Dam anti-seismic performance evaluation method and device and storage medium

Abstract

The invention relates to the technical field of dam safety monitoring, in particular to a dam anti-seismic performance evaluation method, device and equipment and a computer storage medium. According to the dam anti-seismic performance evaluation method, earthquake response analysis and safety evaluation are carried out by comprehensively providing a cross-scale analysis method, a high-performance calculation technology, a whole-process generalized plastic coarse-grained soil constitutive model, inverted constitutive model parameters and an earthquake safety grading evaluation index system; real dynamic characteristics and anti-seismic performance of the dam are revealed, the influence of the rheological effect on dynamic deformation is quantified, and a dam anti-seismic performance evaluation system based on monitoring data is established so as to accurately describe the anti-seismic performance of the dam.

Description

Technical Field

[0001] The present invention relates to the technical field of dam safety monitoring, and in particular to a dam seismic performance evaluation method, device, equipment and computer storage medium. Background Art

[0002] Hydropower resources are an important clean and renewable energy source, playing an important role in meeting energy demand, improving energy structure, promoting economic development, and reducing carbon dioxide emissions. my country has planned, built and operated many high-dam hydropower station projects, which have promoted the sustained and healthy development of the regional economy and achieved significant social and economic benefits. However, in high-intensity earthquake zones with complex geological structures and frequent seismic activities, the probability of a dam encountering a strong earthquake during its service life is high, and there is a risk of damage or even collapse due to a strong earthquake. Therefore, how to reveal the true dynamic characteristics and seismic performance of the dam is an issue we need to pay attention to.

[0003] Due to the scattered soil material sites of earth-rock dam projects, the great differences in the origin and physical and mechanical properties of the soil materials, and the great uncertainty in the calculation parameters of the earth-rock materials, the existing various quantitative calculation and analysis methods based on indoor test material parameters cannot accurately reflect the static behaviors of earth-rock dams such as stress, deformation and permeability, and it is even more difficult to describe the complex dynamic characteristics and seismic performance of earth-rock dams. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that the seismic performance of a high earth-rock dam cannot be accurately described.

[0005] In order to solve the above technical problems, the present invention provides a method for evaluating the seismic performance of a dam, comprising:

[0006] Establishing a geometric entity model of the dam, and discretizing the geometric entity model into a cross-scale fine grid based on an octree algorithm to obtain a volume grid model;

[0007] The volume mesh model is analyzed by using a nonlinear polyhedron proportional boundary finite element method to establish a finite element model;

[0008] Based on the finite element model, a generalized plastic coarse-grained soil constitutive model that adopts the unified static-rheological-dynamic whole process is established, and based on the measured data, an elastic-plastic inverse analysis of the generalized plastic coarse-grained soil constitutive model considering the long-term deformation of the dam is performed;

[0009] The generalized plastic coarse-grained soil constitutive model using the material parameters of the inverse analysis results is used for earthquake input to calculate the dam crest subsidence rate;

[0010] The seismic performance of the dam is evaluated based on the dam crest subsidence rate.

[0011] Preferably, after obtaining the volume mesh model, the step further includes:

[0012] The similar nodes at the interface between the components are merged and shared.

[0013] Preferably, the volume mesh model is analyzed using a nonlinear polyhedron scaled boundary finite element method, and establishing the finite element model comprises:

[0014] Performing block-conical domain integration on the volume mesh model;

[0015] The nonlinear stiffness matrix of the polyhedral element is calculated based on the strain-displacement conversion matrix at the integration points in the domain and the elastic-plastic constitutive matrix of the material;

[0016] Assembling the nonlinear stiffness matrix of the polyhedral unit piecewise according to the degree of freedom to obtain the overall stiffness matrix of the domain;

[0017] According to the surface force load vector and volume force load vector of the polyhedron, the external force load vector is obtained;

[0018] The internal force load vector of the polyhedral element is calculated based on the strain-displacement conversion matrix and the material nonlinear constitutive matrix at the integration points in the domain.

[0019] Preferably, the calculation method of the nonlinear stiffness matrix of the polyhedral unit includes:

[0020] For the cube elements in the volume mesh model, the similar element acceleration algorithm is used to calculate the nonlinear stiffness matrix of the cube elements:

[0021] Pre-calculate and store the stiffness matrix of the unit cube element or the stiffness matrix at the integration point of the unit size element;

[0022] Based on the stiffness matrix of the unit cube unit or the stiffness matrix at the integration point of the unit size unit, the stiffness matrix of any cube unit is obtained according to the corresponding proportional coefficient.

[0023] Preferably, the method for establishing the generalized plastic coarse-grained soil constitutive model comprises:

[0024] Since the nonlinearity of the material is inversely proportional to the load step length, the correlation between the nonlinearity index of the current stress state and the strain integration step length is established based on statistical data;

[0025] The constitutive integration with adaptive step length is performed according to the association relationship to establish the generalized plastic coarse-grained soil constitutive model.

[0026] Preferably, the method for acquiring the earthquake motion input is:

[0027] The earthquake stages are classified according to the characteristics of the seismic waves;

[0028] Different monitoring time steps are used for different levels of earthquake stages, where the earthquake stage level and monitoring time step are inversely proportional;

[0029] Acquire seismic wave monitoring data according to the adaptive monitoring time step;

[0030] The seismic wave monitoring data is subjected to seismic wave interception according to the Arias intensity to obtain the seismic motion input.

[0031] Preferably, evaluating the seismic performance of the dam according to the dam crest subsidence rate includes:

[0032] Since the dam top settlement rate and the dam slope slippage are positively correlated, the dam slope slippage is obtained by calculating the dam top settlement rate;

[0033] If the dam slope slippage amount is not higher than the dam-break index, the extent of earthquake damage is determined based on the dam top subsidence rate and pre-established earthquake safety grading evaluation indicators.

[0034] The present invention also provides a dam seismic performance evaluation device, comprising:

[0035] A grid model building module is used to build a geometric entity model of the dam, and to discretize the geometric entity model into a cross-scale fine grid based on an octree algorithm to obtain a volume grid model;

[0036] A finite element module establishment module is used to analyze the volume mesh model using a nonlinear polyhedron proportional boundary finite element method to establish a finite element model;

[0037] An inverse analysis module is used to establish a generalized plastic coarse-grained soil constitutive model that uses a unified static-rheological-dynamic whole process based on the finite element model, and to perform an elastoplastic inverse analysis of the generalized plastic coarse-grained soil constitutive model taking into account the long-term deformation of the dam based on measured data;

[0038] The seismic index calculation module is used to input seismic motion into the generalized plastic coarse-grained soil constitutive model using the material parameters of the inversion analysis results, and calculate the dam crest subsidence rate;

[0039] The seismic performance evaluation module is used to evaluate the seismic performance of the dam according to the dam crest subsidence rate.

[0040] The present invention also provides a dam seismic performance assessment device, comprising:

[0041] Memory for storing computer programs;

[0042] A processor is used to implement the above-mentioned steps of the method for evaluating the seismic performance of a dam when executing the computer program.

[0043] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned method for evaluating the seismic performance of a dam are implemented.

[0044] The above technical solution of the present invention has the following advantages compared with the prior art:

[0045] The dam seismic performance evaluation method described in the present invention comprehensively proposes a cross-scale analysis method, high-performance computing technology, a generalized plastic coarse-grained soil constitutive model for the whole process, inverted constitutive model parameters and a seismic safety grading evaluation index system to carry out seismic response analysis and safety evaluation, revealing the true dynamic characteristics and seismic performance of the dam, quantifying the influence of rheological effects on dynamic deformation, and establishing a dam seismic performance evaluation system based on monitoring data to accurately describe the seismic performance of the dam. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0047] Figure 1 It is a flow chart of the implementation of a dam seismic performance evaluation method provided by the present invention;

[0048] Figure 2 It is a schematic diagram of the distribution of integration points of integration scheme 1 within the domain;

[0049] Figure 3 It is a comparative diagram of the distribution of the integral points in the triangular domain of the domain integration schemes 1 and 2;

[0050] Figure 4 It is a schematic diagram of the distribution of integration points within each tetrahedron in the domain integration scheme 3;

[0051] Figure 5 It is a schematic diagram of the similarity relationship of the cube element stiffness matrix in the elastic problem;

[0052] Figure 6 It is a schematic diagram of the similarity relationship of the cube element stiffness matrix in the Lee-Fenves plastic damage model;

[0053] Figure 7 It is a schematic diagram of the similarity relationship of the cube element stiffness matrix in the generalized plastic model of soil;

[0054] Figure 8 It is a schematic diagram of the accuracy comparison before and after the optimization of the constitutive integral step size;

[0055] Fig. 9 It is a schematic diagram of time step optimization;

[0056] Fig.10 This is a schematic diagram of the accuracy comparison before and after time step optimization;

[0057] Fig.11 It is a schematic diagram of earthquake motion input;

[0058] Fig.12 It is a schematic diagram of the relationship between the dam crest subsidence rate and the peak acceleration;

[0059] Fig.13 Schematic diagram of post-earthquake deformation. DETAILED DESCRIPTION

[0060] The core of the present invention is to provide a dam seismic performance evaluation method, device, equipment and computer storage medium, which effectively improves the accuracy of the dam seismic performance description.

[0061] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0062] Please refer to Figure 1 , Figure 1 This is a flow chart of the implementation of a dam seismic performance evaluation method provided by the present invention; the specific operation steps are as follows:

[0063] S101: Establish a geometric entity model of the dam, and discretize the geometric entity model into a cross-scale fine grid based on an octree algorithm to obtain a volume grid model;

[0064] S102: Analyzing the volume mesh model using a nonlinear polyhedron scaled boundary finite element method to establish a finite element model;

[0065] S103: Based on the finite element model, a generalized plastic coarse-grained soil constitutive model that adopts a unified static-rheological-dynamic whole process is established, and based on measured data, an elastic-plastic inverse analysis of the generalized plastic coarse-grained soil constitutive model considering the long-term deformation of the dam is performed;

[0066] S104: Performing earthquake motion input on the generalized plastic coarse-grained soil constitutive model using the material parameters of the inversion analysis results to calculate the dam crest subsidence rate;

[0067] S105: Evaluate the seismic performance of the dam according to the dam crest subsidence rate.

[0068] Based on the above embodiments, this embodiment describes step S101 in detail:

[0069] According to the requirements of numerical calculation, the discrete grid size of each component can be set, and the created dam BIM geometric entity model can be directly discretized by Octree cross-scale fine grid. Subsequently, the discretized model encoding data can be converted into finite element data that can be used by CAE software through a self-written program.

[0070] ① Based on the IFC standard, the Dashixia BIM geometric entities are imported into the Octree mesh generation software through intermediate files.

[0071] ② For some mesh generation software, it is necessary to run the error checking function in advance to recheck geometric errors (such as perforated surfaces, free edges, non-manifold nodes, non-manifold edges, etc.). If there are local detail errors, the model must be repaired through the software's automatic repair function or manual edge structure reorganization operation, otherwise subsequent discretization work cannot be performed.

[0072] ③ According to the numerical calculation requirements, the discrete grid size parameters can be set according to the calculation accuracy of each partition component, and some methods can be used to control the local size. Different grid size parameters can be combined into a variety of discrete schemes, and the optimal scheme can be calculated based on the overall quality and quantity ratio of the discrete units.

[0073] ④ Run the Octree discretization program to obtain the volume mesh model.

[0074] ⑤ Use the node fusion (merge) function to share similar nodes at the interface between components, which is convenient for subsequent numerical calculations.

[0075] Based on the above embodiments, this embodiment describes step S102 in detail:

[0076] The volume mesh model is analyzed by using a nonlinear polyhedron proportional boundary finite element method to establish a finite element model, which includes:

[0077] Perform block-conical domain integration on the volume mesh model:

[0078] The present invention provides three different intra-domain integration schemes, which are defined as Scheme 1, Scheme 2 and Scheme 3 respectively to simplify naming and expression.

[0079] 1) In-domain integration scheme 1

[0080] Figure 2 The following is an explanation of the selection of integration points: is the polygon mean interpolation function, N FEM It is the linear interpolation function of the triangle unit. The implementation process is described as follows:

[0081] First, each annular boundary surface unit is converted into the corresponding standard isoparametric regular polygon unit. Then, the center of the circle and the corner points of the regular polygon are connected to divide each polygon into multiple triangles. Three integration points are selected in each triangular domain, and their local coordinates (r, s) are taken as (1 / 6, 1 / 6), (2 / 3, 1 / 6), and (1 / 6, 2 / 3), respectively. The corresponding weight is 1 / 3, and they are called boundary area integration points.

[0082] like Figure 2 As shown, the dimensionless radial coordinate ξ ranges from [0,1], with a value of 0 at the center of the scale and a value of 1 at the boundary. According to the quadrature rule in one-dimensional problems, we can know that: For a three-dimensional problem, the two points in the one-dimensional problem will correspond to the two planes in the three-dimensional problem, see Figure 2 Then, the integration points are inserted on the two selected ξ planes. The positions of the inserted points are exactly the same as the boundary integration points, except that their weights become 1 / 6. These inserted integration points are called in-domain integration points.

[0083] 2) In-domain integration scheme 2

[0084] The idea of ​​Scheme 2 is completely similar to that of Scheme 1. The boundary integration points of the two are exactly the same. The difference is the number of integration points selected in the domain. In Scheme 2, in the two planes where the integration points are inserted, only one integration point is assigned to each triangular domain, that is, the integration accuracy is first-order accuracy, and its coordinates are (1 / 3,1 / 3), see Figure 3 .

[0085] 3) In-domain integration scheme 3

[0086] In a polyhedral unit, different cone units can be obtained by connecting the scale center and the nodes of each annular boundary surface. For any cone unit, by connecting the scale center (O) and the center point of the annular boundary surface (O'), and then connecting the center point of the annular boundary surface to the boundary surface nodes, the cone can be divided into multiple tetrahedral units. Figure 4 As shown, in each tetrahedron, according to the Hammer integration rule, four integration points are introduced (Wang Xucheng, 2002), and their coordinates are expressed as a(α, β, β, β), b(β, α, β, β), c(β, β, α, β), and d(β, β, β, α), where α and β are 0.5854102 and 0.1381966 respectively, and the corresponding weight is 1 / 24.

[0087] Among them, Scheme 3 is the most preferred scheme, which has the highest calculation accuracy and the fastest error reduction rate.

[0088] The nonlinear stiffness matrix of the polyhedral element is calculated based on the strain-displacement conversion matrix at the integration points in the domain and the material elastic-plastic constitutive matrix:

[0089] The calculation formula of the nonlinear stiffness matrix of the polyhedral element can be solved by the strain displacement matrix and the constitutive matrix, as shown in formula (1):

[0090]

[0091] By selecting the integral point in the domain, the definite integral is calculated, and equation (1) can be expanded into (2):

[0092]

[0093] Where m is the number of boundary faces of the polyhedral unit, p k is the total number of integration points in the domain on the kth boundary surface, B i (ξ,ξ1,ξ2) represents the strain-displacement transformation matrix at the i-th integration point; is the material elastoplastic constitutive matrix value at the i-th integration point; V i is the volume V represented by the i-th integration point e .

[0094] · Assemble the nonlinear stiffness matrix of the polyhedral unit piece by piece according to the degree of freedom to obtain the overall stiffness matrix of the domain;

[0095] According to the surface force load vector and volume force load vector of the polyhedron, the external force load vector is obtained:

[0096] External force load vector R ext The expression is (4-1-3).

[0097]

[0098] The first term on the right side of the equation is the surface force load vector. On the boundary surface (ξ=1), the equation can be expanded into equation (4):

[0099]

[0100] The second term on the right side of the equation is the body force load vector, which can be expanded into equation (5) based on the numerical integration calculation of the integration point:

[0101]

[0102] Calculate the internal force load vector of the polyhedral element based on the strain-displacement conversion matrix and the material nonlinear constitutive matrix at the integration point in the domain:

[0103] The calculation formula for the internal force load vector can be written as (6).

[0104]

[0105] According to the unit strain calculation formula, the polyhedron unit strain ε(ξ,ξ1,ξ2) is solved, see formula (7), and the unit stress σ is solved by using Hooke's law i (ξ,ξ1,ξ2), see formula (4-1-8), where is the nonlinear constitutive matrix of the material.

[0106] ε(ξ,ξ1,ξ2)=B(ξ,ξ1,ξ2)u b (7)

[0107]

[0108] By adopting the block cone domain integration scheme and substituting (7) and (8) into equation (6), we can obtain the numerical integration formula of the internal force vector of the polyhedral unit, as shown in (9):

[0109]

[0110] Where m is the number of boundary faces of the polyhedral element, p k is the total number of integration points in the kth boundary surface, B ki (ξ,ξ1,ξ2) represents the strain-displacement transformation matrix at the i-th integration point in the k-th boundary surface, which is calculated by equation (6); is the material nonlinear constitutive matrix value at the i-th integration point; V ki is the volume V represented by the i-th integration point in the k-th boundary surface e .

[0111] Based on the above embodiment, the calculation method of the nonlinear stiffness matrix of the polyhedral unit includes:

[0112] For the cube elements in the volume mesh model, the similar element acceleration algorithm is used to calculate the nonlinear stiffness matrix of the cube elements:

[0113] Pre-calculate and store the stiffness matrix of the unit cube element or the stiffness matrix at the integration point of the unit size element;

[0114] Based on the stiffness matrix of the unit cube unit or the stiffness matrix at the integration point of the unit size unit, the stiffness matrix of any cube unit is obtained according to the corresponding proportional coefficient.

[0115] For the eight-node isoparametric unit in the finite element, the stiffness matrix of each unit is calculated as follows: The calculation formula is expanded to Solving the unit stiffness matrix once will require 32832 addition operations and 35136 multiplication operations. Similarly, the mass matrix, permeability matrix, compression matrix, coupling matrix, etc. in the saturated porous media analysis all require many arithmetic operations. When performing large-scale calculations with millions or even tens of millions of degrees of freedom, the unit operation volume is very large.

[0116] Octree is used for mesh discretization, and the large proportion of cube elements is one of the remarkable characteristics of the mesh. In the representative model of discretization, there are about 50% to 65% cube elements. For cube elements, their shapes are exactly the same, and they only differ by a size coefficient, so the elements are geometrically similar. If the unit matrix of a cube of unit size is given, the unit matrix of other cubes of the same material can be easily described. The following takes the elastic model, concrete plastic damage model and generalized plastic model as examples to explain in detail:

[0117] For elastic problems, when calculating the unit stiffness, the strain displacement matrix B, material constitutive matrix D and unit volume V of the cube unit with side length l and unit size unit exist Figure 5 Substituting into the stiffness matrix calculation formula, K can be easily obtained l The proportional relationship with K1, where the proportional coefficient S c is the unit side length l and the material elastic modulus E l Therefore, the stiffness matrix K1 of the unit cube unit can be pre-calculated and stored, and then the proportional coefficient S c , you can get the cube unit stiffness matrix K1 of any size. According to statistics, after the unit stiffness matrix calculation adopts unit similarity acceleration, no addition operation is required, and 98.4% of the multiplication operations can be reduced, which greatly improves the calculation efficiency of the unit matrix. Similarly, the mass matrix, damping matrix, etc. can also be solved by this idea.

[0118] It can be seen from the elastic similarity unit algorithm that the similarity coefficient S c It is mainly related to the unit size and the elastic modulus of the material. In the Lee-Fenves plastic damage model and the generalized plastic model of soil, when the unit begins to be damaged or the soil enters plasticity, the value of the material modulus at each integration point is different, so the overall unit is not similar.

[0119] However, at the integration point j with the same local coordinates, the material modulus is similar, so the stiffness matrix at this point is similar. Therefore, the stiffness matrix [K l ] j , and then use the proportionality coefficient S at each integration point cj Calculate the stiffness matrix of any element ( Figure 6 and Figure 7). According to statistics, in the solution of each unit stiffness matrix, the use of similar units can reduce the addition operation by 85.9% and the multiplication operation by 88.5% after acceleration, which is quite significant.

[0120] Based on the above embodiment, step S103 is described in detail:

[0121] The sorting and analysis of prototype monitoring data are very important for understanding the real deformation characteristics of earth-rock dams and conducting inversion analysis. For the inversion of rockfill parameters, it is meaningful to carry out inversion analysis only under the premise of ensuring that the monitoring data is reasonable and reliable. Nuozhadu super-high core wall dam has obtained a large amount of measured data during the filling period, water storage period and normal operation period, which is very valuable for the scientific research of earth-rock dams. Therefore, before conducting inversion analysis, this paper first sorts out and analyzes the measured data. On the one hand, it can well understand the real deformation characteristics of the super-high core wall dam, and on the other hand, it provides a reliable basis for the subsequent inversion analysis work, so as to select reasonable and reliable inversion target measurement points and target measurement values.

[0122] The generalized plastic model improved by Dagong has a greater advantage than the Duncan Zhang EB model in simulating the static deformation of the dam. It not only agrees well with the measured values ​​in terms of vertical settlement, but also agrees well with the measured values ​​in terms of displacement along the river. At the same time, the generalized plastic model improved by Dagong can realize static, dynamic and post-seismic deformation analysis with a set of parameters, which is convenient for conducting seismic performance research on the dam.

[0123] Through the analysis and sorting of measured data, it can be seen that the rheological deformation of rockfill is large and should be considered in numerical calculations. In the past, inverse analysis or numerical simulation without considering rheology actually included rheological deformation in the transient deformation by default, weakening the parameters of the transient constitutive model. The rheology of rockfill refers to the change of deformation over time after the load is added (filled), that is, the stones are broken and rearranged over time, which is essentially different from the transient deformation. The transient deformation and rheological deformation should be considered comprehensively.

[0124] Therefore, based on the existing static-dynamic unified generalized plastic model, the present invention proposes a static-dynamic unified elastoplastic coarse-grained soil constitutive model considering rheological effects. The proposed model is used to carry out an elastoplastic inversion analysis considering the long-term deformation of the dam. The results show that: whether in the filling stage or the normal operation stage of the dam, the calculated values ​​of the vertical settlement and the calculated values ​​of the displacement along the river at most of the measuring points in the downstream dam body are in good agreement with the measured values, which proves the reliability of the inversion results and the rationality of the constitutive model parameters. The inversion analysis results considering the long-term deformation of the dam can accurately predict the deformation of the dam in the normal operation stage, and also lay the foundation for the accurate prediction of the dynamic response of the dam.

[0125] Based on the above embodiments, the method for establishing the generalized plastic coarse-grained soil constitutive model includes:

[0126] Since the nonlinearity of the material is inversely proportional to the load step length, the correlation between the nonlinearity index of the current stress state and the strain integration step length is established based on statistical data;

[0127] ·According to the association relationship, a constitutive integration with an adaptive step length is performed to establish the generalized plastic coarse-grained soil constitutive model.

[0128] The accuracy and convergence speed of nonlinear finite element analysis are closely related to the load step size and the degree of material nonlinearity. The stronger the nonlinearity, the smaller the required load step size. For high earth-rock dam projects, the degree of nonlinearity of the entire model is not the same in time and space during the entire earthquake process. The present invention establishes the correlation between the nonlinearity index of the current stress state and the strain integration step size through statistical data, and proposes a constitutive integration method with adaptive step size. While ensuring the accuracy remains unchanged (see Figure 8 ), the computational efficiency of the constitutive integral is improved by 4.2 times.

[0129] Based on the above embodiments, this embodiment describes step S104 in detail:

[0130] Since the dam top settlement rate and the dam slope slippage are positively correlated, the dam slope slippage is obtained by calculating the dam top settlement rate;

[0131] If the dam slope slippage is not higher than the dam-break-free index, the earthquake damage degree is determined based on the dam top collapse rate and the pre-established earthquake safety classification evaluation index.

[0132] The basic understanding of earthquake-resistant design of dams in my country is that moderate earthquakes will not damage them, large earthquakes can be repaired, and extreme earthquakes will not collapse. In other words, under extreme earthquakes, the dam is allowed to suffer a certain degree of damage or even serious earthquake damage, but it should be able to maintain its water storage capacity and avoid dam collapse. The safety of earth-rock dams under strong earthquakes has attracted much attention, namely the ultimate earthquake resistance of earth-rock dams. The main analysis content includes how big an earthquake the earth-rock dam can withstand, the safety margin of the dam under strong earthquakes, what damage will occur to the dam under strong earthquakes, and the failure mode. Because the ultimate earthquake resistance of high earth-rock dams is relatively complicated, many scholars at home and abroad have also conducted a lot of research on it. However, there is currently no unified specification or standard at home and abroad to explain the evaluation criteria for the ultimate earthquake resistance of earth-rock dams.

[0133] Reservoir water overflow is the primary issue in determining earth-rock dam failure in earthquake situations. Under strong earthquakes, earth-rock dams will experience significant dam crest subsidence. If the earthquake causes the dam crest elevation to be lower than the reservoir water level, there will be a risk of dam failure due to overtopping. In order to prevent reservoir water overflow, the allowable earthquake dam crest settlement should be less than the water level superelevation on the upstream side. Therefore, the dam crest subsidence is a key indicator for judging the failure of high earth-rock dams.

[0134] The present invention studies the quantitative indicators of ultimate seismic capacity evaluation under different dam heights, dam crest widths, dam slope gradients, seismic peak intensity and seismic characteristics for high earth-rock dams. For high core wall dams, by summarizing the design of high core wall rockfill dams that have been built, are under construction and are planned to be built in my country, the calculation conditions are set as dam heights of 200m, 250m and 300m, dam crest width of 16m, upstream and downstream dam slopes of 1:1.9 and 1:1.8 respectively, and the finite element model of the typical working conditions of high core wall dams is shown in Figure 1. Figure 7-1 -4, 5, where the dam slope was selected as the most unfavorable design condition for high dams, the seismic waves used the input earthquake motions of actual projects such as Lawa, Dashixia, and Houziyan, the dynamic response calculation adopted the elastoplastic dynamic analysis method, the rockfill constitutive model adopted the generalized plastic model improved by Dagong, and the finite element dynamic stability and sliding deformation analysis methods were used to calculate the dam slope slip, in order to explore the correlation between the settlement rate and the slip amount. In the dynamic calculation, the dam crest settlement rate refers to the ratio of the vertical settlement at the midpoint of the dam crest to the dam height, and the slip amount is calculated using the sliding surface of the sliding arc position passing through the transition and anti-filter junction area. By calculating the different earthquake motion peaks for the set conditions, the relationship between the settlement rate and the slip amount of the core wall dam crest was sorted out. Figure 6-1 -5. It can be found that the dam crest settlement rate shows an obvious positive correlation with the dam slope slip. In addition, since the dam slope slip is only a local shallow sliding, it can be considered that it has been reflected in the dam crest settlement. The dam crest settlement is the true embodiment of the dam deformation.

[0135] When designing a dam, there will be a certain height difference between the normal water level of the dam and the dam crest elevation (referred to as height difference in this project, and its ratio to the dam height is called "height difference rate"). This project summarizes 35 earth-rock dam projects at home and abroad, with dam heights ranging from 126m to 315m. According to the statistical results, the height difference rate of earth-rock dams built at home and abroad is greater than 2%, that is, when the earthquake dam body collapse rate is not greater than 2% during normal water storage, the reservoir water will not overflow.

[0136] The present invention is based on the actual earthquake damage statistics of earth-rock dams by Swaisgood (2003), combined with the earthquake damage of Zipingpu Dam. From the statistical results, it can be seen that with the increase of peak acceleration, the settlement rate of earth-rock dams increases step by step, but there is no sudden change trend between the settlement rate and the peak earthquake acceleration. From the existing earthquake damage results, it can be seen that when the core wall rockfill dam is less than 1.1%, there is no problem that the dam cannot be repaired after the earthquake to meet the subsequent operation function; in addition, there are multiple earth dams and hydraulic filling dams that have a settlement rate greater than 1.5% and no catastrophic damage occurs (earth-rock dams are better than earth dams and hydraulic filling dams because of their construction and control standards. They should be safer under the same settlement rate conditions).

[0137] Taking into account that the current construction quality and control standards of RCD dams are far superior to those of earth dams and hydraulic fill dams, and combining the existing earthquake damage cases of RCD dams with certain conservative treatments, it is recommended that the earthquake subsidence rate of high core wall dams not to fail be 1.3%.

[0138] The calculation results show that there is an obvious positive correlation between the dam crest settlement rate and the dam slope slip. For the core wall dam, when the settlement rate is 1.1%, 1.2% and 1.3%, the boundary maximum values ​​of the dam slope slip are approximately 1.0m, 1.2m and 1.4m respectively. Based on this, it is recommended that the non-dam-break index of the dam slope slip of the high-face dam is 1.2m, and the non-dam-break index of the dam slope slip of the high-core wall dam is 1.4m.

[0139] Since the dam crest settlement is the concentrated manifestation of the overall deformation of the dam, the local shallow slip of the dam slope has been reflected in the dam crest settlement, and the dam crest settlement deformation is the core issue of the seismic safety of modern RRC dams. Therefore, based on the determined non-dam-break index of dam crest settlement, the dam crest settlement is divided into 5 levels, as shown in Table 1, and the seismic safety grading evaluation index of core wall dams is established.

[0140] Table 1 Earthquake safety classification evaluation indicators

[0141]

[0142] Based on the above embodiments, the method for obtaining the earthquake motion input is:

[0143] ·Classify earthquake stages according to the characteristics of seismic waves;

[0144] Different monitoring time steps are used for different levels of earthquake stages, where the earthquake stage level and monitoring time step are inversely proportional;

[0145] Acquire seismic wave monitoring data based on adaptive monitoring time step;

[0146] The time step of nonlinear finite element is related to the load size and nonlinearity. The larger the load and the stronger the nonlinearity, the smaller the time step required. In view of this, according to the characteristics of earthquake waves in earth-rock dam calculation, a larger time step can be used in the small earthquake stage to improve the calculation efficiency; in the strong earthquake stage, a smaller time step can be used to improve the calculation accuracy, see Fig. 9 The comparison of calculation accuracy before and after optimization is shown in Fig.10 , while maintaining the same accuracy, the computational efficiency is improved by 12%.

[0147] Perform seismic wave interception on the seismic wave monitoring data according to the Arias intensity to obtain the seismic motion input.

[0148] The acceleration time history of earthquake events generated by the strong earthquake monitoring system of Nuozadu Project is relatively long, reaching 180s. However, the main energy of the earthquake is concentrated in the middle of several tens of seconds. If the monitoring data is directly used as the seismic input, it is necessary to calculate the earthquake process of 180s, which will greatly increase the calculation time and make it difficult to meet the requirements of rapid earthquake analysis and evaluation. Therefore, the present invention studies the influence of the seismic cutoff time on the calculation results.

[0149] The present invention selects 71 actual seismic motions with shear wave velocities vs30 ranging from 600 to 2000 m / s and magnitudes of 4 to 8.5, conducts elastoplastic dynamic response analysis on a 300m-scale core wall dam, uses Arias intensity to calculate the seismic motion index, and the difference in dam crest settlement before and after seismic wave truncation is quantified as a time-dependent evaluation index.

[0150] The influence of the seismic wave interception length on the calculation results under different seismic motion intensities is shown in Table 2. When 90% of the seismic waves with Arias intensity are intercepted, the average error is about 10%, and the average calculation time is saved by about 60%; when 95% of the seismic waves with Arias intensity are intercepted, the average error is about 5%, and the average calculation time is saved by about 55%; when 99% of the seismic waves with Arias intensity are intercepted, the average error is about 1%, and the average calculation time is saved by about 35%.

[0151] Table 2 The influence of seismic motion interception range on calculation results

[0152]

[0153] The present invention introduces the octave algorithm in the field of computer graphics, and realizes fast cross-scale refined mesh discretization by continuously recursively octaves the discrete domain; the polygonal average interpolation function is used to interpolate the annular boundary surface of the polyhedron, and the SBFEM of the complex polyhedron is derived and numerically realized, which solves the problem of solving the polyhedral unit caused by the difficulty of solving the octave modeling by the conventional finite element method, and finally establishes a cross-scale modeling and analysis method for high earth-rock dams coupled with proportional boundary element-finite element.

[0154] The present invention adopts similar unit acceleration algorithm, which can greatly save the calculation amount of unit stiffness matrix for elastic problems and nonlinear problems of geotechnical materials. Combined with the developed adaptive constitutive integral, variable solution time step and seismic motion truncation algorithm, it realizes the rapid analysis of high earth-rock dams and provides technical support for rapid assessment and early warning of strong earthquake risks.

[0155] Based on the above embodiment, the material parameters of this embodiment are taken from the above inversion analysis results. The damping ratio of all materials is fixed, the bedrock is 0.003, the core wall material and the rockfill material are 0.05. The earthquake motion is given in the vertical, downstream and axial directions of the dam, where the vertical earthquake motion peak is 2 / 3 of the horizontal direction. The earthquake acceleration time history (taking the design earthquake as an example) is shown in Fig.11 , the wave input method based on artificial boundary and equivalent load is used for seismic input. This method takes into account the interaction between dam and bedrock and the damping effect of seismic radiation. Theoretically, the calculation results should be more reasonable. Based on the above settings, the seismic response prediction of the ultra-high core wall dam under the design earthquake (PGA = 0.283g) and the verification earthquake (PGA = 0.345g) was carried out (the seismic peak values ​​of the design earthquake and the verification earthquake refer to the horizontal peak value).

[0156] The dam seismic safety grading evaluation index system established by the present invention is used to evaluate the safety of the extra-high core wall dam under the design earthquake and the verification earthquake. As shown in Table 3, under the design earthquake and the verification earthquake, the seismic subsidence of the dam top is 0.54% and 0.63% respectively, both of which are slight damages.

[0157] In addition, when the rheological effect is not considered, the dam modulus is underestimated, and the post-seismic deformation of the dam is overestimated, with the deformation along the river being 15-40% larger and the vertical deformation being 10% larger.

[0158] Table 3 Dam dynamic response and safety evaluation

[0159]

[0160] The present invention combines the quantitative index system for preventing high earth-rock dams from breaking as described above, and conducts an ultimate seismic capacity analysis based on the results of the elastoplastic inversion analysis of whether or not the rheology is considered in the inversion process. On the basis of the analysis of the design earthquake and the verification earthquake suffered by the dam, the peak acceleration of the seismic motion is gradually increased, and the seismic response prediction of the horizontal peak acceleration of the seismic motion is carried out with 0.6g, 0.65g, 0.7g, 0.75g and 0.8g respectively. From the calculation results, it can be found that the maximum vertical settlement occurs at the dam top near the typical section. The relationship between the dam top settlement rate and the peak acceleration is shown in Fig.12 , the post-earthquake deformation mode is shown in Fig.13 When the inversion parameters considering the rheological effect are used, the ultimate seismic capacity of the dam is about 0.75g; when the inversion parameters without considering the rheological effect are used, the modulus of the dam is underestimated, and the ultimate seismic capacity of the dam is underestimated by about 0.05g.

[0161] The embodiment of the present invention also provides a dam seismic performance evaluation device; the specific device may include:

[0162] A grid model building module is used to build a geometric entity model of the dam, and to discretize the geometric entity model into a cross-scale fine grid based on an octree algorithm to obtain a volume grid model;

[0163] A finite element module establishment module is used to analyze the volume mesh model using a nonlinear polyhedron proportional boundary finite element method to establish a finite element model;

[0164] An inverse analysis module is used to establish a generalized plastic coarse-grained soil constitutive model that uses a unified static-rheological-dynamic whole process based on the finite element model, and to perform an elastoplastic inverse analysis of the generalized plastic coarse-grained soil constitutive model taking into account the long-term deformation of the dam based on measured data;

[0165] The seismic index calculation module is used to input seismic motion into the generalized plastic coarse-grained soil constitutive model using the material parameters of the inversion analysis results, and calculate the dam crest subsidence rate;

[0166] The seismic performance evaluation module is used to evaluate the seismic performance of the dam according to the dam crest subsidence rate.

[0167] The dam seismic performance evaluation device of this embodiment is used to implement the aforementioned dam seismic performance evaluation method. Therefore, the specific implementation method of the dam seismic performance evaluation device can be seen in the embodiment part of the dam seismic performance evaluation method mentioned above. For example, the grid model establishment module, the finite element module establishment module, the inversion analysis module, the seismic index calculation module, and the seismic performance evaluation module are respectively used to implement steps S101, S102, S103, S104 and S105 in the above-mentioned dam seismic performance evaluation method. Therefore, its specific implementation method can refer to the description of the corresponding each part of the embodiment, which will not be repeated here.

[0168] A specific embodiment of the present invention further provides a dam seismic performance assessment device, comprising: a memory for storing a computer program; and a processor for implementing the steps of the above-mentioned dam seismic performance assessment method when executing the computer program.

[0169] A specific embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned method for evaluating the seismic performance of a dam are implemented.

[0170] 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 adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0171] The present application is described with reference to the flowcharts and / or 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 and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or 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 processes in the flowchart and / or block diagram. 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.

[0172] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0173] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0174] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for evaluating the seismic performance of a dam, characterized in that: include: Establishing a geometric entity model of the dam, and discretizing the geometric entity model into a cross-scale fine grid based on an octree algorithm to obtain a volume grid model; The volume mesh model is analyzed by using a nonlinear polyhedron proportional boundary finite element method to establish a finite element model; Based on the finite element model, a generalized plastic coarse-grained soil constitutive model that adopts the unified static-rheological-dynamic whole process is established, and based on the measured data, an elastic-plastic inverse analysis of the generalized plastic coarse-grained soil constitutive model considering the long-term deformation of the dam is performed; The generalized plastic coarse-grained soil constitutive model using the material parameters of the inverse analysis results is used for earthquake input to calculate the dam crest subsidence rate; The seismic performance of the dam is evaluated based on the dam crest subsidence rate.

2. The dam seismic performance evaluation method according to claim 1, characterized in that: After obtaining the volume mesh model, the method further includes: The similar nodes at the interface between the components are merged and shared.

3. The dam seismic performance evaluation method according to claim 1, characterized in that: The volume mesh model is analyzed by using a nonlinear polyhedron proportional boundary finite element method to establish a finite element model, which includes: Performing block-conical domain integration on the volume mesh model; The nonlinear stiffness matrix of the polyhedral element is calculated based on the strain-displacement conversion matrix at the integration points in the domain and the elastic-plastic constitutive matrix of the material; Assembling the nonlinear stiffness matrix of the polyhedral unit piecewise according to the degree of freedom to obtain the overall stiffness matrix of the domain; According to the surface force load vector and volume force load vector of the polyhedron, the external force load vector is obtained; The internal force load vector of the polyhedral element is calculated based on the strain-displacement conversion matrix and the material nonlinear constitutive matrix at the integration points in the domain.

4. The method for evaluating the seismic performance of a dam according to claim 3, characterized in that: The calculation method of the nonlinear stiffness matrix of the polyhedral unit includes: For the cube elements in the volume mesh model, the similar element acceleration algorithm is used to calculate the nonlinear stiffness matrix of the cube elements: Pre-calculate and store the stiffness matrix of the unit cube element or the stiffness matrix at the integration point of the unit size element; Based on the stiffness matrix of the unit cube unit or the stiffness matrix at the integration point of the unit size unit, the stiffness matrix of any cube unit is obtained according to the corresponding proportional coefficient.

5. The dam seismic performance evaluation method according to claim 1, characterized in that: The method for establishing the generalized plastic coarse-grained soil constitutive model includes: Since the nonlinearity of the material is inversely proportional to the load step length, the correlation between the nonlinearity index of the current stress state and the strain integration step length is established based on statistical data; The constitutive integration with adaptive step length is performed according to the association relationship to establish the generalized plastic coarse-grained soil constitutive model.

6. The dam seismic performance evaluation method according to claim 1, characterized in that: The method for obtaining the earthquake motion input is: The earthquake stages are classified according to the characteristics of the seismic waves; Different monitoring time steps are used for different levels of earthquake stages, where the earthquake stage level and monitoring time step are inversely proportional; Acquire seismic wave monitoring data according to the adaptive monitoring time step; The seismic wave monitoring data is subjected to seismic wave interception according to the Arias intensity to obtain the seismic motion input.

7. The method for evaluating the seismic performance of a dam according to claim 1, characterized in that: The evaluating the seismic performance of the dam according to the dam crest subsidence rate comprises: Since the dam top settlement rate and the dam slope slippage are positively correlated, the dam slope slippage is obtained by calculating the dam top settlement rate; If the dam slope slippage amount is not higher than the dam-break index, the extent of earthquake damage is determined based on the dam top subsidence rate and pre-established earthquake safety grading evaluation indicators.

8. A dam seismic performance assessment device, characterized in that: include: A grid model building module is used to build a geometric entity model of the dam, and to discretize the geometric entity model into a cross-scale fine grid based on an octree algorithm to obtain a volume grid model; A finite element module establishment module is used to analyze the volume mesh model using a nonlinear polyhedron proportional boundary finite element method to establish a finite element model; An inverse analysis module is used to establish a generalized plastic coarse-grained soil constitutive model that uses a unified static-rheological-dynamic whole process based on the finite element model, and to perform an elastoplastic inverse analysis of the generalized plastic coarse-grained soil constitutive model taking into account the long-term deformation of the dam based on measured data; The seismic index calculation module is used to input seismic motion into the generalized plastic coarse-grained soil constitutive model using the material parameters of the inversion analysis results, and calculate the dam crest subsidence rate; The seismic performance evaluation module is used to evaluate the seismic performance of the dam according to the dam crest subsidence rate.

9. A dam seismic performance assessment device, characterized in that: include: Memory for storing computer programs; A processor is used to implement the steps of a dam seismic performance assessment method as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a dam seismic performance assessment method as described in any one of claims 1 to 7 are implemented.

Images