Three-dimensional fine numerical model of rockfill concrete, construction method and device

Abstract

The disclosure provides a rockfill concrete three-dimensional fine numerical model, a construction method and a device. A convex polyhedron random aggregate for representing rockfill in rockfill concrete is generated in a sample space, a random placement of rockfill is simulated by simulating a gravity compaction process, and a corresponding surface grid is formed on each rockfill surface. The rockfill surface grid with potential contact is detected, the local surface grid is adjusted, a contact surface is generated, and a rockfill self-supporting framework is obtained. Under the constraint of the rockfill self-supporting framework and the boundary of the sample space, the rockfill, the self-compacting concrete and the interface transition zone are discretized by a three-dimensional body grid, and the rockfill concrete three-dimensional fine numerical model is obtained. The disclosure can truly and accurately reflect the physical characteristics of rockfill concrete based on the polyhedron random aggregate. The rockfill contact surface and the rockfill boundary surface generated by detecting the rockfill grid with potential contact and adjusting the local grid according to the optimal strategy can fully represent the characteristics of the rockfill self-supporting framework.

Description

Technical Field

[0001] This disclosure belongs to the field of riprap concrete modeling technology, and specifically relates to a three-dimensional microscopic numerical model of riprap concrete, its construction method and apparatus. Background Technology

[0002] Rockfill concrete technology, invented by Tsinghua University in 2003, is a novel large-volume concrete technology (Rockfill Concrete Dam Construction Method, Patent No. ZL03102674.5). It consists of ultra-large-diameter boulders and high-performance self-compacting concrete. In the past 20 years, rockfill concrete technology has developed rapidly, with over 160 rockfill concrete dams built or under construction worldwide. The achievements and accumulated engineering practice have laid the foundation for the construction of 100-meter-class high rockfill concrete dams. However, due to the limitation of ultra-large aggregate size, full-scale mechanical property testing of rockfill concrete requires a very large-tonnage electro-hydraulic servo-controlled rigid testing machine. Establishing an accurate numerical model for rockfill concrete numerical simulation can effectively overcome the limitations of mechanical property testing. Establishing an accurate microscopic numerical model of rockfill concrete presents two main difficulties: establishing a sliding contact surface between the gravity-loaded boulders and forming a self-supporting skeleton; and simultaneously, the model must include boulders with a realistic physical shape, an interface transition zone of appropriate thickness, and a three-phase medium of self-compacting concrete.

[0003] Currently, the published or patent-pending modeling methods for riprap concrete are mainly divided into two categories. The first category is the microscopic numerical model of riprap concrete based on the mapping mesh method, where the basic unit of the model is a square (two-dimensional) or a cube (three-dimensional). For example, Tang Xinwei proposed a two-dimensional two-phase mapping mesh model of riprap concrete (Tang Xinwei, Shi Jianjun, Zhang Zhiheng, et al. Microscopic simulation and experimental study on mechanical properties of self-compacting riprap concrete, Journal of Hydraulic Engineering, 2009, 40(7):844-849.), Fang Qin generated a two-phase three-dimensional model of riprap and mortar using the mapping mesh algorithm (Fang Qin, Yan Peng, Zhang Jinhua, et al. Modeling method of three-dimensional mechanical model of riprap concrete, Journal of Building Materials, 2017, 20(1):55-60.), and Li Yang proposed a method for establishing a three-phase microscopic model of riprap concrete (application number: 202010517640.5). However, the riprap mesh established based on the mapping method has stepped edges, which makes the contact between riprap and between riprap and self-compacting concrete significantly different from the actual physical situation, resulting in unrealistic stress concentration and contact stress in numerical simulation. Another type is the microscopic numerical model of riprap concrete based on random aggregates, such as the three-dimensional two-phase riprap concrete model established by Li Ge based on polyhedral random aggregates (Li Ge, Wang Biao, Tian Zhichang. Numerical simulation of riprap concrete compressive strength test based on microscopic modeling. Journal of Inner Mongolia University of Science and Technology, 2021, 40(01):73-76.), but it fails to reflect the self-supporting skeleton characteristics of riprap. The microscopic three-phase finite element model, establishment method and device of riprap concrete proposed by Liang Ting (application number: CN202010517640.5) successfully established the self-supporting skeleton of riprap, but it used spheres to simulate riprap, which cannot reflect the angular characteristics brought about by the use of crushed stone as riprap material in real engineering.

[0004] In summary, current numerical simulations of riprap concrete lack methods for establishing mesoscopic models that can reflect the true physical properties. It is necessary to develop three-dimensional multiphase numerical models of riprap concrete at the mesoscopic level that can characterize the random distribution of riprap and the self-supporting skeleton properties. Summary of the Invention

[0005] This disclosure aims to address at least one of the technical problems existing in the prior art.

[0006] Therefore, the three-dimensional mesoscopic numerical model of riprap concrete provided in the first aspect of this disclosure includes:

[0007] The rockfill unit is the smallest unit obtained by gravity compaction of rockfill simulated by random aggregate of convex polyhedra in the sample space and local surface mesh adjustment of rockfill with potential contact to form a self-supporting skeleton of rockfill, and then dividing the self-supporting skeleton of rockfill into a volume mesh.

[0008] a contact surface, wherein the contact surface is only arranged at the interface between two rockfill blocks with potential contact, and is composed of a first contact surface and a second contact surface that can slide relatively; the first contact surface is generated by performing local surface mesh adjustment on the rockfill blocks with potential contact, and the second contact surface is obtained by copying the first contact surface;

[0009] self-compacting concrete elements, wherein the self-compacting concrete elements are the smallest finite elements obtained by forming self-compacting concrete in a region of the sample space excluding the self-supporting skeleton of the rockfill, and then performing volume meshing on the self-compacting concrete; and

[0010] interfacial transition zone elements, wherein the interfacial transition zone elements only exist at the interface between the rockfill elements and the self-compacting concrete elements, and are simulated by six-node interface elements with no thickness or a certain thickness.

[0011] In some embodiments, the given space is a space formed by stretching the sample space; and / or

[0012] the rockfill elements are solid finite elements or convex polyhedron scaled boundary finite elements.

[0013] In a second aspect of the present disclosure, a construction method of a three-dimensional mesoscopic numerical model of rockfill concrete is provided, comprising:

[0014] Step S1: generating convex polyhedral random aggregates for characterizing rockfill in rockfill concrete in a sample space, simulating a gravity compaction packing process to complete random placement of rockfill, and forming corresponding surface meshes on the surfaces of each rockfill;

[0015] Step S2: detecting rockfill surface meshes with potential contact, performing local surface mesh adjustment thereon to generate contact surfaces, and obtaining a self-supporting rockfill skeleton, specifically comprising the following steps:

[0016] Step S201: for packed rockfill i and rockfill j, detecting whether there is potential contact between rockfill i and rockfill j, 1≤i<N, i<j≤N, N is the total number of packed rockfill blocks; if there is no potential contact between rockfill i and rockfill j, performing step S205, otherwise, for rockfill i and rockfill j with potential contact, performing step S202;

[0017] Step S202: calculating local adjustment surfaces and potential contact points of rockfill i and rockfill j, wherein the potential contact points are defined as shared contact surface control points of the two contacting rockfill blocks, and the local adjustment surfaces are defined as surface meshes that need to be regenerated and adjusted due to contact influence on the rockfill;

[0018] Step S203: Merge all potential contact points between pile i and pile j whose distance is less than the third distance threshold Δd3 to form a set {P′}. Determine two closed boundary control lines with an inner and outer distribution based on the set {P′}. The boundary control line located in the inner circle is defined as the contact boundary line. Pile i and pile j share a single contact boundary line to define the boundary of the contact surface between pile i and pile j. The boundary control line located in the outer circle is defined as the local adjustment boundary line to define the boundary of the local adjustment area of ​​pile i and the boundary of the local adjustment area of ​​pile j, respectively.

[0019] Step S204: Enumerate all potential connection schemes of the triangular mesh formed between the contact boundary lines of pile i and pile j constructed in step S203, the local adjustment boundary line of pile i, and the local adjustment boundary line of pile j. Calculate the geometric quality of all triangular meshes and determine the optimal local adjustment mesh connection scheme. Calculate the midpoint of the region enclosed by the contact boundary line corresponding to the optimal local adjustment mesh connection scheme. Connect each node of the contact boundary line to the midpoint of the contact boundary line in sequence to generate the first contact mesh of pile i. Copy the first contact mesh and flip its normal to obtain the second contact mesh, which is then assigned to pile j.

[0020] Step S205: Enumerate the remaining piles of stones after stacking, and repeat steps S201 to S204 until the potential contact detection of all piles of stones after stacking and the local surface mesh adjustment and contact surface mesh generation of the piles of stones with potential contact are completed, so as to obtain the self-supporting skeleton of the piles.

[0021] Step S3: Under the constraints of the self-supporting skeleton of the riprap and the boundary of the sample space, the riprap, self-compacting concrete and interface transition zone are discretized by a three-dimensional volume mesh to obtain a three-dimensional microscopic numerical model of the riprap concrete.

[0022] In some embodiments, step S201, the specific steps for detecting whether there is potential contact between pile i and pile j include:

[0023] Based on the mesh geometry of pile i and pile j after gravity compaction, the coordinate difference between the centroids of pile i and pile j is calculated as the relative distance between them. If the relative distance between pile i and pile j is greater than the pile spacing threshold D, it is considered that there is no potential contact between pile i and pile j. If the relative distance between pile i and pile j is less than or equal to the pile spacing threshold D, the minimum relative distance of all face meshes of pile i and pile j is further detected by enumeration. If there is a case where the minimum relative distance of face meshes is less than the first distance threshold Δd1, it is considered that there is potential contact between pile i and pile j; otherwise, it is considered that there is no potential contact between pile i and pile j.

[0024] In some embodiments, step S202 specifically includes:

[0025] Construct the set of potential contact points {P} between riprap i and riprap j, and the set of local adjustment surfaces {S} of riprap i. i} and the set of local adjustment surfaces of the riprap j {S j}, initialize {P}, {S} i} and {S j} are all empty sets;

[0026] Iterate through all the faces and lines containing all the edges of pile i and pile j, calculate the intersection points between pile i and pile j, and construct a set of all the intersection points between pile i and pile j. From the set of intersections Intersections that simultaneously satisfy both the first and second conditions are selected and added as potential contact points between two piles of stones to the potential contact point set between pile i and pile j. The surface mesh of the pile corresponding to the intersection point is then added as a local adjustment surface to the local adjustment surface set of that pile. From the intersection point set... Intersections that satisfy the third condition are selected, and only the surface mesh of the rock pile corresponding to the intersection is selected as a local adjustment surface of that rock pile, without selecting the intersection as a potential contact point between the two rock piles; wherein, the first condition is the intersection point. The distance to the surface grid of the rockfill corresponding to the intersection point is less than the first distance threshold Δd1; the second condition is the intersection point. The distance to the edge of the rock pile corresponding to the intersection point is less than the first distance threshold Δd1; the third condition is the intersection point. The distance to the face grid of the rock pile corresponding to the intersection point exceeds the first distance threshold Δd1, but the distance between the endpoint of the edge of the rock pile where the intersection point is located and the face grid of the rock pile corresponding to the intersection point is less than the second distance threshold Δd2.

[0027] In some embodiments, in step S203,

[0028] The contact boundary line is constructed according to the following steps: Calculate the number of potential contact points in the set {P′}. If the number of potential contact points in {P′} is less than 3, set the normal direction of the potential contact surface of pile i and pile j to the direction of the line connecting the centroids of pile i and pile j, and generate an equilateral triangle with a side length of Δd3 based on quaternions. Add each node of this equilateral triangle to the set {P′} to obtain the set {P″}. If the number of potential contact points in the set {P′} is greater than or equal to 3, obtain the potential contact surface of pile i and pile j through principal component analysis, and project all potential contact points in the set {P′} onto the contact surface of pile i and pile j obtained through principal component analysis to obtain the set {P″}. Perform convex hull calculation on the set {P″} to obtain the contact boundary line shared by pile i and pile j.

[0029] The local adjustment boundary line is constructed according to the following steps: Triangular face meshes that share two sides with the local adjustment surface are extracted from pile i and pile j respectively, and these meshes are added to the local adjustment surface set {S} of pile i respectively. i The set of local adjustment surfaces {S} and riprap j j In}, respectively in the local adjustment surface set {S i} and {S j Extract the nodes located at the edge of the face mesh to form the local adjustment face node set {P} of the pile i. Si The set of local adjustment surface nodes {P} and boulders j. Sj}, in clockwise order, respectively {P Si} and {P Sj The edge nodes of the surface mesh in} connect to construct the local adjustment boundary lines of pile i and pile j.

[0030] In some embodiments, in step S204,

[0031] The optimal local adjustment surface mesh connection scheme is found based on the depth-first search method, which is the local adjustment surface mesh connection scheme with the best overall surface mesh quality. The connection scheme needs to satisfy the following two conditions at the same time: (1) The angle between the outward normal direction of all triangular surface meshes and the direction of the line connecting the centroid of the riprap and the centroid of the triangular surface mesh does not exceed 90 degrees; (2) Calculate the geometric quality Q of the triangular surface mesh with the worst geometric quality among all local adjustment surface mesh connection schemes. The optimal local adjustment surface mesh connection scheme needs to ensure that its corresponding Q value is the highest among all schemes.

[0032] The angle between the normal direction of the first contact surface grid and the direction of the line connecting the centroid of the pile i and the midpoint of the contact boundary line does not exceed 90 degrees.

[0033] In some embodiments, step S205 further includes: extracting all nodes in the riprap surface mesh whose distance from the boundary surface of the sample space is less than the fourth distance threshold Δd4, projecting them onto the boundary surface of the sample space to form the exposed riprap boundary surface mesh in the three-dimensional mesoscopic numerical model of the riprap concrete, and adjusting the riprap ratio by fixing the contact surface mesh and the riprap boundary surface mesh and scaling the remaining meshes at the center.

[0034] In some embodiments, step S3, the step of discretizing the self-compacting concrete using a three-dimensional volume mesh, specifically includes:

[0035] The sample space boundary is cut using a riprap boundary surface mesh located on the sample space boundary, and the cut sample space boundary is discretized using a two-dimensional surface mesh. Then, the sample space boundary mesh and the riprap surface mesh are meshed together to form a doubly connected domain, which serves as the control boundary for discretizing the three-dimensional volume mesh of self-compacting concrete. The internal space of the doubly connected domain is discretized using the three-dimensional volume mesh to obtain the volume mesh of self-compacting concrete.

[0036] A third aspect of this disclosure provides an apparatus for constructing a method based on any embodiment of the second aspect of this disclosure, comprising:

[0037] The first module is configured to generate convex polyhedral random aggregates in the sample space to characterize the riprap in riprap concrete, simulate the gravity compaction process to complete the random placement of the riprap, and form corresponding surface grids on the surface of each riprap.

[0038] The second module is configured to detect the mesh of the rockfill surface with potential contact, adjust the local mesh of the surface to generate the contact surface, and obtain the self-supporting skeleton of the rockfill.

[0039] The third module is configured to discretize the riprap, self-compacting concrete, and interface transition zone using a three-dimensional volume mesh under the constraints of the self-supporting skeleton of the riprap and the boundary of the sample space, thereby obtaining a three-dimensional microscopic numerical model of the riprap concrete.

[0040] The three-dimensional microscopic numerical model, construction method, and apparatus for riprap concrete provided in this disclosure have the following characteristics and beneficial effects:

[0041] This embodiment considers that crushed stone is commonly used as the raw material for riprap concrete. Based on a polyhedral random aggregate model, it generates a microscopic numerical model of the riprap raw materials for riprap concrete. This fully utilizes the geometric characteristics of the polyhedral random aggregate, characterizing the angularity of the crushed stone and exhibiting more realistic physical properties compared to spherical aggregate. Simultaneously, it simulates the compaction process under gravity, realizing the random placement of the riprap, which characterizes the actual riprap placement process, forming stable riprap interactions and reflecting the characteristics of this novel riprap concrete process. This embodiment, based on a polyhedral random aggregate model, constructs a microscopic model that accurately reflects the characteristics of riprap concrete, a first and pioneering approach to numerical simulation of riprap concrete.

[0042] This embodiment discloses a complete set of methods for local mesh adjustment of riprap, which can automatically detect riprap meshes with potential contact and adjust the local mesh according to the optimal strategy. The generated riprap contact surfaces and riprap boundary surfaces can fully characterize the self-supporting skeleton characteristics of polyhedral riprap. In addition, after fixing the meshes of the riprap contact surfaces and riprap boundary surfaces, the algorithm for scaling the center of each riprap mesh can effectively control the riprap ratio of the riprap concrete mesoscopic model without affecting the self-supporting skeleton. Based on the polyhedral random aggregate model, this automated local mesh adjustment algorithm for riprap can quickly generate a large number of randomly placed riprap concrete mesoscopic numerical models. Large-scale riprap concrete mesoscopic numerical simulations can be performed through Monte Carlo simulations to explore the mechanical properties of riprap concrete under different factors.

[0043] The three-dimensional, three-phase microscopic numerical model of riprap concrete established in this embodiment can fully characterize the properties of each component of riprap concrete, including riprap, the interface transition zone, and self-compacting concrete. The nonlinear contact between the riprap components is characterized by a matched contact mesh. As a microscopically heterogeneous composite material, riprap concrete uses different element types to discretize each phase, allowing for flexible utilization of the characteristics of various element types when calculating nonlinear behaviors such as damage and cracking. The interface transition zone is discretized using viscous interface elements, which matches the actual microstructure. Furthermore, by fully utilizing the characteristic that the local mesh of the riprap remains a convex polyhedron after adjustment, a single scaled boundary finite element can be used to characterize a riprap component, greatly reducing the degrees of freedom of the riprap concrete microscopic model and achieving high computational efficiency. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of a three-dimensional microscopic numerical model of riprap concrete provided in the first aspect of this disclosure;

[0045] Figure 2 This is an overall flowchart of the method for constructing a three-dimensional microscopic numerical model of riprap concrete provided in the second aspect of this disclosure;

[0046] Figure 3 This is the compaction process of random aggregates in a polyhedral concrete structure under gravity in the construction method provided by the second aspect of this disclosure.

[0047] Figure 4 This is a schematic diagram illustrating the potential contact detection of a pile of stacked rocks using a construction method provided in the second aspect of this disclosure.

[0048] Figure 5 This is the calculation process of the local adjustment surface and potential contact points of a rockfill with potential contact provided in the second aspect embodiment of this disclosure;

[0049] Figure 6 This is a schematic diagram of the contact boundary line and the local adjustment boundary line of the local adjustment zone for a grid of potentially contacting riprap provided by the construction method of the second aspect of this disclosure;

[0050] Figure 7 The construction method provided in the second aspect of this disclosure generates an optimal mesh based on a local adjustment zone of a mesh with potential contact riprap.

[0051] Figure 8 This is a schematic diagram of the composition and distribution of the three-phase medium in the three-dimensional microscopic numerical model of riprap concrete provided in the second aspect embodiment of this disclosure.

[0052] Figure 9 This is a schematic diagram of the structure of an electronic device provided in a third aspect embodiment of the present disclosure. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0054] Conversely, this application covers any alternatives, modifications, equivalent methods, and schemes made within the spirit and scope of this application as defined by the claims. Furthermore, to provide the public with a better understanding of this application, certain specific details are described in detail below. However, this application can be fully understood by those skilled in the art even without these detailed descriptions.

[0055] See Figure 1 This is a structural schematic diagram of a three-dimensional microscopic numerical model of riprap concrete provided in the first aspect of this disclosure. The model includes:

[0056] The rockfill unit 10 is the smallest unit obtained by gravity compaction of rockfill simulated by random aggregate of convex polyhedra in the sample space and local surface mesh adjustment of rockfill with potential contact to form a self-supporting skeleton of rockfill, and then dividing the self-supporting skeleton of rockfill into a volume mesh.

[0057] The contact surface 20 is only set at the interface of two piles of rocks that have potential contact. It consists of a first contact surface and a second contact surface that can slide relative to each other. By detecting piles of rocks that have potential contact and adjusting the local surface mesh of the piles of rocks that have potential contact, the surface mesh of the piles at the contact position is matched with each other, thereby generating the first contact surface. The second contact surface is obtained by copying the first contact surface.

[0058] Self-compacting concrete element 30, wherein the self-compacting concrete element is the smallest finite element obtained by forming self-compacting concrete in the area where riprap has been removed within the sample space, and then performing volume mesh generation on the self-compacting concrete; and

[0059] Interface transition zone unit 40, which exists only at the interface between the riprap unit 10 and the self-compacting concrete unit 30, is simulated by a six-node interface unit with no thickness or a certain thickness.

[0060] Optionally, in order to generate convex polyhedral random aggregates that can meet the target riprap ratio for gravity compaction, the sample space of the simulated riprap concrete is first stretched in the vertical direction (e.g., stretched by 50%) to form a given space.

[0061] Optionally, a single riprap element 10 can be discretized using multiple solid finite element elements (such as C3D4) or by a single convex polyhedral scaled boundary finite element. Compared to solid finite element elements, convex polyhedral scaled boundary finite element elements can reduce the number of degrees of freedom in the three-dimensional mesoscopic numerical model of riprap concrete, thereby improving the efficiency of numerical calculation. However, C3D4 elements have strong flexibility in discretizing complex structures. Therefore, the specific type of riprap element can be selected according to actual needs. In this embodiment, the convex polyhedral scaled boundary finite element is preferred as the riprap element 10.

[0062] Optionally, two piles of rocks that are embedded or whose distance is less than a set threshold are identified as potentially contacting piles. By adjusting the local surface mesh of the piles identified as potentially contacting piles, the surface meshes of the piles at the contact location are matched to each other, thereby generating a matching pile contact surface that conforms to the actual geometry, resulting in higher mesh quality and improved stability of the contact calculation.

[0063] It is understood that the three-dimensional mesoscopic numerical model of riprap concrete provided in the first aspect of this disclosure directly simulates riprap using a convex polyhedral random aggregate model, which can fully characterize the angular characteristics of crushed stone; by adjusting the local surface mesh, a self-supporting skeleton of riprap with matching contact surfaces is generated, which conforms to the real interaction characteristics of riprap, and the riprap ratio can be adjusted by controlling the geometry of the riprap. Existing three-dimensional numerical models of riprap concrete cannot accurately express these characteristics at the same time.

[0064] See Figure 2 The above flowchart illustrates the overall process for constructing a three-dimensional microscopic numerical model of riprap concrete, which mainly includes three steps:

[0065] Step S1: Generate convex polyhedral random aggregates in the sample space to characterize the riprap in riprap concrete, and simulate the gravity compaction process to complete the random placement of the riprap.

[0066] In step S1 of one embodiment of this application, in order to generate convex polyhedral random aggregates that can meet the target riprap ratio for gravity compaction, the sample space of the simulated riprap concrete is stretched by 50% in the vertical direction to form a given space. Combining the riprap particle size distribution used in riprap concrete engineering and the actual riprap ratio, convex polyhedral random aggregates with corresponding riprap particle size distributions that do not contact each other are generated within the given space. The boundary of the given space is constrained by rigid surfaces, and the convex polyhedral random aggregates are discretized using volume meshes. The compaction process of the convex polyhedral random aggregates under gravity is simulated using the finite element explicit dynamics method. After gravity compaction is completed, the surface meshes corresponding to the volume meshes of each random aggregate are extracted to characterize the geometry of the convex polyhedral riprap. See also... Figure 3 , represents the distribution of convex polyhedral random aggregates in riprap concrete before and after gravity loading.

[0067] Optionally, the random aggregate self-weight accumulation process under gravity is simulated using the Explicit / Dynamic module of the commercial finite element software Abaqus. A general contact module is selected to simulate the mutual contact of convex polyhedral random aggregates, ensuring that each aggregate is in a relatively compact and stable accumulation state. Since the penalty function method is used to simulate the contact between aggregates during gravity compaction, and there are limitations in computational accuracy, the meshes of the contacting aggregate surfaces will be inter-embedded, and the mesh node positions of different contacting aggregates will differ, meaning the contact positions are mismatched meshes. Due to the mismatched contact, it is impossible to generate the interface transition zone and self-compacting concrete mesh based on the existing aggregate mesh information. Therefore, the local surface mesh adjustment process defined in step S2 is required to generate a matching contact surface mesh.

[0068] Step S2: detecting rockfill surface meshes with potential contact, automatically performing optimal local surface mesh adjustment, generating contact surfaces, and obtaining a self-supporting rockfill skeleton.

[0069] In one embodiment of the present application, in order to ensure that the characteristics of the self-supporting rockfill skeleton can be characterized before the placement of high-performance self-compacting concrete for rockfill concrete, the automated local rockfill surface mesh adjustment method defined in step S2 is adopted, so that when adjacent rockfills are mutually embedded or have tiny gaps, the surface mesh can be automatically adjusted to generate a matching contact mesh. Based on the adjusted rockfill surface mesh, the morphology of the self-compacting concrete and the interfacial transition zone can be determined. The potential contact detection of rockfill and the adjustment of local contact surface mesh are implemented through the following five steps.

[0070] Step S201: for the accumulated rockfill i and rockfill j, detecting whether there is potential contact between rockfill i and rockfill j, wherein 1≤i<N, i<j≤N, and N is the total number of accumulated rockfills; if there is no potential contact between rockfill i and rockfill j, step S205 is executed; otherwise, if there is potential contact between rockfill i and rockfill j, the procedure proceeds to step S202 to calculate the potential contact point between rockfill i and rockfill j, the local adjustment surface of rockfill i and the local adjustment surface of rockfill j, wherein the potential contact point is defined as a contact surface control point shared by two contacted rockfills, and the local adjustment surface is defined as a rockfill surface mesh that is affected by the contact and needs to be adjusted.

[0071] Further, the specific steps for judging whether there is potential contact between rockfill i and rockfill j comprise:

[0072] First, as preliminary rapid detection, based on the mesh geometric information of rockfill i and rockfill j after gravity dense accumulation, calculating the coordinates of the centers of gravity of the two rockfills, and determining the relative distance L between the two rockfills through the difference of the center of gravity coordinates. If the relative distance L exceeds the rockfill spacing threshold D, it is determined that there is no potential contact between rockfill i and rockfill j, and i and j are updated to detect whether there is potential contact between the next pair of rockfills, thereby greatly reducing the calculation amount; optionally, the rockfill spacing threshold D can generally be 1.5 times the maximum particle size of rockfills in the sample space; if the relative distance L between the two rockfills is less than the rockfill spacing threshold D, all surface meshes of rockfill i and rockfill j are extracted respectively, and the minimum relative distance of all surface meshes of rockfill i and rockfill j is detected sequentially by an enumeration method. If there exists a condition that the minimum relative distance of surface meshes is less than the first distance threshold Δd1, it is determined that there is potential contact between rockfill i and rockfill j, and the procedure proceeds to step S202; if there is no condition that the minimum relative distance of surface meshes is less than the first distance threshold Δd1, it is determined that there is no potential contact between rockfill i and rockfill j, and i and j are updated to detect whether there is potential contact between the next pair of rockfills.

[0073] See Figure 4This is a schematic diagram of potential contact detection of the surface mesh of the piled rubble. Pile i and pile j meet the conditions for potential contact, namely, the distance between the centroids of pile i and pile j does not exceed the pile spacing threshold D, and there is a case where the minimum relative distance between the surface mesh of pile i and the surface mesh of pile j is less than Δd1.

[0074] Step S202: Calculate the local adjustment surfaces and potential contact points of riprap i and riprap j. Potential contact points are defined as control points shared by the two contacting riprap surfaces. Local adjustment surfaces are defined as the surface meshes that need to be regenerated for adjustment due to contact effects. This step requires calculating the local adjustment surfaces of riprap i and riprap j twice, with the potential contact points shared in each step. This includes: constructing the set of potential contact points {P} between riprap i and riprap j, and the set of local adjustment surfaces {S} of riprap i. i} and the set of local adjustment surfaces of the riprap j {S j}, initialize {P}, {S} i} and {S j} are all empty sets; traverse all faces and all edges of pile i and pile j, calculate the intersection points between pile i and pile j, and form the intersection point set between pile i and pile j with all the obtained intersection points. From the set of intersections Intersections that simultaneously satisfy both the first and second conditions are selected and added as potential contact points between two piles of stones to the potential contact point set between pile i and pile j. The surface mesh of the pile corresponding to the intersection point is then added as a local adjustment surface to the local adjustment surface set of that pile. From the intersection point set... Intersections that satisfy the third condition are selected. Only the surface mesh of the rock pile corresponding to the intersection point is selected as a local adjustment surface of that rock pile, and the intersection point itself is not selected as a potential contact point between the two rock piles. The first condition is the intersection point. The distance to the surface grid of the rockfill corresponding to the intersection point is less than the first distance threshold Δd1; the second condition is the intersection point. The distance to the edge of the rock pile corresponding to the intersection point is less than the first distance threshold Δd1; the third condition is the intersection point. The distance to the face grid of the rock pile corresponding to the intersection point exceeds the first distance threshold Δd1, but the distance between the endpoint of the edge of the rock pile where the intersection point is located and the face grid of the rock pile corresponding to the intersection point is less than the second distance threshold Δd2.

[0075] More specifically, taking the calculation of the local adjustment surface of pile j as an example, firstly, each edge of the face mesh of pile i and each face mesh of pile j are extracted. For any edge of pile i, it is extended into a straight line, and the intersection point of this straight line with the plane containing each face mesh of pile j is obtained. According to the intersection Considering the spatial location of the rockfill j, the following two cases are used to determine the set of local adjustment surfaces {S}. j} and the set of potential contact points {P} between pile i and pile j.

[0076] Case 1: Both Condition 1 and Condition 2 are satisfied simultaneously. Condition 1 (used to limit the intersection point) Constraints on the positional relationship between the surface mesh of the boulders j and the rubble mound: intersection points With a certain face grid S of the pile j j The distance between them is equal to 0, which is the intersection point. The grid S falls on one side of the pile j. j Up, or intersection With a certain face grid S of the pile j j The distance between them is not equal to 0 but is less than Δd1; Condition 2 (used to limit the intersection point) (Constraints on the positional relationship between the corresponding edges of the boulders i and the pile i): intersection point The corresponding edge E of the pile i i The distance between them is equal to 0, which is the intersection point. The corresponding edge E that falls on pile i i Up, or intersection The corresponding edge E of the pile i i The distance between them is not equal to 0 but is less than Δd1. When both conditions one and two are satisfied, the intersection point will be... Add the potential contact point set {P} between pile j and pile i, and add the surface mesh corresponding to pile j to the local adjustment surface set {S} of pile j. j}middle.

[0077] Case 2: Satisfies condition 3 (a constraint used to define the positional relationship between the endpoints of the edge of pile i and the face of pile j), that is, although the intersection point With a certain face grid S of the pile j j The distance between them exceeds Δd1, but the corresponding edge E of pile i i The endpoints of the rock pile j and a certain face of the grid S j If the distance between them is less than Δd2, then the mesh S on one side of the pile j will be... j Add the set of local adjustment surfaces {S} to the pile j j In the middle, but the intersection point It is not considered a potential contact point between pile j and pile i.

[0078] See Figure 5 This diagram illustrates the local adjustment surface of rock pile j under scenarios 1 and 2, as well as the process for determining potential contact points between rock pile i and rock pile j. In the diagram, "·" represents the endpoint of a rock pile edge, dashed lines represent the straight lines containing the edges of the rock piles, and "Δ" represents the intersection of two rock piles. E represents the face grid of the riprap. i1 E i2 E i3 Let S be the three sides of the pile i. j1 S j2 S j3 For the three-faced mesh of the rubble pile j, E i1 With S j1 The intersection point P1 falls exactly on the surface mesh S j1 The intersection point P1 and edge E i1 The distance between them is less than Δd1 (i.e., case one), E i2 With S j2 The intersection point P2 falls exactly on edge E. i2 The intersection point P2 and the surface mesh S j2 The distance between them is less than Δd1 (i.e., case one), E i3 With S j3 The intersection point P3 does not fall on edge E i3 It did not fall on the surface grid S. j3 Above, but the intersection point P3 and the surface mesh S j3 The distance between them is greater than Δd1, but the surface mesh S j3 With edge E i3 The distance between one of the endpoints is less than Δd2, therefore, the surface mesh S of the rock pile j is... j1 S j2 and S j3 Add the set of local adjustment surfaces {S} to the pile j j In the process, only intersection points P1 and P2 are added to the set of potential contact points {P} between pile i and pile j. The determination of the local adjustment surface of pile i follows the same steps: each edge in the mesh of pile j is extracted and extended; based on the spatial position of the intersection points, the local adjustment surface of pile i is determined considering the two cases mentioned above, and the remaining potential contact nodes between pile i and pile j are added. Finally, the set of potential contact points {P} between pile i and pile j and the set of local adjustment surfaces {S} of pile i are obtained. i} and the set of local adjustment surfaces of the riprap j {S j Then proceed to step S203.

[0079] Step S203: Construct the inner and outer boundary control lines of the local mesh adjustment areas of rock pile i and rock pile j.

[0080] Merge all potential contact points in the potential contact point set {P} between pile i and pile j whose distance is less than the third distance threshold Δd3 to form a new potential contact point set {P′}. The specific merging method is not limited, as long as the distance between any two points in {P′} is not less than Δd3. Based on the new potential contact point set {P′}, determine two closed boundary control lines distributed in an inner and outer circle. The boundary control line located in the inner circle is defined as the contact boundary line, shared by pile i and pile j, used to define the boundary of the contact surface between them. The boundary control line located in the outer circle is defined as the local adjustment boundary line, used to define the boundaries of the local adjustment areas of pile i and pile j, respectively. The specific construction steps are as follows:

[0081] a. Contact Boundary Line: Calculate the number of potential contact points in the new potential contact point set {P′}. If the number of potential contact points in {P′} is less than 3, set the normal direction of the potential contact surface between pile i and pile j to the direction of the line connecting the centroids of pile i and pile j. Generate an equilateral triangle with side length Δd3 based on quaternions, and add each node of this equilateral triangle to the new potential contact point set {P′} to obtain the updated potential contact point set {P″}. If the number of potential contact points in {P′} is greater than or equal to 3, obtain the potential contact surface between pile i and pile j through principal component analysis. Project all potential contact points in the new potential contact point set {P′} onto the contact surface between pile i and pile j obtained through principal component analysis to obtain the updated potential contact point set {P″}. Finally, perform convex hull calculation on the updated potential contact point set {P″} to obtain the contact boundary line shared by pile i and pile j.

[0082] b. Local Adjustment Boundary Lines: To optimize the shape of the regions formed by the local adjustment surfaces of pile i and pile j, the triangular meshes that share two sides with the local adjustment surfaces in pile i and pile j are extracted respectively, and added to the local adjustment surface set {S}. i} and {S j In}, respectively in the local adjustment surface set {S i} and {S j Extract the nodes located at the edge of the face mesh to form the local adjustment face node set {P} of the pile i. Si The set of local adjustment surface nodes {P} and boulders j. Sj}, in clockwise order, respectively {P Si} and {P Sj The edge nodes of the surface mesh in} connect to construct the local adjustment boundary lines of pile i and pile j.

[0083] See Figure 6This is a schematic diagram showing the generation of the contact boundary line and the local adjustment boundary line of the mesh local adjustment zone for boulders i and j. The contact boundary line is shared by boulders i and j, while the local adjustment boundary line is the mesh control line of the local adjustment zone generated separately by boulders i and j based on their own meshes.

[0084] Step S204: Generate the optimal surface mesh for the local adjustment zones of rockfill i and rockfill j based on the contact boundary line and the local adjustment boundary line.

[0085] Enumerate all potential connection schemes of the triangular mesh formed between the contact boundary lines of pile i and pile j constructed in step S203, the local adjustment boundary line of pile i, and the local adjustment boundary line of pile j. Calculate the geometric quality of all triangular meshes. The closer the shape of the triangular mesh is to an equilateral triangle, the higher its mesh quality. Find the local adjustment mesh connection scheme with the best overall mesh quality based on the depth-first search method (DFS). This connection scheme needs to satisfy the following two conditions simultaneously: (1) The angle between the outward normal direction of all triangular meshes and the direction of the line connecting the centroid of the pile and the centroid of the triangular mesh does not exceed 90 degrees (that is, take the outward normal direction of all triangular meshes as the first direction, take the line connecting the centroid of the pile and the centroid of the triangular mesh as the second direction, and the angle between the first direction and the second direction does not exceed 90 degrees); (2) Calculate the geometric quality Q of the triangular mesh with the worst geometric quality among all local adjustment mesh connection schemes. The optimal local adjustment mesh connection scheme needs to ensure that its corresponding Q value is the highest among all schemes.

[0086] After determining the optimal local adjustment surface mesh connection scheme, the midpoint of the region enclosed by the contact boundary line is calculated. Each node of the contact boundary line is connected to the midpoint of the contact boundary line in turn to generate the first contact surface mesh of the rock pile i. It is necessary to ensure that the angle between the normal direction of the first contact surface mesh and the direction of the line connecting the centroid of rock pile i and the midpoint of the contact boundary line does not exceed 90 degrees. After copying the first contact surface mesh, the normal direction is flipped to obtain a new second contact surface mesh, which is then assigned to rock pile j.

[0087] Step S205: Enumerate the remaining piles of stones after stacking, and repeat steps S201 to S204 continuously until the potential contact detection of all piles of stones after stacking is completed and the local surface mesh adjustment and contact surface mesh generation of the piles of stones with potential contact are completed, and the self-supporting skeleton of the piles is obtained. At this time, the contact surface mesh of all piles of stones with potential contact has been automatically re-divided.

[0088] Furthermore, to simplify the construction of the 3D mesoscopic numerical model of riprap concrete, all nodes in the riprap surface mesh whose distance to the boundary surface of the sample space is less than the fourth distance threshold Δd4 are extracted and projected onto the boundary surface of the sample space, forming the exposed riprap boundary surface mesh in the 3D mesoscopic numerical model of riprap concrete. The riprap ratio of the 3D mesoscopic sample of riprap concrete can also be determined by fixing the contact surface mesh and the riprap boundary surface mesh, and scaling the remaining meshes through the center.

[0089] See Figure 7 This is the result of adjusting the mesh of the local surface of the rockfill with potential contact in one embodiment of this application, forming a matching rockfill contact surface and rockfill boundary surface, which characterizes the complete self-supporting skeleton characteristics of the rockfill.

[0090] During local surface mesh adjustment, the values ​​of distance thresholds Δd1, Δd2, Δd3, and Δd4 are determined by the size of the rockfill mesh. These values ​​need to be specifically chosen based on the actual situation during local surface mesh adjustment. Distance thresholds that are too large or too small may affect the position and number of locally adjusted surfaces, as well as the distribution of potential contact points, leading to distortion or low quality of the adjusted surface mesh.

[0091] As an example, when the original riprap mesh is of high quality and the mesh size is uniform, it is recommended to use Δd1, which is equivalent to one-tenth of the average size of the riprap mesh; Δd2 and Δd3, which are equivalent to one-fifth of the average size of the riprap mesh; and Δd4, which is equivalent to one-tenth of the average size of the riprap mesh, to ensure the best results.

[0092] Step S3: Discretization of each phase medium in the three-dimensional microscopic numerical model of riprap concrete.

[0093] At a microscale, riprap concrete can be considered a three-phase composite material consisting of self-compacting concrete, an interfacial transition zone, and riprap. The adjusted self-supporting riprap mesh controls the discretization of each medium; after the self-supporting riprap mesh is established, all riprap is represented by a surface mesh. Under the constraints of the self-supporting riprap mesh and the sample space boundary, the three-phase media—riprap, self-compacting concrete, and the interfacial transition zone—can be discretized using a three-dimensional volume mesh. The specific steps include:

[0094] Step S301: Discretization of the volumetric mesh of self-compacting concrete. First, the sample space boundary is cut using the surface mesh of the riprap boundary located on the sample space boundary. The cut sample space boundary is then discretized using a two-dimensional surface mesh. Next, the sample space boundary mesh and the surface mesh of the riprap are meshed together to form a biconnected domain, which serves as the control boundary for the three-dimensional volumetric mesh discretization of the self-compacting concrete. Based on the biconnected domain formed by the surface mesh, the internal space of the biconnected domain is discretized using a three-dimensional volumetric mesh to obtain the volumetric mesh of the self-compacting concrete, thus completing the volumetric mesh discretization of the self-compacting concrete.

[0095] As an embodiment of this application, a mesoscopic numerical simulation of riprap concrete is conducted in ABAQUS. Considering the flexibility of C3D4 elements in discretizing complex structures, the self-compacting concrete can be directly discretized using C3D4 elements based on the biconnected domain composed of the riprap surface mesh adjusted by the local surface mesh and the boundary surface mesh of the sample space.

[0096] Step S302: Discretization of the volume mesh in the interface transition zone. The riprap surface mesh adjusted based on the local surface mesh plays a controlling role in the 3D discretization of both the interface transition zone and the riprap body. All nodes on the surface mesh of the riprap body except for the contact area are copied, and according to the node arrangement rules of solid elements, 6-node viscous interface elements with zero thickness or a certain thickness are constructed between the self-compacting concrete and the riprap to characterize the interface transition zone. The viscous interface elements are controlled by the corresponding normal and shear traction separation laws.

[0097] Step S303: Discretization of the volumetric mesh of the riprap. Under the control of the surface mesh of the riprap, each riprap block can be discretized directly through the volumetric mesh, thereby completing the construction of the three-dimensional microscopic model of the riprap concrete.

[0098] As an embodiment of this application, each piece of riprap can also be discretized in ABAQUS using C3D4 elements. To reduce the number of degrees of freedom in the mesoscopic numerical model and improve the efficiency of numerical computation, each riprap aggregate with a convex polyhedral geometry can also be discretized using a polyhedral scaled boundary finite element. Given that all elements in the model, including the finite elements for discrete self-compacting concrete, the viscous interface elements for the discrete interface transition zone, and the polyhedral scaled boundary finite element for discrete riprap, are solved node-based, the element stiffness matrix assembly method of this finite element-scaled boundary finite element coupled model is the same as that of the traditional finite element method. The Standard solver of the commercial finite element software ABAQUS can be used to numerically simulate the riprap concrete mesoscopic coupled model.

[0099] See Figure 8This is a schematic diagram of the three-phase medium composition in the three-dimensional microscopic numerical model of riprap concrete, including three components: riprap, interface transition zone and self-compacting concrete, and shows the spatial distribution of the contact surface.

[0100] The apparatus for establishing a three-dimensional microscopic numerical model of riprap concrete provided in the third aspect embodiment of this disclosure includes:

[0101] The first module is configured to generate convex polyhedral random aggregates in the sample space to characterize the riprap in riprap concrete, simulate the gravity compaction process to complete the random placement of the riprap, and form corresponding surface grids on the surface of each riprap.

[0102] The second module is configured to detect the mesh of the rockfill surface with potential contact, adjust the local mesh of the surface to generate the contact surface, and obtain the self-supporting skeleton of the rockfill.

[0103] The third module is configured to discretize the riprap, self-compacting concrete, and interface transition zone using a three-dimensional volume mesh under the constraints of the self-supporting skeleton of the riprap and the boundary of the sample space, thereby obtaining a three-dimensional microscopic numerical model of the riprap concrete.

[0104] It should be noted that the aforementioned explanation of the embodiment of a method for constructing a three-dimensional microscopic numerical model of riprap concrete also applies to the device for constructing a three-dimensional microscopic numerical model of riprap concrete in this embodiment, and will not be repeated here.

[0105] To implement the above embodiments, this disclosure also proposes a computer-readable storage medium storing a computer program that is executed by a processor to perform the method for constructing a three-dimensional micro-numerical model of riprap concrete according to the above embodiments.

[0106] The following is for reference. Figure 9 The diagram illustrates a structural schematic of an electronic device suitable for implementing embodiments of the present disclosure. It should be noted that the electronic devices in the embodiments of the present disclosure may include, but are not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs, desktop computers, and servers. Figure 9 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments disclosed herein.

[0107] like Figure 9As shown, the electronic device may include a processing unit (e.g., a central processing unit, a graphics processing unit, etc.) 101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 102 or a program loaded from a storage device 108 into a random access memory (RAM) 103. The RAM 103 also stores various programs and data required for the operation of the electronic device. The processing unit 101, ROM 102, and RAM 103 are interconnected via a bus 104. An input / output (I / O) interface 105 is also connected to the bus 104.

[0108] Typically, the following devices can be connected to I / O interface 105: input devices 106 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, etc.; output devices 107 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 108 including, for example, magnetic tapes, hard disks, etc.; and communication devices 109. Communication device 109 allows electronic devices to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 9 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown. More or fewer devices may be implemented or have alternatively.

[0109] In particular, according to embodiments of this disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, this embodiment includes a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from a network via communication device 109, or installed from storage device 108, or installed from ROM 102. When the computer program is executed by processing device 101, it performs the functions defined above in the methods of embodiments of this disclosure.

[0110] It should be noted that the computer-readable medium described in this disclosure can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this disclosure, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this disclosure, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wires, optical fibers, RF (radio frequency), etc., or any suitable combination thereof.

[0111] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device.

[0112] The aforementioned computer-readable medium carries one or more programs, which, when executed by the electronic device, cause the electronic device to perform the aforementioned method for constructing a three-dimensional micro-numerical model of riprap concrete.

[0113] Computer program code for performing the operations of this disclosure can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and Python, as well as conventional procedural programming languages ​​such as the "C-" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0114] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0115] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0116] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.

[0117] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0118] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0119] Those skilled in the art will understand that implementing all or part of the steps of the methods in the above embodiments can be accomplished by instructing related hardware through a program. The developed program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0120] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0121] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for constructing a three-dimensional microscopic numerical model of riprap concrete, characterized in that, include: Step S1: Generate convex polyhedral random aggregates in the sample space to characterize the riprap in the riprap concrete, simulate the gravity compaction process to complete the random placement of the riprap, and form corresponding surface grids on the surface of each riprap. Step S2: Detect the mesh of the rockfill surface with potential contact, adjust the local surface mesh to generate the contact surface, and obtain the self-supporting skeleton of the rockfill. This specifically includes the following steps: Step S201: For the piled-up rubble... and pile stones Detecting rock piles and pile stones Is there any potential contact between them? , , The total number of stones after accumulation. and pile stones If there is no potential contact, proceed to step S205; otherwise, for rockfill with potential contact... and pile stones Then proceed to step S202; Step S202: Calculate the rockfill and pile stones The local adjustment surface and potential contact point are defined as follows: the potential contact point is defined as the contact surface control point shared by two contacting riprap, and the local adjustment surface is defined as the surface mesh that needs to be regenerated and adjusted due to the contact effect of the riprap. Step S203: Pile up the stones and pile stones Among all potential contact points, the distance is less than the third distance threshold. Potential contact points are merged to form a set. According to the set Two closed boundary control lines are established, one inside the other. The boundary control line located in the inner circle is defined as the contact boundary line. (Rockfill) and pile stones They share a common contact boundary line to define the rockfill. and pile stones The boundary of the contact surface is defined by the boundary control line located on the outer ring, which is used to define the local adjustment boundary line and is used to limit the rockfill. The boundary and riprap of the local adjustment area The boundary of the local adjustment area; Step S204: Enumerate the rock piles constructed in step S203 and pile stones Contact boundary line, rubble pile Local adjustment of boundary lines and riprap This involves considering all potential connection schemes for the triangular meshes formed between the locally adjusted boundary lines, calculating the geometric quality of all triangular meshes, determining the optimal connection scheme, calculating the midpoint of the region enclosed by the contact boundary line corresponding to the optimal connection scheme, and sequentially connecting each node of the contact boundary line to the midpoint of the contact boundary line to generate a riprap. The first contact surface mesh is copied and its normal is flipped to obtain the second contact surface mesh, which is then assigned to the rockfill. ; Step S205: Enumerate the remaining piles of stones after stacking, and repeat steps S201 to S204 until the potential contact detection of all piles of stones after stacking and the local surface mesh adjustment and contact surface mesh generation of the piles of stones with potential contact are completed, so as to obtain the self-supporting skeleton of the piles. Step S3: Under the constraints of the self-supporting skeleton of the riprap and the boundary of the sample space, the riprap, self-compacting concrete and interface transition zone are discretized by a three-dimensional volume mesh to obtain a three-dimensional microscopic numerical model of the riprap concrete.

2. The construction method according to claim 1, characterized in that, In step S201, the rockfill is inspected. and pile stones The specific steps to determine whether potential contact exists include: Based on gravity compaction and subsequent riprap and pile stones Mesh geometry information for calculating riprap and pile stones The coordinate difference of the center of gravity is used as the basis for the rubble pile. and pile stones The relative distance, if piled with stones and pile stones The relative distance is greater than the rockfill spacing threshold. Then it is considered a pile of stones and pile stones There is no potential contact between them; if the pile of stones and pile stones The relative distance is less than or equal to the rockfill spacing threshold. Then, the pile of stones is further tested sequentially using an enumeration method. and pile stones The minimum relative distance between all face grids; if there exists a face grid whose minimum relative distance is less than a first distance threshold. In this case, it is considered a pile of stones. and pile stones There is potential contact; otherwise, it is considered a rubble pile. and pile stones There is no potential contact.

3. The construction method according to claim 2, characterized in that, Step S202 specifically includes: Constructing rock piles and pile stones Set of potential contact points , pile of stones Local adjustment surface set and piled stones Local adjustment surface set ,initialization , and All are empty sets; Traversing the stone pile and pile stones Calculate the riprap using the faces containing all the meshes and the lines containing all the edges. and pile stones The intersections between the points will form a pile of stones. and pile stones Set of intersections From the set of intersections Intersections that simultaneously satisfy both the first and second conditions are selected and added to the rockfill as potential contact points between the two rockfills. and pile stones From the set of potential contact points, the surface mesh of the rockfill corresponding to the intersection point is added as a local adjustment surface to the set of local adjustment surfaces of the rockfill; from the set of intersection points... Intersections that satisfy the third condition are selected, and only the surface mesh of the rock pile corresponding to the intersection is selected as a local adjustment surface of that rock pile, without selecting the intersection as a potential contact point between the two rock piles; wherein, the first condition is the intersection point. The distance to the surface grid of the rockfill corresponding to the intersection point is less than the first distance threshold. The second condition is the intersection point. The distance to the edge of the rock pile corresponding to the intersection point is less than the first distance threshold. The third condition is the intersection point. The distance to the face grid of the riprap corresponding to the intersection point exceeds the first distance threshold. However, the distance between the endpoint of the edge of the rock pile where the intersection point is located and the surface grid of the rock pile corresponding to the intersection point is less than the second distance threshold. .

4. The construction method according to claim 3, characterized in that, In step S203, The contact boundary line is constructed according to the following steps: calculating the set The number of potential contact points, if If the number of potential contact points is less than 3, then the rockfill will be... and pile stones The normal direction of the potential contact surface is set as riprap. and pile stones The direction of the line connecting the centroids, and generating a side length of based on quaternions. An equilateral triangle is formed, and each node of the equilateral triangle is added to the set. The set obtained from If set If the number of potential contact points is greater than or equal to 3, then the riprap can be fitted using principal component analysis. and pile stones Potential contact surfaces, and the set All potential contact points are projected onto the rockfill obtained by principal component analysis. and pile stones The collection is obtained on the contact surface. ; for the set Perform convex hull calculation to obtain the rockfill and pile stones Shared contact boundary line; The local adjustment boundary line is constructed according to the following steps: extracting the riprap respectively. and pile stones The triangular mesh that shares two sides with the local adjustment surface is added to the ripple. Local adjustment surface set and pile stones Local adjustment surface set In the middle, respectively in the local adjustment surface set and Extract the nodes located at the edges of the surface mesh to form a pile. Local adjustment surface node set and pile stones Local adjustment surface node set In clockwise order, respectively and Connecting the edge nodes of the surface mesh in the middle to construct the rubble mound Local adjustment of boundary lines and riprap The local adjustment boundary line.

5. The construction method according to claim 1, characterized in that, In step S204, The optimal local adjustment surface mesh connection scheme is found based on the depth-first search method, which is the local adjustment surface mesh connection scheme with the best overall surface mesh quality. The connection scheme needs to satisfy the following two conditions at the same time: (1) The angle between the outward normal direction of all triangular surface meshes and the direction of the line connecting the centroid of the rubble and the centroid of the triangular surface mesh does not exceed 90 degrees; (2) Calculate the geometric quality Q of the triangular surface mesh with the worst geometric quality among all local adjustment surface mesh connection schemes. The optimal local adjustment surface mesh connection scheme needs to ensure that its corresponding Q value is the highest among all schemes. The normal direction of the first contact surface mesh and the pile The angle between the line connecting the center of gravity and the midpoint of the contact boundary line shall not exceed 90 degrees.

6. The construction method according to claim 1, characterized in that, Step S205 also includes: Extract all boundary surfaces in the rockfill mesh whose distance to the sample space is less than the fourth distance threshold. The nodes are projected onto the boundary surface of the sample space to form the exposed rockfill boundary surface mesh in the three-dimensional mesoscopic numerical model of the rockfill concrete. The rockfill ratio is adjusted by fixing the contact surface mesh and the rockfill boundary surface mesh and scaling the remaining meshes at the center.

7. The construction method according to claim 1, characterized in that, In step S3, the discretization of self-compacting concrete using a three-dimensional volumetric mesh specifically includes: The sample space boundary is cut using a riprap boundary surface mesh located on the sample space boundary, and the cut sample space boundary is discretized using a two-dimensional surface mesh. Then, the sample space boundary mesh and the riprap surface mesh are meshed together to form a doubly connected domain, which serves as the control boundary for discretizing the three-dimensional volume mesh of self-compacting concrete. The internal space of the doubly connected domain is discretized using the three-dimensional volume mesh to obtain the volume mesh of self-compacting concrete.

8. An apparatus based on the construction method according to any one of claims 1 to 7, characterized in that, include: The first module is configured to generate convex polyhedral random aggregates in the sample space to characterize the riprap in riprap concrete, simulate the gravity compaction process to complete the random placement of the riprap, and form corresponding surface grids on the surface of each riprap. The second module is configured to detect the mesh of the rockfill surface with potential contact, adjust the local mesh of the surface to generate the contact surface, and obtain the self-supporting skeleton of the rockfill. The third module is configured to discretize the riprap, self-compacting concrete, and interface transition zone using a three-dimensional volume mesh under the constraints of the self-supporting skeleton of the riprap and the boundary of the sample space, thereby obtaining a three-dimensional microscopic numerical model of the riprap concrete.

9. A three-dimensional microscopic numerical model of riprap concrete, characterized in that, The three-dimensional mesoscopic numerical model of the riprap concrete is constructed using the construction method according to any one of claims 1 to 7, and the three-dimensional mesoscopic numerical model of the riprap concrete includes: The rockfill unit is the smallest unit obtained by gravity compaction of rockfill simulated by random aggregate of convex polyhedra in the sample space and local surface mesh adjustment of rockfill with potential contact to form a self-supporting skeleton of rockfill, and then dividing the self-supporting skeleton of rockfill into a volume mesh. The contact surface is set only at the interface of two piles of rocks that have potential contact. It consists of a first contact surface and a second contact surface that can slide relative to each other. The first contact surface is generated by adjusting the local surface mesh of the piles of rocks that have potential contact. The second contact surface is obtained by copying the first contact surface. Self-compacting concrete element, wherein the self-compacting concrete element is the smallest finite element obtained by forming self-compacting concrete in the region within the sample space after removing the self-supporting riprap skeleton, and then meshing the self-compacting concrete; and Interface transition zone unit, which exists only at the interface between the riprap unit and the self-compacting concrete unit, is simulated by a six-node interface unit with no thickness or a set thickness.

10. The three-dimensional microscopic numerical model of riprap concrete according to claim 9, characterized in that, The riprap element is selected from solid finite element elements or convex polyhedral proportional boundary finite element elements.

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