CN-121980111-A - Water-sand asynchronous duration identification method and system based on loop area and balanced sand conveying capacity

CN121980111ACN 121980111 ACN121980111 ACN 121980111ACN-121980111-A

Abstract

The application relates to a water and sand asynchronous duration identification method and a system based on loop area and balanced sand conveying capacity, wherein the method comprises the following steps of data acquisition and pretreatment; the method comprises the steps of sliding fitting, determining integral asynchronous time length, sliding and translating actually measured sand content on a time axis, searching to obtain integral asynchronous time length delta t overall , calculating an asynchronous area after sliding, calculating local asynchronous time length after sliding, and judging water sand asynchronous time length and type. The application realizes the accurate quantification of the water-sand asynchronous time length and the automatic discrimination of the asynchronous type (Sha Feng advance/synchronization/retard).

Inventors

LI XIN
LIU YA
WANG MIN
LIU BAONAN
CHU DONGDONG
Lv Binghan
DENG CHUNYAN
ZENG XIN

Assignees

长江水利委员会长江科学院

Dates

Publication Date: 20260505
Application Date: 20260106

Claims (8)

1. A water and sand asynchronous duration identification method based on loop area and balanced sand conveying capacity is characterized by comprising the following steps: s1, data acquisition and preprocessing, namely acquiring time sequence data of a complete flood event, and carrying out interpolation processing on missing data to ensure data quality; s2, sliding fitting, determining overall asynchronous duration, fitting based on time sequence data of the flood event, sliding and translating the actually measured sand content on a time axis, repeating fitting, and searching to obtain the overall asynchronous duration delta t overall according to fitting precision; S3, calculating an asynchronous area after sliding, translating the actually measured sand content process line by utilizing the integral asynchronous time length delta t overall obtained in the step S2, and calculating to obtain an accumulated loop area A residual according to the translated water sand loop; S4, calculating the local asynchronous time length after sliding, fitting an SSC eq curve to the flow and sand content sequence after translational alignment, and then obtaining the local asynchronous time length delta t Local area ; S5, judging the water and sand asynchronous time length and the type, adding the integral asynchronous time length delta t overall and the local asynchronous time length delta t Local area to obtain integral asynchronous time length delta t total =Δt overall +Δt Local area , , and automatically judging the water and sand asynchronous type based on delta t total .
2. The water-sand asynchronous duration identification method based on loop area and balanced sand conveying capacity according to claim 1, wherein the time sequence data of the complete flood event comprises measured flow rate Q (t) and measured sand content SSC (t).
3. The method for identifying the water-sand asynchronous duration based on the loop area and the balanced sand conveying capacity according to claim 1 is characterized in that the sliding fitting and the overall asynchronous duration determination are specifically carried out by adopting a power law relation SSC eq =aQ b to perform fitting (a and b are respectively parameters of fitting, Q is flow), sliding and translating an actually measured sand content SSC (t) on a time axis, calculating the translated power law relation and a decision coefficient R 2 thereof, and searching to obtain the optimal overall translation duration by taking the decision coefficient R 2 as a maximum target, namely the overall asynchronous duration deltat overall .
4. The method for identifying the water and sand asynchronous time length based on the loop area and the balanced sand conveying capacity according to claim 1 is characterized in that the post-sliding asynchronous area is calculated by translating a measured sand content process line to obtain SSC m (t + Δt overall by utilizing the optimal integral translation time length Deltat overall obtained in the step S2), reconstructing an SSC-Q relation diagram of SSC m (t + Δt overall ) and flow Q (t), and calculating an accumulated loop area A residual surrounded by the relation diagram by adopting a directional area formula A i =0.5*（Q [i] *SSC [i+1] -Q [i+1] *S [i] ).
5. The method for identifying the water-sand asynchronous duration based on the loop area and the balanced sand conveying capacity according to claim 1, wherein the post-sliding local asynchronous duration calculation mainly comprises the following three steps: Firstly, derivative calculation, namely fitting an SSC eq curve to flow and sand content sequences after translational alignment, and then respectively obtaining derivative values dSSC eq /dQ and dQ/dt of the fitted curve; Step two, denominator calculation, namely calculating (dSSC eq /dQ)·(dQ/dt) 2 .delta.t, and taking the sum as denominator; And thirdly, asynchronously calculating, wherein A residual obtained in the step S3 is a molecule, and the local asynchronous duration delta t Local area is obtained.
6. The method for identifying the water and sand asynchronous duration based on the loop area and the balanced sand conveying capacity according to claim 1, wherein the water and sand asynchronous duration and type judgment is specifically that, If delta t total is less than 0.5, judging that Sha Feng is advanced, and enabling the sand content process to reach a peak value before the flow process; if delta t total is more than 0.5, judging that Sha Feng lags, wherein the sand content process is later than the flow process channel peak value; if the absolute delta t total is less than or equal to 0.5, judging that the water and the sand are synchronous.
7. A water-sand asynchronous duration identification system based on loop area and balanced sand delivery capability, characterized by comprising a memory and a processor, wherein the memory comprises a program of a water-sand asynchronous duration identification method based on loop area and balanced sand delivery capability, and the program of the water-sand asynchronous duration identification method based on loop area and balanced sand delivery capability realizes the steps of the water-sand asynchronous duration identification method based on loop area and balanced sand delivery capability according to any one of claims 1 to 6 when being executed by the processor.
8. A computer readable storage medium, characterized in that the computer readable storage medium stores a program code which, when executed by a processor, implements the steps of the water-sand asynchronous duration identification method based on loop area and balanced sand transport capability according to any of claims 1-6.

Description

Water-sand asynchronous duration identification method and system based on loop area and balanced sand conveying capacity Technical Field The invention relates to the technical field of hydrologic sediment and river dynamics, in particular to a water and sediment asynchronous duration identification method and system based on loop area and balanced sediment transport capacity. Background The asynchronous state (water and sand asynchronism) of water flow and sediment transport process during flood is a core feature of river basin sediment movement, and the asynchronous time length and the asynchronous type of the water and sand transport process are accurately identified, so that the method is not only a basic premise of deep revealing of river basin water and sand transport mechanism, but also is crucial to determination and discrimination of the opportunity of the reservoir Sha Feng. The existing water sand asynchronous identification method mainly has the following technical defects: First, the graphic classification method, which is a qualitative judgment and classification method based on the loop shape composed of the sand content (SSC) and the flow rate (Q), can be classified into a clockwise type, a counterclockwise type, a linear type, an 8 type, and a complex type. This approach is intuitive, but does not provide the strength magnitude and time scale differences of the water-sand asynchrony itself. The second, dimensionless hysteresis index HYSTERESIS INDEX (abbreviated as HI index) method is that HI index is an index system represented by ascending/descending branch regression area ratio, which can give direction (forward/reverse) and reflect intensity (amplitude), but can not give time scale difference of water-sand asynchronization. Thirdly, the asynchronous duration measurement from the time perspective is a method of common peak time difference (the occurrence time difference of flood peak Sha Feng) and centroid time difference (the occurrence time difference of the centroids of the flow process line and the sand content process line), and the two methods are simple and visual, but are too simplified for complex and multimodal floods, and have poor application effects in flood events of a plurality of flood peaks. In recent years, an asynchronous time length identification method based on a dynamic time warping algorithm (DTW) is developed, but the original time sequence is distorted and stretched in the processing of the algorithm, so that the actual water sand and loop forming process is indirectly changed, unnecessary errors are introduced, and meanwhile, the obtained asynchronous time is obtained indirectly, and a definite physical basis and a derivation basis are lacked. In summary, the prior art is either physically clear but not robust enough or mathematically strong but physically poorly interpretable. Therefore, there is an urgent need in the art for a quantitative recognition method that can take physical internal mechanisms into consideration, and simultaneously make full use of whole-process information, has strong anti-interference capability, and can provide directivity discrimination. Disclosure of Invention The embodiment of the application aims to provide a water and sand asynchronous duration identification method and system based on loop area and balanced sand conveying capacity, which are simple to calculate and easy to operate, and meanwhile, have harmonious dimensions. In order to achieve the above purpose, the present application provides the following technical solutions: In a first aspect, an embodiment of the present application provides a method for identifying a water-sand asynchronous duration based on a loop area and a balanced sand conveying capability, including the following steps: s1, data acquisition and preprocessing, namely acquiring time sequence data of a complete flood event, and carrying out interpolation processing on missing data to ensure data quality; s2, sliding fitting, determining the integral asynchronous duration, fitting based on time sequence data of the flood event, sliding and translating the actually measured sand content on a time axis, and searching to obtain the integral asynchronous duration delta t overall; S3, calculating an asynchronous area after sliding, and translating the actually measured sand content process line by utilizing the integral asynchronous time length delta t overall obtained in the step S2 to obtain an accumulated loop area A residual; S4, calculating the local asynchronous time length after sliding, fitting SSCeq curves on the flow and sand content sequences after translational alignment, and then obtaining the local asynchronous time length delta t Local area ; S5, judging the water and sand asynchronous time length and the type, adding the integral asynchronous time length delta t overall and the local asynchronous time length delta t Local area to obtain integral asynchronous time length delta t total=Δtove