Method, device, medium and product for evaluating flood discharge capacity of existing railway drainage facilities in mountainous area covered by vegetation

Abstract

The invention discloses a flood discharge capacity evaluation method, equipment, medium and product for existing railway drainage facilities in mountainous areas under vegetation coverage, and relates to the field of railway facility maintaining.The method comprises the steps that hydrological analysis and calculation are carried out according to a digital elevation model without vegetation influence and basic data, and an evaluation result is obtained; dividing a catchment area of each drainage facility in combination with the oblique photography three-dimensional model; determining surface runoff under different rainfall intensity conditions and peak flow of each drainage facility; determining the design flow of each drainage facility and the actual allowable flow under different blockage conditions; and determining a drainage capacity evaluation result of the drainage facilities according to the peak flow and the design flow of each drainage facility under different rainfall intensity conditions and the actual allowable flow under different blockage conditions. According to the method, the relationship between the rainfall intensity along the railway and the allowable flow of the railway drainage facility can be directly established, and the efficiency and accuracy of evaluating the drainage capacity of the existing railway drainage facility in the mountainous area covered by vegetation are improved.

Description

Technical Field

[0001] This application relates to the field of railway facility maintenance, and in particular to a method, equipment, medium and product for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover. Background Technology

[0002] Currently, the total operating mileage of railways exceeds 160,000 kilometers. This vast railway network extensively traverses mountainous areas with complex geological conditions, facing long-term threats from various natural geological disasters, particularly gully erosion and water damage caused by slope runoff. Some railway lines, especially older conventional railways, have relatively low-standard drainage facilities with inherently insufficient water-carrying capacity. Furthermore, over time, the surface environment and runoff conditions along the railway lines often change significantly due to urban development and land reclamation, further exacerbating the inadequacy of the original drainage systems. Against the backdrop of global climate change, extreme weather events are frequent, with abnormal rainfall intensity and temporal distribution, severely testing the discharge capacity of existing culverts and drainage pipes. If existing drainage facilities cannot effectively manage the peak flow caused by short-term heavy rainfall, it may lead to flooding of the track bed, erosion of roadbed slopes, and even engineering disasters such as slope instability and landslides, seriously endangering railway safety.

[0003] Existing technologies mostly focus on calculating catchment area and surface runoff, without directly establishing the relationship between rainfall intensity and the design flow of railway drainage facilities. Furthermore, they do not consider the status and parameters of existing drainage facilities, making it impossible to directly determine whether existing railway drainage facilities can meet the discharge requirements.

[0004] In addition, previous technical methods used digital elevation models (DEMs) in the process of delineating catchment areas were mostly obtained through satellite imagery or simple aerial surveys by UAVs, without taking into account the influence of dense vegetation and micro-topographic features in mountainous areas, which easily leads to distortion of the confluence path simulation.

[0005] Therefore, it is urgent to establish an evaluation method for the drainage capacity of existing railway drainage facilities in mountainous areas under vegetation cover, to assess whether the existing drainage facilities can meet the flood discharge requirements of gullies under extreme rainfall conditions, and to provide core guarantees for the safe operation of railways during the flood season. Summary of the Invention

[0006] The purpose of this application is to provide a method, equipment, medium, and product for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover. This method can directly establish the relationship between rainfall intensity along the railway line and the allowable flow of railway drainage facilities, thereby improving the efficiency and accuracy of evaluating the discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover.

[0007] To achieve the above objectives, this application provides the following solution: Firstly, this application provides a method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover. The method includes: Acquire basic data for the study area; the basic data includes: historical rainfall data, topographic data, satellite remote sensing image data, drainage facility data, and railway alignment data; Based on the basic data, aerial surveying methods were used to determine the digital elevation model and oblique photogrammetry 3D model of the study area after removing the influence of vegetation. Based on the digital elevation model and basic data to remove the impact of vegetation, hydrological analysis and calculations were carried out, and the catchment areas of each drainage facility were divided in conjunction with the oblique photogrammetry 3D model to determine the catchment area corresponding to each drainage facility. Based on the characteristic parameters of the study area and historical rainfall data, the surface runoff under different rainfall intensities was determined; and based on the catchment area corresponding to each drainage facility, the peak flow of each drainage facility under different rainfall intensities was determined; the characteristic parameters include: soil thickness, groundwater level, permeability coefficient, land use type, and soil hydrological conditions. Based on the morphological parameters of drainage facilities, the blockage situation, and basic data of the study area, the design flow rate of each drainage facility and the actual allowable flow rate under different blockage conditions are determined; the morphological parameters of the drainage facilities include the orifice diameter, net height, longitudinal slope, blockage ratio, and material type of the drainage facilities. The evaluation results of the drainage capacity of the drainage facilities in the study area are determined based on the peak flow rate of each drainage facility under different rainfall intensities, the design flow rate of each drainage facility, and the actual allowable flow rate under different blockage conditions.

[0008] Secondly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover.

[0009] Thirdly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover.

[0010] Fourthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover.

[0011] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a method, equipment, medium, and product for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover. It utilizes aerial surveying to obtain a digital elevation model (DEM) and an oblique photogrammetry 3D model of the study area, removing the influence of vegetation. Hydrological calculations are performed on the DEM, and combined with the oblique photogrammetry 3D model, catchment areas are effectively delineated and the catchment area is calculated. By obtaining characteristic parameters of the study area and the morphological parameters and blockage status of the drainage facilities, the peak flow rate of the drainage facilities under different rainfall intensities and the actual allowable flow rate under different blockage conditions are calculated. This allows for a direct determination of whether the existing railway drainage facilities can meet the discharge requirements, thus achieving an evaluation of the discharge capacity of existing railway drainage facilities in mountainous areas. This application directly establishes the relationship between rainfall intensity along the railway line and the allowable flow rate of railway drainage facilities, filling the gap in evaluation methods for the discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover. It provides a rapid, effective, and economical technical method for evaluating the discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover, further providing core guarantees for the safe operation of railways during the flood season. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of a method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover in one embodiment of this application. Figure 2 This is a schematic diagram of the catchment area division. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] In one exemplary embodiment, such as Figure 1 As shown, a method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover is provided. This method includes the following steps S101 to S106. Wherein: S101, Obtain basic data of the study area; the basic data includes: historical rainfall data, topographic data, satellite remote sensing image data, drainage facility data, and railway alignment data; The study included collecting historical rainfall data from rainfall monitoring stations near the study area, including hourly rainfall data for each day of the past 30 years, to calculate rainfall intensity for different rainfall return periods; topographic data, primarily 30m resolution DEM data of the study area; satellite remote sensing imagery of the study area with a resolution of at least 1m and an imaging period of less than 3 years; drainage facility data, including location information, design dimensions, and maintenance records; specifically, collecting the latitude and longitude coordinates or railway mileage locations of drainage facilities in the study area, design parameters such as orifice diameter, clearance height, and longitudinal slope, as well as maintenance records and historical flood damage data; railway alignment data, including railway alignment vector files and railway mileage markers; and collecting vector files of railway alignments and kilometer and hexmeter markers in the study area, such as .kml and .shp format files.

[0017] S102. Based on the basic data, the aerial survey method was used to determine the digital elevation model and oblique photogrammetry three-dimensional model of the study area after removing the influence of vegetation. S102 specifically includes: S21. Determine the three-dimensional map model of the study area based on topographic data and satellite remote sensing image data; S22. Based on the three-dimensional map model of the study area, and taking into account the location of drainage facilities and topographic features, the catchment area is initially delineated; and the aerial survey range is determined based on the catchment area. Specifically, the aerial survey range is extended 50m outward from the catchment area. S23. Determine the terrain-following flight path of the UAV based on the aerial survey range, and determine the real ground high-density lidar point cloud data and oblique photography data under vegetation cover based on the terrain-following flight path. Specifically, in order to obtain real ground high-density lidar point cloud data under vegetation cover, two mutually orthogonal terrain-following flight paths were designed. One path is approximately parallel to the contour lines, and the other path is approximately perpendicular to the contour lines. The two paths are mutually orthogonal to ensure that the real ground lidar point cloud density under dense vegetation conditions is greater than 80 points / square meter. To obtain oblique photography data of the study area, a drone equipped with a five-lens sensor can be used to acquire oblique photography data; S24, filter the real ground high-density lidar point cloud data to obtain a digital elevation model that removes the influence of vegetation; Specifically, based on high-density lidar point cloud data, seed point selection and progressive densification triangular mesh filtering algorithms are used to extract ground points, and after Kriging interpolation, a digital elevation model is formed to remove the influence of vegetation. S25, perform 3D modeling on the oblique photogrammetry data to obtain the oblique photogrammetry 3D model.

[0018] S25 specifically includes: S251, based on oblique photogrammetry data, uses an aerial triangulation algorithm to calculate the position, angle and camera attributes of each image and generate aerial triangulation results; S252, generate point clouds based on aerial triangulation results and construct an irregular triangular mesh model; S253, based on the position of each image, performs texture image registration and attaches it to the irregular triangular mesh model to obtain the oblique photogrammetry 3D model.

[0019] S103. Based on the digital elevation model and basic data after removing the influence of vegetation, hydrological analysis and calculation are carried out, and the catchment areas of each drainage facility are divided in combination with the oblique photogrammetry three-dimensional model to determine the catchment area corresponding to each drainage facility. S103 specifically includes: S31, preprocessing the digital elevation model after removing vegetation influence; the preprocessing includes: outlier removal, elevation smoothing filtering, raster count checking, and resampling. Specifically, based on the digital elevation model that removes the influence of vegetation, the elevation values ​​of the target grid cell are compared one by one with the elevation values ​​of the eight adjacent grid cells. If the elevation value of the target grid cell is less than the elevation values ​​of the eight adjacent grid cells, the target grid cell is regarded as a depression point, and the terrain is filled by reassigning values ​​to eliminate the influence of depressions on hydrological analysis. S32, based on the preprocessed digital elevation model after removing vegetation influence, the flow direction of each grid cell is calculated to determine the flow direction calculation results of the study area; Specifically, based on the preprocessed digital elevation model after removing vegetation influence, the slope between the target grid cell and the eight adjacent grid cells is calculated one by one. The line connecting the center point of the target grid cell and the center point of the grid cell with the largest slope is taken as the water flow direction of the target grid cell, thereby obtaining the flow direction calculation results of the study area. As a specific embodiment, the slope drop between the target grid cell and its surrounding grid cells can be calculated using the following formula: ; Where H0 is the elevation value of the target raster cell, H i L represents the elevation values ​​of the eight grid cells surrounding the target grid cell. iis the distance between the center point of the target grid cell and the center points of its eight surrounding grid cells; i is the index of the eight surrounding grid cells, starting from the grid cell in the due north direction and proceeding clockwise as 1, 2, 3, ..., 8.

[0020] The direction corresponding to the maximum slope value is taken as the flow direction (Direct) of the target raster cell, which can be calculated according to the following formula: ; Where k is the index of the surrounding grid cell corresponding to the maximum slope value.

[0021] S33, Based on the flow direction calculation results, perform flow calculation for each grid cell and determine the cumulative flow calculation results for all grid cells; Based on the flow direction calculation results, the flow rate of each grid cell is calculated. We can first assume that the initial flow rate of each grid cell is a unit value of 1, and then trace back upstream from the target grid cell. Through iterative calculation, the cumulative flow rate of the target grid cell is obtained. Each iteration can be calculated according to the following formula: ; ; ; Where Z0 is the cumulative flow value of the target grid cell, Z i is the cumulative flow value of the 8 grid cells surrounding the target grid cell; Flow is the standard value of the flow direction when the surrounding grid cells can flow into the target grid cell; f(i) is the inflow state determination function of the surrounding grid cells; and j is the grid cell number.

[0022] S34, determine the surface runoff path based on the cumulative flow calculation result and the flow threshold; the surface runoff path is a grid cell where the cumulative flow calculation result is greater than the flow threshold; The determination of the flow threshold requires comprehensive consideration of factors such as the total number of grid cells and slope characteristics within the study area. It typically requires multiple experiments and is generally positively correlated with the number of grid cells in the study area. The flow threshold can be determined using the following method: (1) Calculate the flow threshold (q) based on the number of grid cells (m) in the study area. c ) range, maximum flow threshold (q) c-max ) and minimum flow threshold (q) c-min It can be calculated using the following formula: ; ; (2) Determine the topographic complexity based on the slope standard deviation (σ) of the study area, select an appropriate spatial distribution density of surface runoff paths, and set the corresponding flow threshold. The selection can be made according to Table 1: Table 1

[0023] S35. Based on the flow direction calculation results, surface runoff paths and oblique photography 3D models, the catchment areas of each drainage facility are divided, a table of correspondence between drainage facilities and catchment areas is established, and the catchment area of ​​each drainage facility is determined.

[0024] Specifically, based on the generated surface runoff paths and oblique photogrammetry 3D models, catchment areas are delineated along ridgelines and watersheds. Then, according to the flow direction of railway side ditches, the boundaries of the catchment areas are adjusted to connect drainage facilities with the catchment areas, resulting in a catchment area delineation map (e.g., Figure 2 As shown in Table 2), establish a table showing the correspondence between drainage facilities and catchment areas, and calculate the catchment area (A) of each drainage facility. s ).

[0025] Table 2

[0026] S104. Based on the characteristic parameters of the study area and historical rainfall data, determine the surface runoff under different rainfall intensities; and based on the catchment area corresponding to each drainage facility, determine the peak flow of each drainage facility under different rainfall intensities; the characteristic parameters include: soil thickness, groundwater level, permeability coefficient, land use type, and soil hydrological conditions. S104 specifically includes: S41, Obtain the characteristic parameters of the study area; Among these methods, characteristic parameters can be obtained by drilling and trenching to determine soil thickness; by drilling and test pits to determine groundwater level; by double-ring permeability tests to determine permeability coefficient; by investigating whether the vegetation cover type is cultivated land, grassland, or forest, and by determining soil hydrological conditions based on the surface vegetation status; and by obtaining the average slope (S) of the study area based on field measurements and three-dimensional model analysis. lp ).

[0027] S42, determine the rainfall intensity under different rainfall return periods based on historical rainfall data; Specifically, based on historical hourly rainfall data, the hourly rainfall for 10-year, 20-year, 50-year, and 100-year return periods is estimated using the Pearson type III probability distribution, and is used as the rainfall intensity (P) under different return periods. S43. Based on the characteristic parameters, the surface runoff (Q, mm) under different rainfall intensities is calculated using the slope-corrected runoff curve number model (SASCS-CN). Specifically, based on soil thickness, groundwater level, permeability coefficient, land use type, and soil hydrological parameters of the study area, CN values ​​were obtained through table lookup and calculation in the *National Engineering Handbook* (Chapter 7). CN values ​​can be categorized into CN values ​​for arid conditions based on prior soil moisture levels. I General conditions CN II and humid conditions CN III First, obtain the CN by looking up a table. II The value is then used to calculate CN using the following conversion formula. I and CN III value: ; ; Based on the average slope (S) of the study area lp The corrected CN is calculated using the correction formula. IIs value: ; CN IIs Substitute the values ​​of the rainfall intensity (P) and the rainfall intensity at different return periods into the formula to calculate the surface runoff Q at different return periods: ; The maximum water storage capacity S is represented as: ; S44, based on the surface runoff (Q, mm) under different rainfall intensity conditions and the catchment area (A) corresponding to each drainage facility. s m 2 Determine the peak flow rate (q) of each drainage facility under different rainfall intensities. r m 3 / s).

[0028] Specifically, the peak flow rate (q) of each drainage facility under different rainfall intensities is calculated using the following formula. r ): ; Where t is the unit of time.

[0029] For example, by combining the characteristic parameters of a certain region, CN can be obtained by looking up a table. II The value is 70, and CN can be calculated. I and CN III The values ​​are 51.17 and 85.66; then CN is calculated using the slope correction formula. IIsThe value is 75.21. Further calculations of surface runoff under different rainfall intensities are shown in Table 3, and the peak flow rates of each drainage facility under different rainfall intensities are shown in Table 4.

[0030] Table 3

[0031] Table 4

[0032] S105, Based on the morphological parameters and blockage status of the drainage facilities in the study area, as well as basic data, determine the design flow rate (q) of each drainage facility. s ) and the actual allowable flow rate (q) under different congestion conditions v The morphological parameters of the drainage facilities include the drainage facility aperture, net height, longitudinal slope, blockage ratio, and material type. S105 specifically includes: S51, Obtain the morphological parameters and blockage status (blockage ratio) of the drainage facilities in the study area. S52, calculate the design flow rate of the drainage facility using the Manning formula based on the morphological parameters of the drainage facility; The main drainage facilities in railway engineering are culverts and drainage pipes. The design flow rate under full-flow conditions can be calculated using the Manning formula: ; Where A is the cross-sectional area of ​​the drainage facility, v is the water velocity, n is the roughness coefficient, R=A / P is the hydraulic radius, P is the wetted perimeter, and I is the water surface slope. S53, determine the actual allowable flow rate of the drainage facility based on its design flow rate and the extent of blockage.

[0033] Calculate the actual allowable flow rate of the drainage facility based on its design flow rate and blockage ratio: ; Where, q v To determine the actual allowable traffic, q s The design flow rate is given by D, which is the blockage ratio, i.e., the ratio of the cross-sectional area of ​​the blockage to the cross-sectional area of ​​the drainage facility.

[0034] S106. The evaluation results of the drainage capacity of the drainage facilities in the study area are determined based on the peak flow of each drainage facility under different rainfall intensity conditions, the design flow of each drainage facility, and the actual allowable flow under different blockage conditions.

[0035] S106 specifically includes: S61 compares the peak flow and actual allowable flow of each drainage facility under different rainfall intensities to determine whether the discharge capacity of each drainage facility currently meets the demand. Specifically, to fully consider the impact of rainfall intensities at different levels, it is necessary to compare the design flow rate q. v Once in a decade (q) r-10 ), once every twenty years (q) r-20 ), once every fifty years (q) r-50 ), once in a century (q) r-100 The peak flow rate under rainfall conditions is used to determine whether the current drainage capacity of various facilities meets the demand. ; Where, q r Peak flow rates under different rainfall conditions.

[0036] S62 cross-compares the actual allowable flow rate under different blockage conditions with the peak flow rate of each drainage facility under different rainfall intensities to form a drainage facility discharge capacity evaluation table, and conducts an evaluation of the discharge capacity of existing railway drainage facilities in mountainous areas.

[0037] Specifically, calculate the allowable flow rate (q) for each drainage facility when it is unblocked, 1 / 3 blocked, and 2 / 3 blocked, and combine this with the actual allowable flow rate of the drainage facility, and then compare it with the 10-year return period (q). r-10 ), once every twenty years (q) r-20 ), once every fifty years (q) r-50 ), once in a century (q) r-100 The peak flow under rainfall conditions was cross-compared to form an evaluation table of drainage facility discharge capacity, and the discharge capacity of existing railway drainage facilities in mountainous areas was evaluated.

[0038] For example, Table 5 shows the evaluation table of the drainage capacity of a certain area: Table 5

[0039] In an exemplary embodiment, a computer device is provided, which may be a server or a terminal. The computer device includes a processor, memory, input / output interfaces (I / O), and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is connected to the system bus via the I / O interfaces. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The I / O interfaces of the computer device are used for exchanging information between the processor and external devices. The communication interface of the computer device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover.

[0040] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0041] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0042] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0043] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0044] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0045] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0046] In this application, all actions to acquire signals, information, or data are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with the authorization granted by the owner of the relevant device.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover, characterized in that, The evaluation method for the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover includes: Acquire basic data for the study area; the basic data includes: historical rainfall data, topographic data, satellite remote sensing image data, drainage facility data, and railway alignment data; Based on the basic data, aerial surveying methods were used to determine the digital elevation model and oblique photogrammetry 3D model of the study area after removing the influence of vegetation. Based on the digital elevation model and basic data to remove the impact of vegetation, hydrological analysis and calculations were carried out, and the catchment areas of each drainage facility were divided in conjunction with the oblique photogrammetry 3D model to determine the catchment area corresponding to each drainage facility. Based on the characteristic parameters of the study area and historical rainfall data, the surface runoff under different rainfall intensities was determined; and based on the catchment area corresponding to each drainage facility, the peak flow of each drainage facility under different rainfall intensities was determined; the characteristic parameters include: soil thickness, groundwater level, permeability coefficient, land use type, and soil hydrological conditions. Based on the morphological parameters of drainage facilities, the blockage situation, and basic data of the study area, the design flow rate of each drainage facility and the actual allowable flow rate under different blockage conditions are determined; the morphological parameters of the drainage facilities include the orifice diameter, net height, longitudinal slope, blockage ratio, and material type of the drainage facilities. The evaluation results of the drainage capacity of the drainage facilities in the study area are determined based on the peak flow rate of each drainage facility under different rainfall intensities, the design flow rate of each drainage facility, and the actual allowable flow rate under different blockage conditions.

2. The method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover according to claim 1, characterized in that, Based on the basic data, aerial surveying methods were used to determine the digital elevation model and oblique photogrammetry 3D model of the study area, removing the influence of vegetation. Specifically, this included: A three-dimensional map model of the study area was determined based on topographic data and satellite remote sensing imagery. Based on the three-dimensional map model of the study area, and taking into account the location of drainage facilities and topographic features, the catchment area was initially delineated; and the aerial survey range was determined based on the catchment area. The terrain-following flight path of the UAV is determined based on the aerial survey range, and the real ground high-density lidar point cloud data and oblique photography data under vegetation cover are determined based on the terrain-following flight path. Filtering real ground high-density lidar point cloud data yields a digital elevation model that removes the influence of vegetation. Three-dimensional modeling is performed on the oblique photogrammetry data to obtain the oblique photogrammetry three-dimensional model.

3. The method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover as described in claim 2, characterized in that, The process of performing three-dimensional modeling on oblique photogrammetry data to obtain an oblique photogrammetry three-dimensional model specifically includes: Based on oblique photogrammetry data, aerial triangulation algorithms are used to calculate the position, angle, and camera attributes of each image, generating aerial triangulation results. Point clouds are generated based on aerial triangulation results, and an irregular triangular mesh model is constructed. Based on the location of each image, texture image registration is performed and attached to the irregular triangular mesh model to obtain the oblique photogrammetry 3D model.

4. The method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover according to claim 1, characterized in that, Based on the digital elevation model and basic data after removing the influence of vegetation, hydrological analysis and calculations are carried out, and the catchment areas of each drainage facility are divided using an oblique photogrammetry 3D model to determine the corresponding catchment area of ​​each drainage facility. Specifically, this includes: The digital elevation model to remove vegetation effects is preprocessed; the preprocessing includes: outlier removal, elevation smoothing filtering, raster count checking, and resampling. Based on the preprocessed digital elevation model after removing vegetation influence, flow direction calculations were performed for each grid cell to determine the flow direction calculation results for the study area. Based on the flow direction calculation results, the flow rate of each grid cell is calculated, and the cumulative flow rate of all grid cells is determined. The surface runoff path is determined based on the cumulative flow calculation results and the flow threshold; the surface runoff path is a grid cell where the cumulative flow calculation result is greater than the flow threshold. Based on the flow direction calculation results, surface runoff paths, and oblique photography 3D models, the catchment areas of each drainage facility are divided, a table of correspondence between drainage facilities and catchment areas is established, and the catchment area of ​​each drainage facility is determined.

5. The method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover according to claim 1, characterized in that, The method involves determining surface runoff under different rainfall intensities based on characteristic parameters of the study area and historical rainfall data; and determining the peak flow of each drainage facility under different rainfall intensities based on the catchment area corresponding to each drainage facility. Specifically, this includes: Obtain the characteristic parameters of the study area; Determine rainfall intensity under different rainfall return periods based on historical rainfall data; Based on the characteristic parameters, the surface runoff under different rainfall intensities was calculated using the runoff curve number model after slope correction. Based on the surface runoff under different rainfall intensities and the catchment area corresponding to each drainage facility, the peak flow of each drainage facility under different rainfall intensities is determined.

6. The method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover according to claim 1, characterized in that, The process involves determining the design flow rate of each drainage facility and the actual allowable flow rate under different blockage conditions based on the morphological parameters, blockage status, and basic data of the drainage facilities in the study area. Specifically, this includes: Obtain the morphological parameters and blockage status of drainage facilities in the study area; The design flow rate of the drainage facility is calculated using the Manning formula based on the morphological parameters of the drainage facility. The actual allowable flow rate of the drainage facility is determined based on its design flow rate and the extent of blockage.

7. The method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover according to claim 1, characterized in that, The evaluation results of the drainage capacity of the study area are determined based on the peak flow rate of each drainage facility under different rainfall intensities, the design flow rate of each drainage facility, and the actual allowable flow rate under different blockage conditions. Specifically, this includes: By comparing the peak flow and actual allowable flow of each drainage facility under different rainfall intensities, it can be determined whether the discharge capacity of each drainage facility currently meets the demand. By cross-comparing the actual allowable flow rate under different blockage conditions with the peak flow rate of each drainage facility under different rainfall intensities, an evaluation table of the drainage facility discharge capacity is formed, and the discharge capacity of existing railway drainage facilities in mountainous areas is evaluated.

8. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover as described in any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the method for evaluating the flood discharge capacity of existing railway drainage facilities in mountainous areas under vegetation cover as described in any one of claims 1-7.

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