CN-121766206-B - Novel quantitative calculation method for debris flow sand blocking rate of wedge-shaped beam type grid dam

CN121766206BCN 121766206 BCN121766206 BCN 121766206BCN-121766206-B

Abstract

The invention provides a novel quantitative calculation method for debris flow blocking rate of a wedge-shaped beam type grating dam, which belongs to the technical field of water retaining, drainage or water discharge buildings in hydraulic engineering. According to the invention, quantitative calculation of the debris flow sand blocking rate of the wedge-shaped beam type grid dam is realized through a logic flow of field parameter measurement, dam parameter calculation, opening width design and sand blocking rate model construction.

Inventors

HU GUISHENG
SHEN WENHAO
TIAN SHUFENG
PENG SHUAISHUAI
XU ZENGQIANG

Assignees

中国科学院、水利部成都山地灾害与环境研究所

Dates

Publication Date: 20260508
Application Date: 20260302

Claims (10)

1. The utility model provides a novel wedge beam type grid dam mud-rock flow blocking rate quantitative calculation method which is characterized in that the method comprises the following steps: selecting a section with dam construction conditions in a debris flow basin on site, and acquiring the following basic parameters (1) debris flow related parameters including debris flow volume weight, solid volume concentration and debris flow scale; (2) Channel and block stone parameters, namely, the average width of the channel of the cross section of the dam to be built, the average channel longitudinal slope ratio drop in the cross section range, the mud depth of the mud-rock flow of the cross section in front of the dam and the minimum granularity value of the maximum block stone in the mud-rock flow; (3) The dam body structural parameter is the wedge structure angle ratio of the wedge beam type grating dam, and the ratio is the ratio of the wedge structure angle of the dam body to 60 degrees; Step two, primarily determining dam height of the wedge-shaped beam type grating dam based on mud depth of mud-rock flow of a front section of the dam, and calculating to obtain a ratio of total mud-rock flow solid matters to dam reservoir capacity corresponding to the dam height, namely reservoir capacity ratio, by combining average width of channels, minimum granularity value of maximum block stones, average longitudinal slope ratio reduction of channels, wedge-shaped structure angle ratio and mud-rock flow scale; Step three, acquiring mud-rock flow particle grading curves of different areas in the mud-rock flow, selecting a particle grading curve reflecting the integral characteristics of the flow field by combining the large particle ratio in the flow field, and determining the characteristic particle diameter of a mud-rock flow sample according to the curve And according to the characteristic particle size Designing the opening width of a wedge beam type grating dam; Building a water tank test device, manufacturing a wedge-shaped beam type grating dam model according to the dam height determined in the second step and the opening width designed in the third step, and simulating debris flow movement and the interception process of the model under different working conditions, wherein the working conditions at least cover scenes corresponding to different debris flow volume weights, different debris flow scales, different channel longitudinal slope ratio drops, different opening widths, different wedge-shaped structure angles and different storage capacity ratios; step five, based on the water tank test data of the step four, combining the opening width and the characteristic particle size of the step three Calculating to obtain the relative opening width, comprehensively considering six control factors including the volume weight of the debris flow, the scale of the debris flow, the average channel longitudinal slope ratio drop, the relative opening width, the angle ratio of the wedge-shaped structure and the reservoir capacity ratio, constructing a sand blocking rate prediction model by adopting a multiple regression analysis method, and quantitatively calculating the sand blocking rate of the wedge-shaped beam type grid dam by the model.
2. The quantitative calculation method of the debris flow rate of the novel wedge-shaped beam type grating dam according to claim 1 is characterized in that in the second step, the other mode of calculating the storage capacity ratio is that the wedge-shaped beam type grating dam height meeting the storage capacity ratio is obtained by combining the back calculation of the parameters of the first step according to the preset storage capacity ratio, and the storage capacity of the dam body is determined based on the back calculated dam height, so that the storage capacity ratio is obtained.
3. The quantitative calculation method of the debris flow rate of the novel wedge-shaped beam type grating dam according to claim 1, wherein the angular ratio of the wedge-shaped structure in the first step ranges from 0.75 to 1.25.
4. The quantitative calculation method of the debris flow rate of the novel wedge-shaped beam type grating dam according to claim 1 is characterized in that the dam body reservoir capacity in the second step is obtained by calculating a sine value of the dam height, the average width of a channel and the average longitudinal slope ratio of the channel and a tangent value corresponding to the angle ratio of a wedge-shaped structure, and the influence of the minimum granularity value of the maximum stone block on the reservoir capacity is corrected.
5. The quantitative calculation method of the debris flow blocking rate of the novel wedge-shaped beam type grating dam according to claim 1, wherein different areas of the debris flow basin in the third step comprise a debris flow accumulation area and a circulation area, and the particle grading curve of the integral characteristics of the basin is determined by respectively obtaining particle grading curves of the two areas and combining the occurrence frequency weights of the debris flow in the areas.
6. The quantitative calculation method of the debris flow rate of the novel wedge-shaped beam type grating dam is characterized in that in the water tank test process of the fourth step, actual measurement of the debris flow rate is synchronously carried out, namely, a silted body in front of the dam is shoveled out and dried to be completely dried after the test is finished, the total amount of the intercepted solid matters is obtained through weighing, and the actual measurement value of the debris flow rate is calculated by combining the total mass of the solid matters flowing into the water tank and is used for verifying the reliability of a predicted model of the debris flow rate.
7. The quantitative calculation method of the debris flow rate of the novel wedge-shaped beam type grating dam according to claim 1 is characterized in that in the multiple regression analysis of the fifth step, four function forms of a multiple linear function, a multiple power function, a multiple exponential function and a multiple logarithmic function are tried respectively, and an optimal function is selected according to the fitting effect of each function form to construct a sand flow rate prediction model.
8. The quantitative calculation method of the debris flow rate of the novel wedge-shaped beam type grating dam according to claim 1, wherein the determination coefficient is used for constructing the debris flow rate prediction model in the fifth step Evaluating the fitting goodness of multiple regression analysis, selecting The largest functional form serves as the final predictive model form.
9. The quantitative calculation method of the debris flow rate of the novel wedge-shaped beam type grating dam according to claim 1, wherein in the fifth step, a multi-element self-adaptive regression spline, particle swarm optimization and gradient lifting decision tree algorithm fusion mode is adopted to construct a sand flow rate prediction model, and the method specifically comprises the following steps: (51) Constructing an initial prediction model of the sand blocking rate by adopting a multi-element self-adaptive regression spline algorithm, namely constructing a segmented spline basis function by taking six control factors as input variables and actually measured values of the sand blocking rate as output variables, screening the basis function by combining forward selection with a strategy of backward pruning, solving regression coefficients by a least square method, and substituting the regression coefficients into actual measured parameters on site to calculate to obtain an initial prediction value and a prediction residual; (52) The node parameters of the multi-element self-adaptive regression spline algorithm, the learning rate of the gradient lifting decision tree algorithm and the depth of the decision tree are used as the core of particle positions, the square sum of prediction residual errors of the multi-element self-adaptive regression spline algorithm is used as an fitness function, the particle speed and the position are regulated through inertia weights and learning factors, the overall optimal parameters are obtained through iteration, and then the overall optimal parameters are fed back to the updating basis functions of the multi-element self-adaptive regression spline algorithm and fed back to the gradient lifting decision tree algorithm to serve as initial super parameters; (53) And (3) adopting a gradient lifting decision tree algorithm to fit the residual errors and realize bidirectional interaction, namely taking the multi-element self-adaptive regression spline prediction residual errors optimized by the particle swarm optimization algorithm as a fitting target, constructing a mean square error loss function and iterating a training decision tree, feeding back the gradient of the loss function to the particle swarm optimization algorithm to adjust the particle iteration direction, feeding back the final fitting residual errors to the multi-element self-adaptive regression spline algorithm to correct the regression coefficients, and obtaining the sand blocking rate prediction model after precision optimization through bidirectional interaction iteration of three types of algorithms.
10. The method for quantitatively calculating the debris flow rate of the wedge-shaped beam type grating dam according to claim 9 is characterized in that before a debris flow rate prediction model is built in the fifth step, water tank test data are divided into a training set and a test set according to the proportion of 7:3, training of the model is completed by adopting training set data, prediction accuracy of the model is verified by adopting test set data, verification indexes comprise relative errors and decision coefficients, and algorithm parameters are readjusted and the model is trained again until the accuracy reaches the standard if the model prediction accuracy does not reach engineering requirements, namely the relative errors are greater than 2%.

Description

Novel quantitative calculation method for debris flow sand blocking rate of wedge-shaped beam type grid dam Technical Field The invention relates to the technical field of debris flow disaster prevention and control, in particular to a novel quantitative calculation method for debris flow sand blocking rate of a wedge-shaped beam type grid dam. Background The debris flow is a typical sudden geological disaster in a mountain area, and forms serious threat to towns, traffic lines, hydraulic engineering and the like, and the mountain area faces the disaster prevention and reduction pressure of the debris flow for a long time. In the current engineering measures for intercepting debris flow, the traditional physical dams have the defects of poor water permeability, rapid load increase in front of the dams, easy impact damage and maintenance of functions only by manual dredging caused by indiscriminate interception, while the traditional permeable sand dams such as beam type grating dams, lattice dams, window dams and the like have thick and thin blocking potential, but the design is still in an empirical stage, so that two key problems exist: the key parameter consideration is insufficient, namely the important influencing factor of the debris flow scale is ignored by the existing sand blocking rate calculation model of the permeable sand blocking dam, and the blocking effect under different working conditions cannot be comprehensively reflected only by focusing on a few parameters such as the volume weight, the channel gradient and the like; the traditional permeable type sand blocking dam is lack of structural optimization from the angles of debris flow motion trail and flow reduction, the overflow section is easy to be completely blocked and invalid, the existing experience is used for reference in design, the dam type effect and the applicable condition are not designed pertinently, and the stable regulation and control effect is difficult to realize. Disclosure of Invention The invention provides a novel quantitative calculation method for debris flow blocking rate of a wedge-shaped beam type grating dam, which realizes quantitative calculation of the debris flow blocking rate of the wedge-shaped beam type grating dam through a logic flow of on-site parameter measurement, dam parameter calculation, opening width design and sand blocking rate model construction. A novel quantitative calculation method for debris flow sand blocking rate of a wedge-shaped beam type grating dam comprises the following steps: selecting a section with dam construction conditions in a debris flow basin on site, and acquiring the following basic parameters (1) debris flow related parameters including debris flow volume weight, solid volume concentration and debris flow scale; (2) Channel and block stone parameters, namely, the average width of the channel of the cross section of the dam to be built, the average channel longitudinal slope ratio drop in the cross section range, the mud depth of the mud-rock flow of the cross section in front of the dam and the minimum granularity value of the maximum block stone in the mud-rock flow; (3) The dam body structural parameter is the wedge structure angle ratio of the wedge beam type grating dam, and the ratio is the ratio of the wedge structure angle of the dam body to 60 degrees; Step two, primarily determining dam height of the wedge-shaped beam type grating dam based on mud depth of mud-rock flow of a front section of the dam, and calculating to obtain a ratio of total mud-rock flow solid matters to dam reservoir capacity corresponding to the dam height, namely reservoir capacity ratio, by combining average width of channels, minimum granularity value of maximum block stones, average longitudinal slope ratio reduction of channels, wedge-shaped structure angle ratio and mud-rock flow scale; Step three, acquiring mud-rock flow particle grading curves of different areas in the mud-rock flow, selecting a particle grading curve reflecting the integral characteristics of the flow field by combining the large particle ratio in the flow field, and determining the characteristic particle diameter of a mud-rock flow sample according to the curve And according to the characteristic particle size(Characteristic particle diameter)The opening width of the wedge beam type grating dam is designed for the corresponding particle size value when the accumulated particle content in the integration curve reaches 95 percent); Building a water tank test device, manufacturing a wedge-shaped beam type grating dam model according to the dam height determined in the second step and the opening width designed in the third step, and simulating debris flow movement and the interception process of the model under different working conditions, wherein the working conditions at least cover scenes corresponding to different debris flow volume weights, different debris flow scales, different channel longitudinal slope