An automatic monitoring system and method for sediment deposition height of thick deposition reservoir and water temperature in front of dam

Abstract

The application discloses a kind of thick silt reservoir silt deposition elevation and dam front water temperature automatic monitoring system and method, the pressure of different elevations before dam is collected by pressure sensing device and real-time water level variation, the real-time water temperature data of different elevations before dam is collected by temperature sensor, by data acquisition control system and internet of things technology, real-time information is transferred to computing service terminal, and the water level elevation and silt deposition elevation of real time are determined, the change rule of water temperature under different silt height conditions is analyzed, for mastering reservoir operating state, research reservoir silt deposition form and process, carry out reservoir silt scouring and siltation and dam body temperature control crack prevention measures etc. Provide research basis and technical support.

Description

An automatic monitoring system and method for sediment deposition elevation and upstream water temperature in a thick silt reservoir Technical Field

[0001] This invention relates to a method for monitoring the siltation elevation and upstream water temperature of a thick silt reservoir, belonging to the field of water conservancy and hydropower engineering technology. Background Technology

[0002] Developing clean and renewable energy sources and promoting energy structure transformation has become a broad consensus and common action in the international community. Hydropower is not only the largest source of renewable energy currently, but also the most important guarantee for the grid connection of intermittent energy sources such as wind and solar power. Therefore, reservoirs and dams have become indispensable and important infrastructure in modern society.

[0003] Concrete plays a vital role in water conservancy and hydropower projects. Reservoirs and dams are constructed entirely of concrete, making them key components for temperature control and crack prevention. Unlike ordinary concrete structures, reservoirs and dams are water-related structures, facing complex loads and environmental influences. Especially when constructing dams on silty rivers, the river's flow velocity decreases upon entering the reservoir, reducing its sediment-carrying capacity and altering the original sediment transport patterns. This leads to the gradual deposition and accumulation of large amounts of sediment in the reservoir area. Siltation not only causes losses in flood control and beneficial storage capacity, and the upstream submersion of backwater, affecting the smooth operation and economic benefits of the project, but the siltation load and temperature load caused by sediment deposition also have significant impacts on hydraulic structures.

[0004] Therefore, a thorough understanding of the siltation status in front of the dam and the temperature variation patterns of the reservoir is crucial for formulating and adjusting temperature control and silt flushing measures for concrete dams, and for ensuring the safe operation of water conservancy projects. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to achieve automatic monitoring of reservoir siltation elevation and water temperature in front of the dam during reservoir safety operation monitoring.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] An automatic monitoring system for sediment deposition elevation and upstream water temperature in a thick-silt reservoir includes:

[0008] A locking device is installed at the bottom of the riverbed, and an anti-scouring protective shell and a sensor connecting cylinder are fixedly installed on the locking device; the anti-scouring protective shell is set outside the sensor connecting cylinder;

[0009] The erosion protection shell is fixed to the dam surface by a connecting rod.

[0010] The anti-erosion protective shell is fixedly connected to the sensor connecting cylinder via connecting rod two.

[0011] The radar level gauge is connected to the sensor connecting cylinder via a stainless steel rod.

[0012] The data acquisition room is located on the shore and is connected to pressure sensors, temperature sensors, and radar level gauges via cables. It is used to collect and transmit monitoring data at regular intervals and to calculate the elevation of siltation.

[0013] An automatic monitoring method for sediment deposition elevation and upstream water temperature in a thick silt reservoir includes the following steps:

[0014] Step 1: Select the measurement point;

[0015] Step 2: Fabricate the erosion-resistant protective shell and sensor connecting cylinder;

[0016] Step 3: Install the pressure sensor and temperature sensor onto the sensor connecting cylinder;

[0017] Step 4: Install the anti-scour protective shell at the selected measuring point location. Install the sensor connecting cylinder inside the anti-scour protective shell. Fix the anti-scour protective shell and the sensor connecting cylinder on the locking device. The anti-scour protective shell is fixed to the dam surface by the connecting rod.

[0018] Step 5: Connect the radar level gauge to the sensor connecting cylinder using a stainless steel rod.

[0019] Step 6: Set up a data acquisition room on the shore to collect and transmit monitoring data from pressure sensors, temperature sensors, and water level gauges at regular intervals;

[0020] Step 7: Calibrate the monitoring frequency. Collect data from each sensor according to the set monitoring time interval, and summarize and transmit the data in the shore data acquisition room. Store the data from each sensor in the server database and calculate the average value of the monitoring values ​​of each sensor according to the requirements.

[0021] Step 8: Based on the 24-hour average value of the water level gauge obtained in Step 7, determine the water level elevation at each measuring point, as well as the pressure and water temperature in front of the dam at the water level elevation, and determine the sensor number below the water level elevation at each measuring point.

[0022] Step 9: Based on the average value of each sensor over 24 hours obtained in Step 7, the pressure and water temperature at the water level determined in Step 8, and the number of the sensors below the water level, draw the pressure and water temperature distribution curves and the water level time history curves for each measuring point.

[0023] Step 10: Based on the pressure distribution curve of each measuring point drawn in Step 9, determine the pressure inflection point of each measuring point, and determine the initial value of the silt elevation of the measuring point based on the location of the inflection point.

[0024] Step 11: Based on the initial value of silt thickness determined in Step 10, calculate the calculated value of the reservoir bottom pressure at the measuring point using the average value of the radar water level gauge readings.

[0025] Step 12: Determine the precise value of the siltation elevation by combining the monitoring value of the bottom pressure sensor with the calculated value of the reservoir bottom pressure obtained in Step 11.

[0026] In step one, the measuring points are selected at characteristic locations such as the dam overflow section, the section with the maximum dam height, and the transition section between the riverbed and the bank slope. Locking devices are installed at the bottom of the riverbed at the selected locations to secure the scour protection shell and sensor connecting tube, and the elevation of each measuring point is recorded. k is the measurement point number.

[0027] The locking device is a remote automatic locking device. The automatic locking device is connected to the shore data acquisition room via a cable from the sensor connecting tube. It receives and executes operation commands from the control room through wireless equipment, realizing remote control of the opening and closing of the locking device, and enabling the installation and maintenance of the monitoring equipment.

[0028] In step two, the scour protection shell is made of stainless steel and is a tall structure. A connecting rod is installed at each set interval to fix it to the dam surface to improve stability. The scour protection shell is equipped with inlet and outlet ports at each set interval so that water and sediment can enter the protective shell and come into contact with the sensor.

[0029] The scour protection shell is composed of multiple protective shell sections, which facilitates the assembly and splicing of two protective shell sections. Each protective shell section is equipped with a connecting groove, and the connection points of the protective shells are reinforced with underwater waterproof screws. The total length of the spliced ​​protective shell is 2m higher than the maximum dam height.

[0030] The sensor connecting cylinder is composed of multiple connecting cylinder sections. Each connecting cylinder section is provided with a second connecting groove, and the top of each connecting cylinder section is connected to the anti-erosion protective shell via a second connecting rod, thereby enhancing the stability of the sensor connecting cylinder. After splicing, the total length of the sensor connecting cylinder is 2m higher than the maximum dam height. Sensor fixing devices are installed at predetermined intervals on the sensor connecting cylinder to fix the sensor to the sensor connecting cylinder.

[0031] In step three, the pressure sensor and temperature sensor are installed on the sensor connecting cylinder at predetermined intervals via the sensor fixing device. The sensor installation positions correspond to the reserved positions of silt and reservoir water inlet / outlet on the anti-scour protective shell. The temperature sensor is placed on the water-facing side, and the pressure sensor is placed on the water-repellent side. Both the pressure sensor and temperature sensor are connected to the shore data acquisition room via a four-core cable through the inside of the sensor connecting cylinder for the acquisition and transmission of monitoring data.

[0032] In step five, the radar level gauge is connected to the sensor connecting cylinder via a stainless steel rod to monitor the water level in real time. The level gauge is connected via a four-core cable for power supply and data transmission.

[0033] In step six, the shore-based data acquisition room is equipped with sub-control stations and mobile terminals. These stations communicate in real-time with temperature sensors, pressure sensors, and water level gauges via four-core cables, collecting and summarizing monitoring data from each sensor. The data is then transmitted to the central control service terminal via a wired / wireless transmission system. The service terminal automatically stores the monitoring data in databases such as MySQL, SQL Server, and SQLite.

[0034] In step seven, monitoring data is collected every hour, with the collection time set to the hour, and the data is transmitted to the data acquisition room control station in real time.

[0035] The data terminal calculates the average value of the data collected from each sensor between 00:00 and 23:00 on the same day:

[0036]

[0037]

[0038]

[0039] In the formula, and These are the average values ​​of the monitoring data from the pressure sensor, temperature sensor, and water level gauge from 0:00 to 23:00 on the same day, respectively. (P) k i ) j 、(T k i ) j and (H) k ) j These are the monitoring values ​​from the pressure sensor, temperature sensor, and water level gauge, respectively. i is the number of the pressure sensor and temperature sensor, j is the time, j = 0, 1, 2, ..., 23, and k is the measurement point number.

[0040] In step eight, the average 24-hour value of the radar water level gauge is used as the reservoir water level for the day, and the sensor numbers below the reservoir water level elevation at that measuring point are recorded. Using the reservoir water level elevation and the elevations of each sensor at that measuring point, the pressure and upstream water temperature at the reservoir water level elevation are determined: If the reservoir water level matches the sensor elevation, the pressure and upstream water temperature at the reservoir water level elevation are taken as the 24-hour average values ​​of the pressure and temperature sensors at the same elevation. If the reservoir water level is between two sets of sensors, the pressure at the reservoir water level elevation is recorded as 0, and the water temperature is taken as the 24-hour average value of the temperature sensor below the reservoir water level and closest to the water surface.

[0041] In step nine, pressure and water temperature distribution curves are plotted at each measuring point, using the average values ​​of pressure and temperature sensors located below the reservoir water level at each measuring point. Plot the pressure / temperature distribution curves in front of the dam using pressure / temperature values ​​as the x-axis and elevation as the y-axis. The maximum value on the y-axis is taken as the reservoir water level elevation determined in step eight. The pressure and temperature values ​​at the reservoir water level elevation are determined according to step eight. When plotting the water level time-history curve of the measuring points, the water level gauge readings (H) at the measuring points are used. k ) j The graph is plotted with time on the x-axis and water level on the y-axis, with the x-axis interval being 1 hour.

[0042] In step ten, the initial value of the silt elevation at each measuring point is calculated using the pressure distribution curve of each measuring point. The specific calculation steps are as follows:

[0043] If the pressure distribution curve at the measuring point has an inflection point, then the elevation of that inflection point is the initial value of the silt elevation.

[0044] If the pressure distribution curve at the measuring point has no inflection points, then draw the tangents at the highest and lowest points of the pressure distribution curve, and take the elevation of the intersection of the two tangents as the silt elevation.

[0045] In step eleven, the calculated value of the reservoir bottom pressure at the measuring point is calculated using the following formula:

[0046]

[0047] In the formula, P s k γ is the calculated value of the pressure at the bottom of the reservoir at the measuring point. s For the buoyant density of the silt layer, h s The thickness of the silt at the measuring point, φ s ρ is the internal friction angle of the silt. 水 Let ρ be the density of water, and g be the acceleration due to gravity.

[0048] In step twelfth, the precise value of the silt elevation is calculated by comparing the monitored value of the pressure sensor at the bottom of the measuring point with the calculated value of the reservoir bottom pressure at that measuring point. The specific steps are as follows:

[0049] (1) Determine the accuracy error limit ε;

[0050] (2) when in, The average value of the monitoring values ​​from the pressure sensor at the bottom of the measuring point can be retrieved from the server terminal database using the sensor number;

[0051] (3) When At that time, the initial value of the silt elevation is calculated and adjusted according to the accuracy error limit ε until the set accuracy requirements are met. The specific steps are as follows:

[0052] (31) Based on the reservoir bottom pressure monitoring value, the silt elevation corresponding to the monitoring value is calculated using formula (4). At this time, in equation (4) All replaced by

[0053] (32) Calculate and The difference σ;

[0054] (33) Accumulate half of the difference σ to middle,

[0055] (34) will be revised Substitute into equation (4) and recalculate the pressure P′ at the bottom of the reservoir;

[0056] (35) Compare the pressure P′ at the bottom of the reservoir with the monitoring value of the pressure sensor at the bottom of the measuring point. If If the accuracy requirement is met, the calculation is stopped; otherwise, steps (2) to (5) are repeated until the accuracy requirement is met.

[0057] The beneficial effects achieved by this invention are as follows: The system and method of this invention can monitor the state of sediment and water temperature changes in front of the dam, thereby gaining real-time control of the reservoir's operating status and providing support and basis for the normal operation of the reservoir, as well as for formulating and adjusting the standards and measures for temperature control and crack prevention of the dam. Attached Figure Description

[0058] Figure 1 is a layout diagram of the monitoring system of the present invention;

[0059] Figure 2 is a top view of the monitoring system of the present invention;

[0060] Figure 3 is a schematic diagram of the anti-erosion protective shell and sensor connecting cylinder structure of the present invention;

[0061] Figure 4 is a schematic diagram of the anti-erosion protective shell structure of the present invention;

[0062] Figure 5 is a schematic diagram of the sensor connecting cylinder structure of the present invention;

[0063] Figure 6 is a schematic diagram of the assembly of the temperature and pressure sensors of the present invention;

[0064] Figure 7 is a schematic diagram of the installation of the radar level gauge of the present invention;

[0065] Figure 8 is a water temperature monitoring diagram of the present invention;

[0066] Figure 9 is a graph showing the pressure monitoring values ​​of the present invention;

[0067] Figure 10 is a monitoring curve of water level change process according to the present invention.

[0068] In the diagram: 1. Anti-erosion protective shell; 2. Sensor connecting cylinder; 3. Locking device; 4. Connecting rod one; 5. Inlet and outlet; 6. Connecting groove one; 7. Connecting rod two; 8. Temperature sensor; 9. Pressure sensor; 10. Radar level gauge; 11. Sensor fixing device; 12. Four-core cable; 13. Sub-control station; 14. Data transmission system; 15. Sensor connecting cylinder cover; 16. Dam; 17. Shoreline data acquisition room; 18. Underwater professional waterproof screw; 19. Connecting groove two. Detailed Implementation

[0069] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0070] This invention discloses an automatic monitoring method for sediment deposition elevation and upstream water temperature in a thick silt reservoir. It is based on the formulation of temperature control and crack prevention standards and measures for concrete dams, and studies key factors affecting the dam's stable temperature field and stress field. This method aims to clarify the dam's operating status and main boundary conditions, and provide technical support for long-term safe monitoring of the project.

[0071] The present invention discloses an automatic monitoring system for sediment deposition elevation and upstream water temperature in a thick silt reservoir, as shown in Figure 1, comprising:

[0072] A locking device is installed at the bottom of the riverbed, and an anti-scouring protective shell and a sensor connecting cylinder are fixedly installed on the locking device; the anti-scouring protective shell is set outside the sensor connecting cylinder;

[0073] The erosion protection shell is fixed to the dam surface by a connecting rod.

[0074] The anti-erosion protective shell is fixedly connected to the sensor connecting cylinder via connecting rod two.

[0075] The radar level gauge is connected to the sensor connecting cylinder via a stainless steel rod.

[0076] The data acquisition room is located on the shore and is connected to pressure sensors, temperature sensors, and radar level gauges via cables. It is used to collect and transmit monitoring data at regular intervals and to calculate the elevation of siltation.

[0077] An automatic monitoring method for sediment deposition elevation and upstream water temperature in a thick silt reservoir includes the following steps:

[0078] Step 1: Select the measurement point;

[0079] The measuring points were selected at key locations such as the dam overflow section, the section at maximum dam height, and the transition zone between the riverbed and the bank slope. Locking devices were installed at the bottom of the riverbed at these selected locations to secure the erosion protection shell, sensor housing, etc., and the elevation of each measuring point was recorded. k is the measurement point number.

[0080] The measuring points were selected at characteristic locations such as the dam overflow section, the section at maximum dam height, and the transition section between the riverbed and the bank slope. Locking devices were installed at the bottom of the riverbed at the selected locations to secure the erosion protection shell and sensor connecting tube, and the elevation of each measuring point was recorded. k represents the measurement point number. In this embodiment, five dam sections were selected as measurement points: the dam overflow section, the dam section at maximum dam height, and the transition section between the riverbed and the bank slope. The reservoir bottom elevation is 574m.

[0081] The locking device is a remote automatic locking device. The automatic locking device is connected to the shore data acquisition room via a cable from the sensor connecting tube. It receives and executes operation commands from the control room through wireless equipment, realizing remote control of the opening and closing of the locking device, and enabling the installation and maintenance of the monitoring equipment.

[0082] Step 2: Fabricate the erosion-resistant protective shell and sensor connecting cylinder;

[0083] The scour protection shell must possess functions such as corrosion resistance, scour resistance, impact resistance, and biofouling resistance. The scour protection shell is made of stainless steel with a thickness of 2cm. As a tall structure, to ensure structural stability, connecting rods are installed at fixed intervals to the dam surface to enhance stability; these intervals can be 10m. The scour protection shell also has inlet and outlet ports at fixed intervals, allowing water and sediment to enter the shell and contact the sensors; these intervals can be 5m, or locally reinforced as needed. The inlet and outlet radius of the bottommost scour protection shell is 2.5cm. Connecting grooves, 20cm long and 1cm thick, are pre-drilled at both ends of the shell, with four screw holes at the connection points for securing with professional underwater waterproof screws, as shown in Figure 3. The scour protection shell is uniformly coated inside and out with waterproof and anti-corrosion paint. After coating and curing for 1-2 weeks, it is transported to the site for assembly.

[0084] To facilitate transportation, the scour protection shell is made up of multiple sections, each 5m long, which facilitates the assembly of two sections. Each section has a connecting groove, which is 20cm long and 1cm thick. The joints are reinforced with underwater waterproof screws. The total length of the assembled shell is 2m higher than the maximum dam height.

[0085] The aforementioned sensor connecting cylinder is composed of multiple connecting cylinder sections. Each connecting cylinder section is 5m long and 2cm thick. Each connecting cylinder section is equipped with a second connecting groove, which is 20cm long and 1cm thick. The top of each connecting cylinder section is connected to the anti-erosion protective shell via a second connecting rod, enhancing the stability of the sensor connecting cylinder, as shown in Figure 5. After splicing, the total length of the sensor connecting cylinder is 2m higher than the maximum dam height. Sensor fixing devices are installed at predetermined intervals along the sensor connecting cylinder to fix the sensors to the connecting cylinder. The predetermined intervals can be 5m, or locally densified as needed.

[0086] Step 3: Install the pressure sensor and temperature sensor onto the sensor connecting cylinder;

[0087] Pressure and temperature sensors are installed on the sensor connecting cylinder at predetermined intervals via sensor fixing devices. The sensor installation positions correspond to the reserved positions of silt and reservoir water inlet / outlet on the anti-scour protective shell. The temperature sensor is placed on the water-facing side, and the pressure sensor is placed on the water-repellent side. Both pressure and temperature sensors are connected to the shore data acquisition room via a four-core cable through the inside of the sensor connecting cylinder for the acquisition and transmission of monitoring data.

[0088] This embodiment is a concrete arch dam exceeding 200m. Since the project is located in a river with high sediment content, the sediment deposition elevation is relatively high, and the water temperature changes significantly along the elevation. In order to accurately grasp the sediment pressure and water temperature changes at different elevations, sensors are arranged in 5m sections below the dead water level (756m) and in 2m sections above the dead water level (756m). The temperature sensor and pressure sensor are fixed to the sensor connecting cylinder with screws, and the connection seam is welded to ensure the seal, as shown in Figure 6.

[0089] Step 4: Install the anti-scour protective shell at the selected measuring point location. Install the sensor connecting cylinder inside the anti-scour protective shell. Fix the anti-scour protective shell and the sensor connecting cylinder on the locking device. The anti-scour protective shell is fixed to the dam surface by the connecting rod.

[0090] In this embodiment, after preparing the components according to steps two and three, they are assembled and installed on site. The bottom automatic locking device and the sensor are connected by a four-core cable and then led out through the sensor connecting tube. After installation, the sensor is checked to see if it is working properly, and any faulty sensors are replaced in time.

[0091] Step 5: Connect the radar level gauge to the sensor connecting cylinder using a stainless steel rod.

[0092] In this embodiment, a radar level gauge is installed on the top of the sensor connecting cylinder. The radar level gauge must face the reservoir water surface. A stainless steel connecting rod is used to fix the radar level gauge to the top of the sensor connecting cylinder, as shown in Figure 7. This ensures strong stability at the connection point and allows it to withstand severe weather such as strong winds and heavy rain. Wireless network coverage is provided, and the water level information is transmitted to the shore data acquisition room at regular intervals via a wireless transmission module.

[0093] Step 6: Set up a data acquisition room on the shore to collect and transmit monitoring data from pressure sensors, temperature sensors, and water level gauges at regular intervals;

[0094] A data acquisition room is set up on the shore to collect and transmit monitoring data from pressure sensors, temperature sensors, and water level gauges on a regular basis. The data acquisition room houses sub-control stations and mobile terminals. Real-time communication is established between the temperature sensors, pressure sensors, and water level gauges and the sub-control stations via four-core cables. The monitoring data from each sensor is collected and aggregated in real time, and transmitted to the central control service terminal via a wired / wireless transmission system. The service terminal automatically stores the monitoring data in databases such as MySQL, SQL Server, and SQLite.

[0095] In this embodiment, a data acquisition room was built on the right bank of the dam. The acquisition room is 3m long, 3m wide and 2.5m high. A stainless steel frame is placed inside, and 5 sub-control stations are placed on the top. The sub-control stations are equipped with both wired and wireless transmission modules. The data from the pressure sensor and temperature sensor are connected to the sub-control station via dedicated cables, and the water level gauge transmits data to the sub-control station via a wireless transmission module.

[0096] Step 7: Calibrate the monitoring frequency. Collect data from each sensor according to the set monitoring time interval, and summarize and transmit the data in the shore data acquisition room. Store the data from each sensor in the server database and calculate the average value of the monitoring values ​​of each sensor according to the requirements.

[0097] Considering the insignificant changes in reservoir hydrological and water environment conditions in the short term, as well as factors such as data sample size, the monitoring frequency is planned to be 24 times a day, with monitoring data collected every hour on the hour, and data transmitted to the data acquisition room control station in real time.

[0098] The data terminal calculates the average value of the data collected from each sensor between 00:00 and 23:00 on the same day:

[0099]

[0100]

[0101]

[0102] In the formula, and These are the average values ​​of the monitoring data from the pressure sensor, temperature sensor, and water level gauge from 0:00 to 23:00 on the same day, respectively. (P) k i ) j 、(T k i ) j and (H) k ) j These are the monitoring values ​​from the pressure sensor, temperature sensor, and water level gauge, respectively. i is the number of the pressure sensor and temperature sensor, j is the time, j = 0, 1, 2, ..., 23, and k is the measurement point number.

[0103] In this embodiment, based on the above settings, the internal data acquisition and transmission time interval is 1 hour. Every hour on the hour, the sub-control station issues an acquisition command to collect the current pressure value, water temperature value, and water level from the sensors at each measuring point, and transmits the data to the data terminal server in the engineering monitoring room via a wireless transmission network. This embodiment uses a MySQL database. Based on the measuring point number and sensor number, a data table is pre-established. The data terminal stores the data in the corresponding data table according to the measuring point number and sensor number in chronological order. The average value of the measured values ​​of each sensor is calculated at 0:00 every day. Taking temperature as an example, temperature sensor No. 1 at measuring point 1 is located at the bottom of the reservoir. Due to siltation, the temperature at the bottom of the reservoir is constant. The monitoring data for December 7th is shown in Table 1.

[0104] Table 1 Temperature monitoring values ​​at measuring point 1-1, temperature sensor 12-7

[0105]

[0106]

[0107] Therefore, on December 7th, the average temperature of temperature sensor #1 at measuring point 1 was... =13.8℃.

[0108] Step 8: Based on the 24-hour average value of the water level gauge obtained in Step 7, determine the water level elevation of each measuring point, as well as the pressure and water temperature in front of the dam at the water level elevation. Also determine the sensor number below the water level elevation of each measuring point, and the pressure and water temperature in front of the dam at the reservoir water level elevation.

[0109] If the reservoir water level is consistent with the sensor elevation, the pressure and water temperature at the reservoir water level elevation are taken as the 24-hour average of the pressure and temperature sensors at the same elevation. If the reservoir water level is between the two sets of sensors, the pressure at the reservoir water level elevation is recorded as 0, and the water temperature is taken as the 24-hour average of the temperature sensor below the reservoir water level and closest to the water surface.

[0110] In the embodiment, on December 7, the reservoir water level was 789m, which was consistent with the elevation of the sensor at the top of the measuring point. Therefore, the sensors arranged at measuring point 1 were all located below the reservoir water level. The pressure and water temperature at the reservoir water level were taken as the average value of the sensors at that elevation over 24 hours: 0 kPa and 2.9℃.

[0111] Step 9: Based on the 24-hour average values ​​of each sensor obtained in Step 7, the pressure and water temperature at the water level determined in Step 8, and the sensor numbers below the reservoir water level, plot the pressure and water temperature distribution curves and the water level time history curves for each measuring point.

[0112] Plot the pressure and water temperature distribution curves at each measuring point, using the average values ​​of pressure and temperature sensors located below the reservoir water level at each measuring point. Plot the pressure / temperature distribution curves in front of the dam using pressure / temperature values ​​as the x-axis and elevation as the y-axis. The maximum value on the y-axis is taken as the reservoir water level elevation determined in step eight. The pressure and temperature values ​​at the reservoir water level elevation are determined according to step eight. When plotting the water level time-history curve of the measuring points, the water level gauge readings (H) at the measuring points are used. k ) j The graph is plotted with time on the x-axis and water level on the y-axis, with the x-axis interval being 1 hour.

[0113] In the embodiment, the pressure value, water temperature in front of the dam and water level collected at measuring point 1 on a certain day are plotted as curves as shown in Figures 8, 9 and 10.

[0114] Step 10: Based on the pressure distribution curve of each measuring point drawn in Step 9, determine the pressure inflection point of each measuring point, and determine the initial value of the silt elevation of the measuring point based on the location of the inflection point.

[0115] To calculate the initial value of the silt elevation at a measuring point, if the pressure distribution curve at that point has an inflection point, then the elevation of that inflection point is the initial value of the silt elevation.

[0116] If the pressure distribution curve at the measuring point has no inflection points, then draw the tangents at the highest and lowest points of the pressure distribution curve, and take the elevation of the intersection of the two tangents as the silt elevation.

[0117] In this embodiment, the pressure distribution curve at measuring point 1 is shown in Figure 8. Since there is no obvious turning point, the tangents at the highest and lowest points of measuring point 1 are drawn, and the elevation of the intersection of the tangents is the silt elevation.

[0118] In step eleven, based on the initial value of silt thickness determined in step ten, the average value of radar water level gauge readings is used to calculate the reservoir bottom pressure at the measuring point. The calculation formula is as follows:

[0119]

[0120] In the formula, P s k γ is the calculated value of the pressure at the bottom of the reservoir at the measuring point. s For the buoyant density of the silt layer, h s The thickness of the silt at the measuring point, φ s ρ is the internal friction angle of the silt. 水 Let ρ be the density of water, and g be the acceleration due to gravity.

[0121] In the embodiment, the bulk density of the silt was 6.5 kN / m³. 3 Silt thickness h s =690-574=116m, φ s =14°, ρ 水 =1000kg / m 3 g = 10 N / m 2 The calculated pressure at the bottom of the reservoir at the measuring point is 2749.08 kPa. Step 12: Combine the monitoring value from the bottom pressure sensor with the calculated pressure value at the bottom of the reservoir obtained in Step 11 to determine the precise value of the siltation elevation.

[0122] The specific steps are as follows:

[0123] (1) Determine the accuracy error limit ε;

[0124] (2) when in, The average value of the monitoring values ​​from the pressure sensor at the bottom of the measuring point can be retrieved from the server terminal database using the sensor number;

[0125] (3) When At that time, the initial value of the silt elevation is calculated and adjusted according to the accuracy error limit ε until the set accuracy requirements are met. The specific steps are as follows:

[0126] (31) Based on the reservoir bottom pressure monitoring value, the silt elevation corresponding to the monitoring value is calculated using formula (4). At this time, in equation (4) All replaced by

[0127] (32) Calculate and The difference σ;

[0128] (33) Accumulate half of the difference σ to middle,

[0129] (34) will be revised Substitute into equation (4) and recalculate the pressure P′ at the bottom of the reservoir;

[0130] (35) Compare the pressure P′ at the bottom of the reservoir with the monitoring value of the pressure sensor at the bottom of the measuring point. If If the accuracy requirement is met, the calculation is stopped; otherwise, steps (2) to (5) are repeated until the accuracy requirement is met.

[0131] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for automatically monitoring the siltation elevation and upstream water temperature of a thick silt reservoir, characterized in that, The monitoring is conducted using an automatic monitoring system for sediment deposition elevation and upstream water temperature in a thick silt-filled reservoir. This system includes: a locking device installed at the bottom of the riverbed; an anti-scour protective shell and a sensor connecting cylinder fixedly installed on the locking device; the anti-scour protective shell is located outside the sensor connecting cylinder; the anti-scour protective shell is fixed to the dam surface via a connecting rod; the anti-scour protective shell is fixedly connected to the sensor connecting cylinder via a second connecting rod; a radar level gauge is connected to the sensor connecting cylinder via a stainless steel rod; and a data acquisition room located on the riverbank, connected to the pressure sensor, temperature sensor, and radar level gauge via cables, for periodic data acquisition and transmission. The data is collected and the siltation elevation is calculated. The process includes the following steps: Step 1, selecting the measuring point; Step 2, fabricating an anti-scour protective shell and a sensor connecting cylinder; Step 3, installing the pressure sensor and temperature sensor on the sensor connecting cylinder; Step 4, installing the anti-scour protective shell at the selected measuring point, installing the sensor connecting cylinder inside the anti-scour protective shell, and fixing the anti-scour protective shell and sensor connecting cylinder to the locking device; the anti-scour protective shell is fixed to the dam surface via a connecting rod; Step 5, connecting the radar level gauge to the sensor connecting cylinder via a stainless steel rod; Step 6, setting up a data acquisition room on the bank to collect and analyze the monitoring data from the pressure sensor, temperature sensor, and level gauge. Step 7: Accurately determine the monitoring frequency. Collect data from each sensor according to the set monitoring time interval, and summarize and transmit the data in the shore data acquisition room. Store the data from each sensor in the server database and calculate the average value of each sensor's monitoring value as required. Step 8: Based on the 24-hour average value of the water level gauge obtained in Step 7, determine the water level elevation, pressure at the water level elevation, and water temperature in front of the dam at each measuring point, and determine the sensor number below the water level elevation at each measuring point. Step 9: Based on the 24-hour average value of each sensor obtained in Step 7, the pressure at the water level elevation and water temperature in front of the dam determined in Step 8, and the sensor number below the reservoir water level, plot the pressure at each measuring point. Step 10: Based on the pressure distribution curves of each measuring point drawn in Step 9, determine the pressure inflection points of each measuring point, and determine the initial value of the siltation elevation of that measuring point based on the location of the inflection points; Step 11: Based on the initial value of the siltation thickness determined in Step 10, calculate the calculated value of the reservoir bottom pressure at that measuring point using the average value of the radar water level gauge readings; Step 12: Determine the accurate value of the siltation elevation by combining the monitoring values ​​of the bottom pressure sensors with the calculated value of the reservoir bottom pressure obtained in Step 11; In Step 9, pressure and water temperature distribution curves of each measuring point were drawn, and the average values ​​of the pressure and temperature sensors arranged below the reservoir water level elevation at the measuring points were used. 、 Plot the pressure / temperature distribution curves in front of the dam with pressure / temperature values ​​on the x-axis and elevation on the y-axis. The maximum value of the y-axis is taken as the reservoir water level elevation determined in step eight. The pressure and temperature values ​​at the reservoir water level elevation are determined according to step eight. When plotting the water level time-history curve of the measuring points, the water level gauge readings at the measuring points are used. The graph is plotted with time on the x-axis and water level on the y-axis. In step ten, the initial value of the siltation elevation at each measuring point is calculated using the pressure distribution curve of each measuring point. The specific calculation steps are as follows: If the pressure distribution curve of a measuring point has a turning point, the elevation of the turning point is the initial value of the siltation elevation. If the pressure distribution curve at the measuring point has no inflection point, then draw the tangents at the highest and lowest points of the pressure distribution curve, and take the elevation of the intersection of the two tangents as the silt elevation. In step twelfth, the precise value of the silt elevation is calculated by comparing the monitored value of the pressure sensor at the bottom of the measuring point with the calculated value of the reservoir bottom pressure at that measuring point. The specific steps are as follows: (1) Determine the accuracy error limit ；（2） ,when ,in, The average value of the pressure sensor at the bottom of the measuring point can be retrieved from the server terminal database by the sensor number; (3) when At that time, based on the accuracy error limit The initial value of the silt elevation is calculated and adjusted until the set accuracy requirements are met. The specific steps are as follows: (31) Based on the monitoring value of the reservoir bottom pressure, the silt elevation corresponding to the monitoring value is calculated using formula (4). At this time, in equation (4) All replaced by (32) Calculate and The difference (33) The difference 1 / 2 added to middle, (34) The revised Substitute into equation (4) and recalculate the pressure at the bottom of the reservoir. (35) Increase the pressure at the bottom of the tank Compared with the monitoring value of the pressure sensor at the bottom of the measuring point, if If the accuracy requirement is met, the calculation is stopped; otherwise, steps (2) to (5) are repeated until the accuracy requirement is met.

2. The method for automatic monitoring of siltation elevation and upstream water temperature in a thick silt reservoir according to claim 1, characterized in that: In step one, measuring points are selected at the dam overflow section, the section at maximum dam height, and the transition section between the riverbed and the bank slope; locking devices are installed at the bottom of the riverbed at the selected locations, and the elevations of each measuring point are recorded. k is the measurement point number.

3. The method for automatic monitoring of siltation elevation and upstream water temperature in a thick silt reservoir according to claim 1, characterized in that: In step two, the scour protection shell is made of stainless steel, and a connecting rod is installed at a set interval to fix it to the dam surface; the scour protection shell is equipped with inlet and outlet at a set interval; the scour protection shell is spliced ​​from multiple protective shell sections, and each protective shell section is equipped with a connecting groove. The connection of the protective shell is reinforced by underwater waterproof screws. The total length of the spliced ​​protective shell is 2m higher than the maximum dam height.

4. The method for automatic monitoring of siltation elevation and upstream water temperature in a thick silt reservoir according to claim 1, characterized in that: The sensor connecting cylinder is composed of multiple connecting cylinder sections. Each connecting cylinder section is provided with a connecting groove 2. The top of each connecting cylinder section is connected to the anti-scouring protective shell through a connecting rod 2. After splicing, the total length of the sensor connecting cylinder is 2m higher than the maximum dam height. The sensor connecting cylinder is provided with sensor fixing devices at set intervals to fix the sensor on the sensor connecting cylinder.

5. The method for automatic monitoring of siltation elevation and upstream water temperature in a thick silt reservoir according to claim 1, characterized in that: In step three, the sensor installation position corresponds to the inlet and outlet positions on the anti-scour protective shell. The temperature sensor is placed on the water-facing side, and the pressure sensor is placed on the water-repellent side. Both the pressure sensor and the temperature sensor are connected to the shore data acquisition room through a four-core cable and inside the sensor connecting tube to collect and transmit monitoring data.

6. The method for automatic monitoring of siltation elevation and upstream water temperature in a thick silt reservoir according to claim 1, characterized in that: In step seven, monitoring data is collected every hour, with the collection time set to the hour, and data is transmitted to the data acquisition room control station in real time; the data terminal calculates the average value of the data collected from each sensor from 0:00 to 23:00 on the same day. (1) (2) (3) In the formula, 、 and These are the average values ​​of the monitoring data from the pressure sensor, temperature sensor, and water level gauge from 0:00 to 23:00 on the same day. 、 and These are the monitoring values ​​from the pressure sensor, temperature sensor, and water level gauge, respectively. The numbers are for the pressure sensor and the temperature sensor. For time, =0, 1, 2, …, 23， This is the measurement point number.

7. The method for automatic monitoring of siltation elevation and upstream water temperature in a thick silt reservoir according to claim 1, characterized in that: In step eight, the average value of the radar water level gauge over 24 hours is used as the reservoir water level for the day, and the sensor numbers below the reservoir water level elevation at that measuring point are recorded. Based on the reservoir water level elevation at that measuring point and the elevations of each sensor, the pressure and water temperature in front of the dam at the reservoir water level elevation are determined. If the reservoir water level is consistent with the sensor elevation, the pressure and water temperature in front of the dam at the reservoir water level elevation are taken as the average value of the pressure sensor and temperature sensor over 24 hours at the same elevation. If the reservoir water level is between two sets of sensors, the pressure at the reservoir water level elevation is recorded as 0, and the water temperature is taken as the average value of the temperature sensor below the reservoir water level and closest to the water surface over 24 hours.

8. The method for automatic monitoring of siltation elevation and upstream water temperature in a thick silt reservoir according to claim 1, characterized in that: In step eleven, the calculated value of the reservoir bottom pressure at the measuring point is calculated using the following formula: (4) In the formula, γ is the calculated value of the pressure at the bottom of the reservoir at the measuring point. s The buoyant density of the silt layer, The thickness of the silt at the measuring point, , φ s The internal friction angle of the silt. Let ρ be the density of water, and g be the acceleration due to gravity.

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