A method, device and system for simulating the deterioration and disaster of concrete dams

Abstract

The present invention provides a method, device, and system for simulating concrete dam deterioration and disasters. Based on basic engineering information data and combined with historical experience, the system analyzes and pre-diagnoses factors affecting dam safety, proposes possible major influencing factors of engineering deterioration and disasters, establishes a finite element model, sets deterioration and disaster indicators and classification standards, and assigns thresholds for each classification. A pre-generated isolated unit mesh model is used for calculation and analysis using the finite element method to obtain dam deformation, stress, and damage calculation results. Cracking of the dam concrete is determined based on the cracking index and threshold. The system is loaded and calculated using the finite element method. When any unit in the dam reaches the cracking threshold, local cracking occurs, and the dam mesh is reconstructed. After reconstruction, iterative calculations are performed using the finite element + DDA method until stability is achieved, obtaining dam deformation, stress, damage, and cracking results. The present invention effectively addresses the issues of computational efficiency, computational accuracy, and simulation of concrete deterioration and disasters.

Description

Technical Field

[0001] The present invention provides a method, device and system for simulating the pathological changes and disasters of concrete dams, belonging to the technical field of building monitoring. Background Art

[0002] Concrete dams are a key dam type widely used in water conservancy and hydropower projects. They offer high safety and strong overload capacity, but they also pose challenges such as high foundation quality requirements and the susceptibility of concrete to cracking. To ensure high-quality construction and long-term safe operation of concrete dams, a clear understanding of the dam failure process or catastrophic mechanisms is necessary to predict risks and implement targeted measures. Dam failure processes are primarily studied using geological model tests and numerical simulations. However, geological model tests are time-consuming, expensive, difficult to replicate, and often lack similarity, making them less widely used. Numerical simulations primarily employ the finite element method (FEM), which performs well for small deformation continuity analysis. However, once cracking progresses to large deformation, the method becomes inadequate due to the assumption of small deformations. The discrete element method (DDA) and the discrete element method (FEM) can effectively simulate dam failure processes. Combined FEM and DDA simulation methods have been used in engineering failure analysis, but they suffer from high iteration workload, computational time, limited meshing size, and poor computational precision and accuracy.

[0003] "Application of DDA and FEM coupling method in nonlinear analysis of jointed gravity dams" (Liu Jun, Kong Xianjing, Shyu Kuokai. Application of DDA and FEM coupling method in nonlinear analysis of jointed gravity dams [J]. Journal of Computational Mechanics, 2004, 21(5): 585-591. doi: 10.3969 / j.issn.1007-4708.2004.05.013) proposed a DDA and FEM coupling algorithm, which divides the dam section into blocks according to the longitudinal joints, and uses finite element meshes to divide the interior of the blocks. Contact surfaces are used between the blocks to solve the problem of large deformation of the longitudinal joints.

[0004] "Vibration Analysis of Masonry Structures Based on DDA and FEM" (Geodesy and Geodynamics, 2016, Vol. 36, Issue (6): 520.) also regards the columns, lintels, and floor slabs of masonry structures as independent blocks. Each independent block is divided into finite element meshes, and contact surfaces are used between blocks to solve the damage and collapse of masonry structures under earthquake conditions.

[0005] This method is used to solve the joint or contact problems between structures, but cannot solve the cracking-expansion-catastrophic process of any part of the dam concrete itself.

[0006] The paper "Coupled Analysis Method of Three-Dimensional DDA and Finite Element Method and Its Application" (Chinese Journal of Geotechnical Engineering, 2006, 28(8):998-1001) proposes a coupled DDA and FEM calculation method. This method divides the dam body and foundation into two blocks, simulates the contact between the blocks using DDA, and meshes the interior of the blocks using finite elements to simulate the deformation of the structure and foundation. This method is designed to solve the deformation problem between the structure and foundation, but it cannot effectively address the cracking, expansion, and catastrophic process in any part of the dam concrete itself. Summary of the Invention

[0007] The present invention provides a method, device and system for simulating the deterioration and catastrophe of concrete dams. Firstly, it can effectively solve the simulation of cracking, expansion and catastrophe at any part of the dam concrete. Secondly, it can ensure the simulation accuracy and efficiency. Thirdly, it provides a criterion for distinguishing deterioration and catastrophe in concrete dam analysis.

[0008] The specific technical solutions are:

[0009] A method for simulating the deterioration and disaster of a concrete dam, comprising:

[0010] Step 1: Obtain basic information data on dam project layout, hydrology and meteorology, topography and geology, earthquakes, materials, structure, safety monitoring, testing, construction, operation, scheduling, maintenance and disposal.

[0011] Step 2: Based on the basic engineering information data and combined with historical experience, analyze and predict the factors affecting dam safety, and propose the possible main influencing factors of engineering deterioration and disasters, such as super-high floods, super-standard earthquakes, extreme climate, bedrock deformation, and material performance degradation.

[0012] Step 3: Determine the simulation method and accuracy for dam engineering disasters. Excessive floods are simulated using water level overloads, excessive earthquakes are simulated using seismic intensity overloads, temperature fluctuations in extreme climates are simulated using temperature amplitude increases, bedrock deformations such as valley deformation are simulated using deformation overloads, and material performance degradation is simulated using strength and elastic modulus reductions.

[0013] Furthermore, the scope of the dam geometric model and the unit size requirements are determined; the load loading step is determined. Under the condition that the calculation time allows, the loading step should not be too large. For example, if the water level is overloaded, each loading step should be controlled below 2m.

[0014] Step 4: Create a finite element model, including the geometric mesh model, boundary conditions, and loading conditions. Furthermore, hexahedral elements should be used for the dam body and bedrock meshes within the geometric mesh model, and contact elements should be used for transverse and longitudinal joints. Normal constraints should be applied to the dam foundation bottom surface, left and right sides, and front and rear sides. Loads should be applied according to the step size determined in step 3.

[0015] Step 5: When calculating material elasticity, the dam concrete stress is used as the cracking judgment indicator, and the threshold is determined based on the concrete strength. When calculating material damage nonlinearity, the damage value is used as the cracking judgment indicator, and the threshold is determined based on the degree of damage.

[0016] Step 6: Set the catastrophic index and classification standard, and give the threshold value of each classification; further, dam cracking can be used as the catastrophic index, and the classification threshold value can be determined by the degree of cracking.

[0017] Step 7: Pre-generate an isolated cell mesh model for mesh reconstruction and analysis result display during the calculation process.

[0018] The isolated unit grid model refers to a grid model in which each unit does not share a node. For example, when four units share one node, the node has four numbers, belonging to the four units respectively.

[0019] Step 8: Based on steps 4-7, load the concrete and use the finite element method to calculate and analyze the dam deformation, stress, and damage calculation results. The dam concrete cracking is judged based on the cracking index and threshold.

[0020] Step 9: When all elements of the dam do not reach the cracking threshold, the dam body maintains the original mesh, is further loaded and calculated using the finite element method, and steps 8 and 9 are repeated.

[0021] Step 10: When any unit of the dam reaches the cracking threshold, local cracking occurs and the dam mesh is reconstructed. After reconstruction, the finite element + DDA method is used for iterative calculation until stability is achieved, and the deformation, stress, damage and cracking results of the dam are obtained.

[0022] Furthermore, the dam cracking is realized by mesh unit separation, that is, the common nodes of adjacent units in the finite element continuous mesh are separated into two nodes, and the adjacent units are no longer continuous.

[0023] Furthermore, the finite element and DDA methods were used for iterative calculations, where the continuous part of the dam was calculated using the finite element method, and the cracked area was calculated using the DDA method. The DDA block contact theory was used to determine the contact relationship between the units on both sides of the crack.

[0024] Furthermore, an iterative calculation method based on algebraic multigrid technology with global coarse grid and local fine grid is used to perform iterative solution to improve computational efficiency.

[0025] Step 11. Based on the dam deformation and cracking results in step 10, the pathological disaster index and classification threshold set in step 6 are used to judge the pathological disaster. If the index reaches the final disaster standard, the calculation is completed and the calculation result is output. If the final disaster standard is not reached, further calculation is loaded to judge the pathological disaster.

[0026] Furthermore, the catastrophic indicators of disease are cracking or deformation. The catastrophic classification is based on the degree of cracking or deformation. Typically, under super-standard flood conditions, the first-level threshold for an arch dam could be cracking at the dam heel and cracking at the arch end of the downstream dam face. The second-level threshold could be cracking at the dam heel to the anti-seepage curtain and cracking at the arch end extending upstream and downstream. For a gravity dam, the first-level threshold is cracking at the dam heel, and the second-level threshold is cracking at the dam heel to the anti-seepage curtain. The earthquake catastrophic threshold is when the cracked area of ​​any section of the dam exceeds 30% or when the dam heel cracks to the anti-seepage curtain. The valley deformation catastrophic threshold is when the dam body is locally fractured and continues to expand. The material cracking catastrophic threshold is when cracks exceed 30% of the area or when localized damage continues to expand.

[0027] Step 12: Based on the dam safety monitoring deployment and the results of the catastrophic failure analysis, propose the main catastrophic failure patterns and corresponding monitoring and early warning indicators. Typically, the monitoring and early warning indicator uses dam deformation. The deformation threshold is determined based on the calculation result corresponding to the catastrophic failure threshold in Step 11.

[0028] The present invention provides a concrete dam disease disaster simulation device, comprising:

[0029] The information acquisition module is used to obtain basic information such as dam engineering materials, structures, construction boundaries, and data resources such as safety monitoring and environmental information related to engineering simulation analysis, providing basic data for the modeling module, calculation module, early warning model and display module.

[0030] The modeling module is used to construct the finite element model and boundary conditions, load conditions, and resources for producing isolated unit grids. It is based on the information acquisition module and provides basic model conditions for the calculation module and display module.

[0031] The calculation module is used to calculate the deformation, stress, damage and cracking of dam projects, especially the finite element + DDA calculation method resources. It is based on the modeling module and provides basic data for the judgment module, early warning module and display module.

[0032] The judgment module is used to judge the resources of dam cracks, diseases and disasters. It is based on the information acquisition module and modeling module to provide basic data for engineering early warning and disaster display.

[0033] The early warning module is used to propose resources for early warning indicators, based on the information acquisition module and the judgment module, and provides information for the display module.

[0034] The display module is used to intuitively display the calculation results and early warning indicators of deformation, stress, damage, cracking, etc., and needs to call the data of the above five modules.

[0035] The present invention also provides a concrete dam deterioration and disaster simulation system, comprising a connected controller, a calculator, a memory, and a display terminal. The controller is used to drive the computer and memory to simulate concrete dam deterioration and disasters; the calculator is used to calculate the dam and determine cracking and deterioration; the memory is used to store the data involved in the above method; and the display terminal is used to visualize the data and results.

[0036] Based on the FEM and DDA methods, the present invention provides a concrete dam deterioration disaster simulation method and system, which can effectively solve the problems of calculation efficiency, calculation accuracy and concrete deterioration disaster simulation, and provide technical means for the long-term operation safety management of engineering wind. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of the present invention;

[0038] Figure 2 is a dam structure of an embodiment;

[0039] 1: dam body 2: foundation 3: transverse joint;

[0040] Figure 3 is the change in the upstream and downstream water levels of this embodiment;

[0041] Figure 4 This is a schematic diagram of the deformation overload mode loading of this embodiment;

[0042] 1: dam body 2: foundation 3: transverse joint;

[0043] Figure 5 is a conventional finite element mesh;

[0044] Figure 6 For this embodiment and the isolated unit grid;

[0045] Figure 7 This is a schematic diagram of local cracking in this embodiment;

[0046] Figure 8 This is the compression failure result of this embodiment.

[0047] 1: Dam body 2: Foundation 4: Fracturing area;

[0048] Figure 9 It is a schematic diagram of the concrete dam deterioration and disaster simulation device of the present invention. DETAILED DESCRIPTION

[0049] Example 1: The present invention provides a method for simulating the catastrophic changes of concrete dams. The overall process is shown in FIG. Figure 1 .

[0050] 1. A certain arch dam is 270m high and is a low-heat cement concrete dam with 15 dam sections. The dam structure is as follows: Figure 2 , material parameters are shown in Table 1, and the changes in upstream and downstream water levels are shown in Figure 3 .

[0051] Table 1 Material parameters

[0052] Serial number elastic mold Poisson's ratio tensile strength Compressive strength A 48 0.17 2.9 52 B 46 0.17 2.7 47 C 45 0.17 2.3 40 bedrock 28 0.24 / 60

[0053] 2. The main disaster-causing factor of the project is valley deformation, and the deformation overload mode is used for loading, as shown in the figure below. Figure 4 The specific loading values ​​are loaded in the form of 2mm, 5mm, 10mm up to 150mm, and each loading step is 5mm apart.

[0054] 3. Construct a finite element mesh for the dam and bedrock. Use hexahedral meshes for the dam body and bedrock, and contact elements for joints. For boundary conditions, apply normal constraints to the bedrock bottom and upstream and downstream. Deformation constraints are applied to the left and right banks, with specific deformation values ​​given based on these two conditions. Loads include deadweight, temperature, water pressure, and silt.

[0055] 4. Damage is used as an indicator to judge cracking of dam concrete, and a fixed damage value is used as the cracking threshold, such as 0.5.

[0056] 5. The local tensile cracking of the dam under the action of valley deformation is set as the disease threshold, and the local compressive damage and continuous expansion is set as the disaster threshold.

[0057] 6. Pre-generate isolated cell mesh model for mesh reconstruction and analysis during the calculation process. The results show that the conventional finite element mesh is compared with the isolated cell mesh. Figure 5 and Figure 6 .

[0058] 7. Apply a 2mm valley deformation and calculate using the finite element method to obtain deformation, stress, and damage results. Assess the damage status of all elements. If the set cracking threshold is not reached, the mesh remains unchanged. Further increase the valley deformation to 5mm and repeat the above assessment. If the set cracking threshold is still not reached, the mesh remains unchanged. Apply valley deformations of 10mm, 15mm, and even 55mm. At 55mm, a unit has reached the cracking threshold.

[0059] 8. When the dam is loaded with a 55mm valley deformation and the dam is at dead water level, the damage level of the upstream unit of the crown beam reaches the cracking threshold, and local cracking occurs. Based on the damage area and depth of the dam body, the cracking range and depth of the dam body are determined, and the dam body mesh is reconstructed. The unit common node is separated into two nodes, and the units on both sides are independent of each other. Local cracking is indicated. Figure 7After reconstruction, the finite element method plus DDA method was used for iterative calculations. The DDA method was used to analyze the opening and closing states of the structures on both sides of the crack in the cracked area and the stability of the crack expansion to the surrounding area. The finite element method was still used to analyze the remaining uncracked areas until the crack range and depth were stable and no longer expanded. The deformation, stress, damage and cracking results of the dam were obtained.

[0060] 9. Based on the above dam cracking results, combined with the established disease and catastrophic indicators and classification thresholds, a disease and catastrophic assessment was performed. The dam showed localized cracking, meeting the disease criteria but not the catastrophic criteria. Further loading was performed, and the loading, cracking, and catastrophic assessment steps were repeated.

[0061] 10. When the valley deformation of 115mm is applied, the compressive stress on the downstream side of the dam exceeds the standard and damage occurs, but it stabilizes after iterative adjustment and does not continue to expand. When the valley deformation is increased to 125mm, the compressive damage of the dam continues to expand and reaches the catastrophic standard. The calculation ends and the compressive damage results are shown in Figure 8 . Output dam disease and disaster analysis results.

[0062] 11. The dam is equipped with deformation monitoring instruments on the abutment. Based on the above calculation results, the deformation value of the measuring point when the dam is diseased or catastrophic is proposed, and this value is used as the deformation monitoring threshold of the dam disease and catastrophic.

[0063] In Example 2, the present invention provides a device for simulating the deterioration and disaster of a concrete dam.

[0064] The present invention provides a concrete dam disease disaster simulation device, such as Figure 9 ,include:

[0065] 1. Information acquisition module, used to obtain basic information such as dam engineering materials, structures, construction boundaries, and data resources such as safety monitoring and environmental information related to engineering simulation analysis.

[0066] 2. Modeling module, used to build finite element models and resources for boundary conditions, load conditions, and production of isolated element meshes.

[0067] 3. Calculation module, which is used to calculate the deformation, stress, damage and cracking of dam projects, especially the finite element + DDA calculation method resources.

[0068] 4. Judgment module, used to judge the resources of dam cracks, diseases and disasters.

[0069] 5. Early warning module, used to propose resources for early warning indicators.

[0070] 6. Display module, used to intuitively display calculation results such as deformation, stress, damage, cracking, and early warning indicators.

[0071] In Example 3, the present invention provides a concrete dam deterioration and disaster simulation system, comprising a controller, a calculator, a memory, and a display terminal. The controller drives the computer and memory to simulate concrete dam deterioration and disasters; the calculator calculates the dam and determines cracking and deterioration; the memory stores the data involved in the method; and the display terminal visualizes the data and results.

Claims

1. A method for simulating the deterioration and disaster of a concrete dam, characterized in that: include: Step 1: Obtain basic information data of the dam project; Step 2: Based on basic engineering information data and historical experience, analyze and predict factors affecting dam safety, and propose possible major factors affecting engineering damage and disasters. These possible major factors include super-high floods, super-standard earthquakes, extreme climate, bedrock deformation, and material performance degradation; Step 3: Determine the simulation method and accuracy of dam engineering disaster; determine the scope of the dam geometric model and unit size requirements; determine the load loading step length; Step 4: Establish finite element model; The load is applied according to the step size determined in 3; Step 5: When calculating material elasticity, the dam concrete stress is used as the cracking judgment indicator, and the threshold is determined based on the concrete strength. When calculating material damage nonlinearity, the damage value is used as the cracking judgment indicator, and the threshold is determined based on the damage degree. Step 6: Set the catastrophic index and classification standards, and give the threshold for each classification; use dam cracking as the catastrophic index, and determine the classification threshold based on the degree of cracking; Step 7: Pre-generate an isolated cell mesh model for mesh reconstruction and analysis result display during the calculation process; An isolated unit grid model means that each unit in the grid model does not share any nodes; Step 8: Based on steps 4-7, load the dam and use the finite element method to calculate and analyze the dam deformation, stress, and damage calculation results. The dam concrete cracking is judged based on the cracking index and threshold value. Step 9: When all elements of the dam do not reach the cracking threshold, the dam body retains its original mesh, is loaded and calculated using the finite element method, and steps 8 and 9 are repeated; Step 10: When any unit of the dam reaches the cracking threshold, local cracking occurs and the dam mesh is reconstructed. After reconstruction, the finite element + DDA method is used for iterative calculation until stability is achieved, and the dam deformation, stress, damage and cracking results are obtained; Step 11: Based on the dam deformation and cracking results in step 10, the catastrophic damage index and classification threshold set in step 6 are used to determine the catastrophic damage. When the index reaches the final catastrophic standard, the calculation is completed and the calculation results are output; If the final catastrophic standard is not reached, further calculations are performed to determine the catastrophic status of the disease; Step 12: Based on the deployment of dam safety monitoring and combined with the results of pathological disaster analysis, the main pathological disaster patterns and corresponding monitoring and early warning indicators are proposed. The monitoring and early warning indicators use dam deformation; The deformation threshold is determined based on the calculation result corresponding to the catastrophic threshold in step 11.

2. A method for simulating the deterioration and disaster of a concrete dam according to claim 1, characterized in that: The basic information data of the dam project in step 1 includes basic information data on dam project layout, hydrology and meteorology, topography and geology, earthquake, materials, structure, safety monitoring, testing, construction, operation, scheduling, maintenance and disposal.

3. A method for simulating the deterioration and disaster of a concrete dam according to claim 1, characterized in that: In step 3, super-standard floods are simulated by water level overload, super-standard earthquakes are simulated by earthquake intensity overload, temperature changes in extreme climates are simulated by increasing temperature amplitude, valley deformation in bedrock deformation is simulated by deformation overload, and material performance degradation is simulated by reducing strength and elastic modulus.

4. A method for simulating the deterioration and disaster of a concrete dam according to claim 1, characterized in that: The finite element model established in step 4 includes the geometric mesh model, boundary conditions, and load conditions; In the geometric mesh model, hexahedral elements are used for the dam body and bedrock meshes, and contact elements are used for the transverse and longitudinal joints. Normal constraints are applied to the bottom surface, left and right sides, and front and rear sides of the dam foundation. Load loading is applied according to the step size determined in 3.

5. A method for simulating the deterioration and disaster of a concrete dam according to claim 1, characterized in that: In step 10, the dam body cracking is realized by mesh unit separation, that is, the common nodes of adjacent units in the finite element continuous mesh are separated into two nodes, and the adjacent units are no longer continuous; Iterative calculations using the finite element and DDA methods were performed. The continuous portion of the dam was calculated using the finite element method, while the cracked area was calculated using the DDA method. The DDA block contact theory was used to determine the contact relationship between the elements on both sides of the crack. An iterative solution is obtained by using an iterative calculation method with a global coarse grid and a local fine grid based on algebraic multigrid technology.

6. A concrete dam catastrophic simulation device, characterized in that: A method for simulating the deterioration and disaster of a concrete dam according to any one of claims 1 to 5; comprising: The information acquisition module is used to obtain basic information data of the dam project and resources of safety monitoring and environmental information data related to engineering simulation analysis, providing basic data for the modeling module, calculation module, early warning model and display module; Modeling module, used to build finite element models and boundary conditions, load conditions and resources for producing isolated unit grids, based on the information acquisition module, providing basic model conditions for the calculation module and display module; The calculation module is used to calculate the deformation, stress, damage and cracking of the dam project. The finite element + DDA calculation method resources are based on the modeling module and provide basic data for the judgment module, early warning module and display module; The judgment module is used to judge the sources of dam cracks, diseases and disasters. It is based on the information acquisition module and the modeling module to provide basic data for engineering early warning and disaster display; The early warning module is used to propose resources for early warning indicators, based on the information acquisition module and the discrimination module, and provides information for the display module; The display module is used to intuitively display the calculation results of deformation, stress, damage, cracking and the resources of early warning indicators, and calls the data of the above five modules.

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