Levee stability analysis method and system based on three-dimensional seepage and stress field calculation

Abstract

The present application relates to the technical field of embankment three-dimensional data processing, and particularly relates to a method and system for embankment stability analysis based on three-dimensional seepage and stress field calculation. The method comprises the following steps: using ground measurement and satellite sensing equipment to cooperatively detect the whole embankment and collect embankment engineering survey information; performing heterogeneous fusion and spatial coordinate matching on the survey information to construct a three-dimensional model of the whole embankment; performing three-dimensional grid subdivision on the three-dimensional model of the whole embankment, combining with preset seepage stress field inversion calculation results to give corresponding boundary load parameters to each embankment three-dimensional grid element, and completing load parameter assignment of the three-dimensional model of the whole embankment. The present application realizes simulation of embankment water-soil coupling effect and positioning of hidden weak areas by layering parallel grid subdivision and calculating shear stress reverse correction permeability coefficient, thereby improving the accuracy of embankment stability analysis.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional data processing technology for dikes, and in particular to a method and system for dike stability analysis based on three-dimensional seepage and stress field calculations. Background Technology

[0002] Currently, stability analysis of embankment structures largely relies on finite element numerical simulation (FEM). This involves building a three-dimensional analysis model by collecting foundation survey data, configuring the model mesh and load parameters, and then calculating the seepage and stress fields to determine the overall structural stability. However, existing numerical simulation techniques often employ conventional homogeneous meshing logic, failing to optimize for the layered characteristics of the embankment soil and the slope structure. This results in limited compatibility between the mesh shape and the soil's mechanical transmission path, leading to numerical calculation errors in key local areas. Furthermore, the calculation of seepage and stress fields often uses independent, unidirectional coupling, neglecting the dynamic interaction between the two fields. This results in insufficient matching between soil parameters and field values, and subsequent structural stability assessments rely solely on single numerical comparisons, failing to accurately reflect the true stress and seepage coupling state of the soil. Consequently, the accuracy and reliability of the overall analysis results are ill-suited to the requirements of refined engineering analysis. Summary of the Invention

[0003] Therefore, it is necessary to provide a method and system for levee stability analysis based on three-dimensional seepage and stress field calculations to solve at least one of the above-mentioned technical problems.

[0004] To achieve the above objectives, a method for levee stability analysis based on three-dimensional seepage and stress field calculations is provided, the method comprising the following steps: Step S1: Conduct collaborative surveys of the entire dike area using ground surveying and satellite sensing equipment to collect dike engineering survey information; perform heterogeneous fusion and spatial coordinate matching on the survey information to construct a three-dimensional model of the entire dike area; Step S2: Perform three-dimensional meshing on the three-dimensional model of the entire dike. Combine the preset seepage stress field inversion calculation results, assign corresponding boundary load parameters to each three-dimensional mesh unit of the dike, and complete the load parameter assignment of the three-dimensional model of the entire dike. Step S3: Perform coupled numerical calculations of the three-dimensional seepage field and stress field on the three-dimensional model of the entire dike with assigned load parameters, and calculate the seepage field and stress field values ​​of each grid unit of the dike. Step S4: Based on the seepage field values ​​and stress field values ​​of each grid unit of the dike, perform a coupled analysis of seepage and stress on each grid unit of the dike to obtain the seepage and stress analysis results; determine the structural stability of the entire dike based on the seepage and stress analysis results.

[0005] This invention also provides a levee stability analysis system based on three-dimensional seepage and stress field calculations, used to execute the aforementioned levee stability analysis method based on three-dimensional seepage and stress field calculations. The levee stability analysis system based on three-dimensional seepage and stress field calculations includes: The 3D model construction module for dikes is used to conduct collaborative exploration of the entire dike area using geodetic and satellite sensing equipment, collect dike engineering survey information, perform heterogeneous fusion and spatial coordinate matching on the survey information, and construct a 3D model of the entire dike area. The load assignment module for the embankment model is used to perform three-dimensional meshing on the three-dimensional model of the entire embankment. Combined with the preset seepage stress field inversion calculation results, it assigns corresponding boundary load parameters to each three-dimensional mesh unit of the embankment, thus completing the load parameter assignment of the three-dimensional model of the entire embankment. The seepage stress field coupling calculation module is used to perform three-dimensional seepage field and stress field coupling numerical calculation on the three-dimensional model of the entire dike with load parameters, and to measure the seepage field and stress field values ​​of each grid unit of the dike. The levee stability assessment module is used to perform coupled analysis of seepage and stress on each grid cell of the levee based on the seepage field and stress field values, and obtain the seepage and stress analysis results; and determine the structural stability of the entire levee based on the seepage and stress analysis results.

[0006] The beneficial effects of this invention are as follows: On the one hand, this invention addresses the special working conditions of uneven soil stratification and concentrated stress and seepage coupling at the embankment toe. It uses the soil layer interface, embankment toe, and the upstream and downstream slopes of the embankment as exclusive grid partitioning surfaces, keeping the grid extension direction parallel to the embankment slope surface. At the same time, a three-equal division and densification design is adopted for the two-meter area around the embankment toe, which conforms to the exclusive mechanical laws of seepage transmission along the slope and soil stress distribution along the slope surface. It adapts to the unique water and soil action path of the embankment at the grid architecture level, eliminates stress distortion and seepage path deviation in numerical calculation, achieves seamless fit between the model and the real embankment working conditions, and improves the computational adaptability and numerical accuracy of the three-dimensional model.

[0007] On the other hand, this invention employs a closed-loop coupled calculation logic for dynamic reverse correction of soil permeability coefficient by shear stress. It relies on the weakening mechanism of soil cohesion by pore water pressure to make a dedicated linear correction. Combined with zoned stress limits, spatial superposition and aggregation, and quantitative determination of area proportion, it transforms the implicit interaction between seepage field and stress field into a quantifiable and iterative stability determination system. This system can accurately locate the hidden weak areas of the entire dike area, achieving a precise closed loop from micro-unit numerical calculation to macro-structural stability determination. The results obtained can directly correspond to the real stability state of the dike's physical structure, providing a unique and accurate quantitative basis for dike safety management. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the steps involved in a method for analyzing the stability of a levee based on three-dimensional seepage and stress field calculations. Figure 2 This is a schematic diagram of the entire 3D model of the dike. Figure 3 This is an interface diagram of a levee stability analysis system based on three-dimensional seepage and stress field calculations. The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0009] The technical method of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0010] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor methods and / or microcontroller methods.

[0011] It should be understood that although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are used merely to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0012] To achieve the above objectives, please refer to Figures 1 to 3 A method for analyzing the stability of a levee based on three-dimensional seepage and stress field calculations, the method comprising the following steps: Preferably, step S1: Use geodetic and satellite sensing equipment to conduct collaborative exploration of the entire dike area and collect dike engineering survey information; perform heterogeneous fusion and spatial coordinate matching on the survey information to construct a three-dimensional model of the entire dike area; Optionally, step S1 includes the following steps: Obtain measured topographic elevation information along the dike and collect hydrological monitoring information at the cross-section of the water area adjacent to the dike. The measured topographic elevation information is converted to a unified elevation datum, and the hydrological monitoring information is sampled and normalized at a fixed frequency. To eliminate discrete data collected due to signal interference from the acquisition equipment, the spatial coordinates of all acquired data are uniformly converted to the engineering general geographic coordinate system. By integrating measured topographic elevation information and hydrological survey information according to a one-to-one coordinate correspondence, levee engineering survey information is formed, and a three-dimensional model of the entire levee area is constructed based on the levee engineering survey information.

[0013] In this embodiment, a laser rangefinder is used to set up topographic elevation monitoring points along the dike at equal intervals of 100 meters, collecting elevation data of the dike top, slope, and toe at each point to form measured topographic elevation information along the dike. Simultaneously, a hydrological detector is used to set up hydrological monitoring sections in the water area adjacent to the dike at intervals of 500 meters, with 3 monitoring points set up at each section to collect real-time water level and flow velocity data at each point, forming hydrological monitoring information at the water area adjacent to the dike. The measured topographic elevation information is converted to a unified elevation datum, and the converted elevation values ​​retain three decimal places of precision. The hydrological monitoring information is sampled and normalized at a fixed frequency of once per minute, and non-standard sampling data is supplemented by linear interpolation to form standardized hydrological monitoring information.

[0014] The 3σ criterion was used to screen all measured topographic elevation information and standardized hydrological monitoring information, eliminating discrete data that deviated from the mean by three times the standard deviation. The spatial coordinates of all screened data were uniformly converted to the engineering general geographic coordinate system using a six-degree zone projection method. The plane coordinate values ​​were retained to two decimal places in meters, and the elevation coordinate values ​​were consistent with the accuracy of the converted measured topographic elevation information. Based on the one-to-one correspondence of the three-dimensional coordinates in the engineering general geographic coordinate system, and with coordinate points as the core of association, the topographic elevation data and hydrological monitoring data within the same coordinate range were bound and integrated to form complete dike engineering survey information including three-dimensional spatial coordinates, topographic elevation, water level, and water flow velocity.

[0015] It should be noted that this embodiment uses Midas GTS / NX finite element modeling software to construct a three-dimensional model of the entire dike area. Other simulation software can also be used, and this invention is not limited to this. After creating a new project file, the general geographic coordinate system of the project is set as the global coordinate system of the model, the model scaling factor is set to 1, the modeling accuracy is selected to be at the millimeter level, and the spatial range covers the entire dike area and the adjacent 50-meter water area. The model elevation values ​​are consistent with the measured topographic elevation information converted from the unified elevation datum, and the value range is set to 0-50 meters.

[0016] Draw two-dimensional outlines of the dike crest, water-facing slope, back slope, and toe in sequence according to the actual direction of the dike. The width of the dike crest outline is set to 8-15 meters according to the survey values. The slope ratio of the water-facing and back slope outlines is set to 1:2.5-1:3 according to the measured topographic elevation information. The toe outline is drawn according to the coordinates of the connection between the dike slope and the dike foundation, and the radius of the rounded corner at the connection is set to 2 meters. The two-dimensional outlines are stretched along the direction of the dike to form a three-dimensional solid. The dike body solid is divided into two layers, clay and sand, according to the soil stratification information, and assigned corresponding material properties. The layer thickness is set to 3-8 meters and 5-12 meters according to the survey values.

[0017] The dike body and water area are divided into tetrahedral structured meshes. The side length of the mesh unit in the key area of ​​the dike body is set to 2 meters, and the side length of the mesh unit in the dike foundation and water area is set to 5 meters. The mesh growth rate is set to 1.2, and the minimum mesh angle is not less than 15°. The topographic elevation data of the dike engineering survey information are imported in batches and mapped to the Z-axis coordinates of each node in the model. The water level data of the water area is entered in the form of node attributes, and the water flow velocity data is entered in the form of water area attributes. After all parameters are bound, the model geometry is checked and the mesh quality is verified. After the verification is passed, the three-dimensional model of the entire dike area is generated.

[0018] Please see Figure 2 This is a schematic diagram of the three-dimensional model of the entire dike of the present invention, showing the complete structural morphology of the dike top, the water-facing slope, the back slope, and the toe. The three-dimensional model of the entire dike is based on the layered structure of clay and sand in the dike body. Different colors are used to distinguish the distribution range of the clay layer and the sand layer in the dike body. During the subdivision process, the soil layer interface, the dike slope surface, and the dike toe are used as the grid subdivision surfaces, and the grid extension direction is kept parallel to the dike slope direction.

[0019] Preferably, step S2: perform three-dimensional meshing on the three-dimensional model of the entire dike, and combine the preset seepage stress field inversion calculation results to assign corresponding boundary load parameters to each three-dimensional mesh unit of the dike, thereby completing the assignment of load parameters of the three-dimensional model of the entire dike. Optionally, step S2 involves performing 3D mesh generation on the entire 3D model of the dike as follows: To obtain the layered structural characteristics of clay and sand in the dike body; Based on the layered structure characteristics of clay and sand in the embankment, the three-dimensional model of the entire embankment is divided into tetrahedral meshes. During the meshing process, the interface between each soil layer in the embankment is used as the meshing surface. The interface between each soil layer in the embankment includes: the embankment toe, the embankment slope, the water-facing slope of the embankment, and the water-repelling slope of the embankment. Based on the natural spatial orientation of the embankment from the water-facing side slope to the back slope slope, the grid unit subdivision and extension direction is planned so that the grid unit extension direction remains parallel to the embankment slope surface. Using the toe of the dike as the core dividing node, the grid cells within a two-meter radius around the toe are divided at equal intervals, so that the side length of the grid cells is set to one-third of the non-equal interval area.

[0020] In this embodiment, the layered structural features of clay and sand in the dike body are extracted from the dike engineering survey information. The extracted content includes the actual distribution range of the clay and sand layers, the vertical layer thickness, and the three-dimensional spatial coordinates of the soil layer interfaces. The layered structural feature data of clay and sand are completely imported into the constructed three-dimensional model of the entire dike area to achieve accurate matching between the layered structural features and the spatial coordinates of the model. At the same time, the actual boundary positions of the dike toe, dike slope, water-facing dike slope, and water-repellent dike slope are marked in the model.

[0021] In the Midas GTS / NX finite element modeling software, the meshing function was called, and the tetrahedral meshing mode was selected to perform meshing operations on the entire three-dimensional model of the embankment. During the meshing process, the interface between the clay and sand of the embankment, the embankment toe, the embankment slope, the water-facing slope of the embankment, and the water-repelling slope of the embankment were all set as meshing surfaces. The three-dimensional spatial coordinates of all meshing surfaces were consistent with the measured coordinates in the embankment engineering survey information, and the meshing surfaces conformed to the actual structural layering and shape boundary of the embankment.

[0022] In the modeling software, the mesh extension vector parameters are set according to the natural spatial orientation of the embankment slope from the water-facing side to the back water-facing side. The angle of the vector parameters matches the actual slope angle of the embankment slope, so that the extension direction of the mesh cells is parallel to the embankment slope. The extension direction of the mesh cells is laid out along the natural orientation of the embankment from the water-facing side to the back water-facing side.

[0023] In the modeling software, the three-dimensional spatial coordinates of the dike toe are located and set as the core meshing node. A circular area with a radius of two meters is delineated with this node as the center as the mesh densification area. The densification area is divided into equidistant meshes. The side length of the mesh unit in the densification area is set to 0.5 meters, and the side length of the mesh unit in the remaining non-densification area of ​​the model is set to 1.5 meters. The geometric shape and spatial position of all mesh units after the division are verified to complete the three-dimensional meshing of the entire dike three-dimensional model.

[0024] Most importantly, in step S2, the corresponding boundary load parameters are assigned to each 3D mesh element of the dike as follows: Obtain the preset seepage stress field inversion calculation results; The basic water pressure parameters of different areas of the dike are extracted from the seepage stress field inversion calculation results, and the water pressure parameters of the corresponding dike area are matched according to the three-dimensional spatial coordinates of each grid unit. For the grid cells on the water-facing side of the dike, the water pressure parameter values ​​are adjusted according to the water depth gradient. For every meter increase in water depth, the water pressure parameter value increases by a fixed numerical gradient. The water pressure parameter is anchored to the water-facing geometric edge of each grid cell, and the water pressure parameter is set to act perpendicularly to the water-facing surface of the grid cell along the normal direction of the water-facing side.

[0025] In this embodiment, a preset seepage stress field inversion calculation result file is imported into the Midas GTS / NX finite element modeling software. This file uses the general geographic coordinate system of the project as a reference and stores the basic water pressure parameters of the entire dike area at a spatial grid resolution of 5 meters × 5 meters. The parameter value range is 0-0.5 MPa. The coordinate system of the file is spatially registered with the coordinate system of the three-dimensional model of the entire dike area. Through the batch parameter extraction function of the software, the basic water pressure parameters are imported into the model parameter library to achieve accurate correlation between the parameters and the coordinates of the model grid cells.

[0026] The grid cell parameter matching function is enabled in the modeling software. The three-dimensional spatial coordinates of each embankment three-dimensional grid cell are used as the only matching basis. The water pressure basic parameters within the corresponding coordinate range are retrieved from the model parameter library. Through the attribute assignment function of the software, the matched water pressure basic parameters are directly associated with the load attribute field of the corresponding grid cell. The initial assignment of water pressure basic parameters of all grid cells in the entire domain is completed. During the assignment process, the one-to-one correspondence between parameters and grid cells is realized.

[0027] In the modeling software, all three-dimensional mesh cells on the water-facing side of the dike are selected using the region filtering function. The measured water depth data at the corresponding location of each cell is retrieved, with the data value range being 0-10 meters, and associated with the cell attributes. In the software, a water pressure gradient adjustment rule is set, which stipulates that for every meter increase in water depth, the water pressure parameter value increases by a fixed numerical gradient of 0.0098 MPa. Through the software's batch calculation function, the initial water pressure parameters of all water-facing mesh cells are gradient adjusted to generate the final water pressure parameters of each cell. The parameter value range is synchronized with the water depth to 0-0.098 MPa.

[0028] In the modeling software, locate the water-facing geometric edges of each water-facing grid cell. Use the load anchoring function to bind the final water pressure parameters to the corresponding geometric edges. In the software load setting interface, mark the direction of the water pressure load as the water-facing normal, with the normal vector perpendicular to the embankment slope. Set the load application method to uniform surface load distribution, with the load application surface being the water-facing surface of the grid cell. The surface load application area is consistent with the actual area of ​​the water-facing surface of the grid cell. This completes the final assignment of the boundary load parameters for each embankment 3D grid cell.

[0029] Preferably, step S3: Perform coupled numerical calculation of three-dimensional seepage field and stress field on the three-dimensional model of the entire dike with load parameters assigned, and calculate the seepage field value and stress field value of each grid unit of the dike. Optionally, in step S3, the coupled numerical calculation of the three-dimensional seepage field and stress field of the three-dimensional model of the entire embankment for which load parameters are assigned is specifically as follows: The permeability coefficient of the soil corresponding to each grid cell is extracted as the core basic physical parameter for seepage field calculation. The permeability coefficient is assigned to the corresponding grid cell according to the preset actual soil survey value. Based on the seepage boundary conditions of the embankment model after load parameter assignment, numerical calculations of the seepage field were carried out on grid cells of the entire embankment. During the calculation, each grid cell was taken as an independent calculation unit. The seepage field calculation values ​​of each grid cell are used as the initial input parameters for stress field calculation. Based on these initial input parameters and the assigned water pressure parameters, stress field numerical calculations are carried out on a grid-by-grid basis for the entire dike area.

[0030] In this embodiment, the complete 3D model of the embankment with mesh generation and water pressure load assignment is opened. In the Midas GTS / NX finite element modeling software, the material property configuration interface is accessed, and the soil physical parameters from the embankment engineering survey information are retrieved. The soil permeability coefficient corresponding to each 3D mesh unit is extracted. This parameter is precisely assigned according to the soil layer type, with the permeability coefficient of the clay layer mesh units uniformly set to [value missing]. to The permeability coefficient of the sand layer grid cells is uniformly set to 1. to The permeability coefficients are entered one by one into the physical parameter column of the corresponding grid cell to complete the configuration of the core basic parameters for seepage field calculation. The parameters are bound one-to-one with the grid cells to prevent mismatches or omissions.

[0031] Import the assigned boundary load parameters, set the seepage boundary conditions for the embankment model, set the measured water level line on the upstream side of the embankment as the upstream boundary of seepage, set the ground elevation on the downstream side as the downstream boundary of seepage, and set the top of the embankment and the outer area of ​​the embankment foundation as the impermeable boundary. All boundary parameters are consistent with the previous survey data. Enable the unit independent calculation mode, use a single three-dimensional grid unit as an independent calculation carrier, and perform seepage field numerical calculations on all grid units in the entire domain one by one according to the preset seepage calculation logic. Do not merge calculation units or skip any grid units. Generate the seepage field calculation values ​​of each grid unit in sequence. The values ​​include the core index of pore water pressure. The calculation process maintains parameter consistency.

[0032] After completing the full-domain seepage field calculation, without changing the model mesh structure and load assignment state, perform the parameter import operation. Import the seepage field values ​​of each mesh unit obtained in the previous step into the initial input parameter column of the stress field calculation in batches, so that the seepage field values ​​are accurately associated with the corresponding mesh units, serving as the prerequisite basic parameters for stress field calculation. Simultaneously, retrieve the water pressure parameters that have been anchored in each mesh unit, and integrate the two types of parameters into the complete input conditions for stress field calculation. The parameter association remains unchanged, and no additional calculation parameters are added or deleted.

[0033] Maintaining the independent calculation mode for each grid cell, the stress field numerical calculation process is initiated based on the integrated initial input parameters and water pressure parameters. Following the preset stress calculation logic, the stress field numerical calculation is carried out sequentially for each grid cell of the entire dike area. The entire calculation process relies on the configured soil parameters and boundary conditions without adjusting the previously set model parameters and load parameters, until the stress field numerical calculation of all grid cells is completed. The corresponding stress field values ​​are output, and the calculation results correspond one-to-one with the spatial coordinates of the grid cells, thus completing the coupled numerical calculation of the three-dimensional seepage field and stress field.

[0034] Optionally, step S3 includes calculating the seepage field values ​​for each grid cell of the dike, including: The actual groundwater level of the dike is marked as the upstream boundary for the seepage field calculation, and the actual ground elevation on the back side of the dike is marked as the downstream boundary for the seepage field calculation. The values ​​of the fixed upstream and downstream boundaries are not included in the iterative adjustment. Using the soil permeability coefficient of each grid cell as the reference parameter, the pore water pressure value of the soil is calculated cell by cell. The calculation step size is set according to the permeability coefficient of each grid cell. According to the natural path of seepage in the dike, the pore water pressure calculation value of each grid cell is iteratively verified, and the difference between the calculation values ​​of adjacent grid cells is compared after each iteration. Once the difference between the measured values ​​is less than the preset measured value threshold, the seepage field values ​​of each grid unit of the dike are determined.

[0035] In this embodiment, in the Midas GTS / NX finite element modeling software, the actual measured data of the dike engineering survey are retrieved, and the actual groundwater level of the dike is marked as the upstream boundary for the seepage field calculation. The upstream boundary water head value is fixed according to the measured groundwater level height. The actual ground elevation on the back side of the dike is marked as the downstream boundary for the seepage field calculation, and the downstream boundary water head value is fixed at 0m. The upstream and downstream boundary values ​​are locked, and the boundary parameters are set not to participate in the subsequent iterative calculation process. The boundary values ​​are kept constant throughout the process without any dynamic adjustment.

[0036] Using the soil permeability coefficient of each grid unit as the sole reference parameter, the unit-by-unit calculation mode is enabled. Each grid unit is treated as an independent calculation unit. The calculation step size is set according to the permeability coefficient of the grid unit. The permeability coefficient of the clay layer grid unit is relatively small, so the calculation step size is set to 0.001m. The permeability coefficient of the sand layer grid unit is relatively large, so the calculation step size is set to 0.005m. According to the set step size, the soil pore water pressure value is initially calculated for all grid units in the entire area one by one, and the initial pore water pressure calculation value of each unit is generated in sequence.

[0037] The pore water pressure calculation values ​​of each grid cell are iteratively verified along the natural path of seepage along the dike, i.e., the seepage direction from the upstream groundwater level boundary to the downstream backwater side ground boundary. After each round of full-domain calculation, the pore water pressure values ​​of adjacent grid cells are extracted, and the absolute difference between the two sets of values ​​is compared one by one. The difference data of adjacent cells after each iteration is recorded. During the iteration process, the soil permeability coefficient, calculation step size and boundary conditions are not changed, and all calculation parameters are kept constant.

[0038] The preset threshold for the difference in pore water pressure calculation values ​​is 0.002 MPa. Iterative verification operations are continuously carried out. After each iteration, the difference data of adjacent grid cells in the entire domain are checked until the difference between adjacent calculation values ​​of all grid cells is less than the preset threshold. The iteration process is stopped, and the pore water pressure value at this time is determined as the final seepage field value of each grid cell of the dike, thus completing the accurate calculation of the seepage field value of the entire grid cell.

[0039] Optionally, step S3, which involves calculating the stress field values ​​for each grid element of the dike, includes: The effective stress value of the soil is calculated based solely on the pore water pressure value determined by each grid cell, and the influence of other interfering factors is completely eliminated during the conversion process. The effective stress value of the soil is vector-superimposed with the water pressure parameters assigned to the grid cells. The resultant stress value is calculated according to the actual force direction during superposition. Obtain the actual physical properties of the soil in the corresponding area of ​​the dike; calculate the shear stress value grid by grid unit based on the actual physical properties of the soil in the corresponding area of ​​the dike, and use the resultant stress value as the sole calculation basis; After the shear stress value calculation results show no change for three consecutive times, the stress field value of each grid unit of the dike is determined.

[0040] In this embodiment, the final pore water pressure values ​​of each three-dimensional grid unit of the dike, which have been determined through seepage field calculation, are retrieved. These values ​​are then imported into the stress calculation port of the Midas GTS / NX finite element modeling software. The software's built-in auxiliary calculation functions, such as additional load calculation, soil self-overlap, and external disturbance correction, are turned off to completely eliminate all kinds of non-related interference factors. Only the pore water pressure value is used as the sole calculation basis. The effective stress is calculated as the total stress minus the pore water pressure. The effective stress value of the soil corresponding to each three-dimensional grid unit in the entire domain is converted one by one. The conversion process only calls the single pore water pressure data of the corresponding grid unit without introducing any additional variables. The effective stress value of the soil in each grid unit is bound one-to-one with the previous pore water pressure value to ensure that there are no parameter mismatches or data omissions in the conversion process.

[0041] The water pressure parameters, which were previously assigned and anchored to the geometric edges on the water-facing side of each grid cell, are extracted. The effective soil stress value corresponding to the same grid cell is then vector-superimposed with the water pressure parameters. The superposition operation strictly follows the actual stress direction of the embankment. The water pressure parameters act vertically along the normal direction on the water-facing side of the grid cell, while the effective soil stress is distributed vertically along the soil. Using the three-dimensional spatial coordinates of the grid cell as a reference, the two types of stress are decomposed into the X, Y, and Z coordinate axes. The sum of the stress components in each coordinate axis direction is calculated separately. Then, the magnitude and direction of the resultant stress value are calculated using the vector synthesis formula. The magnitude and direction parameters of the resultant stress value are simultaneously entered into the stress attribute field of the corresponding grid cell. All grid cells in the entire domain are superimposed one by one without skipping any cells or merging the calculated data.

[0042] The actual physical property parameters of the soil in the corresponding area of ​​each grid unit were extracted from the embankment engineering survey information database. The cohesion of the clay layer grid unit was 25 kPa to 35 kPa and the internal friction angle was 12° to 18°. The cohesion of the sand layer grid unit was 2 kPa to 5 kPa and the internal friction angle was 28° to 34°. The above parameters were accurately matched to the material property column of the corresponding grid unit. The resultant stress value calculated in the previous stage was used as the only calculation basis. No other stress parameters were introduced. The shear stress value was calculated for each of the three-dimensional grid units in the whole area. The physical property parameters of the soil were kept constant during the calculation process. The initial shear stress value of each grid unit was generated in sequence. The entire process was carried out in the order of grid unit number to ensure that the calculation order was consistent with the model unit number.

[0043] Three consecutive rounds of repeated calculations were performed on the shear stress values ​​of all grid units. Each round of calculation used the exact same resultant stress value and soil physical property parameters without adjusting any calculation conditions or model settings. After each round of calculation, the corresponding shear stress value was recorded in real time, and a comparison log of the three rounds of calculation values ​​was established. The deviation of the values ​​of the three rounds was checked unit by unit. When the shear stress calculation results of all grid units in the entire region showed no numerical fluctuations for three consecutive times and the deviation value was zero, the values ​​were determined to have reached a stable state, and the calculation process of this round was terminated. The stable shear stress values ​​were officially determined as the final stress field values ​​of each grid unit of the embankment, and the entire calculation work of the stress field values ​​of the entire region was completed.

[0044] Optionally, the numerical calculation of the coupling between the three-dimensional seepage field and the stress field in step S3 is as follows: Based on the shear stress value of each grid unit, the soil permeability coefficient parameter of the corresponding grid unit is adjusted proportionally according to the actual magnitude of the shear stress value. When the shear stress value increases, the adjustment range of the permeability coefficient increases proportionally. Based on the corrected soil permeability coefficient parameters, the pore water pressure value was recalculated on a grid-by-grid basis, and the recalculation used the same step size as the initial calculation. Substitute the recalculated pore water pressure value into the conversion to obtain the updated effective stress value of the soil, and then combine it with the water pressure parameter to calculate the new resultant stress value. The operation of repeatedly iterating and correcting the permeability coefficient and the calculated stress value continues until all values ​​of the seepage field and stress field no longer change.

[0045] In this embodiment, the final shear stress value calculated for each grid cell is retrieved and used as the core basis for correcting the soil permeability coefficient. In the Midas GTS / NX finite element modeling software, a permeability coefficient correction ratio is set: for every 10 kPa increase in shear stress, the correction range for the corresponding grid cell's soil permeability coefficient increases by 5%; for every 10 kPa decrease in shear stress, the correction range decreases by 5%. As shear stress increases, the correction range increases positively according to this ratio; as shear stress decreases, the correction range decreases negatively according to this ratio. This process is repeated for all grid cells across the entire domain to correct the initial soil permeability coefficient, generating corrected soil permeability coefficient parameters that replace the original initial permeability coefficient parameters in the model. The correction process relies solely on the shear stress value of the corresponding grid cell and does not introduce other interfering parameters.

[0046] Based on the corrected soil permeability coefficient parameters, and keeping the boundary conditions of the initial seepage field calculation unchanged, the actual groundwater level of the embankment is still set as the upstream boundary and the actual ground elevation on the back side is set as the downstream boundary. The values ​​of the upstream and downstream boundaries are fixed and do not participate in the iteration. The step size of the graded calculation is used in the initial calculation. The calculation step size of the clay layer grid unit is set to 0.001m and the calculation step size of the sand layer grid unit is set to 0.005m. The independent calculation mode of each grid unit is enabled. Following the operation process that is completely consistent with the initial calculation, the pore water pressure value of all grid units in the entire area is recalculated one by one, and the pore water pressure value of each grid unit is generated in sequence.

[0047] The recalculated pore water pressure values ​​of each grid cell are used to calculate the updated effective stress value of the soil. The calculation method is to directly subtract the pore water pressure value of the same grid cell from the corresponding total stress value of the soil. The calculation process eliminates other irrelevant factors such as soil self-weight and external additional loads. Only the difference between the total stress and the recalculated pore water pressure values ​​is used to calculate the updated effective stress value of the soil. Then, the previously anchored water pressure parameters of the corresponding grid cells are extracted, and the updated effective stress of the soil and the water pressure parameters are vector-superimposed. The stress is decomposed into three coordinate axes (X, Y, and Z) according to the actual force direction. The sum of the stress components of each axis is calculated separately, and the new resultant stress value is obtained by component synthesis. The new resultant stress value is entered into the stress attribute column of the corresponding grid cell to complete the single-round stress parameter update.

[0048] A complete iterative process is employed, consisting of correcting the permeability coefficient, remeasuring pore water pressure, calculating effective stress, synthesizing new resultant stress, and measuring new shear stress values. This process is repeated, with each iteration correcting the corresponding permeability coefficient using the shear stress values ​​calculated in the previous iteration. Throughout the process, the calculation step size, boundary conditions, and stress superposition rules remain completely unchanged. After each iteration, the pore water pressure values ​​of the seepage field and the shear stress and resultant stress values ​​of the stress field for each grid cell are compared between the previous and subsequent iterations. All fluctuations and deviations in these values ​​are recorded until all values ​​of the seepage field and stress field show no fluctuations and the values ​​of the previous and subsequent iterations are completely consistent and without deviation. At this point, the iteration operation is terminated, and the coupled numerical calculation of the three-dimensional seepage field and stress field is completed.

[0049] Preferably, step S4: based on the seepage field values ​​and stress field values ​​of each grid unit of the dike, perform a coupled analysis of seepage and stress on each grid unit of the dike to obtain the seepage and stress analysis results; determine the structural stability of the entire dike based on the seepage and stress analysis results.

[0050] Optionally, step S4 involves performing a coupled analysis of seepage and stress on each grid cell of the dike, specifically as follows: The pore water pressure and shear stress values ​​determined for each grid cell are extracted; the pore water pressure and shear stress values ​​are the final stable values ​​after coupled calculation. The measured physical properties of cohesion of the soil layers corresponding to each grid unit are retrieved, and the cohesion properties are accurately matched to the corresponding grid units according to the actual values ​​of the soil survey. The cohesion index is linearly corrected based on the pore water pressure value. When the pore water pressure value increases, the corrected cohesion index value decreases by a fixed proportion. A correlation analysis was performed between the corrected cohesion index and the shear stress value, and the relationship between the shear stress value and the actual value of the corrected cohesion index was determined on a grid-by-grid basis.

[0051] In this embodiment, the pore water pressure and shear stress values ​​corresponding to each three-dimensional grid cell in the entire embankment are extracted from the three-dimensional seepage field and stress field coupling calculation result file. Only the final stable data with no numerical change after the iteration is terminated are retrieved. The two types of values ​​are arranged in the order of grid cell number and imported into the post-processing analysis interface of the Midas GTS / NX finite element modeling software to establish a cell-specific seepage-stress data group. Each data group corresponds to a single independent grid cell.

[0052] The measured data of soil physical properties from the survey of the embankment project were retrieved, and the soil cohesion strength index corresponding to each soil layer in each grid unit was extracted. This index is the shear strength parameter generated by the bonding of soil particles, which is used to measure the soil's ability to resist shear failure. The measured value of the soil cohesion strength index corresponding to the clay layer of the embankment body is 25kPa-35kPa, and the measured value of the soil cohesion strength index corresponding to the sand layer is 2kPa-5kPa. In the software, the soil cohesion strength index is assigned to the grid unit of the corresponding spatial location through the coordinate matching function, thus completing the accurate association between the index and the unit.

[0053] In the software parameter correction module, a linear correction rule is set, with the final pore water pressure value of each grid cell as the correction variable. For every 0.01 MPa increase in pore water pressure, the soil cohesion index value of the corresponding grid cell is reduced by 1 kPa. When the pore water pressure increases, the corrected index value decreases synchronously according to this fixed ratio. The soil cohesion index of all grid cells in the entire domain is calculated and corrected one by one to generate the corrected index value, which replaces the original measured index value.

[0054] In the software's numerical comparison and analysis module, the soil cohesion strength index value after correction for a single grid cell is imported into the same analysis window along with the shear stress value of the same cell. The difference and proportional relationship between the two types of values ​​are calculated cell by cell. The results of the shear stress value being greater than, equal to, or less than the corrected soil cohesion strength index value are recorded. The correlation analysis of all cells in the entire domain is completed sequentially according to the grid cell number. The analysis results of each cell are saved, and the coupling analysis of seepage and stress is completed.

[0055] Optionally, in step S4, determining the structural stability of the entire dike based on the seepage and stress analysis results specifically involves: According to the pre-set specifications for embankment engineering design, the critical ratio standard of shear stress value and modified cohesion index is defined. This critical ratio standard is the core basis for judging the shear resistance of embankment soil. The numerical relationships and critical ratio standards obtained from the grid cell-by-grid cell comparison analysis are recorded one by one, and the specific comparison results of each grid cell are recorded. Mark the grid cells whose numerical relationships exceed the critical ratio standard, and record the three-dimensional spatial coordinates of the grid cells during the marking process; Based on the three-dimensional adjacency relationship, the marked mesh units are integrated to form a continuous stress anomaly region, and the three-dimensional spatial range and geometric dimensions of the stress anomaly region are determined.

[0056] In this embodiment, in accordance with the mandatory requirements of the embankment engineering design specifications, the critical ratio standard of shear stress and the modified soil cohesion strength index is entered into the structural stability determination module of the Midas GTS / NX finite element modeling software. The critical ratio is set to 1.0, which is the critical threshold for soil shear failure and serves as the sole criterion for determining the stability state of the entire grid unit. After the parameters are entered, the determination rules are locked and no further modifications or dynamic adjustments are made.

[0057] The software retrieves the shear stress values ​​and corrected soil cohesion strength values ​​of each three-dimensional grid unit generated in the previous coupling analysis. It establishes a unit value comparison ledger within the software, retrieves the corresponding two sets of data one by one according to the unique grid unit number, and automatically calculates the actual ratio of the single set of shear stress values ​​to the corrected soil cohesion strength values ​​through the software's built-in numerical calculation function. The calculated actual ratio is compared with the preset critical ratio of 1.0 item by item, and a standardized comparison result table is generated in the order of unit number to clearly distinguish between the two states of unit ratio meeting the standard and exceeding the standard.

[0058] The software automatically captures coordinates, filters grid cells with actual ratios greater than 1.0 in the comparison results table, performs system marking operations on these cells, and automatically extracts the corresponding three-dimensional spatial coordinate parameters, including the plane X coordinate, plane Y coordinate, and vertical Z coordinate. The coordinate accuracy is retained to the millimeter level, and the coordinate parameters are completely consistent with the global engineering geographic coordinate system of the model. The marking information is bound and stored with the corresponding cell coordinates to form a list of out-of-standard cell coordinates.

[0059] The software's 3D spatial neighborhood analysis function is enabled. The list of coordinates of the out-of-standard units is read. The existence of shared nodes and shared edges between units is used as the adjacency criterion. All out-of-standard grid units are spatially clustered and integrated. Adjacent out-of-standard units are connected to form continuous blocks. Isolated out-of-standard units without spatial adjacency are automatically removed. Through the software's geometric calculation function, the boundary coordinates of the continuous blocks are extracted. The longitudinal extension length, lateral distribution width, and vertical burial thickness of the stress anomaly area are calculated and generated. The complete 3D spatial range and physical geometric dimensions of the area are determined, and the structural stability status of the entire dike is determined.

[0060] Of particular importance is that step S4, which determines the structural stability of the entire dike area, specifically involves: According to the pre-set design requirements for the dike project, the allowable limit of shear stress in the soil of the dike toe area and the dike body area is determined, and the limit in the dike toe area is set to be half of that in the dike body area. Compare the final shear stress value with the allowable shear stress limit for the corresponding region on a grid-by-grid basis, and mark the grid cells whose values ​​exceed the allowable limit. By spatially superimposing these grid cells with the stress anomaly region, a comprehensive anomaly region covering the entire dike area is obtained; The distribution area of ​​the comprehensive abnormal area at the dike toe, the water-facing slope, and the back slope is statistically analyzed. Based on the proportion of the distribution area of ​​each part to the total area of ​​the corresponding part, the final structural stability of the entire dike area is determined.

[0061] In this embodiment, based on the preset design requirements of the dike project, the functional areas of the dike are divided in the Midas GTS / NX finite element modeling software, and the two core areas of the dike toe and the dike body are locked. The allowable limit of shear stress in the dike body area is set to 30 kPa, and the allowable limit of shear stress in the dike toe area is set to half of that in the dike body area, i.e., 15 kPa, according to the design requirements. The limits of the two types of areas are entered into the parameter judgment column of the corresponding area in the software. The boundary of the area completely coincides with the spatial boundary of the previously constructed model. The limit parameters are locked throughout the process after being set and no dynamic adjustment is made.

[0062] After retrieving the final shear stress stability values ​​of each grid cell after coupling calculation, the region matching and comparison function is enabled in the software. First, the spatial region of the embankment toe or embankment body to which a single grid cell belongs is identified. Then, the shear stress value of the cell is compared with the allowable limit of shear stress in the corresponding region one by one. Grid cells with shear stress values ​​greater than the allowable limit of the corresponding region are screened out. The software's built-in marking tool is used to mark such cells with special characteristics and the spatial ownership information of the cells with excess values ​​is stored simultaneously.

[0063] Retrieve the stress anomaly area data obtained from the previous coupling analysis, enable the three-dimensional spatial overlay analysis function in the software, and overlay the shear stress exceeding mesh unit layer marked this time with the original stress anomaly area layer with coordinate alignment. Through spatial intersection operation, merge the overlapping parts of the two types of exceeding units and collect the non-overlapping independent exceeding units to generate a comprehensive anomaly area of ​​the entire dike. The overlay process uses the global coordinate system of the model to ensure complete spatial alignment.

[0064] The software utilizes the area calculation function to break down the comprehensive anomaly area into three sub-parts: the dike toe, the water-facing dike slope, and the backwater dike slope. The distribution area of ​​the comprehensive anomaly area in each part is calculated, and then the total model area of ​​the corresponding sub-part is calculated. The proportion of the anomaly area to the total area of ​​the corresponding part is calculated, and the final structural stability of the entire dike is determined based on the proportional value. The entire process of data statistics and stability determination is completed, resulting in a complete dike stability analysis.

[0065] This invention also provides a levee stability analysis system based on three-dimensional seepage and stress field calculations, used to execute the aforementioned levee stability analysis method based on three-dimensional seepage and stress field calculations. The levee stability analysis system based on three-dimensional seepage and stress field calculations includes: The 3D model construction module for dikes is used to conduct collaborative exploration of the entire dike area using geodetic and satellite sensing equipment, collect dike engineering survey information, perform heterogeneous fusion and spatial coordinate matching on the survey information, and construct a 3D model of the entire dike area. The load assignment module for the embankment model is used to perform three-dimensional meshing on the three-dimensional model of the entire embankment. Combined with the preset seepage stress field inversion calculation results, it assigns corresponding boundary load parameters to each three-dimensional mesh unit of the embankment, thus completing the load parameter assignment of the three-dimensional model of the entire embankment. The seepage stress field coupling calculation module is used to perform three-dimensional seepage field and stress field coupling numerical calculation on the three-dimensional model of the entire dike with load parameters, and to measure the seepage field and stress field values ​​of each grid unit of the dike. The levee stability assessment module is used to perform coupled analysis of seepage and stress on each grid cell of the levee based on the seepage field and stress field values, and obtain the seepage and stress analysis results; and determine the structural stability of the entire levee based on the seepage and stress analysis results.

[0066] Please see Figure 3 This is an interface diagram of the embankment stability analysis system based on three-dimensional seepage and stress field calculation of the present invention. The system presents the execution status of the entire embankment stability analysis process. The left side of the interface is the system function navigation bar, corresponding to the four core modules of the present invention: three-dimensional model construction, mesh generation and assignment, seepage stress field calculation, and stability determination. The overview area at the top displays the core analysis parameters, including 24 monitoring sections, 18,642 mesh units, 312 iterations of convergence, and 3 stress anomaly areas. The analysis process progress bar clearly marks the completion status of each stage, and the calculation progress of each module is displayed as 100%. It also synchronously prompts that the coordinate matching of the survey information is completed, fully presenting the closed-loop execution of the entire process of the present invention from data fusion, model construction to coupled calculation and stability determination.

[0067] Therefore, the embodiments should be considered as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the application are intended to be included within the invention.

[0068] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A method for analyzing the stability of a levee based on three-dimensional seepage and stress field calculations, characterized in that, Includes the following steps: Step S1: Conduct collaborative surveys of the entire dike area using ground surveying and satellite sensing equipment to collect dike engineering survey information; perform heterogeneous fusion and spatial coordinate matching on the survey information to construct a three-dimensional model of the entire dike area; Step S2: Perform three-dimensional meshing on the three-dimensional model of the entire dike. Combine the preset seepage stress field inversion calculation results, assign corresponding boundary load parameters to each three-dimensional mesh unit of the dike, and complete the load parameter assignment of the three-dimensional model of the entire dike. Step S3: Perform coupled numerical calculations of the three-dimensional seepage field and stress field on the three-dimensional model of the entire dike with assigned load parameters, and calculate the seepage field and stress field values ​​of each grid unit of the dike. Step S4: Based on the seepage field values ​​and stress field values ​​of each grid unit of the dike, perform a coupled analysis of seepage and stress on each grid unit of the dike to obtain the seepage and stress analysis results; determine the structural stability of the entire dike based on the seepage and stress analysis results.

2. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 1, characterized in that, Step S1 includes the following steps: Obtain measured topographic elevation information along the dike and collect hydrological monitoring information at the cross-section of the water area adjacent to the dike. The measured topographic elevation information is converted to a unified elevation datum, and the hydrological monitoring information is sampled and normalized at a fixed frequency. To eliminate discrete data collected due to signal interference from the acquisition equipment, the spatial coordinates of all acquired data are uniformly converted to the engineering general geographic coordinate system. By integrating measured topographic elevation information and hydrological survey information according to a one-to-one coordinate correspondence, levee engineering survey information is formed, and a three-dimensional model of the entire levee area is constructed based on the levee engineering survey information.

3. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 1, characterized in that, Step S2 involves performing 3D mesh generation on the entire 3D model of the dike as follows: To obtain the layered structural characteristics of clay and sand in the dike body; Based on the layered structure characteristics of clay and sand in the embankment, the three-dimensional model of the entire embankment is divided into tetrahedral meshes. During the meshing process, the interface between each soil layer in the embankment is used as the meshing surface. The interface between each soil layer in the embankment includes: the embankment toe, the embankment slope, the water-facing slope of the embankment, and the water-repelling slope of the embankment. Based on the natural spatial orientation of the embankment from the water-facing slope to the back slope, the grid unit's extension direction is planned so that the grid unit's extension direction remains parallel to the embankment slope surface. Using the toe of the dike as the core dividing node, the grid cells within a two-meter radius around the toe are divided at equal intervals, so that the side length of the grid cells is set to one-third of the non-equal interval area.

4. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 1, characterized in that, Step S3 involves performing coupled numerical calculations of the three-dimensional seepage field and stress field on the full-domain three-dimensional model of the embankment for which load parameters have been assigned. The permeability coefficient of the soil corresponding to each grid cell is extracted as the core basic physical parameter for seepage field calculation. The permeability coefficient is assigned to the corresponding grid cell according to the preset actual soil survey value. Based on the seepage boundary conditions of the embankment model after load parameter assignment, numerical calculations of the seepage field were carried out on grid cells of the entire embankment. During the calculation, each grid cell was taken as an independent calculation unit. The seepage field calculation values ​​of each grid cell are used as the initial input parameters for stress field calculation. Based on these initial input parameters and the assigned water pressure parameters, stress field numerical calculations are carried out on a grid-by-grid basis for the entire dike area.

5. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 4, characterized in that, Step S3 involves calculating the seepage field values ​​for each grid cell of the dike, including: The actual groundwater level of the dike is marked as the upstream boundary for the seepage field calculation, and the actual ground elevation on the back side of the dike is marked as the downstream boundary for the seepage field calculation. The values ​​of the fixed upstream and downstream boundaries are not included in the iterative adjustment. Using the soil permeability coefficient of each grid cell as the reference parameter, the pore water pressure value of the soil is calculated cell by cell. The calculation step size is set according to the permeability coefficient of each grid cell. According to the natural path of seepage in the dike, the pore water pressure calculation value of each grid cell is iteratively verified, and the difference between the calculation values ​​of adjacent grid cells is compared after each iteration. Once the difference between the measured values ​​is less than the preset measured value threshold, the seepage field values ​​of each grid unit of the dike are determined.

6. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 5, characterized in that, Step S3 involves calculating the stress field values ​​for each grid cell of the dike, including: The effective stress value of the soil is calculated based solely on the pore water pressure value determined by each grid cell, and the influence of other interfering factors is completely eliminated during the conversion process. The effective stress value of the soil is vector-superimposed with the water pressure parameters assigned to the grid cells. The resultant stress value is calculated according to the actual force direction during superposition. Obtain the actual physical properties of the soil in the corresponding area of ​​the dike; calculate the shear stress value grid by grid unit based on the actual physical properties of the soil in the corresponding area of ​​the dike, and use the resultant stress value as the sole calculation basis; After the shear stress value calculation results show no change for three consecutive times, the stress field value of each grid unit of the dike is determined.

7. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 6, characterized in that, The numerical calculation of the coupling between the three-dimensional seepage field and the stress field in step S3 is as follows: Based on the shear stress value of each grid unit, the soil permeability coefficient parameter of the corresponding grid unit is adjusted proportionally according to the actual magnitude of the shear stress value. When the shear stress value increases, the adjustment range of the permeability coefficient increases proportionally. Based on the corrected soil permeability coefficient parameters, the pore water pressure value was recalculated on a grid-by-grid basis, and the recalculation used the same step size as the initial calculation. Substitute the recalculated pore water pressure value into the conversion to obtain the updated effective stress value of the soil, and then combine it with the water pressure parameter to calculate the new resultant stress value. The operation of repeatedly iterating and correcting the permeability coefficient and the calculated stress value continues until all values ​​of the seepage field and stress field no longer change.

8. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 1, characterized in that, Step S4 involves performing a coupled analysis of seepage and stress on each grid cell of the dike, specifically as follows: The pore water pressure and shear stress values ​​determined for each grid cell are extracted; the pore water pressure and shear stress values ​​are the final stable values ​​after coupled calculation. The measured physical properties of cohesion of the soil layers corresponding to each grid unit are retrieved, and the cohesion properties are accurately matched to the corresponding grid units according to the actual values ​​of the soil survey. The cohesion index is linearly corrected based on the pore water pressure value. When the pore water pressure value increases, the corrected cohesion index value decreases by a fixed proportion. A correlation analysis was performed between the corrected cohesion index and the shear stress value, and the relationship between the shear stress value and the actual value of the corrected cohesion index was determined on a grid-by-grid basis.

9. The method for levee stability analysis based on three-dimensional seepage and stress field calculation according to claim 1, characterized in that, In step S4, the determination of the structural stability of the entire dike based on the seepage and stress analysis results is specifically as follows: According to the pre-set specifications for embankment engineering design, the critical ratio standard of shear stress value and modified cohesion index is defined. This critical ratio standard is the core basis for judging the shear resistance of embankment soil. The numerical relationships and critical ratio standards obtained from the grid cell-by-grid cell comparison analysis are recorded one by one, and the specific comparison results of each grid cell are recorded. Mark the grid cells whose numerical relationships exceed the critical ratio standard, and record the three-dimensional spatial coordinates of the grid cells during the marking process; Based on the three-dimensional adjacency relationship, the marked mesh units are integrated to form a continuous stress anomaly region, and the three-dimensional spatial range and geometric dimensions of the stress anomaly region are determined.

10. A levee stability analysis system based on three-dimensional seepage and stress field calculation, characterized in that, For performing the levee stability analysis method based on three-dimensional seepage and stress field calculation as described in claim 1, the levee stability analysis system based on three-dimensional seepage and stress field calculation includes: The 3D model construction module for dikes is used to conduct collaborative exploration of the entire dike area using geodetic and satellite sensing equipment, collect dike engineering survey information, perform heterogeneous fusion and spatial coordinate matching on the survey information, and construct a 3D model of the entire dike area. The load assignment module for the embankment model is used to perform three-dimensional meshing on the three-dimensional model of the entire embankment. Combined with the preset seepage stress field inversion calculation results, it assigns corresponding boundary load parameters to each three-dimensional mesh unit of the embankment, thus completing the load parameter assignment of the three-dimensional model of the entire embankment. The seepage stress field coupling calculation module is used to perform three-dimensional seepage field and stress field coupling numerical calculation on the three-dimensional model of the entire dike with load parameters, and to measure the seepage field and stress field values ​​of each grid unit of the dike. The levee stability assessment module is used to perform coupled analysis of seepage and stress on each grid cell of the levee based on the seepage field and stress field values, and obtain the seepage and stress analysis results; and determine the structural stability of the entire levee based on the seepage and stress analysis results.

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