Numerical simulation analysis method of dynamic action of concrete dam by underwater explosion double-path

Abstract

This invention discloses a numerical simulation analysis method for the dynamic effects of underwater explosions along two paths on concrete dams, belonging to the field of engineering protection and numerical simulation technology of explosion effects. The method first establishes a multi-medium fully coupled model including the concrete dam, foundation, water, air, and explosive. A Lagrange-Euler fully coupled method is used to achieve fluid-structure interaction. Gravity and hydrostatic pressure are applied to simulate the initial stress field, and monitoring points are set up. Then, single-path load simulations are conducted with rigid partitions in the water body and foundation, while a fully coupled baseline simulation without partitions is performed simultaneously. Data on dam pressure, vibration velocity, and displacement under the three conditions are compared to separate the characteristics of the dual-path loads and the structural response. Finally, multi-condition analysis is conducted by controlling key parameters such as the explosion center distance using single-variable control to reveal the evolution law of the dual-path effect and the conditions for the conversion of the dominant mechanism, and to quantitatively evaluate the contributions of both. This method provides a controllable and repeatable numerical means for the differential response analysis of underwater explosion load paths in concrete dams, and provides a theoretical basis for the refined blast-resistant protection design of dams.

Description

Technical Field

[0001] This invention belongs to the field of numerical simulation technology of explosion-proof safety and explosion effects in water conservancy projects, and specifically relates to a numerical simulation analysis method for the dynamic effects of underwater explosions on concrete dams via dual paths. Background Technology

[0002] Concrete dams are critical infrastructure projects vital to the national economy and people's livelihoods. When faced with the threat of underwater explosions, the explosive load is transmitted to the dam body through two paths with vastly different physical properties: underwater shock waves and ground vibrations. Due to fundamental differences in wave impedance, energy attenuation characteristics, and wave propagation mechanisms between water and soil, the loads transmitted through these two paths differ in amplitude, time history, spectrum, and the location and manner of their impact on the dam body. Ultimately, this leads to significant differences in the structural dynamic response modes and damage mechanisms.

[0003] Currently, research on the response of concrete dams under explosive loads mainly employs two methods: physical model testing and numerical simulation. Physical testing is costly, lacks controllability, and struggles to separate the coupling effects of the two paths in a single test. In numerical simulation, existing methods largely focus on establishing a fully coupled model of the blast source-medium-structure to simulate the comprehensive response, or simplifying it to a single load path (e.g., considering only water pressure) for analysis. While fully coupled simulation can reflect the final comprehensive failure state, it cannot effectively separate and quantify the contributions of the foundation path and the water path from the results; while single-path analysis ignores the actual dual-path coupling effect, which is inconsistent with reality. Both of these methods fail to reveal the specific roles of different propagation paths in the structural response, the conditions for the transition of dominant mechanisms, and their independent action mechanisms, thus limiting the theoretical basis for differentiated and refined blast-resistant protection design for foundation vibration and underwater shock waves. Summary of the Invention

[0004] This invention addresses the difficulty in separating and quantifying the effects of explosive loads on dam structures via two different media paths—the foundation and the water body—in existing technologies. It provides a numerical simulation analysis method for the dynamic effects of underwater explosive loads on concrete dams through a dual-pathway system. This invention aims to actively and controllably block specific propagation paths within a single, fully coupled model through innovative numerical experimental design. This allows for the separate acquisition of structural responses under explosive loads transmitted solely through the foundation path or solely through the water body path. Ultimately, it achieves effective separation, independent analysis, and comparative evaluation of the dual-path effects, providing key technical means to reveal their respective mechanisms and guide targeted protective design.

[0005] To achieve the above-mentioned technical features, the objective of this invention is as follows: a numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams, comprising the following steps: S1. Establish a multi-media fully coupled analysis model that includes concrete dams, foundation media, water media, air media and explosives to realize fluid-solid coupling simulation; S2, apply initial load to the fully coupled analysis model to simulate the initial stress field of the concrete dam before the underwater explosion, and set monitoring points at key parts of the concrete dam; S3, respectively blocking the water propagation path and the foundation propagation path between the explosion source and the concrete dam, and sequentially carrying out single-path explosion numerical simulations to collect structural response data of the concrete dam under the corresponding single path; S4. Conduct a fully coupled explosion numerical simulation without path obstruction and collect structural response data of concrete dams under the combined action of two paths of underwater explosion. S5. By comparing the structural response data of the single path and the fully coupled path, the dynamic effects of the underwater explosion foundation and the water body dual path on the concrete dam are separated and analyzed. S6. Change the key explosion-related parameters and repeat steps S3 to S5 to conduct multi-condition analysis, revealing the evolution law and dominant mechanism of the dual-path dynamic effect on concrete dams under different explosion scenarios.

[0006] Preferably, in step S1, the Lagrange-Euler fully coupled method is used to realize fluid-structure interaction simulation, wherein the water medium, air medium and explosive are represented by Euler grids, and the foundation medium and concrete dam are represented by Lagrange grids.

[0007] Preferably, the initial load in step S2 includes global gravity and hydrostatic pressure, and the simulation of the initial stress field is completed after the initial stress of the model is balanced; the structural response parameters extracted by the monitoring points include at least one of pressure, vibration velocity, and displacement, and the monitoring points are at least one of pressure measuring points, displacement measuring points, and vibration velocity measuring points.

[0008] Preferably, in step S3, a rigid barrier is used to block the propagation path. The rigid barrier is formed by applying fixed constraints to all degrees of freedom of the nodes in the corresponding medium region.

[0009] Preferably, when blocking the water propagation path, the rigid barrier is set in the water medium area between the blast source and the concrete dam; when blocking the foundation propagation path, the rigid barrier is set in the foundation medium area between the blast source and the concrete dam.

[0010] Preferably, in all explosion numerical simulations conducted in steps S3 and S4, the location of the explosive at the explosion source, the charge equivalent, and the explosive material parameters are kept consistent.

[0011] Preferably, in step S1, non-reflective boundary conditions are applied to the outer boundaries of the foundation medium, water medium, and air medium; the Euler grid of the water medium is locally refined.

[0012] Preferably, in step S1, the concrete dam, foundation medium, and water medium are respectively equipped with matching material models. The concrete dam is equipped with the RHT material model, the foundation medium is equipped with the elastoplastic model, and the water medium is equipped with the Grünesen equation of state.

[0013] Preferably, the analysis of the dual-path dynamic effect in step S5 includes at least one of the following: load characteristic comparison, dynamic response difference analysis, damage mode identification, and quantitative assessment of path contribution weight, wherein the dynamic response is the structural response of the concrete dam under the action of underwater shock wave and foundation vibration.

[0014] Preferably, the explosion-related key parameters mentioned in step S6 include at least one of the following: distance from the blast center, explosive equivalent, water depth of the water medium, and material properties of the foundation medium; a single-variable control method is used to conduct multi-condition analysis, changing only one key parameter each time while keeping the other parameters unchanged.

[0015] The present invention provides a numerical simulation analysis method for distinguishing the dynamic effects of underwater shock waves from underwater explosions and foundation vibrations on concrete dams, which has the following beneficial effects: 1. This invention achieves active and controllable separation of the dual-path effect. By setting a rigid partition in the same fully coupled model, pure single-path load response data are obtained under the same explosion conditions, providing a clear and reliable numerical basis for the study of the dual-path action mechanism.

[0016] 2. This invention reveals the differentiated action mechanism of dual-path loads, clarifies the essential differences between foundation vibration and underwater shock waves in terms of load characteristics, action location, and damage mode, and deepens the understanding of the dynamic response law of concrete dams under underwater explosion.

[0017] 3. This invention supports the refined and differentiated blast-resistant protection design of dams, quantitatively assesses the contribution weight of dual paths and the conditions for the switching of dominant mechanisms under different blast conditions, and can formulate targeted protection strategies to achieve the rational allocation of protection resources.

[0018] 4. This invention combines high fidelity, economy and repeatability. The fully coupled model accurately simulates the fluid-structure interaction process of underwater explosion. The numerical test is low-cost, under controllable conditions, and can be repeated indefinitely, enabling efficient research on multi-condition systems.

[0019] 5. This invention has a wide range of applications and can be extended to the underwater explosion response analysis of various concrete dams, as well as to the explosion resistance research of water-based hydraulic structures such as bridges and wharves. It has good prospects for engineering applications. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a flowchart illustrating the explosion effect of separating the foundation from the water propagation path according to the present invention.

[0022] Figure 2 This is a schematic diagram of the overall layout of the concrete gravity dam model of the present invention.

[0023] Figure 3 This is a schematic diagram of the gradient mesh of the concrete gravity dam model of the present invention.

[0024] Figure 4 This is a schematic diagram of the gravity and hydrostatic pressure loads on the concrete gravity dam model of the present invention.

[0025] Figure 5 This is a schematic diagram illustrating the propagation of shock waves in water and ground vibrations under different working conditions according to the present invention.

[0026] Figure 6 This is a diagram showing the vertical displacement of measuring points on a concrete gravity dam under different propagation paths according to the present invention.

[0027] Figure 7 This is a displacement diagram of measuring points along the water flow direction in a concrete gravity dam under different propagation paths according to the present invention.

[0028] Figure 8 It is the ratio of the peak displacement caused by ground vibration and shock wave along the elevation direction of the concrete gravity dam to the peak value under coupling effect.

[0029] Figure 9 It is the ratio of the peak vibration velocity caused by ground vibration and shock wave along the elevation direction of the concrete gravity dam to the peak value under coupling effect.

[0030] In the diagram, 1 is a concrete dam, 2 is a rigid partition, 3 is a foundation medium, 4 is a water medium, 5 is an air medium, 6 is an explosive, 7 is a pressure measuring point, 8 is a displacement measuring point, 9 is a vibration velocity measuring point, 10 is an underwater shock wave, and 11 is a foundation vibration. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0032] Example 1: The core of this embodiment is to separate and quantify the dual-path effect of foundation vibration 11 and underwater shock wave 10 on concrete dam 1 during underwater explosion by using multi-medium fully coupled modeling, controllable path isolation, and multi-condition univariate analysis. The following describes the invention in further detail with reference to specific implementation methods.

[0033] A numerical simulation analysis method for the dynamic effects of underwater explosions along two paths on concrete dams includes the following steps: S1: Establish a fine fully coupled analysis model for concrete dams suitable for underwater explosion conditions. The model consists of five components: concrete dam 1, foundation medium 3, water medium 4, air medium 5, and explosive 6. The Lagrange-Eulerian fully coupled method is used to realize fluid-structure interaction simulation. Water medium 4, air medium 5, and explosive 6 use Eulerian meshes, while foundation medium 3 and concrete dam 1 use Lagrange meshes. S2: Apply initial loads of global gravity and hydrostatic pressure to the fully coupled analysis model. After the initial stress of the model is balanced, simulate the initial stress field of the concrete dam 1 before the underwater explosion. S3: Set up numerical monitoring points at key structural parts of concrete dam 1. The monitoring points are at least one of pressure measuring point 7, displacement measuring point 8, and vibration velocity measuring point 9. Extract structural response parameters such as pressure, vibration velocity, and displacement. S4: Numerical simulation of water path blocking: A rigid partition 2 is set in the water medium 4 between the explosion source and the concrete dam 1 to block the propagation path of the shock wave 10 in the water. The first explosion numerical simulation is carried out, and the structural response and damage data of the concrete dam 1 under the action of the foundation vibration 11 which only propagates through the foundation path are collected. S5: Numerical simulation of ground path blocking: Keeping the blast source conditions unchanged, a rigid partition 2 is set in the ground medium 3 region between the explosive 6 and the concrete dam 1 at the blast source to block the propagation path of the ground vibration 11 in the ground; a second explosion numerical simulation is carried out to collect the structural response and damage data of the concrete dam 1 under the action of the water shock wave 10 that propagates only through the water medium path at this time. S6: Fully Coupled Path Numerical Simulation: Establish a numerical model with geometric, material, and explosion source parameters completely consistent with the S4 and S5 models. This is a benchmark fully coupled numerical model without path obstruction. A complete explosion numerical simulation is performed on this model, allowing the explosion load to propagate through two paths, the foundation medium 3 and the water medium 4, and act on the concrete dam 1 structure. This realistically simulates the comprehensive load conditions under actual explosion conditions and collects the structural response and damage data of the concrete dam 1 under the combined action of the two paths of underwater explosion. S7: Separation and Comparative Analysis of Effects from Different Paths: Compare the three sets of structural response data obtained in steps S4, S5 and S6, separate and analyze the load characteristics, dynamic response and damage distribution of the concrete dam 1 structure under the action of the explosive load through the foundation medium 3 path and the water medium 4 path, respectively, clarify the contribution of different load propagation paths to the structural response of the concrete dam 1, and the analysis includes at least one of the following: load characteristic comparison, dynamic response difference analysis, damage mode identification, and quantitative assessment of path contribution weight. S8: Multi-condition system analysis and pattern revelation: Based on the basic separation method established in steps S4, S5, S6, and S7, at least one explosion-related key parameter is changed systematically among the following: detonation center distance, explosive equivalent 6, water depth of water medium 4, or material properties of foundation medium 3. Multiple control conditions are formed using a single-variable control method, and the above separation experiments are repeated. The separation results under multiple conditions are compared and analyzed. The relative strength evolution law of the interaction between the foundation medium 3 path and the water medium 4 path under different explosion scenarios, the conditions for the conversion of the dominant mechanism, and the differentiated structural responses induced by them are systematically studied. This comprehensively reveals the characteristics of the role of different propagation paths in the response of concrete dam 1, their contribution weights, and their correlation mechanism with explosion conditions.

[0034] Furthermore, in the fully coupled analysis model, the concrete dam 1, the foundation medium 3, and the water medium 4 are described by matching material models, and the interaction between the multiple media is realized through a coupling algorithm. The concrete dam 1 adopts the RHT material model, the foundation medium 3 adopts the elastoplastic model, and the water medium 4 adopts the Grünesen equation of state.

[0035] Furthermore, the propagation path is blocked by setting a rigid partition 2. The rigid partition 2 is formed by applying fixed constraints to all degrees of freedom of all nodes in the corresponding medium area. This creates an absolutely rigid wall, which will completely block the propagation of water shock wave 10 or foundation vibration 11 to this point, and it cannot penetrate.

[0036] Furthermore, the water medium 4Eulerian grid of the model is locally refined.

[0037] Furthermore, after the initial loads of global gravity and hydrostatic pressure are applied, and the model is in initial stress equilibrium, the explosive 6 is detonated.

[0038] Furthermore, when establishing the fully coupled analysis model, non-reflective boundary conditions are applied to the outer boundaries of the foundation medium 3, the water medium 4, and the air medium 5.

[0039] Furthermore, in the three explosion numerical simulations in steps S4, S5, and S6, the position of explosive 6 at the explosion source, the explosive equivalent, and the explosive material parameters are all kept consistent.

[0040] Furthermore, the structural response parameters include the pressure collected by pressure measuring point 7, the vibration velocity collected by vibration velocity measuring point 9, and the displacement collected by displacement measuring point 8.

[0041] Furthermore, the method also includes a step of conducting multi-condition comparative analysis: by changing at least one variable among the explosion center distance, explosive equivalent 6, water depth of water medium 4, or geological parameters of foundation medium 3, steps S4, S5, and S6 are repeated to systematically study the evolution law of dual-path effect under different explosion scenarios.

[0042] Furthermore, a multi-condition system analysis was conducted: by changing at least one key parameter among the detonation center distance, explosive equivalent 6, water depth of water medium 4, or material properties of foundation medium 3, multiple sets of control conditions were set up, and comparative calculations were performed based on the aforementioned basic separation method, so as to systematically study the relative contribution and evolution law of the path of foundation medium 3 and the path of water medium 4 to the dynamic action of concrete dam 1 under different explosion conditions.

[0043] Example 2: This invention aims to separate and quantify the independent and coupled effects of underwater explosion loads propagating through two paths—foundation medium 3 and water medium 4—on the dynamic action of a concrete dam 1 using numerical methods. The core of its implementation lies in: first, establishing a refined fluid-structure interaction numerical analysis model capable of accurately simulating the entire underwater explosion process; second, by setting different rigid barriers 2 within this unified model, artificially and controllably "closing" a certain propagation path, thereby systematically constructing three distinct load conditions—"foundation medium 3 path only," "water medium 4 path only," and "dual-path combined action of foundation medium 3 and water medium 4." Finally, through systematic comparison and comprehensive analysis of the structural response under these three conditions, the effective identification, separation, and quantitative evaluation of the foundation medium 3 path effect, the water medium 4 path effect, and their coupling effect are achieved.

[0044] I. Model Composition and Geometric Dimensions Taking a concrete gravity dam as the research object, a three-dimensional numerical model was established based on its design drawings and engineering geological data. The model mainly consists of five parts: air medium 5, water medium 4, foundation medium 3 (rock mass), concrete dam 1, and explosive 6 (TNT). Non-reflective boundary conditions were applied to the outer boundaries of air medium 5, water medium 4, and foundation medium 3 to reduce the influence of boundary reflected waves on the response of concrete dam 1. The extent of foundation medium 3 must be sufficient to completely encompass the underground propagation area of ​​stress waves.

[0045] Specifically, the concrete dam 1 has a height of 120 m, a dam section width of 15 m, and an upstream water depth of 80 m. The concrete compressive strength is 30 MPa. Seven dam sections were selected to analyze the response of the concrete dam 1, and a 1 / 2 model was established using symmetry to save computation time. Explosive 6 was selected with a 500 kg TNT equivalent, and the detonation center was 50 m horizontally from the upstream face of the concrete dam 1. The computational domain was extended to the foundation medium 3 region surrounding the foundation of the concrete dam 1 to simultaneously assess the impact of foundation vibration 11. In the 1 / 2 model, the length, height, and width of the foundation medium 3 were 270 m, 80 m, and 52.5 m, respectively. The water medium 4, explosive 6, and air medium 5 were modeled using Eulerian meshes, while the concrete dam 1 and foundation medium 3 were modeled using Lagrange meshes. The interaction between the water medium 4 and either the concrete dam 1 or the foundation medium 3 was realized using a Lagrange-Eulerian fully coupled algorithm.

[0046] The mesh size for explosive zone 6 is approximately 80 mm, while the mesh sizes for other Eulerian regions gradually increase with distance from the blast center. The mesh size for the crest of concrete dam 1 is 250 mm, slightly increasing at the base. Foundation medium 3 employs a multi-scale meshing method: a fine mesh is used in the 0-20 m range to accurately simulate stress wave propagation; a coarser mesh is used in the 20-80 m range; the bottom of foundation medium 3 is set as a non-reflective boundary.

[0047] Non-reflective boundary conditions are applied to the truncated boundaries of the computational domain; non-reflective boundary conditions are also applied to the far-field outer surfaces of air medium 5 and water medium 4 to simulate an infinite domain and prevent reflection interference; fixed constraints are typically applied to the bottom and lateral boundaries of the foundation medium 3 to simulate far-field radiation damping. Initial loads of hydrostatic pressure and global gravity are applied to simulate the actual initial stress state of the concrete dam 1.

[0048] II. Material Model and Parameters The air medium 5 uses the keyword MAT_MULL material model, the water medium 4 uses the Grüneisen equation of state, the TNT explosive 6 uses the MAT_HIGH_EXPLOSIVE_BURN material model and the EOS_JWL equation of state, the material model of the concrete dam 1 uses the RHT material model to simulate the dynamic behavior of concrete under the action of underwater shock wave 10 during an underwater explosion, and the foundation medium 3 uses an elastoplastic model.

[0049] III. Numerical simulation of separation by different paths (corresponding to steps S4, S5, S6, and S7) 1. Water medium 4-path barrier In the case where it is necessary to block the propagation path of the water medium 4 (step S4), a rigid partition 2 is set between the water medium 4 and the concrete dam 1 in the model, or along the expected propagation path of the water shock wave 10. Fixed constraints are applied to all degrees of freedom of all nodes in the area corresponding to the rigid partition 2. The water shock wave 10 cannot penetrate when it propagates to this point, thereby effectively cutting off the propagation path of the water shock wave 10 in the water medium 4. This is used to study the structural response of the concrete dam 1 under the action of the foundation vibration 11 that propagates only through the foundation medium 3.

[0050] 2. Foundation medium 3-path barrier In the case where the propagation path of the foundation medium 3 needs to be blocked (step S5), the position, charge equivalent, and material parameters of the explosive 6 at the blast source remain unchanged. A rigid partition 2 is set in the foundation medium 3 region between the blast source and the concrete dam 1 to block the propagation path of the foundation vibration 11 in the foundation medium 3. A continuous volume region is defined, and fixed constraint boundary conditions are applied to all Lagrange grid nodes in this region, constraining all their degrees of freedom. This prevents the stress wave from propagating to the concrete dam 1 through the rigid partition 2, thereby cutting off the path of the foundation medium 3. The structural response and damage data of the concrete dam 1 under the action of the underwater shock wave 10, which propagates only through the water medium 4, are collected.

[0051] 3. Numerical simulation of fully coupled path A baseline fully coupled numerical model was established, identical in geometry, materials, and blast source parameters to the models in S4 and S5, but without any rigid isolation 2. A complete explosion numerical simulation was performed on this model, allowing the explosion load to propagate simultaneously through both the foundation medium 3 and the water medium 4, acting on the concrete dam 1, thus realistically simulating the combined load conditions under actual explosion conditions. Complete dynamic response and damage data of the structure were collected under this combined load (i.e., the combined action of foundation vibration 11 in the foundation medium 3 and underwater shock wave 10 in the water medium 4). The "full-path" response results obtained in this step will serve as the baseline condition for systematic comparative analysis with the results of the separate conditions in S4 (foundation medium 3 path only) and S5 (water medium 4 path only), to deeply analyze the coupling mechanism, superposition relationship, and comprehensive contribution of the dual-path effects to the structural response.

[0052] 4. Separation and Comparative Analysis of Effects Along Different Pathways By comparing the three sets of structural response data obtained in steps S4, S5 and S6, the load characteristics, dynamic response and damage modes of the concrete dam 1 structure when the explosive load is applied through the ground medium 3 path and the water medium 4 path are separated, and the characteristics of the damage to the concrete dam 1 structure by different propagation paths are clarified.

[0053] IV. Multi-condition design and system analysis (corresponding step S8) To fully reveal the patterns, multivariate parameter studies can be conducted. A single-variable control method can be used, changing only one key explosion-related parameter each time, and repeating the entire process of "water medium 4-path barrier - foundation medium 3-path barrier - full coupling simulation".

[0054] 1. Variable selection The main variables include the detonation center distance (changing the horizontal distance between explosive 6 and concrete dam 1), the equivalent of explosive 6, the water depth of the water medium 4 in front of concrete dam 1, and the mechanical parameters of the foundation medium 3.

[0055] 2. Comparative Analysis Content Load characteristic separation: Compare the peak value, rise time, duration and spectral characteristics of pressure time history at the same monitoring point under the conditions of "ground medium only 3 path" and "water medium only 4 path". The monitoring point is at least one of pressure measuring point 7, displacement measuring point 8 and vibration velocity measuring point 9.

[0056] Dynamic response differences: By comparing the maximum displacement, maximum acceleration, vibration duration and response spectrum of key parts of the concrete dam under two working conditions, the extracted structural response parameters include pressure, vibration velocity, displacement and so on.

[0057] Damage pattern identification: Compare the damage cloud maps (such as the distribution of tensile damage in concrete), the area and depth of the damaged region of concrete dam 1 under two working conditions. For example, it may be found that the damage dominated by the water medium 4 path is concentrated on the upstream face and heel of concrete dam 1, manifested as erosion and delamination; while the damage dominated by the foundation medium 3 path may have a greater impact on the overall sliding trend of concrete dam 1 or crushing of the dam toe and cracking of the dam head.

[0058] Relative Importance Assessment: Based on the separation results under different explosion conditions (such as different detonation distances), the intensity of the two path effects changes with the detonation distance. For example, when the water depth of the water medium 4 in front of the concrete dam 1 is large, the response of the "water medium 4 path only" may far exceed that of the "foundation medium 3 path only". As the water depth of the water medium 4 in front of the concrete dam 1 decreases, the response of the "foundation medium 3 path only" decays more slowly, and its relative contribution gradually increases and may even become dominant. The study confirms the necessity of comprehensively considering the dual-path effects of foundation medium 3 and water medium 4, and the established separation analysis method provides an effective means for accurately assessing explosion threats and formulating differentiated protection strategies.

[0059] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams, characterized in that, Includes the following steps: S1. Establish a multi-medium fully coupled analysis model including concrete dam (1), foundation medium (3), water medium (4), air medium (5) and explosive (6) to realize fluid-solid coupling simulation of fluid and solid. S2, apply initial load to the fully coupled analysis model to simulate the initial stress field of the concrete dam (1) before the underwater explosion, and set monitoring points at key parts of the concrete dam (1); S3, respectively block the water propagation path and the foundation propagation path between the explosion source and the concrete dam (1), and carry out single-path explosion numerical simulation in sequence to collect the structural response data of the concrete dam (1) under the corresponding single path; S4, Conduct a fully coupled explosion numerical simulation without path obstruction and collect structural response data of the concrete dam (1) under the combined action of two paths of underwater explosion; S5. By comparing the structural response data of the single path and the fully coupled path, the dynamic effects of the underwater explosion foundation and the water body dual path on the concrete dam (1) are separated and analyzed. S6, change the key parameters related to the explosion, repeat steps S3 to S5, carry out multi-condition analysis, and reveal the evolution law and dominant mechanism of the dynamic effect of the dual path on the concrete dam (1) under different explosion scenarios.

2. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, In step S1, the Lagrange-Euler fully coupled method is used to realize fluid-structure interaction simulation. The water medium (4), air medium (5) and explosive (6) adopt Euler grids, and the foundation medium (3) and concrete dam (1) adopt Lagrange grids.

3. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, The initial load mentioned in step S2 includes global gravity and hydrostatic pressure. The simulation of the initial stress field is completed after the initial stress of the model is balanced. The structural response parameters extracted from the monitoring points include at least one of pressure, vibration velocity, and displacement. The monitoring points are at least one of pressure measuring point (7), displacement measuring point (8), and vibration velocity measuring point (9).

4. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, In step S3, a rigid partition (2) is set to block the propagation path. The rigid partition (2) is formed by applying fixed constraints to all degrees of freedom of the nodes in the corresponding medium area.

5. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 4, characterized in that, When blocking the propagation path of water, the rigid partition (2) is set in the water medium (4) area between the blast source and the concrete dam (1); when blocking the propagation path of the foundation, the rigid partition (2) is set in the foundation medium (3) area between the blast source and the concrete dam (1).

6. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, All explosion numerical simulations conducted in steps S3 and S4 maintain the same position of the explosive (6) at the explosion source, the equivalent charge, and the explosive material parameters.

7. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, In step S1, non-reflective boundary conditions are applied to the outer boundaries of the foundation medium (3), water medium (4), and air medium (5); the Euler grid of the water medium (4) is locally refined.

8. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, In step S1, the concrete dam (1), the foundation medium (3), and the water medium (4) are respectively equipped with matching material models. The concrete dam (1) is equipped with the RHT material model, the foundation medium (3) is equipped with the elastoplastic model, and the water medium (4) is equipped with the Grünesen equation of state.

9. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, The analysis of the dual-path dynamic action effect in step S5 includes at least one of the following: load characteristic comparison, dynamic response difference analysis, damage mode identification, and path contribution weight quantitative assessment. The dynamic response is the structural response of the concrete dam (1) under the action of underwater shock wave (10) and foundation vibration (11).

10. The numerical simulation analysis method for the dynamic effects of underwater explosion with dual paths on concrete dams according to claim 1, characterized in that, The explosion-related key parameters mentioned in step S6 include at least one of the following: distance from the blast center, explosive equivalent (6), water depth of the water medium (4), and material properties of the foundation medium (3); a single variable control method is used to carry out multi-condition analysis, changing only one key parameter each time while keeping the other parameters unchanged.

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