Safety assessment method and system for ancient seawall structures based on nonlinear bonding elements

Abstract

The present invention discloses a safety assessment method and system for ancient seawall structures based on nonlinear bonding units, which belongs to the field of seawall operation, maintenance and protection technology. The existing technology does not take into account the interaction between the seawall's stone bodies and the soil structure, which makes it difficult to accurately grasp the internal structural state of the ancient seawall and cannot perform safety analysis on the ancient seawall structure. The safety assessment method for ancient seawall structures based on nonlinear bonding units of the present invention can realize the safety assessment of seawall structures by constructing a seawall grid generation model, a seawall boundary search model, a seawall property simulation model, a seawall deformation simulation model, and a seawall safety assessment model, and establishing bonding units that can simulate the interaction between the pond body and the soil and stone bodies. Therefore, the present invention can fully consider the interaction between the seawall's stone bodies and the soil structure, thereby accurately grasping the internal structural state of the ancient seawall, and can help operation and maintenance personnel to carry out ancient seawall protection more comprehensively and flexibly.

Description

Technical Field

[0001] The present invention relates to a safety assessment method and system for ancient seawall structures based on nonlinear bonding units, and belongs to the technical field of seawall operation, maintenance and protection. Background Art

[0002] To protect against tidal surges and the recent intensification of river erosion, many sections of the ancient seawall have undergone reinforcement projects, and a series of measures have been implemented to strengthen monitoring of the ancient seawall's deformation. While the reinforcement projects are intended to protect the ancient seawall, the construction machinery, loads, and disturbances involved in the construction process all affect its structural safety. Furthermore, weather changes and wave action pose challenges to the centuries-old seawall.

[0003] Furthermore, a Chinese patent application (publication number CN110779570A) discloses a safety monitoring and early warning system for the construction period of ancient seawall reinforcement, which includes monitoring equipment, data acquisition equipment, a monitoring and management cloud platform, alarm equipment, and terminals. The monitoring equipment and data acquisition equipment are connected via cables or wireless networks, and the monitoring and management cloud platform is connected to the data acquisition equipment, alarm equipment, and terminals respectively. The monitoring equipment includes deformation monitoring equipment, seepage monitoring equipment, pressure monitoring equipment, environmental quantity monitoring equipment, vibration monitoring equipment, and video monitoring equipment, which are connected to the data acquisition equipment via cables or wireless networks. During the ancient seawall reinforcement construction period, advanced technologies such as new sensors, the Internet of Things, and cloud computing are used to conduct real-time monitoring, analysis, and early warning of deformation, seepage, environmental quantity, and vibration conditions during the ancient seawall reinforcement construction period, ensuring the real-time nature of safety monitoring and strengthening safety management and control during the ancient seawall reinforcement construction period.

[0004] However, the above scheme is mainly used for safety monitoring during the reinforcement construction period of the ancient seawall. It does not take into account the interaction between the seawall's stone bodies and the soil structure, which makes it difficult to accurately grasp the internal structural status of the ancient seawall. Therefore, it is impossible to conduct a safety analysis of the ancient seawall structure, which is not conducive to the protection of the ancient seawall.

[0005] The information disclosed in this Background Art is only for understanding the background of the present inventive concept and therefore it may include information that does not constitute prior art. Summary of the Invention

[0006] In response to the above problem or one of the above problems, an object of the present invention is to provide a method and system for safety assessment of ancient seawall structures based on nonlinear bonding units. By constructing a seawall grid generation model, a seawall boundary search model, a seawall property simulation model, a seawall deformation simulation model, and a seawall safety assessment model, a boundary grid that can characterize the junction between the seawall body and the soil body and the connection between the stone bodies is obtained, and based on a nonlinear constitutive algorithm, the boundary grid is given the properties of a nonlinear unit to form a bonding unit; then, an elastic-plastic algorithm is used to perform simulation calculations to obtain the structural deformation data of the seawall and realize the safety assessment of the seawall structure. Therefore, the interaction between the stone bodies of the seawall and the soil structure can be fully considered, so that the internal structural state of the ancient seawall can be accurately grasped, which is beneficial to the protection of the seawall structure.

[0007] In response to the above problem or one of the above problems, the second purpose of the present invention is to provide an ancient seawall structure safety assessment method and system based on nonlinear bonding units. By establishing a bonding unit that can simulate the interaction between the pond body and the soil and stone body, the deformation data of the interface between the pond body and the soil and stone body can be quickly output, which is convenient for quickly identifying dangerous situations in combination with relevant specifications, improving the dimension of seawall structure safety analysis, and helping operation and maintenance personnel to carry out ancient seawall protection more comprehensively and flexibly.

[0008] To achieve one of the above purposes, the first technical solution of the present invention is:

[0009] The safety assessment method of ancient seawall structure based on nonlinear bonded element includes the following steps:

[0010] Step 1: Process the structural information of a seawall section using the previously constructed seawall grid generation model to obtain a seawall simulation grid.

[0011] Step 2: Using the previously constructed seawall boundary search model, the seawall simulation grid is processed to obtain a boundary grid, which is used to represent the interface between the seawall body and the soil body, as well as the connection between the stone bodies.

[0012] Step 3: Using the previously constructed seawall property simulation model, based on the nonlinear constitutive algorithm, the boundary mesh is assigned the properties of nonlinear elements to form bonding elements;

[0013] Step 4: Using the previously constructed seawall deformation simulation model, loads are applied to the bonding units, and an elastic-plastic algorithm is used for simulation calculation to obtain the structural deformation data of the seawall.

[0014] Step five: Based on the previously constructed seawall safety assessment model, the structural deformation data of the seawall is analyzed to obtain the safety assessment information of the seawall structure and complete the safety assessment of the ancient seawall structure based on the nonlinear bonding unit.

[0015] The present invention constructs a seawall grid generation model, a seawall boundary search model, a seawall property simulation model, a seawall deformation simulation model, and a seawall safety assessment model to obtain a boundary grid that can represent the boundary between the seawall body and the soil body and the connection between the stone bodies. Based on a nonlinear constitutive algorithm, the boundary grid is given the properties of a nonlinear unit to form a bonding unit. Then, an elastic-plastic algorithm is used to perform simulation calculations to obtain structural deformation data of the seawall and realize safety assessment of the seawall structure. Therefore, the present invention can fully consider the interaction between the stone bodies of the seawall and the interaction between the soil structure, thereby accurately understanding the internal structural state of the ancient seawall and facilitating the protection of the seawall structure.

[0016] Furthermore, the present invention can effectively improve the accuracy and speed of contact calculation between the back and bottom stone bodies of the seawall and the soil around the pond by establishing a bonding unit that can simulate the interaction between the pond body and the soil and stone bodies, and effectively solve the convergence problem of the model algorithm when facing complex contact surfaces such as stone dislocation.

[0017] At the same time, the present invention can quickly output the deformation data of the interface between the pond body and the soil and stone body through the above-mentioned simulation model, which is convenient for quickly identifying dangerous situations in combination with relevant specifications, further improving the dimension of seawall structure safety analysis, and helping operation and maintenance personnel to carry out ancient seawall protection more comprehensively and flexibly.

[0018] As preferred technical measures:

[0019] Step 1: Process the cross-sectional structural information of a seawall using the previously constructed seawall mesh generation model to obtain the seawall simulation mesh as follows:

[0020] Obtain the structural information of a seawall section at the current operation stage;

[0021] Based on the cross-sectional structural information of a seawall, the actual cross-sectional structural data is determined, which includes the backfill, the layered soil of the pond foundation, the stone blocks, the pond body, and the supporting piles in front of the pond.

[0022] The backfill behind the pond, the layered soil of the pond foundation, and the supporting piles in front of the pond are unified as the soil part of the model. The scope of action of the pile load, water pressure load, pond body deadweight load and boundary effect are considered to obtain the soil geometry simulation object.

[0023] The stone body is used as a unified model of the pond body, and considering the horizontal surge effect, the stone body is layered in the horizontal direction to obtain the pond body geometric simulation object;

[0024] The soil geometry simulation object and the pond geometry simulation object are meshed separately, and the mesh close to the pond body is locally encrypted to obtain the soil mesh and the pond mesh.

[0025] The nodes of the soil mesh and the pond mesh are merged according to their spatial positions to obtain a complete seawall simulation mesh.

[0026] As preferred technical measures:

[0027] Step 2: Use the previously constructed seawall boundary search model to process the seawall simulation grid. The method to obtain the boundary grid is as follows:

[0028] Obtaining a seawall simulation grid, which includes a soil grid and a pond grid;

[0029] Based on the soil partial grid and the pond partial grid, grid nodes on the interface between the soil and the pond are obtained, and a soil node group and a pond node group are formed; the soil node group and the pond node group have the same geometric position and one-to-one correspondence, and belong to the soil partial grid and the pond partial grid respectively;

[0030] Based on the partial grid of the pond body, at the interface where two stone strips contact each other, select the upper node group at the bottom of the upper stone strip and the lower node group at the top of the lower stone strip; the geometric positions of the upper node group and the lower node group are the same and correspond one to one;

[0031] The soil node group, pond node group, upper node group and lower node group are aggregated to obtain the boundary mesh.

[0032] As preferred technical measures:

[0033] In step three, the previously constructed seawall property simulation model is used. Based on the nonlinear constitutive algorithm, the boundary mesh is assigned nonlinear unit properties. The method for forming bonding units is as follows:

[0034] Obtaining a boundary mesh, which includes a soil node group, a pond node group, an upper node group, and a lower node group;

[0035] According to the order of the nodes in the soil node group and the pond node group, quadrilateral elements with zero thickness are sequentially established as the first mesh element group at the interface between the pond and the soil;

[0036] Based on the nonlinear constitutive algorithm, the first grid unit group is given the properties of nonlinear units, so that the first grid units have elastic-plastic deformation capabilities, thereby obtaining the first bonding unit group, which is used to simulate the contact between the pond body and the soil;

[0037] According to the order of nodes in the upper node group and the lower node group, quadrilateral elements with zero thickness are sequentially established as the second grid element group of the stone body interface;

[0038] Based on the nonlinear constitutive algorithm, the second grid unit group is given the attributes of nonlinear units, so that the second grid units have damage characteristics, thereby obtaining the second bonding unit group, which is used to simulate the bonding effect between the stone bodies;

[0039] The first grid unit group and the second bonding unit group are coupled to obtain bonding units.

[0040] As preferred technical measures:

[0041] Based on the nonlinear constitutive algorithm, the method of assigning nonlinear unit attributes to the first mesh unit group so that the first mesh unit has elastic-plastic deformation capability is as follows:

[0042] From the geological survey data of the seawall section, the physical and mechanical parameters of each layer of the seawall foundation and the backfill are obtained;

[0043] Based on physical and mechanical parameters, the Mohr-Coulomb yield criterion is established to calculate the tangential elastic-plastic deformation to characterize the bonding effect between the pond and the soil as well as the tensile stress characteristics.

[0044] According to the Mohr-Coulomb yield criterion, the model parameters are set, including normal stiffness, tangential stiffness, interface adhesion, interface friction coefficient, and isotropic hardening parameter; the hardening parameter is used to adjust the tangent slope during the sliding stage;

[0045] Based on the elastic part and the plastic part, the interface tangential displacement is calculated;

[0046] Calculate the interface shear stress based on the elastic part and tangential stiffness;

[0047] Calculate the interface normal stress based on the normal stiffness and interface normal displacement

[0048] Calculate the flow criterion value based on the interface shear stress, interface normal stress, interface friction coefficient, interface adhesion, isotropic hardening parameter and cumulative tangential displacement;

[0049] When the flow criterion value is less than zero and the interface is tangentially displaced, the first grid element is in the elastic stage and the plastic part of the tangential displacement remains unchanged; when the flow criterion value is equal to zero and the interface is tangentially displaced, the plastic part of the first grid element begins to accumulate and the plastic displacement increment on the yield surface obeys the Mohr-Coulomb yield criterion.

[0050] According to the flow criterion value, the contact surface of the first grid unit group is assigned with the properties of a nonlinear unit, so that the first grid unit has elastic-plastic deformation ability, thereby realizing the simulation of the contact and friction interaction process of the first grid unit group.

[0051] Furthermore, the physical and mechanical parameters include soil density, Young's modulus, Poisson's ratio, cohesion and internal friction angle; the density, elastic modulus and Poisson's ratio of the support piles in front of the pond are obtained from the construction data of the support piles;

[0052] Generally, soil layers are divided into three types, namely, pond base soil, first layer of pond back soil and second layer of pond back soil;

[0053] The depth of the first layer of soil behind the pond is 0~1.73 meters, and the depth of the second layer of soil behind the pond is 1.73~5.5 meters.

[0054] As preferred technical measures:

[0055] Based on the nonlinear constitutive algorithm, the second mesh unit group is given nonlinear unit attributes so that the second mesh unit has damage characteristics. The method for obtaining the second bonding unit group is as follows:

[0056] Obtain the bonding structure data of the stone body from the seawall material data;

[0057] The bonding structure data of the stone body at least include interface pressure, density, elastic modulus and Poisson's ratio;

[0058] Based on the bonding structure data of the stone strips, the stress-strain curve of the stone strips was generated to characterize the strength of the sticky rice mortar bonding the stone strips.

[0059] According to the stress-strain curve of the stone body, the interface tangential stiffness, normal stiffness and interface tensile strength limit are determined;

[0060] Based on the normal stiffness and softening slope, the relationship between the constitutive interface normal stress and interface normal displacement is established;

[0061] Based on the interface tangential stiffness, interface tensile strength limit and control parameters, the relationship between interface tangential stress, interface tangential displacement and interface normal displacement, namely the relationship between normal cracking and tangential stiffness, is established.

[0062] According to the changing relationship between the constitutive interface normal stress and interface normal displacement and the normal crack-tangential stiffness relationship, the second grid unit group is assigned nonlinear unit properties to simulate the bonding effect between the stone bodies, so that the second grid unit has damage characteristics, thereby obtaining the second bonding unit group.

[0063] As preferred technical measures:

[0064] The relationship between the constitutive interface normal stress and interface normal displacement includes the following:

[0065] When the interface normal displacement exceeds the critical damage displacement, damage begins to occur in the interface normal direction; when the interface normal displacement reaches the fracture limit value, the interface normal direction fractures;

[0066] As the interface normal damage evolves, the critical damage displacement gradually evolves from the initial displacement value to the normal fracture threshold;

[0067] The interface normal stress evolution is divided into four stages, including the normal elastic behavior under the interface compression state, the normal elastic behavior under the interface normal opening state, the normal damage behavior under the interface normal opening state, and the interface tangential complete destruction stage.

[0068] Or / and, the relationship between normal cracking and tangential stiffness, including the following:

[0069] By adjusting the control parameters, different relationships between normal cracking and tangential stiffness are constructed. When the control parameter is equal to zero and the normal displacement is greater than zero, the tangential stiffness of the interface immediately drops to zero. When the control parameter is equal to two, the tangential stiffness of the interface is independent of the normal displacement of the interface and remains constant.

[0070] The evolution of the interface tangential stress is divided into three stages, including the tangential elastic behavior under the interface compression state, the tangential elastic behavior under the interface normal opening state, and the interface tangential complete destruction stage.

[0071] The present invention establishes a bonding unit that simulates the interaction between the stone slabs, links the tangential interaction at the stone slab interface with the normal cracking, simulates the weakening of the tangential stiffness of the seawall stone slab interface caused by cracking under load, and improves the simulation accuracy of the model when facing lateral forces such as waves and soil pressure behind the seawall.

[0072] As preferred technical measures:

[0073] Step 4: Using the previously constructed seawall deformation simulation model, loads are applied to the bonding units and an elastic-plastic algorithm is used for simulation calculations. The method for obtaining the structural deformation data of the seawall is as follows:

[0074] Obtain the loads on the seawall, including hydrostatic pressure, wave force and backfill load;

[0075] Set displacement boundary conditions, including vertical displacement limit at the bottom and horizontal displacement limit on both sides;

[0076] Apply load and displacement boundary conditions to the bonding unit and conduct simulation analysis to obtain the maximum displacement of the pond body and the maximum shear stress between the stone bodies.

[0077] The maximum displacement of the seawall body and the maximum shear stress between the stone blocks are coupled to obtain the structural deformation data of the seawall.

[0078] To achieve one of the above purposes, the second technical solution of the present invention is:

[0079] The safety assessment method of ancient seawall structure based on nonlinear bonded elements includes the following contents:

[0080] Using a previously constructed seawall mesh generation model, and based on the latest drawings of the ancient seawall cross-section, the geometric models of the ancient seawall's stonework, soil behind the seawall, and bottom soil were drawn. Finite element meshes were then divided to obtain the seawall mesh and soil mesh. The nodes of the seawall mesh and soil mesh were then merged, and parameters for each layer of soil, each level of stonework, and bonding material were set based on survey and test data to obtain the seawall simulation mesh.

[0081] Using the previously constructed seawall property simulation model and based on the seawall simulation grid, the bonding units between the seawall body and the soil, and the bonding units between the stone bodies, were obtained.

[0082] Using the previously constructed seawall deformation simulation model, loads were applied to the bonding units, and simulation calculations were performed using an elastic-plastic algorithm to obtain the structural deformation data of the seawall. The structural deformation data of the seawall were then analyzed to obtain safety assessment information for the seawall structure, completing the safety assessment of the ancient seawall structure based on nonlinear bonding units.

[0083] This method fully considers the typical damage patterns of ancient seawalls caused by mortar weakening. By establishing a seawall grid generation model, a seawall property simulation model, and a seawall deformation simulation model, and outputting deformation data for each layer of the ancient seawall interface, this method helps operators quickly identify weak layers under specific working conditions and protect the ancient seawall at a more detailed level. Furthermore, the use of bonding units further improves the accuracy of ancient seawall analysis results, enhances the dimension of ancient seawall structural safety analysis, and helps operators carry out ancient seawall protection more comprehensively and flexibly.

[0084] Furthermore, using the previously constructed seawall property simulation model and based on the seawall simulation grid, the bonding units between the seawall body and the soil and between the stone bodies are obtained as follows:

[0085] Based on the seawall simulation grid, the grid nodes at the interface between the pond mesh and the soil mesh are copied to form two groups of nodes with the same geometric position and one-to-one correspondence. These groups belong to the pond mesh and the soil mesh respectively, thus obtaining independent pond mesh and soil mesh parts. Subsequently, the four corresponding nodes above and below sequentially form a degenerate interface mesh, which is assigned the properties of a nonlinear unit to the interface mesh between the pond and soil, forming a bonding unit between the pond and soil.

[0086] Based on the seawall simulation grid, the unit nodes on the bonding interface between the boulders are replicated to form two groups of unit nodes with the same geometric position and one-to-one correspondence, which belong to the boulders of the two ancient seawalls respectively. A degenerate unit grid is formed based on the unit node groups, and the unit grid between the boulders is then assigned nonlinear unit properties to form bonding units between the boulders.

[0087] To achieve one of the above purposes, the third technical solution of the present invention is:

[0088] The safety assessment system of ancient seawall structure based on nonlinear bonding element includes:

[0089] one or more processors;

[0090] a storage device for storing one or more programs;

[0091] When the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned ancient seawall structure safety assessment method based on nonlinear bonding elements.

[0092] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0093] The present invention constructs a seawall grid generation model, a seawall boundary search model, a seawall property simulation model, a seawall deformation simulation model, and a seawall safety assessment model to obtain a boundary grid that can represent the boundary between the seawall body and the soil body and the connection between the stone bodies. Based on a nonlinear constitutive algorithm, the boundary grid is given the properties of a nonlinear unit to form a bonding unit. Then, an elastic-plastic algorithm is used to perform simulation calculations to obtain structural deformation data of the seawall and realize safety assessment of the seawall structure. Therefore, the present invention can fully consider the interaction between the stone bodies of the seawall and the interaction between the soil structure, thereby accurately understanding the internal structural state of the ancient seawall and facilitating the protection of the seawall structure.

[0094] Furthermore, the present invention can effectively improve the accuracy and speed of contact calculation between the back and bottom stone bodies of the seawall and the soil around the pond by establishing a bonding unit that can simulate the interaction between the pond body and the soil and stone bodies, and effectively solve the convergence problem of the model algorithm when facing complex contact surfaces such as stone dislocation.

[0095] At the same time, the present invention can quickly output the deformation data of the interface between the pond body and the soil and stone body through the above-mentioned simulation model, which is convenient for quickly identifying dangerous situations in combination with relevant specifications, further improving the dimension of seawall structure safety analysis, and helping operation and maintenance personnel to carry out ancient seawall protection more comprehensively and flexibly. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] Figure 1 A schematic diagram of a process for performing pond structure safety analysis according to the present invention;

[0097] Figure 2 A structural schematic diagram of the bonding unit of the present invention;

[0098] Figure 3 A structural schematic diagram of the grid structure of the present invention;

[0099] Figure 4 A schematic structural diagram of a bonding unit between a pond body and a soil body according to the present invention;

[0100] Figure 5 A distribution cloud diagram of the displacement of the present invention;

[0101] Figure 6 This is a distribution cloud diagram of the shear stress of the pond body of the present invention. DETAILED DESCRIPTION

[0102] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0103] Rather, the present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention as defined by the claims. Furthermore, to facilitate a better understanding of the present invention, certain specific details are described in detail below in the detailed description of the present invention. Those skilled in the art will be able to fully understand the present invention without these details.

[0104] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used herein, the term "or / and" includes any and all combinations of one or more of the associated listed items.

[0105] like Figure 1 As shown, the first specific embodiment of the ancient seawall structure safety assessment method based on nonlinear bonding elements of the present invention is as follows:

[0106] The safety assessment method of ancient seawall structure based on nonlinear bonded element includes the following steps:

[0107] Step 1: Process the structural information of a seawall section using the previously constructed seawall grid generation model to obtain a seawall simulation grid.

[0108] Step 2: Using the previously constructed seawall boundary search model, the seawall simulation grid is processed to obtain a boundary grid, which is used to represent the interface between the seawall body and the soil body, as well as the connection between the stone bodies.

[0109] Step 3: Using the previously constructed seawall property simulation model, based on the nonlinear constitutive algorithm, the boundary mesh is assigned the properties of nonlinear elements to form bonding elements;

[0110] Step 4: Using the previously constructed seawall deformation simulation model, loads are applied to the bonding units, and an elastic-plastic algorithm is used for simulation calculation to obtain the structural deformation data of the seawall.

[0111] Step five: Based on the previously constructed seawall safety assessment model, the structural deformation data of the seawall is analyzed to obtain the safety assessment information of the seawall structure and complete the safety assessment of the ancient seawall structure based on the nonlinear bonding unit.

[0112] The second specific embodiment of the ancient seawall structure safety assessment method based on nonlinear bonding elements of the present invention:

[0113] The safety assessment method of ancient seawall structure based on nonlinear bonded element includes the following steps:

[0114] Step 1: Using the previously constructed seawall mesh generation model, based on the latest drawings of the ancient seawall section, draw the geometric models of the ancient seawall stone body, the soil behind the pond, and the soil at the bottom of the pond. Divide the finite element mesh to obtain the pond body mesh and the soil mesh and merge the nodes. At this point, the mesh is a single-node mesh. Based on the survey and test data, define the parameters of each layer of soil, each level of stone, and the bonding material for subsequent finite element calculations.

[0115] Step 2: Using the previously constructed seawall property simulation model, the grid nodes on the interface between the seawall and the soil grid are copied to form two groups of nodes with the same geometric position and one-to-one correspondence, which belong to the seawall grid and the soil grid respectively, forming independent seawall grid and soil grid parts. At this time, there are two nodes in the grid. Then, the four corresponding nodes above and below form a degenerate interface grid in sequence, giving the interface grid between the seawall and the soil the properties of a nonlinear unit, forming a bonding unit between the seawall and the soil.

[0116] Step 3: Using the previously constructed seawall property simulation model, copy the unit nodes on the bonding interface between the stone slabs. Using the same operation as step 2, form a series of degenerate interface meshes. Assign the interface mesh between the seawall body and the soil the properties of nonlinear units to form bonding units between the stone slabs.

[0117] Step 4: Based on the previously constructed seawall deformation simulation model, loads are applied to the bonding units to obtain the relative sliding (cracking), displacement, and tilt between the seawall and the soil, which are used for the structural safety evaluation of the ancient seawall.

[0118] Based on a nonlinear bonding unit, the present invention analyzes the safety status of ancient seawall structures by considering the effects of normal damage between the stone contact surfaces on the tangential stiffness of the bonding material and the frictional contact between the seawall and the soil. Furthermore, the present invention improves the precision of the safety analysis of ancient seawall structures and increases the accuracy of the safety analysis of local seawall structures. Furthermore, the seawall analysis model of the present invention exhibits excellent robustness, enabling rapid iterative calculations and is suitable for structural safety analysis of ancient seawalls during construction and under extreme operating conditions. Furthermore, the nonlinear bonding unit proposed in the present invention exhibits excellent compatibility with static and dynamic finite element calculation models, enabling multi-condition analysis within the same model.

[0119] In step 1 of this embodiment, the following steps are specifically included:

[0120] The first step was to obtain cross-sectional structural information for the ancient seawall during its current operational phase from the latest reinforcement drawings. Key monitoring sections were selected and, based on their actual structural composition, a two-dimensional geometric model was constructed, encompassing the main structures affecting the safety analysis of the ancient seawall, including the backfill, the layered foundation soil, the stone embankment, and the supporting piles in front of the embankment. During the geometric modeling, the foundation soil, backfill soil, and supporting piles in front of the embankment were collectively drawn as the soil component, and the stone embankment as the pond body.

[0121] Comprehensively consider the scope of action and boundary effects of loads such as heap loads, water pressure, and the deadweight of the pond. Because the main loading condition of the pond body is horizontal surge, the stone body can be modeled in layers in the horizontal direction during modeling to achieve appropriate simplification. On this basis, the soil part model and the pond body model are divided separately to obtain a quadrilateral mesh, and the mesh close to the pond body is locally encrypted. After merging the nodes of the soil part mesh and the pond body mesh according to their spatial position, a complete finite element mesh model of the ancient seawall section is obtained. When merging nodes, it is necessary to ensure that the number of nodes at the contact point of the pond body mesh and the soil part mesh is consistent and aligned.

[0122] The second step is to obtain the physical and mechanical parameters of each layer of soil in the ancient seawall and the backfill from the geological survey report of the ancient seawall section, including soil density, Young's modulus, Poisson's ratio, cohesion, and internal friction angle; obtain the density, elastic modulus, and Poisson's ratio of the stone body and the supporting piles in front of the pond from the pond material report and the support pile construction report of the ancient seawall, and define the strength of the glutinous rice mortar bonding the stone body under different pressures.

[0123] In step 2 of this embodiment, the following steps are specifically included:

[0124] The first step is to copy the grid nodes on the interface between the pond body and the soil mesh to form two groups of node groups with the same geometric position and one-to-one correspondence, which belong to the pond body mesh and the soil mesh respectively, forming independent pond body mesh parts and soil mesh parts. At the interface where the pond body mesh and the soil mesh contact, select node group 1 on the contact edge of the pond body mesh and node group 2 on the contact edge of the soil mesh. According to the order of the nodes in node group 1 and node group 2, quadrilateral elements (with zero thickness) are sequentially established as the bonding element group between the pond body and the soil. Figure 2 As shown, node group 1 contains nodes A, B, C, and D; node group 2 contains nodes a, b, c, and d, and quadrilateral element 1 (nodes A, B, b, and a), quadrilateral element 2 (nodes B, C, c, and b), and quadrilateral element 3 (nodes C, D, d, and c) can be established.

[0125] The second step is to assign a nonlinear constitutive model to the interface bonding element group between the pond and soil to simulate the contact between the pond and soil. This model simulates the contact-friction interaction process by introducing elastic-plastic deformation in the tangential direction of the contact surface. Compared with traditional contact algorithms, this model does not need to consider complex contact settings such as the position of the master and slave contact surfaces, mesh density, and relative slip, thus avoiding the complex contact surface search and iterative calculation, and has good robustness.

[0126] The main principle of this constitutive model is that when the normal compressive stress on the contact surface is large, the friction between the two contact surfaces is stronger, and the contact interface is less likely to enter the slip stage where the relative displacement develops rapidly, because the Coulomb friction law only depends on one parameter It achieves the boundary condition criterion of non-invasion of the contact boundary by establishing the relationship between tangential and normal stresses in the local area during the slip phase. The relationship between tangential and normal stresses is as follows:

[0127]

[0128] in, is the interface shear stress, is the interface normal stress, is the friction coefficient of the interface.

[0129] To express these criteria, it is necessary to assume that the mechanical behavior of the contact surface follows the laws of elasticity, as does the slope of the sliding direction in the tangential behavior criterion. Furthermore, to simplify the description of sliding between the pond and the soil, a certain degree of adhesion between the pond and the soil in contact is considered, allowing the interface to withstand a certain degree of tensile stress. Based on these two considerations, the Mohr-Coulomb yield criterion is used in this constitutive model to control the development of tangential elastic-plastic deformation.

[0130] The flow law of the tangential deformation of this model is the interface and the sliding cone shear plane Orthogonal, the normal behavior of the interface remains elastic and does not introduce plastic characteristics. The maximum tensile strength of the interface is calculated as follows:

[0131]

[0132] in, is the interfacial adhesion, is the maximum tensile strength of the interface.

[0133] This model relies on the following four parameters: normal stiffness , tangential stiffness , interfacial adhesion , the friction coefficient of the interface , and an isotropic hardening parameter is introduced , which is used to adjust the tangent slope during the sliding phase. The tangential displacement of the model can be decomposed into the elastic part and plastic part , the mechanical formulas involved in this model are as follows:

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140] in, is the deformation characterization function, is stress, is the interface tangential displacement, is the interface shear stress, is the interface normal stress, is the interface normal displacement, is the cumulative tangential displacement, is the tangential displacement increment, is the isotropic hardening modulus.

[0141] when When the interface tangential behavior is in the elastic stage, the plastic part of the tangential displacement Remain unchanged when The plastic part of the interface tangential displacement Start accumulation, plastic displacement increment on the yield surface Obey the flow rule shown in the above formula.

[0142] In step three of this embodiment, the following steps are specifically included:

[0143] In the first step, at the interface where the stone bodies contact each other, select node group 1 at the bottom of the upper stone body and node group 2 at the top of the lower stone body, and establish quadrilateral elements (with zero thickness) as the stone body interface bonding element group according to the node order in node group 1 and node group 2. Figure 2 As shown, node group 1 contains nodes A, B, C, and D, and node group 2 contains nodes a, b, c, and d. Quadrilateral element 1 (nodes A, B, b, and a), quadrilateral element 2 (nodes B, C, c, and b), and quadrilateral element 3 (nodes C, D, d, and c) can be established.

[0144] The second step is to assign a nonlinear constitutive model to the interface bonding unit group between the stone blocks to simulate the bonding effect between the stone blocks. This constitutive model introduces damage behavior in the normal direction of the interface. When the normal displacement of the interface exceeds the critical damage displacement, that is, the interface stress reaches the ultimate tensile stress After that, damage begins to appear in the normal direction of the interface, and the critical damage displacement The calculation formula is as follows:

[0145]

[0146] When the normal displacement reaches the fracture limit, the interface fractures normally. The fracture limit is calculated as follows:

[0147]

[0148] in, is the softening damage parameter, is the fracture limit value.

[0149] The constitutive interface normal stress and interface normal displacement The following relationship is satisfied:

[0150]

[0151] in, is the interface normal stress and interface normal displacement The relationship formula.

[0152] in is the initial normal stiffness of the interface. In the initial tension and stretching stage, the interface normal behaves as a linear elastic behavior. When the interface normal enters the softening stage, the normal stiffness gradually decreases, and the softening slope is As the interface normal damage evolves, the critical displacement of damage From the initial Gradually towards the normal fracture threshold Evolution. The evolution of interface normal stress can be divided into four stages:

[0153] (1) Normal elastic behavior under interface compression, normal contact threshold The larger the value of , the smaller the interpenetration value of the interface normal; (2) normal elastic behavior of the interface in the normal opening state; (3) normal damage (softening) behavior of the interface in the normal opening state; (4) in the stage of complete tangential destruction of the interface, the interface tangential stiffness is controlled by the interface normal displacement.

[0154] The constitutive interface tangential stress , interface tangential displacement and interface normal displacement The following relationship is satisfied:

[0155]

[0156]

[0157] in, is the interface tangential stress , interface tangential displacement and interface normal displacement The relationship formula.

[0158] in represents the initial tangential stiffness of the interface, represents the equilibrium point offset of tangential slip when the interface opens normally, The value of the interface is hour The final value of is the tangential fracture threshold, and the control parameter .

[0159] Therefore, by adjusting the control parameters , different normal cracking and tangential stiffness relationships can be constructed. , when the normal displacement is greater than zero, the tangential stiffness of the interface immediately drops to zero; when When the interface tangential stiffness is independent of the interface normal displacement, it remains constant. The evolution of interface tangential stress can be divided into three stages:

[0160] (1) Tangential elastic behavior under interface compression, (2) Tangential elastic behavior under interface normal expansion, and (3) complete tangential destruction of the interface.

[0161] Step 4 of this embodiment specifically includes the following steps:

[0162] The first step is to assign material and constitutive properties to each part of the ancient seawall cross-section mesh, including the interface bonding unit between the pond body and the soil body, and the interface bonding unit between the stone and stone. The Mohr-Coulomb model is used for the soil body, and the elastic model is used for the pond body and the supporting piles in front of the pond. The specific material model parameter values are taken from the second step of step 1. The normal stiffness of the pond-soil interface bonding unit is selected. , tangential stiffness , interface adhesion , the friction coefficient of the interface Four constitutive parameters; the initial normal stiffness of the contact surface is selected for the stone interface bonding unit , initial tangential stiffness of the contact surface , contact threshold of contact surface , softening damage parameters , initial normal tensile strength of contact surface Five constitutive parameters. The specific constitutive model parameter values are taken from the second step of step one.

[0163] The second step was to set displacement boundary conditions for the finite element model of the ancient seawall cross-section. The vertical displacement limit at the bottom of the model was DY = 0, and the horizontal displacement limit on both sides of the model was DX = 0. The ancient seawall is primarily subject to static loads such as backfill, wave forces, and hydrostatic pressure. During actual implementation, the magnitude and location of each load were determined based on specific working conditions.

[0164] The third step was to conduct a structural safety analysis of the ancient seawall. The results of the finite element model of the ancient seawall section were processed to determine the horizontal and vertical displacements of each node within the seawall. The tilt of the seawall was calculated from the horizontal and vertical displacements of each node. The output of the soil-soil interface bonding unit provided the width of the cracks between the seawall and the soil, while the output of the stone-slab interface bonding unit provided the normal and shear stresses at the interface. Combined with the finite element model analysis results and in accordance with relevant structural safety regulations for ancient seawalls, the structural safety of the ancient seawall section was comprehensively assessed based on the horizontal displacement of the seawall, the width of the cracks between the seawall and the soil, and the interlayer shear stress.

[0165] Therefore, by establishing a nonlinear bonding element that simulates the interaction between the ancient seawall, soil, and stone shingles, this method enhances the accuracy and speed of contact calculations between the stone shingles at the back and bottom of the ancient seawall and the surrounding soil, effectively avoiding the convergence issues of traditional contact algorithms when dealing with complex contact surfaces such as stone shingle dislocation. Furthermore, the element rapidly outputs the development of cracks at the interface between the seawall, soil, and stone shingles, facilitating rapid identification of hazardous situations in conjunction with relevant standards.

[0166] Furthermore, by establishing a nonlinear bonding unit to simulate the interaction between the stone slabs, the tangential interaction at the stone slab interface was linked to normal cracking. This model simulated the weakening of the tangential stiffness of the ancient seawall due to cracking at the stone slab interface under load, improving the model's accuracy under lateral forces such as waves and soil pressure behind the slab. Furthermore, failure caused by mortar weakening is a typical failure mode of ancient seawalls. The nonlinear interface bonding unit can directly output the shear stress and normal stress at each interface of the ancient seawall, helping operators to quickly identify weak layers under specific working conditions and protect the ancient seawall at a more detailed level.

[0167] Furthermore, the nonlinear bonding element is highly compatible with common elastic and elastoplastic materials, as well as dynamic and static solution methods. The use of the nonlinear bonding element further improves the accuracy of the finite element analysis results of the ancient seawall. Combined with the stress, cracking, and other outputs of the nonlinear bonding element, this further enhances the safety analysis of the ancient seawall structure, enabling operators to more comprehensively and flexibly carry out ancient seawall protection.

[0168] A specific embodiment of applying the present invention to perform structural safety assessment on an ancient seawall:

[0169] An ancient seawall is a fish-scale stone embankment, and its structure can be divided into the pond body, pond base, pond toe water structure, soil behind the pond, and foundation soil. The pond body is made of stone blocks stacked in a straight line, with a height of 5.44m and a bottom width of 3.48m, and it is stepped from bottom to top to a top width of 1.44m. The cross section of the stone blocks is 32cm×38.4cm, and there are 17 layers in total. According to the ancient seawall analysis method based on nonlinear bonding units proposed in the present invention, the deformation and stress of the ancient seawall section under static loads such as back-pond pile load, wave force, and hydrostatic pressure are analyzed to evaluate the status of the ancient seawall; specifically, the following steps are included:

[0170] Step 1: Based on the latest drawings of the ancient seawall section, draw the geometric model of the ancient seawall's stone embankment, the soil behind the embankment, and the soil at the bottom of the embankment. Divide and merge the finite element mesh nodes of each part into an overall mesh. Define the parameters of each layer of soil, each level of stone embankment, and the bonding material based on survey and test data for subsequent finite element calculations.

[0171] Step 2: Copy the grid nodes on the interface between the pond body and the soil mesh to form two groups of nodes with the same geometric position and one-to-one correspondence. These nodes belong to the pond body mesh and the soil mesh respectively, forming independent pond body mesh and soil mesh parts. The four corresponding nodes above and below form a degenerate interface mesh in sequence, and the boundary mesh between the pond body and the soil is given the properties of a nonlinear unit to form a bonding unit between the pond body and the soil.

[0172] Step 3: Copy the unit nodes on the bonding interface between the stone blocks and use the same operation as step 2 to form a series of degenerate interface meshes. Assign nonlinear unit properties to the boundary mesh between the pond body and the soil to form bonding units between the stone blocks.

[0173] Step 4: Use the Mohr-Coulomb elastic-plastic model of soil to set boundary conditions and load conditions to conduct a safety analysis of the ancient seawall structure, and obtain the interlayer stress between the stone bodies, the relative sliding (cracking) between the seawall body and the soil, the displacement and inclination of the seawall body for the structural safety evaluation of the ancient seawall body.

[0174] In step 1 of this embodiment, the following steps are specifically included:

[0175] The first step was to obtain cross-sectional structural information for the ancient seawall during its current operational phase from the latest reinforcement drawings. Key monitoring sections were selected and, based on their actual structural composition, a two-dimensional geometric model was constructed, encompassing the main structures affecting the safety analysis of the ancient seawall, including the backfill, the layered foundation soil, the stone embankment, and the supporting piles in front of the embankment. During the geometric modeling, the foundation soil, backfill soil, and supporting piles in front of the embankment were collectively drawn as the soil component, and the stone embankment as the pond body.

[0176] Considering the scope of action of loads such as heap load, water pressure, pond body deadweight and boundary effect, the geometric modeling size of the soil part is recommended to be selected. Because the main load condition of the pond body is horizontal surge, the stone body can be modeled in layers in the horizontal direction during modeling to simplify it appropriately. On this basis, the pond body model and the soil body model are divided into structured quadrilateral grids respectively. The grid close to the pond body can be locally encrypted. After merging the nodes of the soil body grid and the pond body grid according to their spatial positions, a complete finite element grid model of the ancient seawall section can be obtained, as shown in the figure. Figure 3 As shown in Figure 1, the mesh model has a total of 13,307 nodes, 1,352 one-dimensional line elements, and 12,994 two-dimensional quadrilateral surface elements, using first-order elements for meshing. Verification of mesh independence and trial calculations have proven that the mesh meets the requirements of the finite element simulation in step two.

[0177] The second step is to obtain the physical and mechanical parameters of each layer of soil in the ancient seawall and the backfill from the geological survey report of the ancient seawall section, including soil density, Young's modulus, Poisson's ratio, cohesion and internal friction angle; and obtain the density, elastic modulus and Poisson's ratio of the stone body and the support piles in front of the seawall from the pond material report and support pile construction report of the ancient seawall.

[0178] According to relevant reports, the soil layers are divided into three types: pond base soil, pond back soil with a depth of 0 to 1.73 meters, and pond back soil with a depth of 1.73 to 5.5 meters. The Mohr-Coulomb model is used for the soil, and the linear elastic model is used for the stone body and the supporting piles in front of the pond. The specific parameters are shown in Table 1.

[0179] Table 1: Material parameters of ancient seawall

[0180]

[0181] The strength of the glutinous rice mortar for bonding stone strips can be calculated using the following formula:

[0182]

[0183] In the formula is the interfacial pressure of the stone body, is the interface strain, is the interface stress. By plotting the stress-strain curve, the slope of the rising section of the curve is the interface tangential and normal stiffness, and the extreme stress value of the curve is the ultimate tensile strength of the interface.

[0184] In step 2 of this embodiment, the following steps are specifically included:

[0185] The first step is to copy the mesh nodes at the interface between the pond and soil meshes, forming two groups of nodes with identical geometric positions and a one-to-one correspondence. These nodes belong to the pond mesh and the soil mesh, respectively, forming independent pond and soil mesh components. At the interface where the pond and soil meshes meet, select node group 1 on the contact edge of the pond mesh and node group 2 on the contact edge of the soil mesh. Quadrilateral elements (with zero thickness) are created sequentially, following the order of the nodes in node group 1 and node group 2, as the bonding element group for the pond and soil interface. For example, if node group 1 contains nodes A, B, C, and D, and node group 2 contains nodes a, b, c, and d, then quadrilateral element 1 (nodes A, B, b, and a), quadrilateral element 2 (nodes B, C, c, and b), and quadrilateral element 3 (nodes C, D, d, and c) are created.

[0186] According to the above method, a unit with a thickness of 0 is established between the pond body and the soil body. The location of the unit and the result are as follows: Figure 3 shown.

[0187] The second step is to assign a nonlinear constitutive model to the interface bonding element group between the pond and soil to simulate the contact between the pond and soil. This model simulates the contact-friction interaction process by introducing elastic-plastic deformation in the tangential direction of the contact surface. Compared with traditional contact algorithms, this model does not need to consider complex contact settings such as the position of the master and slave contact surfaces, mesh density, and relative slip, thus avoiding the complex contact surface search and iterative calculation, and has good robustness.

[0188] The main principle of this constitutive model is that when the normal compressive stress on the contact surface is large, the friction between the two contact surfaces is stronger, and the contact interface is less likely to enter the slip stage where the relative displacement develops rapidly, because the Coulomb friction law only depends on one parameter . It realizes the non-invasion boundary condition criterion of the contact boundary by establishing the relationship between the tangential and normal stresses in the local area during the slip phase. In order to express the above criteria using the formula, it is necessary to assume that the mechanical behavior of the contact surface follows the law of elasticity, and the slope of the change in the sliding direction in the tangential behavior criterion is also the same. At the same time, in order to simplify the description of the sliding between the stone body and the soil, considering that there is a certain bonding effect between the stone body and the soil in contact with it, the interface can withstand a certain degree of tensile stress. Based on the above two points, the constitutive model uses the Mohr Coulomb yield criterion to control the development of tangential elastic-plastic deformation.

[0189] This model relies on the following four parameters: normal stiffness , tangential stiffness , interfacial adhesion , the friction coefficient of the interface , and an isotropic hardening parameter is introduced , which is used to adjust the tangent slope during the sliding phase. The tangential displacement of the model can be decomposed into the elastic part and plastic part , the mechanical formulas involved in this model are as follows:

[0190]

[0191]

[0192]

[0193]

[0194]

[0195]

[0196] in is the interface tangential displacement, is the interface shear stress, is the interface normal stress, is the interface normal displacement, is the cumulative tangential displacement, is the tangential displacement increment, is the isotropic hardening modulus.

[0197] when When the interface tangential behavior is in the elastic stage, the plastic part of the tangential displacement Remain unchanged when The plastic part of the interface tangential displacement Start accumulation, plastic displacement increment on the yield surface Obey the flow rule shown in the above formula.

[0198] In this example, the model constitutive parameters used are shown in Table 2 below:

[0199] Table 2: Model constitutive parameters

[0200]

[0201] In step three of this embodiment, the following steps are specifically included:

[0202] In the first step, at the interface where the stone blocks meet, select node group 1 at the bottom of the upper stone block and node group 2 at the top of the lower stone block. Quadrilateral elements (with zero thickness) are created sequentially as the stone block interface bonding element group, following the order of the nodes in node group 1 and node group 2. For example, if node group 1 contains nodes A, B, C, and D, and node group 2 contains nodes a, b, c, and d, quadrilateral element 1 (nodes A, B, b, and a), quadrilateral element 2 (nodes B, C, c, and b), and quadrilateral element 3 (nodes C, D, d, and c) can be created.

[0203] According to the above method, a unit with a thickness of 0 is established between the stone bodies. The position of the unit is as follows: Figure 4 Shown in yellow.

[0204] The second step is to assign a nonlinear constitutive model to the interface bonding unit group of the stone pond to simulate the bonding effect between the stone bodies. This constitutive model introduces damage behavior in the normal direction of the interface. When the normal displacement of the interface exceeds the critical damage displacement, that is, the interface stress reaches the ultimate tensile stress After that, damage begins to appear in the normal direction of the interface. When the normal displacement reaches the fracture limit, the interface fractures in the normal direction.

[0205] The constitutive interface normal stress and interface normal displacement The following relationship is satisfied:

[0206]

[0207] in is the initial normal stiffness of the interface. In the initial tension and stretching stage, the interface normal behaves as a linear elastic behavior. When the interface normal enters the softening stage, the normal stiffness gradually decreases, and the softening slope is .

[0208] The constitutive interface tangential stress , interface tangential displacement and interface normal displacement The following relationship is satisfied:

[0209]

[0210] in represents the initial tangential stiffness of the interface, represents the equilibrium point offset of tangential slip when the interface opens normally, The value of the interface is hour The final value of . is the tangential fracture threshold, parameter .

[0211] According to the calculation formula in the second step of step 1, the mortar material parameters between each layer of stone bodies from top to bottom can be obtained. The specific values are shown in Table 3.

[0212] Table 3: Material parameters of stone mortar

[0213]

[0214] Step 4 of this embodiment specifically includes the following steps:

[0215] The first step is to assign material and constitutive properties to each part of the ancient seawall cross-section mesh, which has the pond-soil interface bonding unit and the stone interface bonding unit. The Mohr-Coulomb model is used for the soil part, and the elastic model is used for the pond body and the supporting piles in front of the pond. The specific material model parameter values are taken from the second step of step 1. The normal stiffness of the pond-soil interface bonding unit is selected as , tangential stiffness , interface adhesion , the friction coefficient of the interface Four constitutive parameters; the initial normal stiffness of the contact surface is selected for the stone interface bonding unit , initial tangential stiffness of the contact surface , contact threshold of contact surface , softening damage parameters , initial normal tensile strength of contact surface Five constitutive parameters. The specific constitutive model parameter values are taken from the second step of step one.

[0216] The second step is to set displacement boundary conditions for the finite element model of the ancient seawall cross section. The vertical displacement limit at the bottom of the model is DY = 0, and the horizontal displacement limit on both sides of the model is DX = 0. In this case, the ancient seawall is mainly subjected to hydrostatic pressure, wave force, and backfill load. The specific values are shown in Table 4:

[0217] Table 4: Ancient seawall load table

[0218]

[0219] The third step is to carry out the structural safety analysis of the ancient seawall, process the calculation results of the finite element model of the ancient seawall section, and obtain the relevant results of the seawall body, such as Figure 5 、 Figure 6 and as shown in Table 5.

[0220] Table 5: Results of pond simulation analysis using the present invention

[0221]

[0222] For the same case, calculations were performed using a commercial software with the same settings. The results are shown in Table 6.

[0223] Table 6: Results of pond simulation analysis using a commercial software

[0224]

[0225] Comparing the data in Table 5 with the data in Table 6, it can be seen that the calculation results of the present invention are similar to those of a commercial software, indicating that the method proposed in the present invention is accurate and reliable.

[0226] Therefore, the use of the ancient seawall structure safety analysis method based on nonlinear bonding units proposed in the present invention can accurately evaluate and analyze the relevant behaviors of the ancient seawall, so that relevant departments can timely understand the operating status of the ancient seawall and assist in operation and maintenance decision-making.

[0227] An embodiment of a device applying the method of the present invention:

[0228] An electronic device comprising:

[0229] one or more processors;

[0230] a storage device for storing one or more programs;

[0231] When the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned ancient seawall structure safety assessment method based on nonlinear bonding elements.

[0232] A computer medium embodiment of the method of the present invention:

[0233] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the aforementioned ancient seawall structure safety assessment method based on nonlinear bonding elements.

[0234] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, optical storage, etc.) containing computer-usable program code.

[0235] The present application is described in terms of flowcharts or / and block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process or / and block in the flowchart or / and block diagram, as well as the combination of processes or / and blocks in the flowchart or / and block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0236] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0237] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0238] The model in this application is an object that objectively describes the morphological structure with the help of physical or virtual representation. The object is not equal to the physical body and is not limited to physical and virtual. It can be a data processing function, software program, processing mode, usage method, operation method, workflow, application process, electronic hardware, circuit module, processing system, system imitation or simulation object.

[0239] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field can still modify or replace the specific implementation methods of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. The safety assessment method of ancient seawall structure based on nonlinear bonding element is characterized by: The following steps are involved: Step 1: Process the structural information of a seawall section using the previously constructed seawall grid generation model to obtain a seawall simulation grid. Step 2: Using the previously constructed seawall boundary search model, the seawall simulation grid is processed to obtain a boundary grid, which is used to represent the interface between the seawall body and the soil body, as well as the connection between the stone bodies. Step 3: Using the previously constructed seawall property simulation model, based on a nonlinear constitutive algorithm, the boundary mesh is assigned nonlinear element properties to form bonded elements. The method is as follows: Obtaining a boundary mesh, which includes a soil node group, a pond node group, an upper node group, and a lower node group; According to the order of the nodes in the soil node group and the pond node group, quadrilateral elements with zero thickness are sequentially established as the first mesh element group at the interface between the pond and the soil; Based on the nonlinear constitutive algorithm, the first grid unit group is given the properties of nonlinear units, so that the first grid units have elastic-plastic deformation capabilities, thereby obtaining the first bonding unit group, which is used to simulate the contact between the pond body and the soil; According to the order of nodes in the upper node group and the lower node group, quadrilateral elements with zero thickness are sequentially established as the second grid element group of the stone body interface; Based on the nonlinear constitutive algorithm, the second grid unit group is given the attributes of nonlinear units, so that the second grid units have damage characteristics, thereby obtaining the second bonding unit group, which is used to simulate the bonding effect between the stone bodies; coupling the first grid unit group and the second bonding unit group to obtain a bonding unit; Step 4: Using the previously constructed seawall deformation simulation model, loads are applied to the bonding units, and an elastic-plastic algorithm is used for simulation calculation to obtain the structural deformation data of the seawall. Step five: Based on the previously constructed seawall safety assessment model, the structural deformation data of the seawall is analyzed to obtain the safety assessment information of the seawall structure and complete the safety assessment of the ancient seawall structure based on the nonlinear bonding unit.

2. The method for safety assessment of ancient seawall structures based on nonlinear bonding elements according to claim 1, characterized in that: Step 1: Process the cross-sectional structural information of a seawall using the previously constructed seawall mesh generation model to obtain the seawall simulation mesh as follows: Obtain the structural information of a seawall section at the current operation stage; Based on the cross-sectional structural information of a seawall, the actual cross-sectional structural data is determined, which includes the backfill, the layered soil of the pond foundation, the stone blocks, the pond body, and the supporting piles in front of the pond. The backfill behind the pond, the layered soil of the pond foundation, and the supporting piles in front of the pond are unified as the soil part of the model. The scope of action of the pile load, water pressure load, pond body deadweight load and boundary effect are considered to obtain the soil geometry simulation object. The stone body is used as a unified model of the pond body, and considering the horizontal surge effect, the stone body is layered in the horizontal direction to obtain the pond body geometric simulation object; The soil geometry simulation object and the pond geometry simulation object are meshed separately, and the mesh close to the pond body is locally encrypted to obtain the soil mesh and the pond mesh. The nodes of the soil mesh and the pond mesh are merged according to their spatial positions to obtain a complete seawall simulation mesh.

3. The safety assessment method for ancient seawall structures based on nonlinear bonding elements according to claim 1 is characterized in that: Step 2: Use the previously constructed seawall boundary search model to process the seawall simulation grid. The method to obtain the boundary grid is as follows: Obtaining a seawall simulation grid, which includes a soil grid and a pond grid; Based on the soil partial grid and the pond partial grid, grid nodes on the interface between the soil and the pond are obtained, and a soil node group and a pond node group are formed; the soil node group and the pond node group have the same geometric position and one-to-one correspondence, and belong to the soil partial grid and the pond partial grid respectively; Based on the partial grid of the pond body, at the interface where two stone strips contact each other, select the upper node group at the bottom of the upper stone strip and the lower node group at the top of the lower stone strip; the geometric positions of the upper node group and the lower node group are the same and correspond one to one; The soil node group, pond node group, upper node group and lower node group are aggregated to obtain the boundary mesh.

4. The method for safety assessment of ancient seawall structures based on nonlinear bonding elements according to claim 1, characterized in that: Based on the nonlinear constitutive algorithm, the method of assigning nonlinear unit attributes to the first mesh unit group so that the first mesh unit has elastic-plastic deformation capability is as follows: From the geological survey data of the seawall section, the physical and mechanical parameters of each layer of the seawall foundation and the backfill are obtained; Based on physical and mechanical parameters, the Mohr-Coulomb yield criterion is established; According to the Mohr-Coulomb yield criterion, the model parameters are set, including normal stiffness, tangential stiffness, interface adhesion, interface friction coefficient and isotropic hardening parameter; Based on the elastic part and the plastic part, the interface tangential displacement is calculated; Calculate the interface shear stress based on the elastic part and tangential stiffness; Calculate the interface normal stress based on the normal stiffness and interface normal displacement Calculate the flow criterion value based on the interface shear stress, interface normal stress, interface friction coefficient, interface adhesion, isotropic hardening parameter and cumulative tangential displacement; When the flow criterion value is less than zero for the tangential behavior of the interface, the first grid element is in the elastic stage and the plastic part of the tangential displacement remains unchanged; When the interface tangential displacement is equal to zero when the flow criterion value is equal to zero, the plastic part of the first grid element begins to accumulate, and the plastic displacement increment on the yield surface obeys the Mohr-Coulomb yield criterion; According to the flow criterion value, the contact surface of the first grid unit group is assigned with the properties of a nonlinear unit, so that the first grid unit has elastic-plastic deformation ability, thereby realizing the simulation of the contact and friction interaction process of the first grid unit group.

5. The method for safety assessment of ancient seawall structures based on nonlinear bonding elements according to claim 1, characterized in that: Based on the nonlinear constitutive algorithm, the second mesh unit group is given nonlinear unit attributes so that the second mesh unit has damage characteristics. The method for obtaining the second bonding unit group is as follows: Obtain the bonding structure data of the stone body from the seawall material data; The bonding structure data of the stone body at least include interface pressure, density, elastic modulus and Poisson's ratio; Based on the bonding structure data of the stone strips, the stress-strain curve of the stone strips was generated to characterize the strength of the sticky rice mortar bonding the stone strips. According to the stress-strain curve of the stone body, the interface tangential stiffness, normal stiffness and interface tensile strength limit are determined; Based on the normal stiffness and softening slope, the relationship between the constitutive interface normal stress and interface normal displacement is established; Based on the interface tangential stiffness, interface tensile strength limit and control parameters, the relationship between interface tangential stress, interface tangential displacement and interface normal displacement, namely the relationship between normal cracking and tangential stiffness, is established. According to the changing relationship between the constitutive interface normal stress and interface normal displacement and the normal crack-tangential stiffness relationship, the second grid unit group is assigned nonlinear unit properties to simulate the bonding effect between the stone bodies, so that the second grid unit has damage characteristics, thereby obtaining the second bonding unit group.

6. The safety assessment method for ancient seawall structures based on nonlinear bonding elements according to claim 5, characterized in that: The relationship between the constitutive interface normal stress and interface normal displacement includes the following: When the interface normal displacement exceeds the critical damage displacement, damage begins to occur in the normal direction of the interface; When the interface normal displacement reaches the fracture limit, the interface fractures normally; As the interface normal damage evolves, the critical damage displacement gradually evolves from the initial displacement value to the normal fracture threshold; The interface normal stress evolution is divided into four stages, including the normal elastic behavior under the interface compression state, the normal elastic behavior under the interface normal opening state, the normal damage behavior under the interface normal opening state, and the interface tangential complete destruction stage. Or / and, the relationship between normal cracking and tangential stiffness, including the following: By adjusting the control parameters, different relationships between normal cracking and tangential stiffness are constructed. When the control parameter is equal to zero and the normal displacement is greater than zero, the tangential stiffness of the interface immediately drops to zero. When the control parameter is equal to two, the tangential stiffness of the interface is independent of the normal displacement of the interface and remains constant. The evolution of the interface tangential stress is divided into three stages, including the tangential elastic behavior under the interface compression state, the tangential elastic behavior under the interface normal opening state, and the interface tangential complete destruction stage.

7. The method for safety assessment of ancient seawall structures based on nonlinear bonding elements according to claim 6, characterized in that: Step 4: Using the previously constructed seawall deformation simulation model, loads are applied to the bonding units and an elastic-plastic algorithm is used for simulation calculations. The method for obtaining the structural deformation data of the seawall is as follows: Obtain the loads on the seawall, including hydrostatic pressure, wave force and backfill load; Set displacement boundary conditions, including vertical displacement limit at the bottom and horizontal displacement limit on both sides; Apply load and displacement boundary conditions to the bonding unit and conduct simulation analysis to obtain the maximum displacement of the pond body and the maximum shear stress between the stone bodies. The maximum displacement of the seawall body and the maximum shear stress between the stone blocks are coupled to obtain the structural deformation data of the seawall.

8. The safety assessment method for ancient seawall structures based on nonlinear bonding elements is characterized by: Includes the following: Using a previously constructed seawall mesh generation model, and based on the latest drawings of the ancient seawall cross-section, the geometric models of the ancient seawall's stonework, soil behind the seawall, and bottom soil were drawn. Finite element meshes were then divided to obtain the seawall mesh and soil mesh. The nodes of the seawall mesh and soil mesh were then merged, and parameters for each layer of soil, each level of stonework, and bonding material were set based on survey and test data to obtain the seawall simulation mesh. Using the previously constructed seawall property simulation model and based on the seawall simulation grid, the bonding units between the seawall body and the soil, and the bonding units between the stone bodies, were obtained. The method is as follows: Based on the seawall simulation grid, the grid nodes at the interface between the pond mesh and the soil mesh are copied to form two groups of nodes with the same geometric position and one-to-one correspondence. These groups belong to the pond mesh and the soil mesh respectively, thus obtaining independent pond mesh and soil mesh parts. Subsequently, the four corresponding nodes above and below sequentially form a degenerate interface mesh, which is assigned the properties of a nonlinear unit to the interface mesh between the pond and soil, forming a bonding unit between the pond and soil. Based on the seawall simulation grid, the unit nodes on the bonding interface between the stone strips are copied to form two groups of unit nodes with the same geometric position and one-to-one correspondence, one belonging to the stone strips of the two ancient seawalls. A degenerate unit grid is formed based on the unit node groups, and the unit grid between the stone strips is then assigned nonlinear unit properties to form bonding units between the stone strips. Using the previously constructed seawall deformation simulation model, loads were applied to the bonding units, and simulation calculations were performed using an elastic-plastic algorithm to obtain the structural deformation data of the seawall. The structural deformation data of the seawall were then analyzed to obtain safety assessment information for the seawall structure, completing the safety assessment of the ancient seawall structure based on nonlinear bonding units.

9. The safety assessment system for ancient seawall structures based on nonlinear bonding elements is characterized by: It includes: one or more processors; a storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the ancient seawall structure safety assessment method based on nonlinear bonding elements as described in any one of claims 1 to 8.

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