Calcareous sand numerical simulation method, system and equipment

Abstract

The invention discloses a calcareous sand numerical simulation method, system and equipment, and the method comprises the steps: obtaining a calcareous sand particle image, and processing the calcareous sand particle image to obtain a corresponding non-particle element coordinate; performing three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information; constructing a particle model based on the non-particle element coordinates and the vertex coordinates, and repeatedly stacking the particle model to obtain an initial test model; setting the initial test model to obtain a target test model; and performing iterative calculation on the target test model based on the stress and mass information of the spherical unit, and judging whether the target test model is deformed and damaged or not according to an iterative calculation result. According to the method, an existing discrete element numerical simulation method is improved, the real particle shape and the inner pore structure of the calcareous sand can be accurately constructed, deformation and damage of the calcareous sand material can be accurately predicted, and the method can be further used for predicting settlement deformation of the island-reef blow-filled calcareous sand foundation.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering, and in particular to a calcareous sand numerical simulation method, system and equipment. Background Art

[0002] Calcareous sand is a kind of geomaterial formed by the death of marine calcareous organisms. It has rich internal pores, low strength, irregular shape and easy to break. It has certain application value in the field of engineering. For example, it can be used as a basic filler to enhance the stability of buildings. Numerical simulation has important application value in the study of the deformation characteristics of calcareous sand. It can reveal the deformation characteristics and stress distribution of calcareous sand and provide theoretical basis and technical support for engineering practice.

[0003] Existing numerical simulation methods mainly include discrete element method. Discrete element method is a numerical method based on Newton's second law of motion. It is mainly used to simulate and analyze the mechanical properties and motion characteristics of granular materials. It replaces granular materials with spherical units and cluster units. The velocity, acceleration and displacement of the unit are calculated by Newton's second law of motion to simulate the motion state of granular materials over time, avoiding the disadvantage of the method based on continuity assumption that cannot simulate particle crushing.

[0004] However, due to the irregular surface morphology and rich internal pores of calcareous sand, the discrete element method is modeled with regular spherical units or a simple combination of several spherical units, which is more suitable for quartz sand particles with regular shapes and is not suitable for simulating the deformation characteristics of calcareous sand materials. Therefore, it is necessary to improve the existing discrete element numerical simulation method to simulate the deformation characteristics of calcareous sand materials. Summary of the invention

[0005] In view of the shortcomings of the existing discrete element method, the present invention provides a calcareous sand numerical simulation method, system and equipment.

[0006] In a first aspect, an embodiment of the present invention provides a calcareous sand numerical simulation method, comprising:

[0007] Acquire a calcareous sand particle image, and process the calcareous sand particle image to obtain corresponding non-particle element coordinates;

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

[0009] A particle model is constructed based on the non-particle element coordinates and the vertex coordinates, and the particle model is repeatedly stacked to obtain an initial test model; wherein the particle model is a single particle model composed of a plurality of spherical units;

[0010] Setting the initial test model to obtain a target test model; wherein the setting at least includes boundary condition setting, loading mode setting and material property setting;

[0011] Based on the force magnitude and mass information of the spherical unit, the target test model is iteratively calculated, and it is determined whether the target test model has deformation damage according to the iterative calculation result; wherein each iterative calculation result at least includes the relative displacement between the spherical units.

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

[0013] Computed tomography was used to obtain images of calcareous sand particles;

[0014] Binarization is performed on the calcareous sand particle image to obtain a corresponding binary matrix;

[0015] The coordinates of non-particle elements in the binary matrix are obtained; wherein the elements with a value of 1 in the binary matrix are non-particle elements.

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

[0017] Based on the calcareous sand particle image, computer tomography is used to perform three-dimensional reconstruction to obtain particle surface information.

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

[0019] Performing three-dimensional processing on the coordinates of the non-particle elements to obtain three-dimensional internal coordinates;

[0020] Screening the vertex coordinates to obtain three-dimensional external coordinates;

[0021] constructing a particle model based on a 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 the initial angle to obtain an initial test model.

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

[0024] Determine a dense area on the particle surface; wherein the dense area is an area where the number of triangular meshes is higher than a first preset threshold;

[0025] Iteratively screen the vertex coordinates in the dense area to obtain three-dimensional external coordinates; wherein the number of iterative screening is the number of vertex coordinates in the dense area, and each iterative screening includes:

[0026] Randomly select a vertex of a triangular mesh in the dense area, and determine a search range based on the vertex;

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

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

[0029] Using random number generation to determine the initial position and initial angle of the particle model;

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

[0031] Preferably, the boundary conditions include at least a first displacement restriction condition of the spherical unit at the rigid shear box and a second displacement restriction condition of the spherical unit at the base, and the loading mode includes at least a stress control mode and a displacement control mode;

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

[0033] Preferably, the iterative calculation of the target test model based on the force magnitude and mass information of the spherical unit, and judging whether the target test model has deformation damage according to the iterative calculation result, 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 iterative calculations is the total number of time steps;

[0035] Based on the relative displacement, determining whether the corresponding particle model is broken;

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

[0037] In a second aspect, an embodiment of the present invention provides a calcareous sand numerical simulation system, comprising:

[0038] A coordinate retrieval module is used to obtain a calcareous sand particle image and process the calcareous sand particle image to obtain corresponding non-particle element coordinates;

[0039] A three-dimensional reconstruction module, used for performing three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information; wherein the particle surface is composed of a plurality of 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, used to build a particle model based on the non-particle element coordinates and the vertex coordinates, and repeatedly stack the particle model to obtain an initial test model; wherein the particle model is a single particle model composed of a plurality of spherical units;

[0041] A target model building module is used to set the initial test model to obtain a target test model; wherein the setting at least includes boundary condition setting, loading mode setting and material property setting;

[0042] The deformation and damage judgment module is used to iteratively calculate the target test model based on the force magnitude and mass information of the spherical unit, and judge whether the target test model has deformation and damage according to the iterative calculation results; wherein each iterative calculation result at least includes the relative displacement between the spherical units.

[0043] In a third aspect, an embodiment of the present invention provides a terminal device, comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements the calcareous sand numerical simulation method as described above when executing the computer program.

[0044] Compared with the prior art, the method, system and device for numerical simulation of calcareous sand in the embodiment of the present invention have the following beneficial effects: the existing discrete element numerical simulation method is improved, the real particle shape and internal pore structure of calcareous sand can be accurately constructed, the deformation and damage of calcareous sand materials can be accurately predicted, and the calcareous sand foundation can be further predicted for settlement deformation of island reef fill calcareous sand foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic flow chart of a numerical simulation method for calcareous sand according to an embodiment of the present invention;

[0046] Figure 2 is a schematic diagram of a process for obtaining coordinates of non-particle elements in an embodiment of the present invention;

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

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

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

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

[0051] Figure 7 is a schematic diagram of the process of particle accumulation in an embodiment of the present invention;

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

[0053] Fig. 9 is a schematic diagram of a flow chart of determining whether there is deformation damage according to an embodiment of the present invention;

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

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

[0056] Fig.11 It is a structural schematic diagram of a calcareous sand numerical simulation system according to an embodiment of the present invention;

[0057] Fig.12 It is a schematic diagram of the structure of a terminal device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

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

[0060] like Figure 1 As shown, an embodiment of the present invention provides a calcareous sand numerical simulation method, comprising the steps of:

[0061] S1, obtaining a calcareous sand particle image, and processing the calcareous sand particle image to obtain corresponding non-particle element coordinates;

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

[0063] S101, obtaining an image of calcareous sand particles by computer tomography;

[0064] The image of the dried calcareous sand particles was obtained by X-ray computed tomography (CT). Figure 3 The white part in the picture is the calcareous sand particle entity with a higher density, the black part is the air with a lower density, and some white particles have scattered black dots inside, which are the internal pores.

[0065] S102, performing binarization processing on the calcareous sand particle image to obtain a corresponding binarization matrix;

[0066] In this embodiment, MATLAB is used to perform binarization processing on the calcareous sand particle image, and the image is processed into an image matrix including only two values ​​of 0 and 1, namely, a binarization matrix, through threshold segmentation. It should be noted that, in order to facilitate the distinction of particles, the black part of the binarized image represents the calcareous sand particles, the white part is the air or pores, and the elements with a value of 0 in the binarization matrix are the calcareous sand particles. Among them, the image after binarization processing is as follows Figure 4 shown.

[0067] S103, obtaining the coordinates of non-particle elements in the binary matrix.

[0068] Retrieve the coordinates of the elements in the binarized matrix whose value is 1. The elements in the binarized matrix whose value is 1 are non-particle elements.

[0069] S2, performing three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information;

[0070] Specifically, based on the calcareous sand particle image, computed tomography is used for three-dimensional reconstruction to obtain particle surface information. CT can reconstruct the shape of the scanned particles by stacking a series of scanned slices. It should be noted that the particles obtained by three-dimensional reconstruction are hollow particles and only have particle surface information. Among them, 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.

[0071] Since the discrete element method requires unit contact to generate force transmission, the three-dimensional reconstruction information cannot be directly imported into the discrete element method for use. It is necessary to combine the non-particle element coordinates in step S1 for particle modeling to obtain a calcareous sand particle model with a real shape.

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

[0073]

[0074] Among them, K n represents the normal stiffness, X n represents the normal relative displacement, X b It represents the fracture displacement, which is related to the macroscopic mechanical parameters of the material and is expressed as follows:

[0075]

[0076] Among them, T u represents the tensile strength of the material, d represents the diameter of the spherical unit, K s represents the 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 Represents the tangential relative displacement.

[0080] The failure criterion of tangential force obeys the Mohr-Coulomb failure criterion, and 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 represents the inter-element tangential force, u p Denotes the friction coefficient, F n represents the normal force between elements. Specifically, the friction coefficient u p Use the following expression:

[0083]

[0084] Among them, u i Represents the internal friction coefficient.

[0085] S3, constructing a particle model based on the non-particle element coordinates and vertex coordinates, and repeatedly stacking the particle model to obtain an initial test model;

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

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

[0088] The coordinates of non-particle elements are two-dimensional coordinates, and need to be converted into three-dimensional coordinates according to the reconstruction interval of step S2 when modeling particles. That is, the coordinate matrix of each image needs to be stacked according to the reconstruction interval to obtain the three-dimensional internal coordinates.

[0089] S302, screening vertex coordinates to obtain three-dimensional external coordinates;

[0090] The triangular mesh of step S2 is too dense in some areas of the particle surface. Directly using it for particle modeling will increase the tensile strength of the area and make the particles show obvious plasticity. Therefore, the dense area mesh needs to be screened during modeling.

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

[0092] S302-A, determining a dense area on the particle surface;

[0093] The dense area is an area where the number of triangle meshes is higher than a first preset threshold.

[0094] S302-B, iteratively screen the vertex coordinates in the dense area to obtain three-dimensional external coordinates.

[0095] The number of iterative screening is the number of vertex coordinates in the dense area. Specifically, each iterative screening includes:

[0096] 1) Randomly select a vertex of a triangle mesh in a dense area and determine the search range based on the vertex;

[0097] A vertex of a triangular mesh in a dense area is randomly selected, and a search is performed around the vertex with a preset length as the radius to determine the search range. Specifically, in this embodiment, a vertex of a triangular mesh in a dense area is randomly selected, and a search is performed around the vertex with a preset length as the radius to determine the search range.

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

[0099] S303, constructing a particle model based on a combination of the three-dimensional internal coordinates and the three-dimensional external coordinates;

[0100] The three-dimensional internal coordinates and the three-dimensional external coordinates are combined and imported into the discrete element to construct a particle model. 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 unit in the discrete element to obtain all the spherical unit information of a single particle, and these spherical units are combined and set as cluster units to form a single particle model with a real calcareous sand particle shape and internal pore structure. In other words, the particle model is a single particle model composed of several spherical units.

[0101] S304, obtaining an initial position and an initial angle of the particle model, and repeatedly stacking the particle model based on the initial position and the initial angle to obtain an initial test model.

[0102] Different from the spherical unit whose initial angle is consistent in all directions, the real shape particle stacking process needs to consider the influence of particle shape, initial position and initial angle on the stacking process.

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

[0104] S304-A, using random number generation to determine the initial position and initial angle of the particle model;

[0105] The random number generation in this embodiment conforms to the standard normal distribution density function. It should be noted that the initial position of the random number generation is a three-dimensional coordinate. Placing the center of the particle at the generated three-dimensional coordinate is the initial position of the particle. The initial angle is to rotate the particle in the X, Y, and Z directions at different angles. Among them, the rotation angle is obtained by generating three groups of 0-360° arrays, and rotating in the order of X→Y→Z. For details, please refer to Figure 8 The expression for angular rotation through coordinate transformation is as follows:

[0106]

[0107] in, represents the rotated coordinates, R represents the transformation matrix, Represents the initial coordinates. The specific expression of the transformation matrix R is as follows:

[0108]

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

[0110] S304-B, based on the initial position and initial angle, repeatedly stack the particle model by gravity to obtain an initial test model.

[0111] It should be noted that for different simulation conditions, the discrete element method needs to use basic spherical units or cluster units to stack test models, such as specimens and foundation models of different sizes. The real shape particles constructed in step S303 are only single particles, and it is necessary to repeat the particles constructed in step S303 in step S304 to stack the required specimens. Specifically, based on the initial position and initial angle, the particles are stacked into specimens of different sizes, namely the initial test model, by gravity. In other words, the initial test model is formed by stacking several particle models.

[0112] S4, setting the initial test model to obtain the target test model;

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

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

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

[0116] S5. Based on the force magnitude and mass information of the spherical unit, iterative calculation is performed on the target test model, and whether the target test model has deformation damage is determined according to the iterative calculation results.

[0117] Specifically, Fig. 9 As shown, step S5 includes:

[0118] S501, based on the force magnitude and mass information of the spherical unit, use Newton's second law of motion to iteratively calculate the target test model to obtain the relative displacement between the spherical units;

[0119] The iterative calculation is based on Newton's second law of motion. According to the force magnitude and mass information of the spherical unit, the velocity, acceleration and displacement of the spherical unit in one time step are calculated, so as to obtain the force condition and motion information of the spherical unit. After completing one time step, the calculation of the next time step is carried out, and the calculation is iterated continuously. Each iteration will recalculate the interaction force, velocity, acceleration and displacement between the spherical units. According to the displacement calculated in each iteration, the relative displacement between the spherical units is obtained. Among them, the number of iterative calculations is the total number of time steps, and the result of each iterative calculation includes at least the relative displacement between the spherical units.

[0120] S502, judging whether the corresponding particle model is broken based on the relative displacement;

[0121] Determine whether the relative displacement between the spherical units is greater than the fracture displacement X b If yes, the corresponding particle model is broken, otherwise the corresponding particle model is not broken.

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

[0123] It is understandable that the continuous accumulation of multiple broken particle models eventually causes macroscopic deformation and destruction of the target test model.

[0124] In order to demonstrate the effectiveness of a numerical simulation method for calcareous sand in an embodiment 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 round pancake-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. The total time step stepn=2000, the normal load is 50kPa, and the shear displacement is 6mm. The numerical calculation results of the shear process displacement and stress distribution images are as follows: Fig.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 and failure position of the cylindrical specimen of calcareous sand material.

[0125] The embodiment of the present invention provides a calcareous sand numerical simulation method, which improves the existing discrete element numerical simulation method, can accurately construct the real particle shape and internal pore structure of the calcareous sand, can accurately predict the deformation and damage of the calcareous sand material, and can be further used to predict the settlement deformation of the calcareous sand foundation of the island reef.

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

[0127] The coordinate retrieval module 1 is used to obtain the calcareous sand particle image and process the calcareous sand particle image to obtain the corresponding non-particle element coordinates;

[0128] The three-dimensional reconstruction module 2 is used to perform three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information; wherein the particle surface is composed of a number of triangular meshes, and the particle surface information includes the vertex coordinates of each triangular mesh and the connection information of adjacent triangular meshes;

[0129] The initial model building module 3 is used to build a particle model based on the non-particle element coordinates and vertex coordinates, and repeatedly stack the particle model to obtain an initial test model; wherein the particle model is a single particle model composed of a number of spherical units;

[0130] The target model building module 4 is used to set the initial test model to obtain the target test model; wherein the setting at least includes boundary condition setting, loading mode setting and material property setting;

[0131] The deformation and damage judgment module 5 is used to perform iterative calculation on the target test model based on the force size and mass information of the spherical unit, and judge whether the target test model has deformation and damage according to the iterative calculation results; wherein each iterative calculation result at least includes the relative displacement between the spherical units.

[0132] It should be noted that each module in the above-mentioned calcareous sand numerical simulation system can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules. For the specific definition of a calcareous sand numerical simulation system, please refer to the definition of a calcareous sand numerical simulation method above. The two have the same functions and effects, which will not be repeated here.

[0133] An embodiment of the present invention further provides a terminal device, the terminal device comprising:

[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 used to call the operation instruction, and the executable instruction enables the processor to perform the operation corresponding to the above-mentioned calcareous sand numerical simulation method of the present invention.

[0138] In an optional embodiment, a terminal device is provided, such as Fig.12 As shown, Fig.12 The terminal device 5000 shown includes: a processor 5001 and a memory 5003. The processor 5001 and the memory 5003 are connected, such as through a bus 5002. Optionally, the terminal device 5000 may also include a transceiver 5004. It should be noted that in actual applications, the transceiver 5004 is not limited to one, and the structure of the 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, a transistor logic device, a hardware component or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of the present invention. Processor 5001 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

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

[0141] The memory 5003 may be a ROM or other type of static storage device that can store static information and instructions, a RAM or other type of dynamic storage device that can store information and instructions, or an EEPROM, a CD-ROM or other optical disk storage, an optical disk storage (including a compressed optical disk, a laser disk, an optical disk, a digital versatile disk, a Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.

[0142] The memory 5003 is used to store application code for executing the solution of the present invention, and the 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 above method embodiments.

[0143] In summary, the embodiments of the present invention provide a method, system and device for numerical simulation of calcareous sand, which improve the existing discrete element numerical simulation method, can accurately construct the real particle shape and internal pore structure of calcareous sand, accurately predict the deformation and damage of calcareous sand materials, and can be further used to predict the settlement deformation of calcareous sand foundations filled on islands and reefs.

[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 technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not 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 is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A calcareous sand numerical simulation method, characterized in that: include: Acquire a calcareous sand particle image, and process the calcareous sand particle image to obtain corresponding non-particle element coordinates; Performing three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information; wherein the particle surface is composed of a number of triangular meshes, and the particle surface information includes vertex coordinates of each triangular mesh and connection information of adjacent triangular meshes; A particle model is constructed based on the non-particle element coordinates and the vertex coordinates, and the particle model is repeatedly stacked to obtain an initial test model; wherein the particle model is a single particle model composed of a plurality of spherical units; Setting the initial test model to obtain a target test model; wherein the setting at least includes boundary condition setting, loading mode setting and material property setting; Based on the force magnitude and mass information of the spherical unit, the target test model is iteratively calculated, and it is determined whether the target test model has deformation damage according to the iterative calculation result; wherein each iterative calculation result at least includes the relative displacement between the spherical units.

2. The calcareous sand numerical simulation method according to claim 1, characterized in that: The step of acquiring a calcareous sand particle image and processing the calcareous sand particle image to obtain corresponding non-particle element coordinates includes: Computed tomography was used to obtain images of calcareous sand particles; Binarization is performed on the calcareous sand particle image to obtain a corresponding binary matrix; The coordinates of non-particle elements in the binary matrix are obtained; wherein the elements with a value of 1 in the binary matrix are non-particle elements.

3. The calcareous sand numerical simulation method according to claim 1, characterized in that: The three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information includes: Based on the calcareous sand particle image, computer tomography is used to perform three-dimensional reconstruction to obtain particle surface information.

4. The calcareous sand numerical simulation method according to claim 1, characterized in that: The step of constructing a particle model based on the non-particle element coordinates and the vertex coordinates, and repeatedly stacking the particle model to obtain an initial test model includes: Performing three-dimensional processing on the coordinates of the non-particle elements to obtain three-dimensional internal coordinates; Screening the vertex coordinates to obtain three-dimensional external coordinates; constructing a particle model based on a 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 test model.

5. The calcareous sand numerical simulation method according to claim 4, characterized in that: The step of screening the vertex coordinates to obtain three-dimensional external coordinates includes: Determine a dense area on the particle surface; wherein the dense area is an area where the number of triangular meshes is higher than a first preset threshold; Iteratively screen the vertex coordinates in the dense area to obtain three-dimensional external coordinates; wherein the number of iterative screening is the number of vertex coordinates in the dense area, and each iterative screening includes: Randomly select a vertex of a triangular mesh in the dense area, and determine a search range based on the vertex; The vertex coordinates of all triangular meshes within the search range are filtered out.

6. The calcareous sand numerical simulation method according to claim 4, characterized in that: 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 test model includes: Using random number generation to determine the initial position and initial angle of the particle model; Based on the initial position and the initial angle, the particle model is repeatedly stacked by gravity to obtain an initial test model.

7. The calcareous sand numerical simulation method according to claim 1, characterized in that: The boundary conditions at least include a first displacement restriction condition of the spherical unit at the rigid shear box and a second displacement restriction condition of the spherical unit at the base, and the loading mode at least includes a stress control mode and a displacement control mode; Material properties include at least Young's modulus, compressive strength, tensile strength, Poisson's ratio, and internal friction coefficient.

8. The calcareous sand numerical simulation method according to claim 1, characterized in that: The iterative calculation of the target test model based on the force magnitude and mass information of the spherical unit, and judging whether the target test model has deformation damage according to the iterative calculation result, 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 iterative calculations is the total number of time steps; Based on the relative displacement, determining whether the corresponding particle model is broken; The number of broken particle models is counted, and if the number of the particle models is higher than a second preset threshold, it is determined that the target test model is deformed and damaged.

9. A calcareous sand numerical simulation system, characterized in that: include: A coordinate retrieval module is used to obtain a calcareous sand particle image and process the calcareous sand particle image to obtain corresponding non-particle element coordinates; A three-dimensional reconstruction module, used for performing three-dimensional reconstruction based on the calcareous sand particle image to obtain particle surface information; wherein the particle surface is composed of a plurality of 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, used to build a particle model based on the non-particle element coordinates and the vertex coordinates, and repeatedly stack the particle model to obtain an initial test model; wherein the particle model is a single particle model composed of a plurality of spherical units; A target model building module is used to set the initial test model to obtain a target test model; wherein the setting at least includes boundary condition setting, loading mode setting and material property setting; The deformation and damage judgment module is used to iteratively calculate the target test model based on the force magnitude and mass information of the spherical unit, and judge whether the target test model has deformation and damage according to the iterative calculation results; wherein each iterative calculation result at least includes the relative displacement between the spherical units.

10. A terminal device, characterized in that: The invention comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements the calcareous sand numerical simulation method according to any one of claims 1 to 8 when executing the computer program.

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