Finite element analysis and research method matched with attribute size of earth and rockfill dam

Abstract

The invention discloses a finite element analysis and research method matched with the attribute size of an earth and rockfill dam, and belongs to the technical field of water conservancy and hydropower engineering. The method comprises the following steps that S1, the attribute size of the earth and rockfill dam is determined; s2, determining the mesh size of the finite element calculation model according to the attribute size of the earth and rockfill dam; s3, establishing a finite element calculation model comprehensively considering the filling layer thickness and the filling time sequence of the earth and rockfill dam; s4, calculating a settlement deformation result of each layer of dam body; s5, continuously optimizing and adjusting the model parameters of the new filling layer based on an optimization algorithm; s6, correcting the calculation parameters, and then returning to the step S4 to continue recalculation; and S7, after n times of updating iterative calculation, the settlement deformation result of the dam body is basically consistent with the monitoring result of the construction site. The actual physical significance of grid engineering of the calculation model is clear, the quality of the calculation model can be effectively guaranteed, and calculation parameters basically approach actual mechanical parameters of the field original grading dam material.

Description

Technical Field

[0001] The invention relates to a finite element analysis research method matching the property size of an earth-rock dam, and belongs to the technical field of water conservancy and hydropower engineering. Background Art

[0002] Compared with other dam types such as arch dams and gravity dams, earth-rock dams have some structural peculiarities, such as multiple dam body divisions, large differences in material properties, complex construction phases and filling and loading processes, variable topographic and geological boundaries, and nonlinear solution processes, which determine the complexity of earth-rock dam modeling.

[0003] Unit mesh division is a key step in establishing a finite element model. The form and size of the divided mesh have a significant impact on the calculation accuracy. Generally speaking, as the number of meshes increases, the calculation accuracy will be improved, but at the same time the calculation scale will also increase. Therefore, it is usually necessary to weigh these two factors when determining the number of meshes. In the past, due to limitations such as computer capacity and speed, the unit size was mainly determined based on the outer contour of the building structure. An appropriate unit size should be used, and the number of units should not be too large to avoid too long calculation time. The development of computer capacity and speed has provided conditions for unit division based on basic size, but there is currently no in-depth research on the appropriate unit division size.

[0004] Finite element method can simulate the filling process of rockfill dam through the unit "life and death" function. The so-called "killing" unit does not mean deleting the unit from the model, but multiplying its stiffness matrix by a very small factor so that it has no effect on the load vector. When a unit is reactivated, its stiffness, mass, unit load, etc. will return to their original values, and there will be no strain record. The filling of rockfill dam is a step-by-step loading process. The more commonly used method is that each layer of units is a filling layer as the first-level loading. Some scholars have also studied the simultaneous activation of several layers of units as a filling layer to simulate the filling process. There are differences in the results obtained by different simulation methods, which is difficult to reflect the actual filling and compaction construction process of earth-rock dams.

[0005] As mentioned above, the existing finite element calculation methods for earth-rock dams have great limitations in terms of grid size and construction simulation. The calculation grid model lacks actual engineering physical significance, and the numerical calculation process cannot reflect the actual construction process of the earth-rock dam. Therefore, it is of great significance to study a finite element research and analysis method that matches the attribute size of the earth-rock dam. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a finite element analysis research method that matches the attribute dimensions of an earth-rock dam.

[0007] The present invention is achieved through the following technical solutions:

[0008] A finite element analysis research method matching the property size of an earth-rock dam includes a method for determining the mesh size of a finite element calculation model of an earth-rock dam. The method for determining the mesh size of a finite element calculation model of an earth-rock dam includes the following steps:

[0009] S1. Determine the attribute dimensions of earth-rock dam;

[0010] S2. Determine the mesh size of the finite element calculation model according to the attribute size of the earth-rock dam;

[0011] S3. Establish a finite element calculation model that comprehensively considers the filling layer thickness and filling sequence of earth-rock dam.

[0012] The earth-rock dam attribute dimensions include the particle size of the earth-rock dam filling material and the indoor test specimen size, as well as the construction filling size of the earth-rock dam.

[0013] The particle size is the maximum particle size of the earth-rock dam filling material. The earth-rock dam filling material includes stone and soil. The particle size of the stone is between 0.075mm and 1000mm, and the particle size of the soil is between 0.05mm and 150mm.

[0014] The indoor test specimen size is the actual diameter of the indoor triaxial test specimen of the earth-rock dam filling material. The indoor test specimen size specifications of stone are φ300mm, φ500mm, φ800mm and φ2000mm, and the indoor test specimen size specifications of soil are φ300mm, φ500mm and φ800mm.

[0015] The construction filling size is the actual layer thickness of the earth-rock dam during construction and rolling. The construction filling size of stone is between 300mm and 1000mm, and the construction filling size of soil is between 250mm and 300mm.

[0016] The principle for determining the mesh size of the finite element calculation model in step S2 is that the mesh size is larger than the particle size of the earth-rock dam filling material, and smaller than the indoor test specimen size and the construction filling size.

[0017] In the step S3, the earth-rock dam is divided into a plurality of material partitions according to the material properties of the filling material of the earth-rock dam; the earth-rock dam is divided into a plurality of filling stages in the height direction according to the filling sequence of the earth-rock dam, and the filling stages are divided into a plurality of filling partitions in the horizontal direction according to the needs of the filling stages; at the same time, in order to simulate different filling stages and water storage processes in numerical calculations, the earth-rock dam is divided into a plurality of loading layers; the area enclosed by the material partition boundary line, the filling stage boundary line, the filling partition boundary line and the loading layer boundary line is divided into units of different sizes according to the material type of the filling material of the earth-rock dam, and a finite element calculation model is established accordingly.

[0018] The invention also includes a method for real-time simulation of the rolling process of an earth-rock dam body and intelligent dynamic feedback of parameters during the construction period. The method for real-time simulation of the rolling process of an earth-rock dam body and intelligent dynamic feedback of parameters during the construction period includes the following steps:

[0019] S4. According to the actual construction and filling sequence of the earth-rock dam, finite element calculations are performed to simulate the filling process of the dam layer by layer to obtain the settlement and deformation results of each layer of the dam body;

[0020] S5: According to the relationship between compression modulus and deformation measured in field tests during actual construction, the model parameters of the new filling layer are continuously optimized and adjusted based on the optimization algorithm;

[0021] S6: Compare and analyze the calculated dam settlement deformation results with the construction site monitoring results, calibrate the calculation parameters, and then return to step S4 to continue recalculation;

[0022] S7: After the above n times of iterative calculation, the calculation parameters will basically approach the actual mechanical parameters of the original graded dam materials on site, and the calculated dam settlement and deformation results are basically consistent with the monitoring results of the construction site.

[0023] In step S4, the finite element calculation model is loaded layer by layer through the unit life and death function to simulate the filling process of the earth-rock dam and obtain the settlement deformation results of each layer of the dam body.

[0024] The dam body settlement deformation results in step S6 include the earth-rock dam settlement law and settlement extreme value.

[0025] The beneficial effects of the present invention are:

[0026] 1. The determined finite element calculation model grid size matches the earth-rock dam material, structure and construction process. The simulation is carried out layer by layer based on the actual filling and rolling size. The actual physical meaning of the calculation model grid engineering is clear, which can effectively ensure the quality of the calculation model.

[0027] 2. Real-time simulation of the rolling process of the earth-rock dam body and intelligent dynamic feedback method of parameters during the construction period. The relationship between the compression modulus and deformation measured in the field test during the actual construction process is used to iteratively update and correct the calculation parameters of the new fill layer of the model. The calculation parameters are updated in real time throughout the construction process. The calculation parameters are basically close to the actual mechanical parameters of the original graded dam materials on site. The predicted settlement and deformation results of the dam body are basically consistent with the monitoring results at the construction site. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the present invention.

[0029] Figure 2 This is the three-dimensional structural design drawing of a certain earth-rock dam project.

[0030] Figure 3 This is the material zoning diagram of a typical section of a certain earth-rock dam project.

[0031] Figure 4 This is a filling phase diagram of a typical section of a certain earth-rock dam project.

[0032] Figure 5 This is a schematic diagram of the finite element mesh of a typical section of a certain earth-rock dam project.

[0033] Figure 6 This is a diagram showing the calculation results of vertical displacement distribution of a typical section of an earth-rock dam project. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0035] Embodiment 1:

[0036] like Figure 1 As shown, the finite element analysis research method matching the property size of the earth-rock dam described in the present invention includes a method for determining the mesh size of the finite element calculation model of the earth-rock dam, and the method for determining the mesh size of the finite element calculation model of the earth-rock dam includes the following steps:

[0037] S1. Determine the attribute dimensions of earth-rock dam;

[0038] S2. Determine the mesh size of the finite element calculation model according to the attribute size of the earth-rock dam;

[0039] S3. Establish a finite element calculation model that comprehensively considers the filling layer thickness and filling sequence of earth-rock dam.

[0040] The earth-rock dam attribute dimensions include the particle size of the earth-rock dam filling material and the indoor test specimen size, as well as the construction filling size of the earth-rock dam.

[0041] The particle size is the maximum particle size of the earth-rock dam filling material. The earth-rock dam filling material includes stone and soil. The particle size of the stone is between 0.075mm and 1000mm, and the particle size of the soil is between 0.05mm and 150mm.

[0042] The indoor test specimen size is the actual diameter of the indoor triaxial test specimen of the earth-rock dam filling material. The indoor test specimen size specifications of stone are φ300mm, φ500mm, φ800mm and φ2000mm, and the indoor test specimen size specifications of soil are φ300mm, φ500mm and φ800mm.

[0043] The construction filling size is the actual layer thickness of the earth-rock dam during construction and rolling. The construction filling size of stone is between 300mm and 1000mm, and the construction filling size of soil is between 250mm and 300mm.

[0044] The principle for determining the mesh size of the finite element calculation model in step S2 is that the mesh size is larger than the particle size of the earth-rock dam filling material, and smaller than the indoor test specimen size and the construction filling size.

[0045] In the step S3, the earth-rock dam is divided into a plurality of material partitions according to the material properties of the filling material of the earth-rock dam; the earth-rock dam is divided into a plurality of filling stages in the height direction according to the filling sequence of the earth-rock dam, and the filling stages are divided into a plurality of filling partitions in the horizontal direction according to the needs of the filling stages; at the same time, in order to simulate different filling stages and water storage processes in numerical calculations, the earth-rock dam is divided into a plurality of loading layers; the area enclosed by the material partition boundary line, the filling stage boundary line, the filling partition boundary line and the loading layer boundary line is divided into units of different sizes according to the material type of the filling material of the earth-rock dam, and a finite element calculation model is established accordingly.

[0046] The invention also includes a method for real-time simulation of the rolling process of an earth-rock dam body and intelligent dynamic feedback of parameters during the construction period. The method for real-time simulation of the rolling process of an earth-rock dam body and intelligent dynamic feedback of parameters during the construction period includes the following steps:

[0047] S4. According to the actual construction and filling sequence of the earth-rock dam, finite element calculations are performed to simulate the filling process of the dam layer by layer to obtain the settlement and deformation results of each layer of the dam body;

[0048] S5: According to the relationship between compression modulus and deformation measured in field tests during actual construction, the model parameters of the new filling layer are continuously optimized and adjusted based on the optimization algorithm;

[0049] S6: Compare and analyze the calculated dam settlement deformation results with the construction site monitoring results, calibrate the calculation parameters, and then return to step S4 to continue recalculation;

[0050] S7: After the above n times of iterative calculation, the calculation parameters will basically approach the actual mechanical parameters of the original graded dam materials on site, and the calculated dam settlement and deformation results are basically consistent with the monitoring results of the construction site.

[0051] In step S4, the finite element calculation model is loaded layer by layer through the unit life and death function to simulate the filling process of the earth-rock dam and obtain the settlement deformation results of each layer of the dam body.

[0052] The dam body settlement deformation results in step S6 include the earth-rock dam settlement law and settlement extreme value.

[0053] Embodiment 2:

[0054] Take the three-dimensional finite element calculation and analysis of a certain earth-rock dam project as an example. Its three-dimensional structural design diagram is as follows: Figure 2 shown.

[0055] S1. Determine the attribute dimensions of earth-rock dam.

[0056] The attribute dimensions of earth-rock dam include the particle size of earth-rock dam filling materials, the size of indoor test specimens and the construction filling size;

[0057] Determine the attribute size of earth-rock dam according to the design data. The material division of earth-rock dam is as follows: Figure 3 The material partitions and particle size ranges are shown in Table 1.

[0058] Table 1 Material partition and particle size range

[0059]

[0060]

[0061] The indoor test specimen size is the actual diameter of the indoor triaxial test specimen of the earth-rock dam fill material, as shown in Table 2.

[0062] Table 2 Size range of indoor test specimens for earth-rock dam partition filling materials

[0063] Serial number project Indoor test particle size 1 Rockfill Area I Extra large triaxial test, test diameter φ = 1000mm 2 Rockfill II area Extra large triaxial test, test diameter φ = 1000mm 3 Transition material Large triaxial test, test diameter φ = 300mm 4 Anti-filter material Large triaxial test, test diameter φ = 300mm Gravel soil core wall Large triaxial test, test diameter φ = 300mm 5 Contact Clay Large triaxial test, test diameter φ = 300mm

[0064] The construction filling size is the actual construction compaction layer thickness, 800mm for the rockfill area (stone), and 300-350mm for the core wall area (soil).

[0065] S2. Determine the mesh size of the finite element calculation model according to the attribute size of the earth-rock dam.

[0066] According to the principle of determining the mesh size of the finite element calculation model, the mesh size is larger than the particle size of the earth-rock dam filling material, and smaller than the indoor test specimen size and the construction filling size. The mesh size of the finite element calculation model is determined as: 800mm~1000mm for stone and 60~300mm for soil.

[0067] S3. Establish a finite element calculation model that comprehensively considers the filling layer thickness and filling sequence of earth-rock dam.

[0068] In order to meet the requirements of seepage stability, dam deformation coordination, excavation material utilization, etc., rockfill dams are often divided into multiple material zones according to different material properties, and different material zones use different calculation parameters; according to the material properties of earth-rock dam filling materials, earth-rock dams are divided into upstream rockfill zone I, downstream rockfill zone I, downstream rockfill zone II, transition material, filter material I, filter material II and gravel soil core wall, etc. Figure 3 According to the filling sequence of the earth-rock dam, the earth-rock dam is divided into multiple filling stages in the height direction, as shown in Figure 4As shown. According to the needs of filling stages, the filling stages are divided into multiple filling zones in the horizontal direction. At the same time, the rockfill dam has obvious complex stress path problems. In numerical calculations, in order to simulate different filling stages and water storage processes, the earth-rock dam is divided into several loading layers. The area surrounded by the material partition boundary line, filling stage boundary line, filling zone boundary line and loading layer boundary line is divided into units of different sizes according to the material type of the earth-rock dam filling material, and a finite element calculation model is established accordingly, as shown in Figure 5 shown.

[0069] S4. According to the actual construction and filling sequence of the earth-rock dam, finite element calculations are performed to simulate the dam filling process layer by layer to obtain the settlement and deformation results of each layer of the dam body.

[0070] During the actual construction process, the thickness and sequence of the filling layers are often adjusted dynamically according to the actual objective conditions. The filling materials in different areas on the same layer will also be filled and compacted in order. The filling and compaction sequence of each subdivided area is planned according to the construction schedule, and the corresponding calculation parameters are assigned to each subdivided area in advance according to the design parameters. The finite element calculation model is loaded layer by layer through the unit "life and death" function to simulate the filling process of the rockfill dam, and the settlement deformation results are obtained. Figure 6 shown.

[0071] S5. According to the relationship between the compression modulus and deformation measured in the field test during the actual construction process, the model parameters of the new fill layer are continuously optimized and adjusted based on the optimization algorithm.

[0072] During the entire construction process, due to the complexity of construction conditions, the actual material parameters of different filling partitions in the same material partition may not be the same, such as the parameters of the first-phase filling layer rockfill material and the second-phase filling layer rockfill material parameters may be different. Since the finite element calculation model generated by this method sets different material partitions for each compaction layer, field tests can be carried out for each construction layer to obtain the actual material parameters of each material partition in each filling layer. According to the relationship between the compression modulus and deformation measured by the field test during the actual construction process, the model parameters of the new filling layer are optimized and adjusted based on the optimization algorithm, so that the calculation parameters and boundary conditions are more in line with the actual situation, and the deformation results calculated after the filling and compaction of this layer are more in line with the actual deformation of the earth-rock dam.

[0073] S6. Compare and analyze the calculated dam settlement deformation results with the construction site monitoring results, calibrate the calculation parameters, and then return to step S4 to continue recalculation.

[0074] The settlement law and settlement extremes of the earth-rock dam obtained by numerical analysis are compared with the actual monitoring results. If there are large differences, the causes of the differences are found in stages and regions. According to the preliminary analysis conclusions, the model or material parameters are adjusted and the calculation is repeated in step S4 until the problem is solved.

[0075] S7. After the above n times of iterative calculation, the calculation parameters will basically approach the actual mechanical parameters of the original graded dam materials on site, and the calculated dam settlement and deformation results are basically consistent with the monitoring results of the construction site.

Claims

1. A finite element analysis research method matching the attribute dimensions of earth-rock dam, characterized by: The invention comprises a method for determining the mesh size of a finite element calculation model of an earth-rock dam, and the method for determining the mesh size of a finite element calculation model of an earth-rock dam comprises the following steps: S1. Determine the attribute dimensions of earth-rock dam; S2. Determine the mesh size of the finite element calculation model according to the attribute size of the earth-rock dam; S3. Establish a finite element calculation model that comprehensively considers the filling layer thickness and filling sequence of earth-rock dam.

2. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 1 is characterized by: The earth-rock dam attribute dimensions include the particle size of the earth-rock dam filling material and the indoor test specimen size, as well as the construction filling size of the earth-rock dam.

3. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 2 is characterized by: The particle size is the maximum particle size of the earth-rock dam filling material. The earth-rock dam filling material includes stone and soil. The particle size of the stone is between 0.075mm and 1000mm, and the particle size of the soil is between 0.05mm and 150mm.

4. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 3 is characterized by: The indoor test specimen size is the actual diameter of the indoor triaxial test specimen of the earth-rock dam filling material. The indoor test specimen size specifications of stone are φ300mm, φ500mm, φ800mm and φ2000mm, and the indoor test specimen size specifications of soil are φ300mm, φ500mm and φ800mm.

5. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 3 is characterized by: The construction filling size is the actual layer thickness of the earth-rock dam during construction and rolling. The construction filling size of stone is between 300mm and 1000mm, and the construction filling size of soil is between 250mm and 300mm.

6. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 2 is characterized by: The principle for determining the mesh size of the finite element calculation model in step S2 is that the mesh size is larger than the particle size of the earth-rock dam filling material, and smaller than the indoor test specimen size and the construction filling size.

7. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 1 is characterized by: In the step S3, the earth-rock dam is divided into a plurality of material partitions according to the material properties of the filling material of the earth-rock dam; the earth-rock dam is divided into a plurality of filling stages in the height direction according to the filling sequence of the earth-rock dam, and the filling stages are divided into a plurality of filling partitions in the horizontal direction according to the needs of the filling stages; at the same time, in order to simulate different filling stages and water storage processes in numerical calculations, the earth-rock dam is divided into a plurality of loading layers; the area enclosed by the material partition boundary line, the filling stage boundary line, the filling partition boundary line and the loading layer boundary line is divided into units of different sizes according to the material type of the filling material of the earth-rock dam, and a finite element calculation model is established accordingly.

8. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 1 is characterized by: The invention also includes a method for real-time simulation of the rolling process of an earth-rock dam body and intelligent dynamic feedback of parameters during the construction period. The method for real-time simulation of the rolling process of an earth-rock dam body and intelligent dynamic feedback of parameters during the construction period includes the following steps: S4. According to the actual construction and filling sequence of the earth-rock dam, finite element calculations are performed to simulate the filling process of the dam layer by layer to obtain the settlement and deformation results of each layer of the dam body; S5: According to the relationship between compression modulus and deformation measured in field tests during actual construction, the model parameters of the new filling layer are continuously optimized and adjusted based on the optimization algorithm; S6: Compare and analyze the calculated dam settlement deformation results with the construction site monitoring results, calibrate the calculation parameters, and then return to step S4 to continue recalculation; S7: After the above n times of iterative calculation, the calculation parameters will basically approach the actual mechanical parameters of the original graded dam materials on site, and the calculated dam settlement and deformation results are basically consistent with the monitoring results of the construction site.

9. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 8, characterized in that: In step S4, the finite element calculation model is loaded layer by layer through the unit life and death function to simulate the filling process of the earth-rock dam and obtain the settlement deformation results of each layer of the dam body.

10. The finite element analysis research method matching the attribute dimensions of earth-rock dam according to claim 8, characterized in that: The dam body settlement deformation results in step S6 include the earth-rock dam settlement law and settlement extreme value.

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