Method and device for predicting propagation time of sand peak in reservoir area based on different types of floods

Abstract

The present invention provides a method and device for predicting the propagation time of sediment peaks in a reservoir area based on different types of floods, which can quickly and accurately determine the propagation time of sediment peaks in the reservoir area for different flood types. The method for predicting the propagation of sediment peaks in the reservoir area includes: Step 1, select the hydrological station at the end of the reservoir backwater as the incoming flow inlet hydrological station, obtain the daily data of the flow rate and sediment concentration, the relevant data of sediment particle size, and the relevant data of the water depth in front of the reservoir dam at this station, and statistically analyze the relevant characteristic quantities when floods occur at the incoming flow hydrological station; Step 2, determine the specific flood type based on the fisher time and the peak shape of the flood itself; Step 3, deduce the movement speed of the water body propagating to the hydrological station in the reservoir area according to the characteristics of the incoming flood events and the position relationship of the hydrological stations in the reservoir area, and calculate the movement time of the water flow in the reservoir area; Step 4, calculate the influence of the asynchronous sediment peak of the initial flood peak and the flood duration; Step 5, calculate the propagation time of the sediment peak of this flood event according to the type of the flood event.

Description

Technical Field

[0001] The present invention belongs to the technical field of water conservancy river engineering, and particularly relates to a method and device for predicting the propagation time of sand peaks in a reservoir area based on different types of floods. Background Art

[0002] During natural river floods, the sand peak propagates downstream synchronously with the flood peak. After the construction of a reservoir, due to the increase in water depth, the propagation speed of the flood peak accelerates while the propagation speed of the sand peak slows down, resulting in the phenomenon that the propagation of the sand peak gradually lags behind the flood peak. This asynchronous movement characteristic of the flood peak and sand peak makes it difficult for the sediment carried by the flood to be discharged from the reservoir in a timely manner. Therefore, in order to improve the sediment discharge ratio during the flood season of the reservoir and maintain its long-term use, a new flood season sand peak scheduling and sediment discharge mode of "lowering the water level when the flood peak arrives and increasing the discharge for sediment discharge when the sand peak arrives" has been carried out mainly using the Three Gorges Reservoir, taking advantage of the asynchronous propagation characteristics of the flood peak and sand peak of single floods, enabling more sediment of single floods to move to the front of the dam, thereby improving the sediment discharge efficiency of the reservoir. The Three Gorges Reservoir has attempted sand peak sediment discharge scheduling in the actual flood regulation in 2012, 2013, 2018, and 2020, achieving good sediment discharge and silt reduction effects, which also provides valuable experience and relevant theoretical basis for the long-term use of scheduling and sediment discharge of other large reservoirs. The accurate prediction of the sand peak propagation time is an important basis and prerequisite for carrying out more refined sand peak scheduling and sediment discharge. However, the types of reservoir inflow floods are not single but multiple, which also leads to different movement characteristics of the sand peak under different flood conditions. Therefore, the accurate prediction of the sand peak propagation time cannot ignore the differences in flood types, which is crucial for further accurately determining the timing of the reservoir sand peak scheduling and sediment discharge and formulating the scheduling plan.

[0003] The existing prediction of the sand peak propagation time in the reservoir area mainly uses a one-dimensional unsteady flow sediment transport mathematical model to calculate the prediction of the sand peak propagation time. The prerequisite conditions for this method include a large amount of data such as a one-dimensional unsteady flow sediment transport mathematical model with high accuracy, reservoir topography and cross-section data, prediction results of inflow water and sediment and sediment gradation, and prediction results of the water level process in front of the dam. The construction of the previous one-dimensional unsteady flow sediment transport mathematical model also depends on relevant professionals. The use of the prediction technology requires professionals with relevant knowledge backgrounds and the ability to use the water and sediment mathematical model for operation, and the calculation accuracy is affected by the entire inflow water and sediment conditions, sediment gradation, and the prediction accuracy of the water level process in front of the dam. Therefore, there are deficiencies such as a large amount of required measured data and difficult and timely acquisition, the need for relevant technical personnel to operate, and low prediction accuracy, causing great inconvenience to the rapid and accurate prediction of the sand peak propagation time. In addition, the existing methods for predicting the sand peak propagation time in the reservoir area proposed by the prior art do not consider the influence of different flood types, different initial phase relationships between the flood peak and sand peak, and the particle size of the incoming sediment, resulting in a large error between the prediction result and the measured propagation time. Summary of the Invention

[0004] The present invention is made to solve the above problems, and aims to provide a method and device for predicting the propagation time of sand peaks in a reservoir area based on different types of floods, which can quickly and accurately determine the propagation time of sand peaks in the reservoir area for different flood types, making the prediction results more in line with the actual situation.

[0005] In order to achieve the above object, the present invention adopts the following solutions:

[0006] <Method>

[0007] The present invention provides a method for predicting the propagation time of sand peaks in a reservoir area based on different types of floods, including the following steps:

[0008] Step 1: Select the hydrological station at the end of the reservoir backwater as the incoming flow inlet hydrological station, obtain the daily average data of the flow rate and sediment concentration at this station, the relevant data of sediment particle size, and the relevant data of the water depth in front of the reservoir dam, and statistically calculate the relevant characteristic quantities when floods occur at the incoming flow hydrological station;

[0009] Step 2: Determine the specific flood type based on the fisher time and the flood peak shape itself;

[0010] Step 3: Deduce the movement speed of the water body propagating to the hydrological station in the reservoir area according to the characteristics of the incoming flood events and the position relationship of the hydrological stations in the reservoir area, and calculate the movement time of the water flow in the reservoir area;

[0011] Step 4: Calculate the influence K of the initial flood peak sand peak asynchrony and the flood duration 异步 :

[0012]

[0013] In the formula, and Q0 are respectively the daily average flood peak flow rate and the starting flow rate when the flood starts to rise at the incoming flow control station, and Δt 超前or滞后 represents the asynchrony duration between the sand peak and the flood peak = T 沙峰 -T 洪峰 ; T rise and T down are respectively the time for the flood at the incoming flow control station to rise from the starting flow rate to the flood peak and the time to drop from the flood peak to the starting flow rate;

[0014] Step 5: Determine the propagation time of the sand peak of the flood event;

[0015] The propagation time of the sand peak in the reservoir area is calculated using the following formula:

[0016]

[0017] In the formula, k0, a, b, and c are all constants related to the flood event type, based on the reservoir sediment particle size d 50Obtain the generalized term K of sediment particle size d = d 50 / 0.002, based on the peak sediment concentration SSC peak and the ratio of the starting sediment concentration SSC0 to obtain the generalized term K of the sand peak rise ssc = SSC peak / SSC0, t 水流 is the movement time of the water flow in the interval;

[0018] According to the type of flood event, substitute the constants corresponding to different types of floods into Equation 2 to calculate the sand peak propagation time of this flood event.

[0019] Preferably, in the method for predicting the sand peak propagation time in the reservoir area based on different types of floods provided by the present invention, in step 1, the relevant characteristic quantities to be statistically analyzed include flood characteristic quantities, sediment inflow characteristic quantities, water depth characteristic quantities in front of the dam, the initial asynchronous state Δt 异步 between the flood peak and the sand peak, and the water depth H 坝前 in front of the dam before the flood comes; the flood characteristic quantities include the peak flow of the incoming flood, the starting flow Q0, the total flood volume R sum , the rising duration T rise , the falling duration T down , the water depth H 入库 when the flood peak appears at the incoming hydrological station, and the average water flow velocity The sediment inflow characteristic quantities include the sediment concentration SSC peak of the incoming sand peak, the starting sediment concentration SSC0 of the sand peak, and the median sediment particle size d 50 in the current month during the flood season.

[0020] Preferably, in the method for predicting the sand peak propagation time in the reservoir area based on different types of floods provided by the present invention, in step 2, according to calculate the fisher time, then determine the range it is in, and combine the peak shape of the specific flood process to further determine the type of the incoming flood; represents the total flood volume of the entire flood process.

[0021] Preferably, in the method for predicting the sand peak propagation time in the reservoir area based on different types of floods provided by the present invention, step 3 includes the following sub-steps: Step 3-1, collect the average water flow velocity when the flood peak appears at the incoming hydrological station, the water depth H 入库 when the flood peak appears, and the water depth H 坝前 in front of the dam before the flood comes; calculate the water depth of the next hydrological station based on the positions of the incoming hydrological station and the next hydrological station The flow velocity of the next hydrological station is The flow velocity of the water at the dam front position is L represents the distance; in step 3-2, the range between two adjacent hydrological stations is taken as an interval, and the average flow velocity between the two hydrological stations is divided by the distance between the two adjacent hydrological stations Thereby obtaining the water flow movement time Similarly, the water flow movement times of the remaining intervals can be obtained, and the sum of the water flow movement times of each interval is used to obtain the total time for the water flow to move in the reservoir area.

[0022] Preferably, for the method for predicting the propagation time of sand peaks in the reservoir area based on different types of floods provided by the present invention, in step 5, the determination methods of the constants k0, a, b, and c corresponding to different types of floods are as follows: based on the historical measured data including different types of floods in the prediction area, multiple groups of K under each type of flood are calculated by substituting into Equation 1 异步 , and then based on the multiple known groups of K under each type of flood 异步 , t 沙峰 , K d , K ssc Substitute into Equation 2 to fit and obtain the corresponding constants.

[0023] Preferably, for the method for predicting the propagation time of sand peaks in the reservoir area based on different types of floods provided by the present invention, in step 5, when the prediction area is the Three Gorges area, the constants corresponding to each flood type are as follows:

[0024] When the flood type is short-duration and sharp-shaped, k0 = 0.139, a = 0.806, b = 0.220, c = -0.908;

[0025] When the flood type is short-medium-duration and conventional, k0 = 0.0013, a = 3.822, b = 0.087, c = -3.856;

[0026] When the flood type is medium-duration and conventional, k0 = 0.037, a = 0.995, b = 0.678, c = 0;

[0027] When the flood type is medium-duration and double-peak-shaped, k0 = 0.612, a = 0, b = 0.204, c = -0.455;

[0028] When the flood type is long-duration and intense, k0 = 0.255, a = 0.5, b = 0.4, c = -0.883;

[0029] When the flood type is long-duration and short and fat, k0 = 0.255, a = 0.497, b = 0.184, c = -0.883.

[0030] <Device>

[0031] Furthermore, the present invention also provides a device for predicting the propagation time of sand peaks in the reservoir area based on different types of floods that automatically implements the above <method>, which is characterized in that it includes:

[0032] The data acquisition unit selects the hydrological station at the end of the reservoir backwater as the incoming reservoir inlet hydrological station, obtains the daily average data of the flow rate and sediment concentration, the relevant data of the sediment particle size, and the relevant data of the water depth in front of the reservoir dam at this station, and statistics the relevant characteristic quantities when a flood occurs at the incoming reservoir hydrological station;

[0033] The type judgment unit judges the specific flood type based on the fisher time and the peak shape of the flood itself;

[0034] The movement time calculation unit calculates the movement speed of the water body propagating to the reservoir area hydrological station according to the characteristics of the flood events entering the reservoir and the positional relationship of the reservoir area hydrological stations, and calculates the movement time of the water flow in the reservoir area;

[0035] The asynchronous influence calculation unit calculates the asynchronous influence of the initial flood peak and sediment peak and the influence K of the flood duration 异步 :

[0036]

[0037] In the formula, and Q0 are the daily average flood peak flow rate and the starting flow rate when the flood starts to rise at the incoming reservoir control station, respectively, and Δt 超前or滞后 represents the asynchronous duration of the sediment peak and the flood peak = T 沙峰 -T 洪峰 ; T rise and T down are the times for the flood at the incoming reservoir control station to rise from the starting flow rate to the flood peak and to drop from the flood peak to the starting flow rate, respectively;

[0038] The sediment peak propagation time prediction unit substitutes the constants corresponding to different types of floods into Equation 2 according to the type of flood events, and calculates the sediment peak propagation time of this flood event:

[0039] t 沙峰 = k0·(K d ) a ·(K ssc ) b ·(K 异步 ) c ·t 水流 (Equation 2)

[0040] In the formula, k0, a, b, and c are all constants related to the type of flood events, and based on the reservoir sediment particle size d 50 the sediment particle size generalization term K is obtained d = d 50 / 0.002, and based on the ratio of the peak sediment concentration SSC peak and the starting sediment concentration SSC0, the sediment peak rise generalization term K ssc = SSC peak / SSC0, t水流 is the movement time of water flow in the interval;

[0041] The control unit is communicatively connected to the data acquisition unit, the type judgment unit, the movement time calculation unit, the asynchronous influence calculation unit, and the sand peak propagation time prediction unit, and controls their operations.

[0042] Preferably, the device for predicting the sand peak propagation time in the reservoir area based on different types of floods provided by the present invention may further include: an input display unit, communicatively connected to the control unit, for allowing a user to input operation instructions, and displaying the input, output, and intermediate processing data of the corresponding unit in the form of text, table, graph, or three-dimensional dynamic model according to the operation instructions.

[0043] Preferably, in the sand peak propagation time prediction unit of the device for predicting the sand peak propagation time in the reservoir area based on different types of floods provided by the present invention, the determination methods of the constants k0, a, b, and c corresponding to different types of floods are as follows: based on the historical measured data of different types of floods in the prediction area, substitute them into Equation 1 to calculate multiple groups of K under each type of flood 异步 , and then according to the known multiple groups of K under each type of flood 异步 , t 沙峰 , K d , K ssc Substitute into Equation 2 to fit the corresponding constants.

[0044] Preferably, in the sand peak propagation time prediction unit of the device for predicting the sand peak propagation time in the reservoir area based on different types of floods provided by the present invention, when the prediction area is the Three Gorges area, the constants corresponding to each flood type are as follows:

[0045] When the flood type is short-duration sharp and thin type, k0 = 0.139, a = 0.806, b = 0.220, c = -0.908;

[0046] When the flood type is short-to-medium-duration conventional type, k0 = 0.0013, a = 3.822, b = 0.087, c = -3.856;

[0047] When the flood type is medium-duration conventional type, k0 = 0.037, a = 0.995, b = 0.678, c = 0;

[0048] When the flood type is medium-duration double-peak type, k0 = 0.612, a = 0, b = 0.204, c = -0.455;

[0049] When the flood type is long-duration intense type, k0 = 0.255, a = 0.5, b = 0.4, c = -0.883;

[0050] When the flood type is long-duration and short and fat, k0 = 0.255, a = 0.497, b = 0.184, c = -0.883.

[0051] Functions and effects of the invention

[0052] The method and device for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods provided by the present invention aim at the asynchronous movement phenomenon of the flood peak and sediment peak during a single flood event, and fully consider the differences in different flood types, the asynchrony of different initial flood peaks and sediment peaks, different sediment particle sizes, the rise amplitudes of the flood peak and sediment peak, as well as the influence of the entire water level regulation in front of the dam on the propagation of the sediment peak. It can more comprehensively and accurately predict the propagation time of the sediment peak of different types of floods, which helps to grasp the favorable sediment discharge timing and improve the sediment discharge efficiency. Moreover, the present invention does not require river channel topography, the water and sediment discharge process at the reservoir outlet, and the mathematical model of water and sediment transport. The required data is less and easy to obtain, the calculation is simple, and the accuracy is high. It provides a more convenient and accurate method for the prediction of sediment peak discharge scheduling based on the asynchronous characteristics of the flood peak and sediment peak, and provides a scientific basis for the refined scheduling mode of the sediment peak process discharge in the reservoir (group). Description of the drawings

[0053] Figure 1 It is a schematic diagram of the characteristics of the incoming flood, the characteristics of the incoming sediment volume, and the characteristics of the water level in front of the dam related to the embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the initial phase relationship between the flood peak and sediment peak related to the embodiment of the present invention, where (a) is in advance, (b) is synchronous, and (c) is lagging;

[0055] Figure 3 It is a schematic diagram of the Three Gorges Reservoir area related to the embodiment of the present invention;

[0056] Figure 4 It is the prediction effect and comparison effect diagram related to the comparative example of the present invention. Detailed implementation manners

[0057] The following describes in detail the method and device for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods according to the present invention with reference to the drawings.

[0058] <Example 1>

[0059] As Figure 1 shown, the method for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods provided in this embodiment includes the following steps:

[0060] Step 1: Select a representative station at the tail of the reservoir as the representative incoming station, and obtain the flow rate and sediment concentration processes when a flood occurs at the representative incoming station. As Figure 1 shown, count the characteristic quantities of the flood peak and sediment peak and the characteristic quantity of the water depth in front of the dam for this single flood event, including the characteristics of the incoming flood (flood peak flow rate Initial flow rate Q0, total flood volume R sum , rising stage duration T rise , falling stage duration T down , water depth H at the time of flood peak 入库 and average flow velocity ), initial asynchrony Δt between flood peak and sediment peak 异步 , incoming sediment characteristics (sediment concentration SSC at sediment peak peak , initial sediment concentration SSC0 at the start of sediment peak rise, median sediment grain size d in the month of flood season 50 ), water depth H in front of the dam before the flood 坝前 .

[0061] Step 2: Calculate the Fisher time according to the formula Equivalent the entire flood process to the movement duration of the flood peak flow rate by calculating the Fisher time. Determine the range it is in by calculating the Fisher time, and then judge the specific flood category of this flood in combination with the flood peak shape of the flood itself.

[0062] Step 3: Collect the average flow velocity corresponding to the flood peak at the incoming flow hydrological station Water depth H at the time of flood peak 入库 and water depth H in front of the dam before the flood 坝前 . Calculate the water depth at the next hydrological station based on the location of the incoming flow hydrological station and the location of the next hydrological station The flow velocity at the next hydrological station is The flow velocity at the location in front of the dam is Take the range between two adjacent hydrological stations as an interval, and divide the distance between the two hydrological stations by the average flow velocity between the two hydrological stations to obtain the flow movement time Similarly, the flow movement times of the remaining intervals can be obtained. Adding up the flow movement times of each interval can get the total time t for the flow to move in the reservoir area 水流 = t 入库-1 + t 1-坝前 .

[0063] Step 4: Use to calculate the influence of the initial flood peak and sediment peak asynchrony and flood duration and perform normalization processing; use the incoming sediment grain size d 50 to calculate the generalized item K of sediment grain size d = d 50 / 0.002; use the ratio of peak sediment concentration SSC peak and initial sediment concentration SSC0 to obtain the generalized item K of sediment peak rise ssc = SSC peak / SSC0.

[0064] Step 5: Calculate the propagation time of the sediment peak in the reservoir area The values vary for different types of floods. Substitute the relevant parameters of the flood type to which this flood event belongs into the calculation to obtain the propagation time of the sediment peak for this flood event.

[0065] In the above steps, the symbols, physical meanings, and units are as follows: $Q_m$ and $Q_0$ are the average daily peak flow and the starting flow when the flood starts to rise at the reservoir inflow control station, with the unit of $m^3 / s$; $T_1$ 3 / s; $T_1$ rise 、$T_2$ down are the times for the flood at the reservoir inflow control station to rise from the starting flow to the peak and to drop from the peak to the starting flow, respectively, with the unit of days; $R$ represents the total flood volume during the entire flood process, with the unit of $10^4 m^3$; 8 $m^3$ 3 ; $SSC_m$ and $SSC_0$ represent the average daily sediment concentration of the sediment peak and the starting sediment concentration of the sediment peak at the reservoir inflow control station, respectively, with the unit of $kg / m^3$; 3 ; $H$ 坝前 is the water depth in front of the dam when the peak flow appears at the reservoir inflow control station, with the unit of m; $d$ 50 is the median sediment particle size in the sediment during the flood season of the month at the reservoir inflow control station, with the unit of mm; $\Delta t$ 异步 $=\ T_3$ 沙峰 $-T_4$ 洪峰 is the initial asynchronous situation between the peak flow and the sediment peak, that is, the initial asynchronous situation is the time when the sediment peak appears minus the time when the peak flow appears, and there are three situations: the sediment peak is ahead, the peak flow and the sediment peak are synchronous, and the sediment peak lags behind, Figure 2 as shown; $v$ is the average flow velocity of the water flow, with the unit of m / s; $L$ is the distance between the upper and lower hydrological stations, with the unit of m; $t$ is the movement time of the water flow in the interval, with the unit of s.

[0066] In this embodiment, as Figure 3 shown, taking the Three Gorges Reservoir as an example, the selected control station is the Cuntan Station, the inflow control station of the Three Gorges Reservoir. Six typical flood events from 2003 to 2020 at this station are selected, and the propagation time of the sediment peak of different types of flood events is predicted according to the following discrimination steps by combining the measured average daily flow, sediment concentration data, sediment particle size data, and average daily data of the water level in front of the dam.

[0067] I. Select flood events and count relevant characteristic quantities.

[0068] Based on the measured data of the Cuntan Station, six typical flood processes are selected, and the specific flood characteristic quantities, sediment peak characteristic quantities, and water level characteristic quantities in front of the dam of these six flood events are counted, including the peak flow of the inflow flood starting flow $Q_0$, total flood volume $R$ sum 、rising duration $T_1$ rise, the falling time T down , the initial asynchronous situation Δt of the flood peak and sediment peak 异步 , the sediment concentration SSC of the incoming sediment peak peak , the sediment concentration SSC0 at the rising of the sediment peak, the water depth H at the occurrence of the flood peak 入库 , the water flow velocity at the incoming station when the flood peak appears The water depth H in front of the dam before the flood comes 坝前 , the median grain size d of sediment in the flood season of the current month 50 , as shown in Table 1 below.

[0069] Table 1 Statistical table of relevant elements required for predicting the propagation time of typical flood sediment peaks in the embodiments of the present invention

[0070]

[0071] II. Calculate the fisher time and determine the flood type.

[0072] Adopt Calculate the fisher time of 6 typical floods respectively, and further distinguish the flood type based on the fisher time and the specific flood peak type. For the floods entering the Three Gorges Reservoir, if T fisher is around 4 - 5.5, it is considered that the flood belongs to a short-duration flood; if T fisher is around 5.5 - 7, it is considered that the flood belongs to a short-medium-duration conventional flood; if T fisher is around 7 - 8 and there is no double peak, it is considered that the flood belongs to a medium-duration conventional flood type; if T fisher is between 8 - 9 and there is a double peak in the flood, it is considered that the flood belongs to a medium-duration multi-peak flood type; if T fisher is around 9 - 11 and the flood rise is large, it is considered that the flood belongs to a long-duration intense type, otherwise it is a long-duration short and fat type. The discrimination results of the 6 selected typical floods are shown in Table 2 below.

[0073] Table 2 Fisher time calculation and flood type discrimination table in the embodiments of the present invention

[0074]

[0075] III. Calculate the water flow movement time

[0076] Adopt the water depth H corresponding to the occurrence of the flood peak at the representative incoming station Cuntan Station 入库 and the water depth H of Miaohe Station 庙河 (Miaohe Station is close to the front of the dam, and its water depth is used to replace the water depth in front of the dam), to obtain the water depth relationship corresponding to Qingxichang Station and Wanxian Station Use to obtain the average water flow velocity corresponding to when the flood peak propagates to the hydrological station in the reservoir area As shown in Table 3 below.

[0077] Table 3 Flow Velocity and Travel Time of 6 Typical Floods in the Embodiment of the Invention

[0078]

[0079] Then use to calculate the travel time of the water flow in different intervals respectively, and add the above travel times to get t 水流 = t 寸滩-清溪场 + t 清溪场-万县 + t 万县-庙河 The total travel time of the water flow in the reservoir area can be obtained, and the calculation results are shown in Table 4 below.

[0080] Table 4 Travel Time of 6 Typical Floods in the Embodiment of the Invention Unit: days

[0081]

[0082] IV. Calculate the Relevant Variables Required for the Invention

[0083] Use to calculate the influence of the asynchronous initial flood peak and sediment peak and the flood duration and perform normalization processing; use the sediment particle size d 50 to calculate the generalized item K of the sediment particle size d = d 50 / 0.002; use the ratio of the peak sediment concentration SSC peak and the initial sediment concentration SSC0 to obtain the generalized item K of the sediment peak rise ssc = SSC peak / SSC0. The specific calculation values are shown in Table 6.

[0084] V. Calculate the Travel Time of the Sediment Peak of Different Types of Floods

[0085] Use t 沙峰 = k0·(K d ) a ·(K ssc ) b ·(K 异步 ) c ·t 水流 to predict the travel time of the sediment peak of different types of floods. The selection of coefficients under different types of flood conditions is shown in Table 5, and the specific calculation results are shown in Table 6 below.

[0086] Table 5 Prediction Parameters for the Travel Time of the Sediment Peak of Different Types of Floods in the Embodiment of the Invention

[0087]

[0088] Table 6 Prediction results and comparison results of the peak propagation time of different types of floods in the embodiments of the present invention

[0089]

[0090] <Comparative example>

[0091] This comparative example takes the measured data of the Three Gorges Reservoir as an example, and compares the prediction method of the peak propagation time of the existing technology with the prediction results of the peak propagation duration of different flood types of the present invention.

[0092] By comparing the measured peak propagation time of the Three Gorges Reservoir during 6 typical floods between 2003 and 2020 and the prediction results of the prediction method of the peak propagation time in the reservoir area of the existing technology, Table 6 and Figure 4 present the comparison effect of the peak propagation time fitted by the existing technology method and the present invention with the measured value, and the absolute error of the present invention method in predicting the peak propagation time of different types. Compared with the prediction method of the existing technology, the method of the present invention is derived based on the physical process of peak movement and considers the peak propagation prediction method considering different types of floods and initial asynchronous influence. Therefore, it can more accurately predict the peak propagation time of different types of incoming floods into the reservoir, providing a certain reference for the Three Gorges Reservoir to carry out a more refined peak scheduling and sediment discharge mode.

[0093] The above embodiments are only illustrative examples of the technical solutions of the present invention. The method for predicting the peak propagation time of different types of incoming floods involved in the present invention is not limited to the content described in the above embodiments, but is subject to the scope defined by the claims. Any modification, supplement, or equivalent replacement made by those skilled in the art to which the present invention pertains based on this embodiment is within the scope protected by the claims of the present invention.

[0094] <Embodiment 2>

[0095] Furthermore, Embodiment 2 of the present invention provides a device for predicting the peak propagation time in the reservoir area based on different types of floods that can automatically implement the above method. The device includes a data acquisition unit, a type judgment unit, a movement time calculation unit, an asynchronous influence calculation unit, a peak propagation time prediction unit, an input display unit, and a control unit.

[0096] The data acquisition unit executes the content described in step 1 above, selects the hydrological station at the end of the reservoir backwater as the incoming water inlet hydrological station, obtains the daily average data of the flow rate and sediment concentration of this station, the relevant data of the sediment particle size, and the relevant data of the water depth in front of the reservoir dam, and counts the relevant characteristic quantities when floods occur at the incoming water hydrological station.

[0097] The type judgment unit executes the content described in step 2 above and judges the specific flood type based on the fisher time and the peak shape of the flood itself.

[0098] The movement time calculation unit executes the content described in step 3 above, calculates the movement speed of the water body propagating to the reservoir area hydrological station based on the flood characteristics of the stored flood events and the positional relationship between the reservoir area hydrological stations, and calculates the movement time of the water flow in the reservoir area.

[0099] The asynchronous influence calculation unit executes the content described in step 4 above, and calculates the asynchronous influence K of the initial flood peak and sediment peak and the flood duration. 异步 。

[0100] The sediment peak propagation time prediction unit executes the content described in step 5 above. According to the type of the flood event, the constants corresponding to different types of floods are substituted into Equation 2 to calculate the sediment peak propagation time of the flood event.

[0101] The input and display unit allows the user to input operation instructions, and displays the input, output, and intermediate processing data of the corresponding unit in the form of text, tables, graphs, or three-dimensional dynamic models according to the operation instructions.

[0102] The control unit is communicatively connected to the data acquisition unit, the type judgment unit, the movement time calculation unit, the asynchronous influence calculation unit, the sediment peak propagation time prediction unit, and the input and display unit to control their operations.

[0103] The above embodiments are merely illustrative examples of the technical solutions of the present invention. The method and device for predicting the sediment peak propagation time in the reservoir area based on different types of floods involved in the present invention are not limited to the content described in the above embodiments, but are subject to the scope defined by the claims. Any modification, supplement, or equivalent replacement made by those skilled in the art to the present invention on the basis of this embodiment is within the scope protected by the claims of the present invention.

Claims

1. A method for predicting the propagation time of sediment peaks in a reservoir area based on different types of floods, characterized in that, It includes the following steps: Step 1: Select the hydrological station at the end of the reservoir backwater as the incoming reservoir inlet hydrological station, obtain the daily average data of the flow rate and sediment concentration of this station, the relevant data of sediment particle size, and the relevant data of the water depth in front of the reservoir dam, and statistically analyze the relevant characteristic quantities when floods occur at the incoming reservoir hydrological station; Step 2: Based on the fisher time and the peak shape of the flood itself, judge the specific flood type; Step 3: According to the characteristics of the flood events entering the reservoir and the positional relationship between the hydrological stations in the reservoir area, deduce the movement speed of the water body propagating to the hydrological stations in the reservoir area, and calculate the movement time of the water flow in the reservoir area; Step 4: Calculate the influence K of the asynchronous initial flood peak and sediment peak and the flood duration 异步 : In the formula, and Q0 are respectively the average daily peak flow of the incoming flow control station and the starting flow when the flood begins to rise, and Δt 超前or滞后 represents the asynchronous duration between the sediment peak and the flood peak = T 沙峰 -T 洪峰 ; T rise and T down are respectively the time for the flood at the incoming flow control station to rise from the starting flow to the peak flow and to drop from the peak flow to the starting flow; Step 5: Determine the propagation time of the sediment peak of the flood event; The following formula is used to calculate the propagation time of the sediment peak in the reservoir area: t 沙峰 = k0·(K d ) a ·(K ssc ) b ·(K 异步 ) c ·t 水流 (Equation 2) In the formula, k0, a, b, and c are all constants related to the flood type of each event. Based on the sediment particle size d 50 the generalized term K of sediment particle size is obtained d = d 50 / 0.

002. Based on the ratio of the peak sediment concentration SSC peak and the initial sediment concentration SSC0, the generalized term K of the sediment peak rise is obtained ssc = SSC peak / SSC0, and t 水流 is the movement time of the water flow in the interval; According to the type of the flood event, substitute the constants corresponding to different flood types into Equation 2 to calculate the propagation time of the sediment peak of this flood event.

2. The method for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods according to claim 1, wherein: Among them, In step 1, the relevant characteristic quantities to be statistically calculated include flood characteristic quantities, sediment inflow characteristic quantities, water depth characteristic quantities in front of the dam, and the initial asynchronous state Δt of the flood peak and sediment peak 异步 and the water depth H in front of the dam before the flood comes 坝前 ; The flood characteristic quantities include the peak discharge of the inflow flood the initial discharge Q0, the total flood volume R sum , the rising duration T rise , the falling duration T down , the water depth H when the peak flood occurs at the inflow hydrological station 入库 and the average flow velocity The incoming sediment characteristics include the sediment concentration SSC of the incoming sediment peak peak , the initial sediment concentration SSC0 of the sediment peak, and the median grain size d of the sediment in the current month during the flood season 50 .

3. The method for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods according to claim 1, wherein: Among them, In step 2, according to calculate the Fisher time, then determine the range it is in, and combine the peak shape of the specific flood process to further determine the type of the corresponding reservoir inflow flood; represents the total flood volume of the entire flood process.

4. The method for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods according to claim 1, wherein: Among them, Step 3 includes the following sub-steps: Step 3-1: Collect the average flow velocity corresponding to the flood peak at the incoming flow hydrological station The water depth H at the time of the flood peak 入库 and the water depth H in front of the dam before the flood arrives 坝前 ; Calculate the water depth of the next hydrological station based on the location of the incoming flow hydrological station and the location of the next hydrological station The flow velocity of the next hydrological station is The flow velocity of the water flow at the position in front of the dam is L represents the distance; Step 3-2: The range between two adjacent hydrological stations is taken as an interval, and the average flow velocity between the two hydrological stations is divided by the distance between the two adjacent hydrological stations. Furthermore, the flow movement time is obtained. Similarly, the flow movement times of the remaining intervals can be obtained, and the sum of the flow movement times of each interval is used to obtain the total flow movement time in the reservoir area.

5. The method for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods according to claim 1, wherein: Among them, In step 5, the determination methods of the constants k0, a, b, and c corresponding to different types of floods are as follows: Based on the historical measured data of different types of floods included in the prediction area, multiple groups of K under each type of flood are calculated by substituting into Equation 1 异步 , and then, according to the known multiple groups of K under each type of flood 异步 , t 沙峰 , K d , K ssc are substituted into Equation 2 to fit and obtain the corresponding constants.

6. The method for predicting the propagation time of the sediment peak in the reservoir area based on different types of floods according to claim 1, wherein: Among them, In Step 5, when the prediction area is the Three Gorges area, the constants corresponding to each flood type are as follows: When the flood type is short-duration and sharp-shaped, k0 = 0.139, a = 0.806, b = 0.220, c = -0.908; When the flood type is short-medium-duration and conventional, k0 = 0.0013, a = 3.822, b = 0.087, c = -3.856; When the flood type is medium-duration and conventional, k0 = 0.037, a = 0.995, b = 0.678, c = 0; When the flood type is medium-duration and double-peak-shaped, k0 = 0.612, a = 0, b = 0.204, c = -0.455; When the flood type is long-duration and intense, k0 = 0.255, a = 0.5, b = 0.4, c = -0.883; When the flood type is long-duration and short and fat, k0 = 0.255, a = 0.497, b = 0.184, c = -0.

883.

7. Prediction device for the propagation time of sediment peaks in the reservoir area based on different types of floods, characterized in that, It includes: Data acquisition unit, which selects the hydrological station at the end of the reservoir backwater as the incoming reservoir inlet hydrological station, obtains the daily average data of the flow rate and sediment concentration of this station, the relevant data of sediment particle size, and the relevant data of the water depth in front of the reservoir dam, and statistically analyzes the relevant characteristic quantities when floods occur at the incoming reservoir hydrological station; Type judgment unit, which judges the specific flood type based on the fisher time and the peak shape of the flood itself; Movement time calculation unit, which deduces the movement speed of the water body propagating to the hydrological stations in the reservoir area according to the characteristics of the flood events entering the reservoir and the positional relationship between the hydrological stations in the reservoir area, and calculates the movement time of the water flow in the reservoir area; The asynchronous impact calculation unit calculates the impact K of the initial flood peak and sediment peak asynchrony and the flood duration 异步 : In the formula, and Q0 are respectively the average daily peak flow of the incoming flow control station and the starting flow when the flood begins to rise, and Δt 超前or滞后 represents the asynchronous duration between the sediment peak and the flood peak = T 沙峰 -T 洪峰 ; T rise and T down are respectively the time for the flood at the incoming flow control station to rise from the starting flow to the peak and to drop from the peak to the starting flow; The sand peak propagation time prediction unit substitutes the constants corresponding to different types of floods into Equation 2 according to the type of flood in a flood event, and calculates the sand peak propagation time of this flood event: t 沙峰 = k0·(K d ) a ·(K ssc ) b ·(K 异步 ) c ·t 水流 (Equation 2) In the formula, k0, a, b, and c are all constants related to the flood type of each event. Based on the sediment particle size d 50 the generalized term K of the sediment particle size is obtained d = d 50 / 0.

002. Based on the ratio of the peak sediment concentration SSC peak and the initial sediment concentration SSC0, the generalized term K of the sediment peak rise is obtained ssc = SSC peak / SSC0, and t 水流 is the movement time of the water flow in the interval; The control unit is communicatively connected to the data acquisition unit, the type judgment unit, the movement time calculation unit, the asynchronous influence calculation unit, and the sand peak propagation time prediction unit, and controls their operations.

8. The apparatus for predicting the propagation time of sediment peaks in a reservoir area based on different types of floods according to claim 7, wherein It further includes: The input and display unit is communicatively connected to the control unit, allowing the user to input operation instructions, and displaying the input, output, and intermediate processing data of the corresponding unit in the form of text, table, graph, or three-dimensional dynamic model according to the operation instructions.

9. The reservoir area sand peak propagation time prediction device based on different types of floods according to claim 7, wherein: Among them, In the sand peak propagation time prediction unit, the determination method of the constants k0, a, b, and c corresponding to different types of floods is as follows: Based on the historical measured data of different types of floods included in the prediction area, multiple groups of K under each type of flood are calculated by substituting into Equation 1 异步 , and then, according to the multiple known groups of K under each type of flood 异步 , t 沙峰 , K d , K ssc are substituted into Equation 2 for fitting to obtain the corresponding constants.

10. The reservoir area sand peak propagation time prediction device based on different types of floods according to claim 7, wherein: Among them, In the sand peak propagation time prediction unit, when the prediction area is the Three Gorges area, the constants corresponding to each flood type are as follows: When the flood type is short-duration and pointed, k0 = 0.139, a = 0.806, b = 0.220, c = -0.908; When the flood type is short-medium duration and conventional, k0 = 0.0013, a = 3.822, b = 0.087, c = -3.856; When the flood type is medium-duration and conventional, k0 = 0.037, a = 0.995, b = 0.678, c = 0; When the flood type is medium-duration and double-peak, k0 = 0.612, a = 0, b = 0.204, c = -0.455; When the flood type is long-duration and intense, k0 = 0.255, a = 0.5, b = 0.4, c = -0.883; When the flood type is long-duration and short and fat, k0 = 0.255, a = 0.497, b = 0.184, c = -0.883.

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