimensional flow field map of the monitoring pond area.

4. The method for prototype observation of underwater topography and water flow structure in a pond according to claim 1, characterized in that: In step 4, based on the three-dimensional flow field map obtained in step 3, the maximum flow velocity and the location of the larger flow velocity gradient in the crater zone are determined, and the turbulence intensity in the crater zone is obtained according to equations (3)-(5). The expressions for the instantaneous velocity, time-averaged velocity, and turbulence intensity in the x, y, and z directions are as follows: ， ， （3） ， ， （4） ， ， （5） In the formula: , , The instantaneous flow velocity is expressed in m / s along the x, y, and z directions. , , The average flow velocity is expressed in m / s. , , The velocity is the pulsating flow rate, expressed in m / s. , , The turbulence intensity is expressed in m / s.

5. The method for prototype observation of underwater topography and water flow structure in a pond according to claim 4, characterized in that: The turbulence intensity in the plane region not located on the survey line is processed using the linear interpolation method to generate a turbulence intensity plane distribution map.

6. The observation device for the prototype observation method of underwater topography and water flow structure in a pond according to claim 1, characterized in that, include: Two guide rails, perpendicular to the direction of water flow, are fixed to the two riverbanks on either side of the measurement area and extend a certain distance upstream and downstream. Two remote-controlled cable rewinding and unwinding devices are slidably connected to two guide rails, each equipped with an adjustment mechanism; The test line has two ends respectively set in the two remote-controlled wire take-up and release devices, and the wire is taken up or released by the adjustment structure respectively. ADCP, fixed to the survey line, moves across the water surface via the survey line to collect water depth data within the measurement range. h Water flow velocity vector And the horizontal position of the instrument in the water flow. ; RTK positioning device is used to locate ADCP and remote cable rewinding device and store data.

7. The prototype observation device for underwater topography and water flow structure in a pond according to claim 6, characterized in that: The adjustment structure includes a slider, a fixed bracket, a reel, a steel rope, a rotating shaft, a first bevel gear, a second bevel gear, an electric rotating wheel, a remote control host, and a remote control. The slider is slidably connected to a guide rail, the fixed bracket is fixed to the slider, the reel is rotatably connected to the fixed bracket, and the steel rope is wound around the reel. One end of the rotating shaft is fixedly connected to the reel, and the other end is fixed to the first bevel gear. The electric rotating wheel is fixed to the fixed bracket and connected to a second bevel gear that meshes with the first bevel gear. The remote control host is connected to a power supply device via a wire. The remote control transmits a take-up / release signal to the remote control host through the take-up / release device. After receiving the signal, the remote control host drives the electric rotating wheel to rotate clockwise / counterclockwise, which in turn drives the rotating shaft to rotate through the second bevel gear. The rotating shaft further drives the reel to rotate to complete the take-up or release of the line.

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