A numerical simulation method, system and equipment for calcareous sand

Abstract

This invention discloses a numerical simulation method, system, and device for calcareous sand. The method includes: acquiring images of calcareous sand particles and processing these images to obtain the coordinates of corresponding non-particle elements; performing three-dimensional reconstruction based on the calcareous sand particle images to obtain particle surface information; constructing a particle model based on the non-particle element coordinates and vertex coordinates, and repeatedly stacking the particle model to obtain an initial experimental model; setting the initial experimental model to obtain a target experimental model; performing iterative calculations on the target experimental model based on the force magnitude and mass information of the spherical elements, and determining whether the target experimental model has deformation or failure based on the iterative calculation results. This invention improves upon existing discrete element numerical simulation methods, accurately constructing the true particle shape and internal pore structure of calcareous sand, accurately predicting the deformation and failure of calcareous sand materials, and further predicting the settlement deformation of calcareous sand foundations for island and reef reclamation.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to a numerical simulation method, system and equipment for calcareous sand. Background Technology

[0002] Calcareous sand, formed from the sedimentation of dead marine calcareous organisms, is a type of soil material characterized by abundant internal porosity, low strength, irregular shape, and fracturing. It has certain applications in engineering. For example, it can be used as foundation filler to enhance the stability of structures. Numerical simulation plays a crucial role in studying the deformation characteristics of calcareous sand, revealing its deformation features and stress distribution patterns, and providing theoretical basis and technical support for engineering practice.

[0003] Existing numerical simulation methods mainly include the discrete element method (DEM). The DEM is a numerical method based on Newton's second law of motion, mainly used to simulate and analyze the mechanical properties and motion characteristics of granular materials. It approximates granular materials as spherical and clustered elements, and calculates the velocity, acceleration, and displacement of the elements using Newton's second law of motion to simulate the motion state of granular materials over time, thus avoiding the shortcomings of methods based on the continuity assumption that cannot simulate particle breakage.

[0004] However, due to the irregular surface morphology and abundant internal pores of calcareous sand, the discrete element method (DEM), which uses regular spherical elements or simple combinations of several spherical elements for modeling, is more suitable for quartz sand particles with relatively regular shapes and is not applicable to simulating the deformation characteristics of calcareous sand. Therefore, it is necessary to improve the existing discrete element numerical simulation method to simulate the deformation characteristics of calcareous sand. Summary of the Invention

[0005] To address the shortcomings of existing discrete element methods, this invention provides a numerical simulation method, system, and equipment for calcareous sand.

[0006] In a first aspect, embodiments of the present invention provide a numerical simulation method for calcareous sand, comprising:

[0007] Acquire images of calcareous sand particles and process the images to obtain the coordinates of the corresponding non-particle elements;

[0008] Three-dimensional reconstruction is performed based on the image of the calcareous sand particles to obtain particle surface information; wherein, the particle surface is composed of several triangular meshes, and the particle surface information includes the vertex coordinates of each triangular mesh and the connection information of adjacent triangular meshes;

[0009] A particle model is constructed based on the coordinates of the non-particle elements and the coordinates of the vertices, and the particle model is repeatedly stacked to obtain an initial experimental model; wherein, the particle model is a single particle model, which is composed of several spherical units;

[0010] The initial test model is configured to obtain the target test model; wherein, the configuration includes at least boundary condition settings, loading method settings, and material property settings.

[0011] Based on the force magnitude and mass information of the spherical element, the target test model is iteratively calculated, and the deformation and failure of the target test model are determined according to the iterative calculation results; wherein, the result of each iterative calculation includes at least the relative displacement between the spherical elements.

[0012] Preferably, the step of acquiring an image of calcareous sand particles and processing the image to obtain the corresponding coordinates of non-particle elements includes:

[0013] Images of calcareous sand particles were obtained using computed tomography.

[0014] The image of the calcareous sand particles is binarized to obtain the corresponding binarized matrix;

[0015] Obtain the coordinates of the non-granular elements in the binarized matrix; wherein, the elements with a value of 1 in the binarized matrix are non-granular elements.

[0016] Preferably, the step of performing three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information includes:

[0017] Based on the image of the calcareous sand particles, three-dimensional reconstruction was performed using computed tomography to obtain the particle surface information.

[0018] Preferably, the step of constructing a particle model based on the coordinates of the non-particle elements and the vertex coordinates, and repeatedly stacking the particle model to obtain an initial experimental model, includes:

[0019] The coordinates of the non-particulate elements are processed into three dimensions to obtain three-dimensional internal coordinates;

[0020] The vertex coordinates are filtered to obtain the three-dimensional external coordinates;

[0021] A particle model is constructed based on the combination of the three-dimensional internal coordinates and the three-dimensional external coordinates;

[0022] The initial position and initial angle of the particle model are obtained, and the particle model is repeatedly stacked based on the initial position and initial angle to obtain an initial experimental model.

[0023] Preferably, the step of filtering the vertex coordinates to obtain the three-dimensional external coordinates includes:

[0024] Identify dense regions on the particle surface; wherein, the dense region is a region where the number of triangular meshes is higher than a first preset threshold.

[0025] The vertex coordinates within the dense region are iteratively filtered to obtain the three-dimensional external coordinates; wherein the number of iterations is equal to the number of vertex coordinates within the dense region, and each iteration includes:

[0026] Randomly select a vertex of a triangular grid within the dense region, and determine the search range based on the vertex;

[0027] The vertex coordinates of all triangular meshes within the search range are filtered out.

[0028] Preferably, the step of obtaining the initial position and initial angle of the particle model, and repeatedly stacking the particle model based on the initial position and initial angle to obtain an initial experimental model, includes:

[0029] The initial position and initial angle of the particle model are determined by random number generation;

[0030] Based on the initial position and the initial angle, the particle model is repeatedly stacked by gravity to obtain the initial experimental model.

[0031] Preferably, the boundary conditions include at least the first displacement constraint condition of the spherical element at the rigid shear box and the second displacement constraint condition of the spherical element at the base, and the loading method includes at least the stress control method and the displacement control method;

[0032] Material properties include at least Young's modulus, compressive strength, tensile strength, Poisson's ratio, and coefficient of internal friction.

[0033] Preferably, the step of iteratively calculating the target test model based on the force magnitude and mass information of the spherical unit, and determining whether the target test model has deformation or failure based on the iterative calculation results, includes:

[0034] Based on the force magnitude and mass information of the spherical unit, Newton's second law of motion is used to iteratively calculate the target test model to obtain the relative displacement between the spherical units; wherein, the number of iterations is the total number of time steps;

[0035] Based on the relative displacement, determine whether the corresponding particle model has broken;

[0036] The number of broken particle models is counted. If the number of particle models is higher than a second preset threshold, the target test model is determined to be deformed and damaged.

[0037] Secondly, embodiments of the present invention provide a numerical simulation system for calcareous sand, comprising:

[0038] The coordinate retrieval module is used to acquire images of calcareous sand particles and process the images to obtain the coordinates of the corresponding non-particle elements.

[0039] The three-dimensional reconstruction module is used to perform three-dimensional reconstruction based on the image of the calcareous sand particles to obtain particle surface information; wherein, the particle surface is composed of several triangular meshes, and the particle surface information includes the vertex coordinates of each triangular mesh and the connection information of adjacent triangular meshes;

[0040] An initial model building module is used to build a particle model based on the coordinates of the non-particle elements and the coordinates of the vertices, and to repeatedly stack the particle model to obtain an initial experimental model; wherein, the particle model is a single particle model, which is composed of several spherical units;

[0041] The target model construction module is used to set the initial test model to obtain the target test model; wherein, the setting includes at least boundary condition setting, loading method setting and material property setting;

[0042] The deformation and failure judgment module is used to perform iterative calculations on the target test model based on the force magnitude and mass information of the spherical element, and to determine whether the target test model is deformed or failed based on the iterative calculation results; wherein, each iterative calculation result includes at least the relative displacement between the spherical elements.

[0043] Thirdly, embodiments of the present invention provide a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor executes the computer program to implement the numerical simulation method for calcareous sand as described above.

[0044] Compared with the prior art, the numerical simulation method, system and equipment for calcareous sand of the present invention have the following advantages: the existing discrete element numerical simulation method has been improved, which can accurately construct the real particle shape and internal pore structure of calcareous sand, accurately predict the deformation and failure of calcareous sand materials, and can be further used to predict the settlement and deformation of calcareous sand foundations for island and reef reclamation. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating a numerical simulation method for calcareous sand according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the process for obtaining the coordinates of non-particulate elements according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of calcium sand particles according to an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the image after binarization processing according to an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the process for constructing the initial experimental model according to an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of the process of obtaining three-dimensional external coordinates according to an embodiment of the present invention;

[0051] Figure 7 This is a schematic diagram of the particle stacking process according to an embodiment of the present invention;

[0052] Figure 8 This is a schematic diagram of the same particle angle transformation in an embodiment of the present invention;

[0053] Figure 9 This is a schematic diagram of the process for determining whether deformation or damage exists according to an embodiment of the present invention;

[0054] Figure 10 (a) is a schematic diagram of the displacement during the shearing process in an embodiment of the present invention;

[0055] Figure 10 (b) is a schematic diagram of stress distribution during the shearing process in an embodiment of the present invention;

[0056] Figure 11 This is a schematic diagram of the structure of a numerical simulation system for calcareous sand according to an embodiment of the present invention;

[0057] Figure 12 This is a schematic diagram of the structure of a terminal device according to an embodiment of the present invention. Detailed Implementation

[0058] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0059] In the description of this invention, it should be understood that the terms "first" and "second," etc., are used to distinguish different objects, rather than to describe a specific order.

[0060] like Figure 1 As shown, this embodiment of the invention provides a numerical simulation method for calcareous sand, including the following steps:

[0061] S1. Obtain images of calcareous sand particles and process them to obtain the coordinates of the corresponding non-particle elements.

[0062] Specifically, such as Figure 2 As shown, step S1 includes:

[0063] S101. Images of calcareous sand particles were obtained using computed tomography.

[0064] Images of dried calcareous sand particles were obtained using X-ray computed tomography (CT) imaging technology. For details, please refer to [link to relevant documentation]. Figure 3 In the diagram, the white parts represent denser calcareous sand particles, while the black parts represent less dense air. Some white particles have scattered black dots inside, which are the internal pores.

[0065] S102. Perform binarization processing on the image of calcareous sand particles to obtain the corresponding binarization matrix;

[0066] This embodiment uses MATLAB to binarize an image of calcareous sand particles. Thresholding segmentation is used to process the image into a binary matrix containing only 0 and 1 values. It should be noted that, for easy particle differentiation, black areas in the binarized image represent calcareous sand particles, while white areas represent air or pores. Elements with a value of 0 in the binarized matrix represent calcareous sand particles. The binarized image is shown below. Figure 4 As shown.

[0067] S103. Obtain the coordinates of non-granular elements in the binarized matrix.

[0068] Retrieve the coordinates of elements with a value of 1 in the binarized matrix. Elements with a value of 1 in the binarized matrix are non-granular elements.

[0069] S2. Perform three-dimensional reconstruction based on the image of calcareous sand particles to obtain particle surface information;

[0070] Specifically, based on images of calcareous sand particles, three-dimensional reconstruction is performed using computed tomography (CT) scans to obtain particle surface information. CT can reconstruct the shape of the scanned particles by stacking a series of scan slices. It should be noted that the particles obtained from the three-dimensional reconstruction are hollow particles, and only particle surface information is available. The particle surface consists of several triangular meshes, and the particle surface information includes the vertex coordinates of each triangular mesh and the connection information of adjacent triangular meshes.

[0071] Since the discrete element method requires the transmission of force through element contact, the 3D reconstruction information cannot be directly imported into the discrete element method. It is necessary to combine the coordinates of the non-particle elements in step S1 to perform particle modeling, so as to obtain a calcareous sand particle model with a real shape.

[0072] Specifically, in the discrete element method, the normal force F of the elastic contact of the element... n Use the following expression:

[0073]

[0074] Among them, K n Indicates normal stiffness, X n X represents the normal relative displacement. b The fracture displacement, which is related to the macroscopic mechanical parameters of the material, is expressed by the following formula:

[0075]

[0076] Among them, T u The tensile strength of the material is represented by d, the diameter of the spherical element is represented by K. s This indicates tangential stiffness.

[0077] Unit elastic contact tangential force F s Use the following expression:

[0078] F s =K s X s

[0079] Among them, X s This indicates the tangential relative displacement.

[0080] The failure criterion for tangential force follows the Mohr-Coulomb failure criterion, with the maximum tangential force F. s,max Use the following expression:

[0081] F s,max =F s0 -u p F n

[0082] Among them, F s0 u represents the tangential force between elements. p F represents the coefficient of friction. n This represents the normal force between elements. Specifically, the coefficient of friction, u. p Use the following expression:

[0083]

[0084] Among them, u i This represents the coefficient of internal friction.

[0085] S3. Construct a particle model based on the coordinates of non-particle elements and vertex coordinates, and repeatedly stack the particle model to obtain the initial experimental model;

[0086] Specifically, such as Figure 5 As shown, step S3 includes:

[0087] S301. Perform three-dimensional processing on the coordinates of non-particle elements to obtain three-dimensional internal coordinates;

[0088] The coordinates of non-particle elements are two-dimensional coordinates. When modeling particles, they need to be three-dimensional according to the reconstruction interval in step S2. That is, the coordinate matrices of each image need to be stacked according to the reconstruction interval to obtain the three-dimensional internal coordinates.

[0089] S302. Filter the vertex coordinates to obtain the three-dimensional external coordinates;

[0090] The triangular mesh in step S2 is too dense in some areas of the particle surface. Directly using it for particle modeling will increase the tensile strength in that area, causing the particle to exhibit obvious plasticity. Therefore, it is necessary to filter the dense mesh area during modeling.

[0091] Specifically, such as Figure 6 As shown, step S302 includes:

[0092] S302-A, Identify the dense areas on the particle surface;

[0093] Dense regions are those where the number of triangular grids exceeds a first preset threshold.

[0094] S302-B: Iteratively filter the vertex coordinates within the dense region to obtain the three-dimensional external coordinates.

[0095] The number of iterations is equal to the number of vertex coordinates within the dense region. Specifically, each iteration includes:

[0096] 1) Randomly select a vertex of a triangular grid within a dense region, and determine the search range based on the vertex;

[0097] A vertex of a triangular mesh within a dense region is randomly selected. The search area is then determined by traversing outwards from this vertex with a preset radius. Specifically, in this embodiment, a vertex of a triangular mesh within a dense region is randomly selected. The search area is then determined by traversing outwards from this vertex with a radius equal to 0.8 times the diameter of the spherical element.

[0098] 2) Filter out the vertex coordinates of all triangular grids within the search range.

[0099] S303. Based on the combination of three-dimensional internal coordinates and three-dimensional external coordinates, a particle model is constructed;

[0100] The particle model is constructed by combining three-dimensional internal and three-dimensional external coordinates and importing them into the discrete element method (DEM). Specifically, the X, Y, and Z coordinates of the internal and external coordinates are used as the X, Y, and Z coordinates of the spherical elements in the DEM to obtain the information of all spherical elements of a single particle. These spherical elements are then combined to form cluster elements, resulting in a single particle model with the actual shape and internal pore structure of calcareous sand particles. In other words, the particle model is a single particle model composed of several spherical elements.

[0101] S304. Obtain the initial position and initial angle of the particle model, and repeatedly stack the particle model based on the initial position and initial angle to obtain the initial experimental model.

[0102] Unlike spherical units where the initial angle is consistent in all directions, the stacking process of real-shaped particles needs to consider the influence of particle shape, initial position, and initial angle on the stacking process.

[0103] Specifically, such as Figure 7 As shown, step S304 includes:

[0104] S304-A: The initial position and initial angle of the particle model are determined by random number generation;

[0105] In this embodiment, the random number generation conforms to the standard normal distribution density function. It should be noted that the initial position for random number generation is a three-dimensional coordinate system; placing the particle center at this generated coordinate system gives the initial particle position. The initial angle is achieved by rotating the particle by different angles in the X, Y, and Z directions. The rotation angles are obtained by generating three sets of arrays from 0 to 360°, rotating in the order X→Y→Z. For details, please refer to [link to documentation]. Figure 8 The expression for angular rotation using coordinate transformation is shown below:

[0106]

[0107] in, R represents the rotated coordinates, and R represents the transformation matrix. The initial coordinates are represented. The specific expression for the transformation matrix R is as follows:

[0108]

[0109] in, Let R represent the transformation matrix from A to B. Z (α), R Y (β), R X (γ) represents the transformation matrix for rotating the Z, Y, and X axes by α, β, and γ degrees, respectively.

[0110] S304-B: Based on the initial position and initial angle, the particle model is repeatedly stacked by gravity to obtain the initial experimental model.

[0111] It should be noted that the Discrete Element Method (DEM) requires the use of basic spherical or clustered elements to build up experimental models for different simulation conditions, such as specimens and foundation models of different sizes. The realistically shaped particles constructed in step S303 are only single particles, and the required specimens need to be built up by repeating the particle buildup in step S304. Specifically, based on the initial position and initial angle, the particles are piled up into specimens of different sizes, i.e., the initial experimental model, by gravity. In other words, the initial experimental model is composed of several particle models stacked together.

[0112] S4. Set up the initial experimental model to obtain the target experimental model;

[0113] Specifically, the settings include at least boundary condition settings, loading method settings, and material property settings.

[0114] In the discrete element method, boundary conditions and loading methods are set using spherical elements. The boundary conditions include at least a first displacement constraint condition for the spherical elements at the rigid shear box and a second displacement constraint condition for the spherical elements at the base, achieved by restricting the displacement of the spherical elements at the rigid shear box and the base in different directions. The loading methods include at least stress control and displacement control methods, achieved by applying force or displacement to the spherical elements at the pressure plate.

[0115] Input the parameters for the calcareous sand material and set its properties. These properties must include at least Young's modulus, compressive strength, tensile strength, Poisson's ratio, and coefficient of internal friction.

[0116] S5. Based on the force magnitude and mass information of the spherical element, perform iterative calculations on the target test model, and determine whether the target test model is deformed or damaged based on the iterative calculation results.

[0117] Specifically, such as Figure 9 As shown, step S5 includes:

[0118] S501. Based on the force magnitude and mass information of the spherical elements, Newton's second law of motion is used to iteratively calculate the target test model to obtain the relative displacement between the spherical elements.

[0119] The iterative calculation is based on Newton's second law of motion. Based on the magnitude of the forces acting on the spherical elements and their mass information, the velocity, acceleration, and displacement of each spherical element are calculated within a time step, thus obtaining the force and motion information of the spherical element. After completing one time step, the calculation for the next time step is performed, continuously iterating. Each iteration recalculates the interaction forces, velocities, accelerations, and displacements between the spherical elements. Based on the displacement calculated in each iteration, the relative displacements between the spherical elements are obtained. The number of iterations is equal to the total number of time steps, and the result of each iteration includes at least the relative displacements between the spherical elements.

[0120] S502. Determine whether the corresponding particle model has broken based on relative displacement;

[0121] Determine whether the relative displacement between spherical elements is greater than the fracture displacement X. b If so, the corresponding particle model will break; otherwise, the corresponding particle model will not break.

[0122] S503. Count the number of broken particle models. If the number of particle models is higher than the second preset threshold, it is determined that the target test model has been deformed and damaged.

[0123] Understandably, the continuous accumulation of multiple broken particle models eventually caused macroscopic deformation and damage to the target test model.

[0124] To demonstrate the effectiveness of the numerical simulation method for calcareous sand according to embodiments of the present invention, in a specific embodiment, the method is verified based on a direct shear test of calcareous sand. The direct shear test specimen is a disc-shaped specimen with a diameter of 618 mm and a height of 20 mm. The loading method is displacement control, and the loading speed is 1.2 mm / min. The material parameters are Young's modulus E = 0.3 MPa, compressive strength Cu = 0.3 MPa, tensile strength Tu = 30 kPa, Poisson's ratio v = 0.15, and internal friction coefficient μ. i =0.81. Total time step n = 2000, normal load is 50 kPa, and shear displacement is 6 mm. The numerical calculations yielded the displacement and stress distribution images during the shear process, as shown below. Figure 10 As shown in (a) and (b), it can be seen that the present invention can accurately predict the shear surface morphology and particle deformation failure location of cylindrical specimens made of calcareous sand.

[0125] This invention provides a numerical simulation method for calcareous sand, which improves upon existing discrete element numerical simulation methods. It can accurately construct the true particle shape and internal pore structure of calcareous sand, accurately predict the deformation and failure of calcareous sand materials, and can be further used to predict the settlement and deformation of calcareous sand foundations for island and reef reclamation.

[0126] Based on the above-mentioned numerical simulation method for calcareous sand, such as Figure 11 As shown, an embodiment of the present invention provides a numerical simulation system for calcareous sand, comprising:

[0127] Coordinate retrieval module 1 is used to acquire images of calcareous sand particles and process the images to obtain the coordinates of the corresponding non-particle elements.

[0128] 3D reconstruction module 2 is used to perform 3D reconstruction based on calcareous sand particle images to obtain particle surface information; wherein, the particle surface is composed of several triangular meshes, and the particle surface information includes the vertex coordinates of each triangular mesh and the connection information of adjacent triangular meshes;

[0129] Initial model building module 3 is used to build a particle model based on the coordinates of non-particle elements and vertex coordinates, and to repeatedly stack the particle model to obtain the initial experimental model; wherein, the particle model is a single particle model, which is composed of several spherical units;

[0130] The target model construction module 4 is used to set up the initial test model to obtain the target test model; the setting includes at least boundary condition settings, loading method settings, and material property settings.

[0131] The deformation and failure judgment module 5 is used to perform iterative calculations on the target test model based on the force magnitude and mass information of the spherical elements, and to judge whether the target test model has deformation and failure based on the iterative calculation results; wherein, the calculation results of each iteration include at least the relative displacement between the spherical elements.

[0132] It should be noted that each module in the aforementioned numerical simulation system for calcareous sand can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module. For specific limitations regarding the numerical simulation system for calcareous sand, please refer to the limitations regarding the numerical simulation method for calcareous sand described above; both have the same function and role, and will not be repeated here.

[0133] This invention also provides a terminal device, which includes:

[0134] Processor, memory, and bus;

[0135] The bus is used to connect the processor and the memory;

[0136] The memory is used to store operation instructions;

[0137] The processor is configured to execute operations corresponding to the numerical simulation method for calcareous sand described above by invoking the operation instructions.

[0138] In one alternative embodiment, a terminal device is provided, such as Figure 12 As shown, Figure 12 The terminal device 5000 shown includes a processor 5001 and a memory 5003. The processor 5001 and the memory 5003 are connected, for example, via a bus 5002. Optionally, the terminal device 5000 may also include a transceiver 5004. It should be noted that in practical applications, the transceiver 5004 is not limited to one type, and the structure of this terminal device 5000 does not constitute a limitation on the embodiments of the present invention.

[0139] Processor 5001 may be a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It may implement or execute the various exemplary logic blocks, modules, and circuits described in connection with this disclosure. Processor 5001 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0140] Bus 5002 may include a path for transmitting information between the aforementioned components. Bus 5002 may be a PCI bus or an EISA bus, etc. Bus 5002 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 12 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0141] The memory 5003 may be a ROM or other type of static storage device capable of storing static information and instructions, RAM or other type of dynamic storage device capable of storing information and instructions, or it may be an EEPROM, CD-ROM or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.

[0142] The memory 5003 is used to store application code that executes the present invention, and its execution is controlled by the processor 5001. The processor 5001 is used to execute the application code stored in the memory 5003 to implement the content shown in any of the foregoing method embodiments.

[0143] In summary, the numerical simulation method, system, and equipment for calcareous sand of the present invention improves upon the existing discrete element numerical simulation method. It can accurately construct the true particle shape and internal pore structure of calcareous sand, accurately predict the deformation and failure of calcareous sand materials, and can be further used to predict the settlement and deformation of calcareous sand foundations for island and reef reclamation.

[0144] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the various technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0145] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A numerical simulation method for calcareous sand, characterized in that, include: Acquire images of calcareous sand particles and process the images to obtain the coordinates of the corresponding non-particle elements; Three-dimensional reconstruction is performed based on the image of the calcareous sand particles to obtain particle surface information; wherein, the particle surface is composed of several triangular meshes, and the particle surface information includes the vertex coordinates of each triangular mesh and the connection information of adjacent triangular meshes; A particle model is constructed based on the coordinates of the non-particle elements and the coordinates of the vertices, and the particle model is repeatedly stacked to obtain an initial experimental model; wherein, the particle model is a single particle model, which is composed of several spherical units; The initial test model is configured to obtain the target test model; wherein, the configuration includes at least boundary condition settings, loading method settings, and material property settings. Based on the force magnitude and mass information of the spherical element, iterative calculations are performed on the target test model, and the deformation and failure of the target test model are determined based on the iterative calculation results; wherein, each iterative calculation result includes at least the relative displacement between the spherical elements; The process of constructing a particle model based on the coordinates of the non-particle elements and the vertex coordinates, and repeatedly stacking the particle model to obtain an initial experimental model, includes: The coordinates of the non-particulate elements are processed into three dimensions to obtain three-dimensional internal coordinates; The vertex coordinates are filtered to obtain the three-dimensional external coordinates; A particle model is constructed based on the combination of the three-dimensional internal coordinates and the three-dimensional external coordinates; The initial position and initial angle of the particle model are obtained, and the particle model is repeatedly stacked based on the initial position and the initial angle to obtain an initial experimental model; The process of filtering the vertex coordinates to obtain the three-dimensional external coordinates includes: Identify dense regions on the particle surface; wherein, the dense region is a region where the number of triangular meshes is higher than a first preset threshold. The vertex coordinates within the dense region are iteratively filtered to obtain the three-dimensional external coordinates; wherein the number of iterations is equal to the number of vertex coordinates within the dense region, and each iteration includes: Randomly select a vertex of a triangular grid within the dense region, and determine the search range based on the vertex; The vertex coordinates of all triangular meshes within the search range are filtered out.

2. The numerical simulation method for calcareous sand according to claim 1, characterized in that, The process of acquiring an image of calcareous sand particles and processing the image to obtain the corresponding coordinates of non-particle elements includes: Images of calcareous sand particles were obtained using computed tomography. The image of the calcareous sand particles is binarized to obtain the corresponding binarized matrix; Obtain the coordinates of the non-granular elements in the binarized matrix; wherein, the elements with a value of 1 in the binarized matrix are non-granular elements.

3. The numerical simulation method for calcareous sand according to claim 1, characterized in that, The process of performing three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information includes: Based on the image of the calcareous sand particles, three-dimensional reconstruction was performed using computed tomography to obtain the particle surface information.

4. The numerical simulation method for calcareous sand according to claim 1, characterized in that, The process of obtaining the initial position and initial angle of the particle model, and repeatedly stacking the particle model based on the initial position and initial angle to obtain an initial experimental model, includes: The initial position and initial angle of the particle model are determined by random number generation; Based on the initial position and the initial angle, the particle model is repeatedly stacked by gravity to obtain the initial experimental model.

5. The numerical simulation method for calcareous sand according to claim 1, characterized in that, The boundary conditions include at least the first displacement constraint condition of the spherical element at the rigid shear box and the second displacement constraint condition of the spherical element at the base, and the loading methods include at least the stress control method and the displacement control method. Material properties include at least Young's modulus, compressive strength, tensile strength, Poisson's ratio, and coefficient of internal friction.

6. The numerical simulation method for calcareous sand according to claim 1, characterized in that, The step of iteratively calculating the target test model based on the force magnitude and mass information of the spherical unit, and determining whether the target test model has deformation or failure based on the iterative calculation results, includes: Based on the force magnitude and mass information of the spherical unit, Newton's second law of motion is used to iteratively calculate the target test model to obtain the relative displacement between the spherical units; wherein, the number of iterations is the total number of time steps; Based on the relative displacement, determine whether the corresponding particle model has broken; The number of broken particle models is counted. If the number of particle models is higher than a second preset threshold, the target test model is determined to be deformed and damaged.

7. A numerical simulation system for calcareous sand, characterized in that, The system, applied to the numerical simulation method for calcareous sand as described in any one of claims 1 to 6, comprises: The coordinate retrieval module is used to acquire images of calcareous sand particles and process the images to obtain the coordinates of the corresponding non-particle elements. The three-dimensional reconstruction module is used to perform three-dimensional reconstruction based on the image of the calcareous sand particles to obtain particle surface information; wherein, the particle surface is composed of several triangular meshes, and the particle surface information includes the vertex coordinates of each triangular mesh and the connection information of adjacent triangular meshes; An initial model building module is used to build a particle model based on the coordinates of the non-particle elements and the coordinates of the vertices, and to repeatedly stack the particle model to obtain an initial experimental model; wherein, the particle model is a single particle model, which is composed of several spherical units; The target model construction module is used to set the initial test model to obtain the target test model; wherein, the setting includes at least boundary condition setting, loading method setting and material property setting; The deformation and failure judgment module is used to perform iterative calculations on the target test model based on the force magnitude and mass information of the spherical element, and to determine whether the target test model is deformed or failed based on the iterative calculation results; wherein, each iterative calculation result includes at least the relative displacement between the spherical elements.

8. A terminal device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements the numerical simulation method for calcareous sand as described in any one of claims 1 to 6.

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