A three-dimensional finite element calculation grid generation method for earth-rock dams adapted to the foundation surface

Abstract

This application relates to the field of finite element calculations for water conservancy projects, and specifically discloses a method for generating a three-dimensional finite element calculation grid for earth-rock dams that adapts to the foundation surface. The method includes the following steps: first, applying the planar standard grid of the largest section to all transverse segmented sections with equal distances, then fine-tuning the ground lines of all sections, and finally, classifying the three-dimensional initial grids obtained by connecting adjacent sections in pairs into three categories: A, B, and C. These are then processed by retaining, splitting, and collapsing to obtain three-dimensional grid units that meet the requirements of the Solid185 unit, and then summarizing them to obtain a three-dimensional finite element grid. Compared to the method of adapting the foundation surface to the terrain by cutting the three-dimensional grid, this application takes into account the unevenness of the dam foundation and the complexity of the foundation surface. By classifying and processing according to specific unit requirements, it improves the time-consuming, labor-intensive, and error-prone problems of manual modeling, and provides a tool for innovation in hydraulic finite element analysis.

Description

Technical Field

[0001] The present application relates to the field of finite element calculation of water conservancy projects, and in particular to a method for generating a three-dimensional finite element calculation grid for earth-rock dams that is adapted to a foundation surface. Background Art

[0002] Pumped-storage power stations, with their dynamic capabilities like frequency and phase regulation and emergency backup, are crucial tools for optimizing grid operation and ensuring power safety. Their upper reservoirs are typically constructed using earth-rock dams, the design and construction of which are crucial aspects of pumped-storage power station construction.

[0003] With the rapid development of computer technology, the finite element method (FEM) has become widely used as a powerful structural analysis tool. When analyzing earth-rockfill dam settlement using the FEM, establishing a finite element mesh model that conforms to the dam's engineering geological and topographical conditions is a key component of the pre-processing phase of the FEM analysis. This modeling process must account for the unevenness of the dam foundation and the complexity of the foundation surface. In many cases, different models must be created based on different design options for comparison. However, existing modeling methods are labor-intensive, time-consuming, and prone to errors, making them unsuitable for rapid simulation. Summary of the Invention

[0004] In order to improve the problems of current modeling methods such as large workload, time-consuming and error-prone, the present application provides a three-dimensional finite element calculation grid generation method for earth-rock dams that is adapted to the foundation surface.

[0005] This application provides a method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to the foundation surface, which adopts the following technical solutions:

[0006] A method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface comprises the following steps:

[0007] The plane standard grid of the largest section of the earth-rock dam is pushed evenly along the dam axis to obtain the plane standard grids of all transverse sections used to construct the three-dimensional finite element grid of the earth-rock dam;

[0008] Adjust the position of the ground line of each section so that the ground line only passes through the nodes on the plane standard grid of each section and does not intersect with the edges of the plane standard grid to generate new nodes;

[0009] According to the relationship between the nodes and the ground line in the plane standard grid, all nodes on the plane standard grid of each section are given node existence;

[0010] According to the existence of all nodes in the unit, all units on the plane standard grid of each section are given unit existence;

[0011] Cut the plane standard grid of each section using the ground line of the section to obtain the plane cutting grid of each section;

[0012] Traverse all sections, project and connect the plane grid units between adjacent sections along the dam axis to construct a three-dimensional initial grid;

[0013] According to the existence of the unit, all three-dimensional initial grid units are assigned connection classes; all three-dimensional initial grid nodes are given sequential numbers;

[0014] According to the classification of the three-dimensional initial grid cells, the three-dimensional initial grid cells are processed, and the processing methods include retention, splitting and collapse splitting, so that the processed three-dimensional grid cells meet the requirements of Solid185 cells;

[0015] All processed three-dimensional mesh elements are aggregated to generate a three-dimensional finite element mesh for the earth-rock dam.

[0016] Furthermore, the step of adjusting the ground line position of each section includes:

[0017] Calculate the coordinates of the cutting nodes generated by the intersection of the ground line of the current section and all the grid edges on the plane standard grid;

[0018] Connect each cutting node forward and backward according to the original ground line path to replace the original ground line;

[0019] The coordinates of each cutting node are replaced by the coordinates of the endpoint closest to the two endpoints on the cutting edge where the cutting node is located.

[0020] Furthermore, the step of assigning node existence includes:

[0021] Use the ray method to send a ray from the node in a vertical downward direction and count the number of times the ray crosses the ground line;

[0022] For nodes on the boundary of the ground line, the node existence is assigned to 0;

[0023] For nodes that are not on the ground line boundary but cross the ground line 1 times, the node existence is assigned to 1;

[0024] For nodes that are not on the ground line boundary but cross the ground line 0 times, the node existence is assigned to -1.

[0025] Furthermore, the step of assigning unit existence includes:

[0026] Calculate the node existence sum value NS of all nodes in the unit;

[0027] For units with NS>0, the unit existence is assigned to 1;

[0028] For units with NS=0, assign unit existence to 0;

[0029] The unit existence of the unit with NS<0 is assigned -1.

[0030] Furthermore, the step of constructing a three-dimensional initial grid includes:

[0031] If the plane grid cells at the same projection position of two adjacent sections have not been cut or selected by the ground line, their corresponding nodes are connected;

[0032] If the plane grid cells at the same projection position of two adjacent sections are cut and selected by the ground line, and the cutting diagonals are consistent, then the corresponding nodes are connected;

[0033] If the plane grid cells at the same projection position of two adjacent sections are cut by the ground line, but the cutting diagonals are inconsistent, only the corresponding nodes are connected, and the remaining independent nodes of the two sections are directly connected;

[0034] If only one section of the plane mesh unit at the same projection position of two adjacent sections is cut and selected by the ground line, only the corresponding nodes are connected, and the remaining nodes of the uncut quadrilateral mesh are temporarily not connected.

[0035] Furthermore, the step of assigning a connection class to the three-dimensional initial grid unit includes:

[0036] For the three-dimensional initial grid cells formed by connecting two plane grid cells with cell existence equal to 1 at the same projection position between adjacent sections, the connection type is assigned to A;

[0037] For the three-dimensional initial grid cells at the same projection position between adjacent sections, which are formed by connecting two plane grid cells with the same cell existence of 0 and the same cutting direction of the ground line, the connection type is assigned to A;

[0038] For the three-dimensional initial grid cells formed by connecting two plane grid cells with cell existence of 1 and 0, or 0 and 1, at the same projection position between adjacent sections, the connection type is assigned to B;

[0039] For the three-dimensional initial grid cells at the same projection position between adjacent sections, which are formed by connecting two plane grid cells whose cell existence is 0 but whose cutting directions are inconsistent with those of the ground line, the connection type is assigned to B;

[0040] In other three-dimensional initial meshes that have not yet been assigned a connection class, except for the three-dimensional initial mesh formed by connecting two plane mesh cells with unit existence of -1 at the same projection position between adjacent sections, that is, the three-dimensional initial mesh formed by connecting two plane mesh cells with unit existence of 0 and -1, or 1 and -1, or -1 and 0, or -1 and 1, the connection class is assigned C.

[0041] Furthermore, the step of processing the three-dimensional initial grid unit includes:

[0042] The three-dimensional initial grid cells of type A are retained.

[0043] Furthermore, the step of processing the three-dimensional initial grid unit includes:

[0044] Split the type B three-dimensional initial grid cell consisting of two plane grid cells whose existence is 0 into three tetrahedral grid cells;

[0045] A type B three-dimensional initial grid cell consisting of two plane grid cells whose existences are 0 and 1, or 0 and 1, is split into two pyramid grid cells.

[0046] Furthermore, the step of processing the three-dimensional initial grid unit includes:

[0047] For the plane-cut grid cells of type C 3D initial grid cells with a cell existence of -1, all nodes are migrated to the nearest ground line node in the section. If the migrated plane grid cell collapses to a point, turning the 3D initial grid cell into a pyramid or tetrahedron, the 3D grid is directly retained; if the migrated plane grid cell collapses to a line segment, the 3D initial grid cell is split in the subsequent steps according to the situation.

[0048] After the above collapse steps, if the uncollapsed plane mesh of the three-dimensional initial mesh unit is a triangular mesh, the three-dimensional initial mesh unit is split into two tetrahedral mesh units; if the uncollapsed plane mesh of the three-dimensional initial mesh unit is a quadrilateral mesh, the three-dimensional initial mesh unit is split into a three-dimensional mesh unit, a pyramid mesh unit, and a tetrahedral mesh unit.

[0049] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements a method for generating a three-dimensional finite element calculation grid for an earth-rock dam that is adapted to a foundation surface.

[0050] In summary, this application has the following beneficial technical effects:

[0051] The method provided in this application takes into account the unevenness of the dam foundation and the complexity of the foundation surface when modeling the earth-rock dam, and meets the Solid185 unit modeling and calculation requirements in the ANSYS software; compared with the method of cutting the three-dimensional grid to adapt to the terrain foundation surface, the method provided in this application improves the time-consuming and error-prone problems of manual modeling by classifying and processing according to specific unit requirements, and provides a tool for innovation in hydraulic finite element analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1This is a flow chart of a method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface in an embodiment of the present application;

[0053] Figure 2 This is the standard grid of the largest cross-section plane in the embodiment of this application;

[0054] Figure 3 The plane standard mesh of all transverse segmented sections used to construct the three-dimensional finite element mesh of the earth-rock dam in the embodiment of the present application, in which three-dimensional elements have not yet been connected;

[0055] Figure 4 The plane standard grid and ground line of one of the cross sections in the embodiment of the present application;

[0056] Figure 5 for Figure 4 A magnified view near the ground line in ;

[0057] Figure 6 For the general Figure 4 The new ground line map obtained after fine-tuning the ground lines in ;

[0058] Figure 7 for Figure 6 A zoomed-in view of the area near the new ground line;

[0059] Figure 8 Schematic diagram of a method for fine-tuning the focus of a ground line on a grid unit in an embodiment of the present application;

[0060] Figure 9 A schematic diagram of assigning existence of a grid node in an embodiment of the present application;

[0061] Figure 10 A schematic diagram of assigning existence of a grid unit in an embodiment of the present application;

[0062] Figure 11 The three-dimensional initial mesh of the earth-rock dam in the embodiment of this application;

[0063] Figure 12 This is a schematic diagram of a three-dimensional initial grid unit connected in type A in an embodiment of the present application;

[0064] Figure 13 This is a schematic diagram of a three-dimensional initial grid unit of type B connection in an embodiment of the present application;

[0065] Figure 14 This is a schematic diagram of a three-dimensional initial grid unit of type C connection in an embodiment of the present application;

[0066] Figure 15 Schematic diagram of splitting a type B three-dimensional initial grid unit consisting of two planar grid units whose existences are both 0 into three tetrahedral grid units in an embodiment of the present application;

[0067] Figure 16 Schematic diagram of splitting a type B three-dimensional initial grid unit consisting of two planar grid units whose existences are 0 and 1, or 0 and 1, into two pyramid grid units in an embodiment of the present application;

[0068] Figure 17 In the embodiment of the present application, the pyramid three-dimensional grid cell is directly retained after all nodes of the plane-cut grid cell with a cell existence of -1 in the C-type three-dimensional initial grid cell are migrated to the same point;

[0069] Figure 18 In the embodiment of the present application, the tetrahedral three-dimensional grid cell is directly retained after all nodes of the plane-cut grid cell with a cell existence of -1 in the type C three-dimensional initial grid cell are migrated to the same point;

[0070] Figure 19 Schematic diagram of a three-dimensional initial mesh unit of type C in an embodiment of the present application, in which a plane-cut mesh unit with a unit existence of -1 is collapsed into a line segment, and a three-dimensional initial mesh unit whose plane mesh of another section is a triangular mesh is split into two tetrahedral mesh units;

[0071] Figure 20 Schematic diagram of a three-dimensional initial grid cell of type C in an embodiment of the present application, in which a plane cut grid cell with a unit existence of -1 is collapsed into a line segment, and a three-dimensional initial grid cell whose plane mesh of another section is a quadrilateral grid is split into a pyramid grid cell and a tetrahedron grid cell;

[0072] Figure 21 This is the three-dimensional finite element calculation grid for the earth-rock dam in the embodiment of this application. DETAILED DESCRIPTION

[0073] The following is combined with Figure 1-21 This application is described in further detail.

[0074] The embodiment of the present application discloses a method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to the foundation surface. Figure 1 The three-dimensional finite element calculation grid generation method for earth-rock dams adapted to the foundation surface includes the following steps:

[0075] S100: Figure 2 The plane standard grid of the largest section of the earth-rock dam shown is pushed evenly along the dam axis to obtain Figure 3 The plane standard mesh of all transverse segmented sections used to construct the three-dimensional finite element mesh of the earth-rock dam is shown.

[0076] The maximum cross-section is obtained by analyzing the contour information of all cross-sections of the earth-rock dam and projecting all cross-sections onto the same plane to obtain the union of the two, taking advantage of the similarity of the cross-section shapes of the earth-rock dam. The shape of each cross-section is only a part of the maximum cross-section due to the different positions of the ground baseline.

[0077] The plane standard grid is a two-dimensional plane grid composed only of triangles and quadrilaterals generated when dividing the grid of the largest section of the earth-rock dam.

[0078] Before adapting each section to the terrain, the plane standard grids of all sections are derived from the plane standard grid of the largest section. Therefore, the plane standard grids of all sections are the same, except that the positions of each section along the dam axis are different.

[0079] S200: Adjust the position of the ground line of each section so that the ground line only passes through the nodes on the standard grid of each section plane and does not intersect with the grid edge to generate new nodes, such as Figure 8 As shown, the specific steps include:

[0080] S210: Calculating the coordinates of the cutting nodes generated by the intersection of the ground line of the current section and all the grid edges on the plane standard grid;

[0081] S220: Connecting each cutting node forward and backward along the original ground line path to replace the original ground line;

[0082] S230: replacing the coordinates of each cutting node with the coordinates of the endpoint closest to the two endpoints on the cutting edge where the cutting node is located;

[0083] S240: Repeat steps S210-S230, traverse each section and complete the ground line fine-tuning of all sections.

[0084] Will Figure 4 and Figure 5 The ground line position of each section is fine-tuned to Figure 6 and Figure 7 As shown in FIG, the fine-tuned ground line only passes through the nodes on the standard grid of each cross-section plane without intersecting with the grid edge to generate new nodes.

[0085] S300: According to the relationship between the nodes and the ground line in the plane standard grid, all nodes on the plane standard grid of each section are given node existence, such as Figure 9 As shown, the specific steps include:

[0086] S310: Using the ray method, a ray is emitted from the node in a vertical downward direction (negative direction of the Y axis) and the number of times the ray crosses the ground line is calculated;

[0087] S320: For nodes on the boundary of the ground line, assign node existence to 0;

[0088] For nodes that are not on the ground line boundary but cross the ground line 1 times, the node existence is assigned to 1;

[0089] For nodes that are not on the ground line boundary but cross the ground line 0 times, the node existence is assigned to -1;

[0090] S330: Traverse all nodes of each section and assign node existence to all nodes.

[0091] S400: According to the existence of all nodes in the unit in the plane standard grid, all units on the plane standard grid of each section are given unit existence, such as Figure 10 As shown in the figure, a unit is formed by connecting nodes along the edge of a polygonal mesh in a counterclockwise direction. One polygonal mesh corresponds to one unit.

[0092] The specific steps include:

[0093] S410: Calculate the node existence sum NS of all nodes in the unit;

[0094] S420: assigning unit existence to 1 for units with NS>0;

[0095] For units with NS=0, assign unit existence to 0;

[0096] For units with NS < 0, the unit existence is assigned to -1;

[0097] Among them, the cells with cell existence of 0 only exist in the quadrilateral grids that are diagonally crossed by the ground line after step S200;

[0098] S430: Traverse all units of each section and assign unit existence to all units.

[0099] Here, the term "grid" is used as a holistic concept, referring to the network lattice composed of countless polygons. The corresponding term, "grid cell," is an individual concept formed by connecting nodes counterclockwise along a polygonal mesh edge. One polygon corresponds to one grid cell. Furthermore, because this method uses a specific planar mesh generation path, cells with an existence of "0" only exist in quadrilateral meshes that are diagonally intersected by a ground line.

[0100] S500: cutting the plane standard grid of each section using the ground line of the section to obtain the plane cutting grid of each section;

[0101] The plane cut mesh is formed by cutting the plane standard mesh by the ground line, including the original plane mesh that is not cut by the ground line and the original quadrilateral mesh that is cut into two triangular meshes by the ground line. For the two triangular meshes obtained by cutting the quadrilateral mesh along the diagonal line, the triangular mesh below the ground line elevation is discarded, and the triangular mesh above the ground line elevation is retained and replaced by the original quadrilateral mesh. The unit existence is still set to 0.

[0102] S600: Traverse all sections and project the plane grid units between adjacent sections along the dam axis to construct Figure 11 The three-dimensional initial mesh shown in the figure includes the following steps:

[0103] S610: If the plane grid cells at the same projection position of two adjacent sections are not cut or discarded by the ground line, then the corresponding nodes are connected;

[0104] S620: If the plane grid cells at the same projection position of two adjacent sections are both cut and discarded by the ground line, and the cut diagonals are consistent, then the corresponding nodes are connected;

[0105] S630: If the plane grid cells at the same projection position of two adjacent sections are both cut and discarded by the ground line, but the cutting diagonals are inconsistent, only the corresponding nodes are connected, and the remaining independent nodes of the two sections are directly connected;

[0106] S640: If only one section of the plane mesh unit at the same projection position of two adjacent sections is cut and discarded by the ground line, only the corresponding nodes are connected, and the remaining nodes of the uncut quadrilateral mesh are temporarily not connected;

[0107] S650: Traverse all sections and complete the connection of all plane grid units between any two adjacent sections.

[0108] Except for the two three-dimensional initial meshes in step S630 and step S640 which require further processing, the other three-dimensional initial meshes are only composed of triangular prisms and hexahedrons and do not require further processing.

[0109] S700: assigning connection classes to all three-dimensional initial grid cells according to cell existence; and assigning sequential numbers to all three-dimensional initial grid nodes, specifically including the following steps:

[0110] S710: Assign connection classes to all three-dimensional initial grid cells. The specific method is as follows:

[0111] S711: Figure 12 As shown:

[0112] For the three-dimensional initial grid cells formed by connecting two plane grid cells with cell existence equal to 1 at the same projection position between adjacent sections, the connection type is assigned to A;

[0113] For the three-dimensional initial grid cells at the same projection position between adjacent sections, which are formed by connecting two plane grid cells with the same cell existence of 0 and the same cutting direction of the ground line, the connection type is assigned to A;

[0114] S712: If Figure 13 As shown:

[0115] For the three-dimensional initial grid cells formed by connecting two plane grid cells with cell existence of 1 and 0, or 0 and 1, at the same projection position between adjacent sections, the connection type is assigned to B;

[0116] For the three-dimensional initial grid cells at the same projection position between adjacent sections, which are formed by connecting two plane grid cells whose cell existence is 0 but whose cutting directions are inconsistent with those of the ground line, the connection type is assigned to B;

[0117] S713: If Figure 14 As shown:

[0118] In other 3D initial meshes that have not been assigned a connection class, except for the 3D initial mesh formed by connecting two plane mesh elements with unit existence of -1 at the same projection position between adjacent sections, that is, the 3D initial mesh formed by connecting two plane mesh elements with unit existence of 0 and -1, or 1 and -1, or -1 and 0, or -1 and 1, the connection class is assigned to C;

[0119] S714: Traverse all three-dimensional initial grids and assign connection classes to all three-dimensional initial grid cells.

[0120] S720: Sequentially number all three-dimensional initial mesh nodes. The specific method is as follows:

[0121] S721: Assign the sequence number "1" to the node at the upper left position in the first cross-section of the 3D initial mesh (upper first, left first), and assign the sequence numbers 2 and 3 to the other nodes in a counterclockwise order. If the mesh is a quadrilateral mesh, the last node is assigned the sequence number "4";

[0122] S722: Assign the sequence number "5" to the node at the upper left position in the second cross-section of the 3D initial mesh (upper first, left first), and assign the sequence numbers 6 and 7 to the other nodes in a counterclockwise order. If the mesh is a quadrilateral mesh, the last node is assigned the sequence number "8".

[0123] S723: Traverse all three-dimensional initial grids and assign sequential numbers to all three-dimensional initial grid nodes.

[0124] S800: Processing the 3D initial mesh cells according to their classification, including retaining, splitting, and collapsing and splitting, to obtain a processed 3D mesh cell that meets the Solid185 cell requirements. Specifically, the following steps are included:

[0125] S810: For type A three-dimensional initial grid cells, the processing method is as follows:

[0126] Type A three-dimensional initial mesh units are composed of triangular prisms and hexahedrons. They are finite element meshes that meet the modeling requirements of Solid185 units. Therefore, they are directly retained without the need for adjustment like type B and type C three-dimensional initial mesh units.

[0127] S820: For type B three-dimensional initial grid cells, the processing method is as follows:

[0128] like Figure 15 As shown, the type B three-dimensional initial grid unit composed of two plane grid units with existence of 0 is split into the following three three-dimensional grid units: a tetrahedral grid unit composed of nodes "2-6-3-1", a tetrahedral grid unit composed of nodes "3-1-6-7", and a tetrahedral grid unit composed of nodes "5-7-6-1".

[0129] like Figure 16 As shown, the three-dimensional initial grid unit of type B, which is composed of two plane grid units whose existences are "0" and "1" or "0" and 1, is split into the following two three-dimensional grid units: a pyramid grid unit composed of nodes "1-5-6-7-8" and a pyramid grid unit composed of nodes "1-6-2-3-7";

[0130] Traverse all Class B three-dimensional initial grids, complete the splitting of all Class B three-dimensional initial grids, and obtain tetrahedral grids and pyramid grids that meet the requirements of Solid185 units.

[0131] S830: For type C three-dimensional initial mesh cells, the processing method is as follows:

[0132] S831: Migrate all nodes of the plane cutting grid unit with unit existence of -1 in the C type three-dimensional initial grid unit to the nearest ground line node in the section. If the migrated plane grid unit collapses to a point, the three-dimensional initial grid unit becomes as follows: Figure 17 and Figure 18 If the pyramid or tetrahedron shown is used, the three-dimensional grid is directly retained;

[0133] S832: If, in step S831, the migrated plane mesh unit collapses into a line segment, the subsequent steps are performed on this three-dimensional initial mesh unit according to the situation. First, the collapsed line segment nodes are assigned sequence numbers 1 and 2, and then the plane mesh nodes of the other section that have not collapsed are assigned sequence numbers according to step S722.

[0134] S833: After step S832, if the uncollapsed plane mesh of the three-dimensional initial mesh unit is a triangular mesh, the three-dimensional initial mesh unit is split into the following two three-dimensional mesh units: a tetrahedral mesh unit composed of nodes "1-5-6-2" and a tetrahedral mesh unit composed of nodes "7-5-2-6", such as Figure 19 As shown;

[0135] S834: After step S832, if the uncollapsed plane mesh of the three-dimensional initial mesh unit is a quadrilateral mesh, the three-dimensional initial mesh unit is split into the following two three-dimensional mesh units: a pyramid mesh unit composed of nodes "1-5-6-7-8" and a tetrahedral mesh unit composed of nodes "2-1-7-8", such as Figure 20 As shown;

[0136] S835: Traverse all Class C three-dimensional initial grids, complete the collapse and splitting of all Class C three-dimensional initial grids, and obtain tetrahedral grids and pyramid grids that meet the requirements of Solid185 units.

[0137] S900: Summarize all processed three-dimensional grid cells to generate Figure 21 The obtained 3D finite element mesh of the earth-rock dam is composed of the 3D mesh of triangular prisms and hexahedrons retained in step S810, the 3D mesh of tetrahedrons and pyramids obtained after splitting in step S820, and the 3D mesh of tetrahedrons and pyramids obtained after collapsing and splitting in step S830.

[0138] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements a method for generating a three-dimensional finite element calculation grid for an earth-rock dam that is adapted to a foundation surface.

[0139] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for generating a three-dimensional finite element computational grid for an earth-rock dam adapted to a foundation surface, characterized by: The following steps are involved: The plane standard grid of the largest section of the earth-rock dam is pushed evenly along the dam axis to obtain the plane standard grids of all transverse sections used to construct the three-dimensional finite element grid of the earth-rock dam; Adjust the position of the ground line of each section so that the ground line only passes through the nodes on the plane standard grid of each section and does not intersect with the edges of the plane standard grid to generate new nodes; According to the relationship between the nodes and the ground line in the plane standard grid, all nodes on the plane standard grid of each section are given node existence; The step of assigning node existence includes: using a ray method to emit a ray from the node in a vertical downward direction and counting the number of times the ray passes through the ground line; assigning a node existence of 0 to a node on the ground line boundary; assigning a node existence of 1 to a node that is not on the ground line boundary but has passed through the ground line 1 time; assigning a node existence of -1 to a node that is not on the ground line boundary but has passed through the ground line 0 times; Assigning unit existence to all units on the plane standard grid of each section according to the existence of all nodes in the unit in the plane standard grid; the step of assigning unit existence includes: calculating the sum of node existence values ​​NS of all nodes in the unit; assigning unit existence of 1 to units with NS>0; assigning unit existence of 0 to units with NS=0; and assigning unit existence of -1 to units with NS<0; Cut the plane standard grid of each section using the ground line of the section to obtain the plane cutting grid of each section; Traverse all sections, project and connect the plane grid units between adjacent sections along the dam axis to construct a three-dimensional initial grid; According to the existence of the unit, all three-dimensional initial grid units are assigned connection classes; all three-dimensional initial grid nodes are given sequential numbers; According to the classification of the three-dimensional initial grid cells, the three-dimensional initial grid cells are processed, and the processing methods include retention, splitting and collapse splitting, so that the processed three-dimensional grid cells meet the requirements of Solid185 cells; All processed three-dimensional mesh elements are aggregated to generate a three-dimensional finite element mesh for the earth-rock dam.

2. The method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface according to claim 1, characterized in that: The step of adjusting the ground line position of each section includes: Calculate the coordinates of the cutting nodes generated by the intersection of the ground line of the current section and all the grid edges on the plane standard grid; Connect each cutting node forward and backward along the original ground line path to replace the original ground line: The coordinates of each cutting node are replaced by the coordinates of the endpoint closest to the two endpoints on the cutting edge where the cutting node is located.

3. The method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface according to claim 2, characterized in that: The step of constructing the three-dimensional initial grid comprises: If the plane grid cells at the same projection position of two adjacent sections have not been cut or selected by the ground line, their corresponding nodes are connected; If the plane grid cells at the same projection position of two adjacent sections are cut and selected by the ground line, and the cutting diagonals are consistent, then the corresponding nodes are connected; If the plane grid cells at the same projection position of two adjacent sections are cut by the ground line, but the cutting diagonals are inconsistent, only the corresponding nodes are connected, and the remaining independent nodes of the two sections are directly connected; If only one section of the plane mesh unit at the same projection position of two adjacent sections is cut and selected by the ground line, only the corresponding nodes are connected, and the remaining nodes of the uncut quadrilateral mesh are temporarily not connected.

4. The method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface according to claim 3, characterized in that: The steps for assigning connection classes to the 3D initial mesh cells include: For the three-dimensional initial grid cells formed by connecting two plane grid cells with cell existence equal to 1 at the same projection position between adjacent sections, the connection type is assigned to A; For the three-dimensional initial grid cells at the same projection position between adjacent sections, which are formed by connecting two plane grid cells with the same cell existence of 0 and the same cutting direction of the ground line, the connection type is assigned to A; For the three-dimensional initial grid cells formed by connecting two plane grid cells with cell existence of 1 and 0, or 0 and 1, at the same projection position between adjacent sections, the connection type is assigned to B; For the three-dimensional initial grid cells at the same projection position between adjacent sections, which are formed by connecting two plane grid cells whose cell existence is 0 but whose cutting directions are inconsistent with those of the ground line, the connection type is assigned to B; In other three-dimensional initial meshes that have not yet been assigned a connection class, except for the three-dimensional initial mesh formed by connecting two plane mesh cells with unit existence of -1 at the same projection position between adjacent sections, that is, the three-dimensional initial mesh formed by connecting two plane mesh cells with unit existence of 0 and -1, or 1 and -1, or -1 and 0, or -1 and 1, the connection class is assigned C.

5. The method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface according to claim 4, characterized in that: The steps for processing the three-dimensional initial grid cells include: The three-dimensional initial grid cells of type A are retained.

6. The method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface according to claim 4, characterized in that: The steps for processing the three-dimensional initial grid cells include: Split the type B three-dimensional initial grid cell consisting of two plane grid cells whose existence is 0 into three tetrahedral grid cells; A type B three-dimensional initial grid cell consisting of two plane grid cells whose existences are 0 and 1, or 0 and 1, is split into two pyramid grid cells.

7. The method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface according to claim 4, characterized in that: The steps for processing the three-dimensional initial grid cells include: For the plane-cut grid cells of type C 3D initial grid cells with a cell existence of -1, all nodes are migrated to the nearest ground line node in the section. If the migrated plane grid cell collapses to a point, turning the 3D initial grid cell into a pyramid or tetrahedron, the 3D grid is directly retained; if the migrated plane grid cell collapses to a line segment, the 3D initial grid cell is split in the subsequent steps according to the situation. After the above collapse steps, if the uncollapsed plane mesh of the three-dimensional initial mesh unit is a triangular mesh, the three-dimensional initial mesh unit is split into two tetrahedral mesh units; if the uncollapsed plane mesh of the three-dimensional initial mesh unit is a quadrilateral mesh, the three-dimensional initial mesh unit is split into a three-dimensional mesh unit, a pyramid mesh unit, and a tetrahedral mesh unit.

8. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method for generating a three-dimensional finite element calculation grid for an earth-rock dam adapted to a foundation surface as claimed in any one of claims 1 to 7 is implemented.

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