A creep simulation analysis method and system for rockfill dams based on implicit iteration

Abstract

The present invention discloses a rockfill dam creep simulation analysis method and system based on implicit iteration, which belongs to the technical field of numerical simulation of rockfill dam creep. In the existing rockfill dam creep simulation analysis scheme, the origin of the model parameters depends on the observation data of the rockfill dam, lacks versatility and has poor scalability. The present invention discloses a rockfill dam creep simulation analysis method based on implicit iteration, which completes the rockfill dam creep simulation analysis based on implicit iteration by constructing an object generation unit, a solution strategy setting unit, a rockfill dam strain calculation unit and an implicit iteration calculation unit, thereby not relying on the specific expression form and parameters of the nonlinear elastic model and the rockfill dam creep model, and only processes the output of the nonlinear elastic model and the rockfill dam creep model as an intermediate variable, so that it can be coupled with different existing nonlinear elastic models and creep models, and has good scalability and versatility.

Description

Technical Field

[0001] The invention relates to a rockfill dam creep simulation analysis method and system based on implicit iteration, belonging to the technical field of rockfill dam creep numerical simulation. Background Art

[0002] The deformation of rockfill dam panels is primarily due to the deformation of the rockfill body. Excessive deformation of the rockfill body can cause cracks in the panels, weakening the anti-seepage effect and even endangering the overall stability of the dam. Therefore, accurately predicting rockfill deformation is key to improving the accuracy of rockfill dam deformation prediction. Rockfill deformation can be divided into transient deformation and time-dependent deformation. Transient deformation is primarily caused by the deadweight of the dam body and water pressure, while time-dependent deformation results from creep after the dam body is filled with water. Currently, nonlinear elastic models are commonly used in China to simulate transient deformation of rockfill bodies, while research on time-dependent deformation caused by rockfill creep is limited.

[0003] A Chinese document (Shen Changsong, Gu Ganchen. Parameter back-analysis and deformation law discussion of face rockfill dams [J]. Journal of Hohai University, 1996, 24(6):13-19) discloses a scheme for parameter back-analysis and deformation law discussion of face rockfill dams. Based on the deformation observation data of the Xibeikou concrete face rockfill dam during construction and operation, the authors applied hydraulic engineering, geotechnical mechanics, mathematical statistics, and optimization theories to establish a four-element model and a Duncan-Zhang model. The four-element model is a creep model for rockfill dams, and the Duncan-Zhang model is a nonlinear elastic model. This rationally analyzes the filling component, water pressure component, and creep component of dam deformation at different times. Furthermore, through a large number of finite element calculations, the relationships between the various parameters in the Duncan-Zhang model and the settlement deformation were found, and the values of the model parameters were determined.

[0004] The above scheme obtains relatively reasonable model parameters by comparing the observed data, which results in the origin of the model parameters being heavily dependent on the observed data of the rockfill dam. Therefore, the model parameters are only applicable to the Duncan-Zhang model and four-element model of this scenario, and cannot be applied to other scenarios and other nonlinear elastic models and rockfill dam creep models. It lacks versatility and has poor scalability.

[0005] Furthermore, the above scheme requires the collection of a large amount of deformation observation data and a large number of finite element calculations to obtain model parameters. The development process of the rockfill dam coupling model is relatively complex, and the amount of data that needs to be processed is large, which is not conducive to the promotion and use of the rockfill dam creep simulation analysis scheme.

[0006] 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

[0007] In response to the above problem or one of the above problems, the purpose of the present invention is to provide a rockfill dam creep simulation analysis method and system based on implicit iteration. By constructing an object generation unit, a solution strategy setting unit, a rockfill dam strain calculation unit and an implicit iteration calculation unit, it is possible to be independent of the specific expression form and parameters of the nonlinear elastic model and the rockfill dam creep model, and only process the output of the nonlinear elastic model and the rockfill dam creep model as an intermediate variable. Therefore, it can be coupled with different existing nonlinear elastic models and creep models, has good scalability and versatility, can simplify the rockfill dam coupling model development process, and requires a small amount of data to be processed, which is conducive to the development of rockfill dam numerical simulation technology.

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

[0009] A creep simulation analysis method for rockfill dams based on implicit iteration includes the following contents:

[0010] Using pre-built object generation units, combined with dam construction classification data and dam material information, a rockfill dam simulation object is created;

[0011] Create an integration time step sequence based on the rockfill dam simulation object and dam construction classification data through the pre-built solution strategy setting unit;

[0012] Using the pre-built rockfill dam strain calculation unit, the applied load is applied to the rockfill dam simulation object. Based on the nonlinear elastic algorithm and the creep characteristics of the rockfill dam, the initial strain data of the rockfill dam is obtained to estimate the instantaneous deformation and time-dependent deformation of the rockfill dam.

[0013] Using the pre-built implicit iterative calculation unit, the initial strain data of the rockfill dam is implicitly integrated based on the integral time step sequence to obtain the dam settlement data, completing the creep simulation analysis of the rockfill dam based on implicit iteration.

[0014] The present invention constructs an object generation unit, a solution strategy setting unit, a rockfill dam strain calculation unit and an implicit iteration calculation unit, and creates an integral time step sequence according to the rockfill dam simulation object and the dam construction classification data; and obtains the initial strain data of the rockfill dam based on the nonlinear elastic algorithm and the creep characteristics of the rockfill dam; then implicitly integrates the initial strain data of the rockfill dam to obtain the dam settlement data, thereby completing the rockfill dam creep simulation analysis based on implicit iteration. Therefore, it is not dependent on the specific expression form and parameters of the nonlinear elastic model and the rockfill dam creep model, and only processes the output of the nonlinear elastic model and the rockfill dam creep model as an intermediate variable. Therefore, it can be coupled with different existing nonlinear elastic models and creep models, has good scalability and versatility, can simplify the rockfill dam coupling model development process, and requires a small amount of data to be processed, which is beneficial to the development of rockfill dam numerical simulation technology and facilitates the promotion and use of rockfill dam creep simulation analysis solutions.

[0015] As preferred technical measures:

[0016] The method for creating a rockfill dam simulation object using pre-built object generation units, combined with dam construction classification data and dam material information, is as follows:

[0017] Obtain dam construction classification data and dam material information;

[0018] Dam construction classification data is information about the construction of the dam according to the time period and sequence, including information about the constructed zones, the zones under construction, and the zones not under construction;

[0019] Dam material information includes foundation material information, transition layer material information, upstream rockfill layer material information, and downstream rockfill layer material information;

[0020] The information of constructed partitions and partitions under construction is processed to obtain several three-dimensional non-structural elements. The integration point of each three-dimensional non-structural element contains three translational degrees of freedom.

[0021] Based on the dam material information, rockfill material data is applied to each 3D non-structural unit to obtain a rockfill dam simulation unit, which is used to characterize the actual rockfill material filled in different partitions.

[0022] Several rockfill dam simulation units are coupled to obtain a rockfill dam simulation object.

[0023] As preferred technical measures:

[0024] Using the pre-built solution strategy setup unit, the method for creating an integration time step sequence based on the rockfill dam simulation object and dam construction classification data is as follows:

[0025] According to the construction information of the rockfill dam simulation object, the global construction time of the rockfill dam is obtained;

[0026] Based on the dam construction classification data, the global construction time is divided into several construction classification cycles. The integration time step is set at the initial moment of each construction classification cycle, and the integration time step is aligned with the change time of the construction classification cycle to ensure that the time step is set at the time of the construction classification cycle change.

[0027] Based on the integration time step set at the initial moment, several evenly distributed calculation time steps are set for the construction classification period;

[0028] Using a non-uniform time step strategy, the calculation time step is encrypted in the early and late time periods of the new construction classification cycle to obtain multiple encrypted time steps;

[0029] The integration time step, calculation time step and encryption time step of each construction classification cycle are sorted to obtain the integration time step sequence.

[0030] As preferred technical measures:

[0031] Using the pre-built rockfill dam strain calculation unit, the applied load is applied to the rockfill dam simulation object. Based on the nonlinear elastic algorithm and the creep characteristics of the rockfill dam, the initial strain data of the rockfill dam is obtained as follows:

[0032] Based on the creep characteristics of the rockfill dam simulation object, a dam creep calculation formula is constructed to describe the relationship between the creep strain tensor and the parameter vector to estimate the time-dependent deformation of the rockfill dam;

[0033] Obtain the applied load of the rockfill dam to be simulated and analyzed, and set the initial value of the parameter vector;

[0034] Substitute the initial values of the parameter vector and the applied load into the dam creep calculation formula, perform simulation calculations, and obtain the initial creep strain tensor;

[0035] Based on the rockfill dam simulation object and nonlinear elastic algorithm, a nonlinear elastic calculation formula is constructed to describe the relationship between the rockfill dam parameter group, stress tensor, and strain tensor to estimate the instantaneous deformation of the rockfill dam;

[0036] Set the initial value of the parameter group; substitute the initial value of the parameter group and the initial creep strain tensor into the nonlinear elastic calculation formula, perform simulation calculation, and obtain the initial stress tensor;

[0037] The initial creep stress tensor and initial strain tensor are summed up to obtain the initial strain data of the rockfill dam.

[0038] As preferred technical measures:

[0039] Substituting the initial values of the parameter vector and the applied load into the dam creep calculation formula and performing simulation calculations, the method to obtain the initial creep strain tensor is as follows:

[0040] According to the creep characteristics of the rockfill dam simulation object, set Young's modulus, Poisson's ratio, parameter vector and continuous time;

[0041] Discretize the continuous moments to obtain several time steps;

[0042] For each time step, Young's modulus, Poisson's ratio and parameter vector are substituted into the dam creep calculation formula to obtain the creep strain increment corresponding to each time step;

[0043] Based on the creep strain increment, the initial creep strain tensor is determined.

[0044] As preferred technical measures:

[0045] The method for obtaining dam settlement data is as follows:

[0046] Step 1: Determine the time difference between adjacent time steps based on the integrated time step sequence;

[0047] Obtaining initial strain data of the rockfill dam, which includes initial creep stress tensor and initial strain tensor;

[0048] Step 2: Based on the initial creep stress tensor and the time difference, the creep strain increment of a certain integration step is calculated using the Newton-Raphson iterative integration method.

[0049] Step 3: Based on the creep strain increment of a certain integration step, the elastic strain increment of the current integration step is updated in real time to obtain a new elastic strain increment;

[0050] Step 4: Calculate the unit internal force vector of the rockfill dam simulation object based on the new elastic strain increment, strain-displacement matrix, unit volume, and linear elastic stiffness matrix;

[0051] Step 5, summarizing the unit internal force vectors into the overall internal force vector;

[0052] Step 6: Check the convergence of the overall internal force vector. If converged, execute step 7. If not converged, reduce the time difference by half and execute step 2.

[0053] Step 7: Obtain the strain tensor based on the creep strain increment, and obtain the dam displacement information through the strain-displacement matrix;

[0054] Step 8: Based on the dam displacement information, the vertical displacement value of the dam is selected as the dam settlement data.

[0055] Furthermore, the linear elastic stiffness matrix is constructed based on Poisson's ratio; the strain-displacement matrix is composed of the shape functions and their derivatives of the mesh nodes in the rockfill dam simulation object; and the unit volume is calculated by Gaussian integral.

[0056] As preferred technical measures:

[0057] The method for judging the convergence of the overall internal force vector is as follows:

[0058] Obtaining the applied load and converting the applied load into an applied load vector;

[0059] Calculate the difference between the global internal force vector and the applied load vector;

[0060] Determine whether the difference satisfies the relative convergence criterion and the absolute convergence criterion, which includes the following:

[0061] Setting a relative convergence benchmark value based on a relative threshold constant and an applied load vector;

[0062] Based on the absolute threshold constant, set the absolute convergence benchmark value;

[0063] When the difference is less than the relative convergence reference value, the relative convergence criterion is met. At this time, the absolute convergence criterion is not judged and the judgment result is convergence;

[0064] When the difference is greater than the relative convergence reference value and less than the absolute convergence reference value, the result is convergence;

[0065] When the difference is greater than the relative convergence reference value and the absolute convergence reference value, the result is judged as non-convergence.

[0066] As preferred technical measures:

[0067] The method for obtaining dam settlement data is as follows:

[0068] Step 1: Determine the time difference between adjacent time steps based on the integrated time step sequence;

[0069] Obtaining initial strain data of the rockfill dam, which includes initial creep stress tensor and initial strain tensor;

[0070] Step 2: Based on the initial creep stress tensor and the time difference, the creep strain increment of a certain integration step is calculated using the Newton-Raphson iterative integration method.

[0071] Step 3, calculate the total strain increment based on the displacement increment and the strain displacement matrix;

[0072] The displacement increment is a known quantity in the Newton-Raphson iterative integral, and the strain-displacement matrix consists of the shape functions of the mesh nodes and their derivatives;

[0073] Step 4, subtract the total strain increment from the creep strain increment to obtain the elastic strain increment;

[0074] Step 5: Calculate the unit internal force vector of the rockfill dam simulation object based on the elastic strain increment, the strain-displacement matrix, the unit volume, and the linear elastic stiffness matrix;

[0075] Step 6, summarizing the unit internal force vectors into the overall internal force vector;

[0076] Step 7: Check the convergence of the overall internal force vector. If converged, execute step 8. If not, reduce the time difference by half and execute step 2.

[0077] Step 8: Obtain the strain tensor based on the creep strain increment, and obtain the dam displacement information through the strain-displacement matrix;

[0078] Step 9: According to the dam displacement information, the vertical displacement value of the dam is screened out to obtain the dam settlement data.

[0079] Furthermore, the linear elastic stiffness matrix is constructed based on Poisson's ratio; the strain-displacement matrix is composed of the shape functions and their derivatives of the mesh nodes in the rockfill dam simulation object; and the unit volume is calculated by Gaussian integral.

[0080] To achieve the above object, the second technical solution of the present invention is:

[0081] A creep simulation analysis method for rockfill dams based on implicit iteration includes the following steps:

[0082] S1: Use the pre-built object generation unit, combined with the dam construction classification data and dam material information to create a rockfill dam simulation object;

[0083] S2: Using the pre-built calculation model construction unit, a nonlinear elastic model and a creep empirical parameter model are established according to the rockfill dam simulation object;

[0084] S3: Use pre-built solution strategy settings to create integration time step sequences and initial state variables based on nonlinear elastic models and creep empirical parameter models.

[0085] S4: Using a pre-built implicit iterative calculation unit, the initial state variables are substituted into the nonlinear elastic model and the creep empirical parameter model to obtain the initial strain data of the rockfill dam. This initial strain data is then implicitly integrated according to the integral time step sequence to obtain the dam settlement value, completing the creep simulation analysis of the rockfill dam based on implicit iteration.

[0086] To achieve the above object, the third technical solution of the present invention is:

[0087] A rockfill dam creep simulation analysis system based on implicit iteration, comprising:

[0088] one or more processors;

[0089] a storage device for storing one or more programs;

[0090] When the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned rockfill dam creep simulation analysis method based on implicit iteration.

[0091] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0092] The present invention constructs an object generation unit, a solution strategy setting unit, a rockfill dam strain calculation unit and an implicit iteration calculation unit, and creates an integral time step sequence according to the rockfill dam simulation object and the dam construction classification data; and obtains the initial strain data of the rockfill dam based on the nonlinear elastic algorithm and the creep characteristics of the rockfill dam; then implicitly integrates the initial strain data of the rockfill dam to obtain the dam settlement data, thereby completing the rockfill dam creep simulation analysis based on implicit iteration. Therefore, it is not dependent on the specific expression form and parameters of the nonlinear elastic model and the rockfill dam creep model, and only processes the output of the nonlinear elastic model and the rockfill dam creep model as an intermediate variable. Therefore, it can be coupled with different existing nonlinear elastic models and creep models, has good scalability and versatility, can simplify the rockfill dam coupling model development process, and requires a small amount of data to be processed, which is beneficial to the development of rockfill dam numerical simulation technology and facilitates the promotion and use of rockfill dam creep simulation analysis solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 A schematic diagram of a flow chart of a rockfill dam creep simulation analysis method according to the present invention;

[0094] Figure 2 A schematic diagram of a grid and material partitioning of a rockfill dam according to the present invention;

[0095] Figure 3 The present invention is used to generate a schematic diagram of the settlement cloud map of a rockfill dam. DETAILED DESCRIPTION

[0096] 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.

[0097] 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.

[0098] 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.

[0099] like Figure 1 As shown, the first specific embodiment of the rockfill dam creep simulation analysis method based on implicit iteration of the present invention is as follows:

[0100] A creep simulation analysis method for rockfill dams based on implicit iteration includes the following contents:

[0101] Using pre-built object generation units, combined with dam construction classification data and dam material information, a rockfill dam simulation object is created;

[0102] Create an integration time step sequence based on the rockfill dam simulation object and dam construction classification data through the pre-built solution strategy setting unit;

[0103] Using the pre-built rockfill dam strain calculation unit, the applied load is applied to the rockfill dam simulation object. Based on the nonlinear elastic algorithm and the creep characteristics of the rockfill dam, the initial strain data of the rockfill dam is obtained to estimate the instantaneous deformation and time-dependent deformation of the rockfill dam.

[0104] Using the pre-built implicit iterative calculation unit, the initial strain data of the rockfill dam is implicitly integrated based on the integral time step sequence to obtain the dam settlement data, completing the creep simulation analysis of the rockfill dam based on implicit iteration.

[0105] The second specific embodiment of the rockfill dam creep simulation analysis method based on implicit iteration of the present invention:

[0106] A creep simulation analysis method for rockfill dams based on implicit iteration includes the following steps:

[0107] S1: Use the pre-built object generation unit, combined with the dam construction classification data and dam material information to create a rockfill dam simulation object;

[0108] S2: Using the pre-built calculation model construction unit, a nonlinear elastic model and a creep empirical parameter model are established according to the rockfill dam simulation object;

[0109] S3: Use pre-built solution strategy settings to create integration time step sequences and initial state variables based on nonlinear elastic models and creep empirical parameter models.

[0110] S4: Using a pre-built implicit iterative calculation unit, the initial state variables are substituted into the nonlinear elastic model and the creep empirical parameter model to obtain the initial strain data of the rockfill dam. This initial strain data is then implicitly integrated according to the integral time step sequence to obtain the dam settlement value, completing the creep simulation analysis of the rockfill dam based on implicit iteration.

[0111] The third specific embodiment of the rockfill dam creep simulation analysis method based on implicit iteration of the present invention:

[0112] The implicit iteration-based rockfill dam creep simulation analysis method is a numerical simulation calculation method that can perform creep coupling analysis of rockfill dams, which includes the following steps:

[0113] S1: Establish a finite element model of the rockfill dam based on the dam construction classification and dam material zoning.

[0114] S2: Select appropriate nonlinear elastic model and creep empirical parameter model.

[0115] S3: Create a reasonable sequence of integration time steps and store the initial state variables of the elastic model and creep model.

[0116] S4: For each time step, implicit integration is performed according to the integration strategy until the convergence condition is met.

[0117] S5: Judge the time step sequence. If the maximum time step has been reached, stop. Otherwise, judge and update the state variables of the elastic model and creep model respectively, update the time step and return to S4 for execution.

[0118] In this embodiment S1, the finite element model of the rockfill dam utilizes three-dimensional nonstructural elements, with each element integration point containing three translational degrees of freedom. This construction, combined with tiered dam construction, involves constructing the dam according to different material zones, following a specific time period and sequence. Within the construction period, the dam can be divided into constructed zones, zones under construction, and unconstructed zones. The constructed zones remain unchanged within this period, while the zones under construction are updated within this time period. The geometric model of the unconstructed zones is not considered within this time period. Because different material zones contain different rockfill materials, a nonlinear elastic model and an empirical creep parameter model consistent with the actual filling material are applied to each zone.

[0119] In this embodiment S2, the nonlinear elastic model can be expressed as 、 ,in and are Young’s modulus and Poisson’s ratio of the elastic model, respectively. 、 、 are the stress tensor, strain tensor and parameter group, respectively.

[0120] strain tensor It is obtained by the displacement gradient tensor and its transposed symmetric part, and its calculation formula is as follows:

[0121]

[0122] in is the displacement component, and thus the strain tensor It can be expressed as:

[0123]

[0124] in , and are the x-direction positive strain component, y-direction positive strain component and z-direction positive strain component of the stress tensor respectively, , and They are the shear strain component in the xy direction, the shear strain component in the xz direction, and the shear strain component in the yz direction.

[0125] Stress tensor From the elastic stiffness tensor Acting on the strain tensor The specific calculation formula is as follows:

[0126]

[0127] Stress tensor It can be expressed as:

[0128]

[0129] in , and are the x-direction normal stress component, y-direction normal stress component and z-direction normal stress component of the stress tensor respectively, , and They are the shear stress component in the xy direction, the shear stress component in the xz direction, and the shear stress component in the yz direction.

[0130] The model parameter set It can be expressed as:

[0131]

[0132] in For this model parameters, is the total number of parameters of the model.

[0133] For rockfill dams, the nonlinear elastic model describes the Young's modulus of the rockfill material. , Poisson's ratio and the element stress tensor and the strain tensor The relationship between them.

[0134] The creep model can be expressed as ,in is the creep strain tensor, 、 are Young's modulus and Poisson's ratio, respectively. For the moment, is the parameter vector of the creep model, which can be expressed as:

[0135]

[0136] in For this model parameters, and M is the total number of parameters of the model.

[0137] For rockfill dams, the creep parameter model describes the creep strain tensor and physical parameters and time The strain tensor output by the creep parameter model participates in the calculation of the stress tensor of the nonlinear elastic model.

[0138] In finite element calculation, continuous moments Discretization, for the The creep model is expressed as follows:

[0139]

[0140] in For the The creep strain tensor for each time step, , is the creep strain increment, and Representing the Elastic modulus, Poisson's ratio, and time step value for each time step.

[0141] In this embodiment S3, the time step sequence needs to be set according to the dam construction level. During the construction process, the dam construction level is usually carried out according to a certain time period. Therefore, the time step needs to be aligned with the change time of the construction level. A global construction time is set. , which is divided into Construction grading cycle , in each construction grading cycle Set the time step at the initial moment , to ensure that the time step is set when the construction classification cycle changes. The time step needs to be reasonably encrypted before and after the change of different construction classification cycles. The non-uniform time step strategy is adopted to subdivide the first 10%~20% time period of the new dam construction classification cycle into 10~20 time steps; and subdivide the last 10%~20% time period into 12~15 time steps. Each time step accounts for about 1.2%~1.5% of the entire cycle. At the initial time step Save the state parameters related to the element state in the parameter vectors of the elastic model and creep model to ensure that they can be updated in subsequent time steps.

[0142] In this embodiment S4, for the time steps , and the time steps The time difference is . At time step Stress tensor at Gaussian integration point of known element and the strain tensor There are three ways to calculate the The stress tensor for each time step and the strain tensor .

[0143] The first way is to think The Young's modulus and Poisson's ratio of the internal nonlinear elastic model remain unchanged and the creep strain increment remains unchanged. The Young's modulus and Poisson's ratio of the elastic model are respectively and , according to the creep model, the creep strain increment The calculation formula is as follows:

[0144] ,

[0145] in, For the The creep strain increment in a time step is For the The creep strain tensor for each time step, and Representing the elastic modulus, Poisson's ratio and time step value for each time step, For the The creep model parameter vector is known for each time step.

[0146] According to the linear elastic method, calculate The elastic stress tensor , which is calculated as follows:

[0147]

[0148] in, is the elastic strain increment, is the stress tensor at the i-th time step, is the total strain tensor, is the known linear elastic stiffness matrix at the i-th time step.

[0149] The linear elastic stiffness matrix is expressed as follows:

[0150]

[0151] in, and For the Young's modulus and Poisson's ratio for each integration step.

[0152] The second way is that Internal creep strain increment The expression is as follows:

[0153]

[0154] For nonlinear elastic models, the Newton-Raphson iterative integral is used to calculate the elastic stress tensor, that is, the new stress tensor is calculated based on the stiffness update matrix. The expression of the stiffness update matrix is as follows:

[0155]

[0156] The elastic strain increment is the total strain increment Subtract creep strain increment , the specific expression is as follows:

[0157]

[0158]

[0159] in, is the total strain increment, is the displacement increment, which is a known quantity in the Newton-Raphson iterative integration. is the strain-displacement matrix, which consists of the shape functions and their derivatives of the model mesh nodes.

[0160] Stiffness matrix In the iterative integration, according to the current The integration step is updated in real time, and its expression is as follows:

[0161]

[0162] in, and For the Young's modulus and Poisson's ratio for each integration step are given by the nonlinear elastic model.

[0163] The third way is that The Young's modulus and Poisson's ratio of the internal nonlinear elastic model remain unchanged, and the creep strain increment of the creep model is calculated using the Newton-Raphson iterative integration, where Creep strain increment per integration step The calculation formula is as follows:

[0164]

[0165] Elastic strain increment In the iterative integration, according to the current The creep strain increment of each integration step is updated in real time, and its expression is as follows:

[0166] .

[0167] exist At this moment, calculate the unit internal force vector , and summarized as the overall internal force vector , element internal force vector The calculation formula is as follows:

[0168]

[0169] in Represents the volume of the cell, calculated by Gaussian integration.

[0170] Determining and applying load vectors The difference between the time difference and the absolute convergence criterion is checked. If the relative convergence criterion is met, the absolute convergence criterion is not judged. If the relative convergence criterion is not met, the absolute convergence criterion is judged. If the absolute convergence criterion is not met, the time difference is tried. Reduce it by half and then recalculate the strain tensor and the stress tensor , which is calculated as follows:

[0171]

[0172] The relative convergence criterion is:

[0173]

[0174] in is the relative threshold constant, usually taken as .

[0175] The absolute convergence criterion is:

[0176]

[0177] in is the absolute threshold constant, which is defined by the user and is usually .

[0178] In this embodiment S5, further, it is determined Is it equal to the maximum time? If so, the calculation process ends. Otherwise, the Young's modulus of the nonlinear elastic model is updated and saved. and Poisson's ratio , update the respective state variables according to the specific expressions of the nonlinear elastic model and creep model and ,make And execute S4.

[0179] A specific embodiment of the method for simulation analysis of a concrete face rockfill dam using the present invention:

[0180] The numerical simulation method for a concrete face rockfill dam is as follows:

[0181] Step 1: Take a concrete face rockfill dam in central China as an example. The maximum dam height is 114m, the top width is 10m, the dam top length is 328m, and the upstream and downstream slope ratios are According to the dam construction zoning and material zoning, the dam body is divided into four areas, namely foundation, transition layer, upstream rockfill area and downstream rockfill area. Figure 2 As shown, construction is carried out in the order of transition layer, upstream rockfill layer and downstream rockfill layer.

[0182] Step 2: Select the Duncan-Zhang EB model widely used in engineering as the nonlinear elastic model and the nine-parameter power function rheological model as the creep model. The expression is as follows:

[0183]

[0184] in 、 、 are known test parameters, The value range is 0.78~0.89, The value range of is 1150~1800, the value range of n is 0.35~0.47, and The first and third principal stresses are respectively, is the Mohr-Coulomb yield stress, 、 and It can be calculated from the stress tensor, is atmospheric pressure.

[0185] Poisson's ratio The expression is as follows:

[0186]

[0187] in and are known test parameters, The value range is 550~640. The value range is 0.2~0.4.

[0188] Axial creep in the nine-parameter power function creep model The expression is as follows:

[0189]

[0190]

[0191] in is the atmospheric pressure, which is ; is the characteristic time, which takes a value of 1 hour; For confining pressure, is the stress level, and It can be calculated from the stress tensor at the integration point, is the axial creep stress ratio coefficient; 、 、 and are known test parameters, The value range is 0.2745~1.3546, The value range is 0.2247~0.7968, The value range is 0.1107~0.1457, The value range is 0.3568~1.0253.

[0192] Volume creep The expression is as follows:

[0193]

[0194] in 、 、 、 and are known test parameters, where The value range is 0.3149~0.4879, The value range is 0.5698~1.9872, The value range is 0.1779~0.3989, The value range is 0.9156~1.4526, The value range is 0.0606~0.0899.

[0195] Calculate axial creep and volume creep The time derivative of is written in differential format. The specific expression is as follows:

[0196]

[0197]

[0198] in, is the axial creep increment; is the volume creep increment.

[0199] Furthermore, the creep stress increment Can be written as:

[0200]

[0201] in is a unit fourth-order tensor, is the deviatoric stress tensor, is the Mises equivalent stress, and can be Calculated.

[0202] Step 3: Create a reasonable time series based on the construction sequence and construction period , is the total number of discrete time steps. The state variables of the Duncan EB model and the nine-parameter creep model are saved at the initial time. For the Duncan EB model, the expression of its state variables is as follows:

[0203]

[0204] For the creep model, the expressions of its state variables are as follows:

[0205]

[0206]

[0207] Step 4: Integrate according to the first method of the integration strategy, assuming that During this period, the Young's modulus and Poisson's ratio of the Duncan EB model remain unchanged, and the creep strain tensor of the nine-parameter creep model remains unchanged. The stress tensor at the moment and perform convergence judgment. If the relative convergence criterion is met, end step 4. Otherwise, arrive Time is divided into 、 、 The time difference is calculated as follows:

[0208]

[0209] from The time starts to be calculated according to the new time series The stress tensor at time and the strain tensor . Stress tensor Acting on the strain tensor through the elastic stiffness matrix tensor Get the strain tensor The calculation formula is as follows:

[0210]

[0211] in, is the total strain increment.

[0212] Then, based on the strain tensor, the dam displacement is obtained through the strain-displacement matrix.

[0213] Step 5: Judgment Is it equal to If they are equal, stop the calculation, otherwise update the state variables of Duncan EB model respectively. 、 and the state variables of the nine-parameter creep model 、 and , and update The value of , repeat step 4.

[0214] The final calculated rockfill dam settlement distribution cloud map is as follows: Figure 3As shown in the figure, the maximum absolute value of the vertical numerical component in the displacement result is taken as the maximum dam settlement, and its unit is meter (m). It can be found that the maximum dam settlement after coupling the creep model occurs in the middle and lower part of the dam body. The distribution is reasonable and the numerical value is similar to the experimental monitoring results, which proves the rationality of the calculation method of coupling the nonlinear elastic model and the creep model in the present invention.

[0215] An embodiment of a device applying the method of the present invention:

[0216] An electronic device comprising:

[0217] one or more processors;

[0218] a storage device for storing one or more programs;

[0219] When the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned rockfill dam creep simulation analysis method based on implicit iteration.

[0220] A computer medium embodiment of the method of the present invention:

[0221] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned rockfill dam creep simulation analysis method based on implicit iteration.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] The unit 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.

[0227] 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. A creep simulation analysis method for rockfill dams based on implicit iteration, characterized by: Includes the following: Using pre-built object generation units, combined with dam construction classification data and dam material information, a rockfill dam simulation object is created; Create an integration time step sequence based on the rockfill dam simulation object and dam construction classification data through the pre-built solution strategy setting unit; Using the pre-built rockfill dam strain calculation unit, the applied load is applied to the rockfill dam simulation object. Based on the nonlinear elastic algorithm and the creep characteristics of the rockfill dam, the initial strain data of the rockfill dam is obtained to estimate the instantaneous deformation and time-dependent deformation of the rockfill dam. It includes the following: Based on the creep characteristics of the rockfill dam simulation object, a dam creep calculation formula is constructed to describe the relationship between the creep strain tensor and the parameter vector to estimate the time-dependent deformation of the rockfill dam; Obtain the applied load of the rockfill dam to be simulated and analyzed, and set the initial value of the parameter vector; Substitute the initial values of the parameter vector and the applied load into the dam creep calculation formula, perform simulation calculations, and obtain the initial creep strain tensor; Based on the rockfill dam simulation object and nonlinear elastic algorithm, a nonlinear elastic calculation formula is constructed to describe the relationship between the rockfill dam parameter group, stress tensor, and strain tensor to estimate the instantaneous deformation of the rockfill dam; Set the initial value of the parameter group; substitute the initial value of the parameter group and the initial creep strain tensor into the nonlinear elastic calculation formula, perform simulation calculation, and obtain the initial stress tensor; The initial creep stress tensor and initial strain tensor are summed up to obtain the initial strain data of the rockfill dam; Using the pre-built implicit iterative calculation unit, the initial strain data of the rockfill dam is implicitly integrated based on the integral time step sequence to obtain the dam settlement data, completing the creep simulation analysis of the rockfill dam based on implicit iteration.

2. The rockfill dam creep simulation analysis method based on implicit iteration according to claim 1, characterized in that: The method for creating a rockfill dam simulation object using pre-built object generation units, combined with dam construction classification data and dam material information, is as follows: Obtain dam construction classification data and dam material information; Dam construction classification data is information about the construction of the dam according to the time period and sequence, including information about the constructed zones, the zones under construction, and the zones not under construction; Dam material information includes foundation material information, transition layer material information, upstream rockfill layer material information, and downstream rockfill layer material information; The information of constructed partitions and partitions under construction is processed to obtain several three-dimensional non-structural elements. The integration point of each three-dimensional non-structural element contains three translational degrees of freedom. Based on the dam material information, rockfill material data is applied to each 3D non-structural unit to obtain a rockfill dam simulation unit, which is used to characterize the actual rockfill material filled in different partitions. Several rockfill dam simulation units are coupled to obtain a rockfill dam simulation object.

3. The rockfill dam creep simulation analysis method based on implicit iteration according to claim 1, characterized in that: Using the pre-built solution strategy setup unit, the method for creating an integration time step sequence based on the rockfill dam simulation object and dam construction classification data is as follows: According to the construction information of the rockfill dam simulation object, the global construction time of the rockfill dam is obtained; Based on the dam construction classification data, the global construction time is divided into several construction classification cycles. The integration time step is set at the initial moment of each construction classification cycle, and the integration time step is aligned with the change time of the construction classification cycle to ensure that the time step is set at the time of the construction classification cycle change. Based on the integration time step set at the initial moment, several evenly distributed calculation time steps are set for the construction classification period; Using a non-uniform time step strategy, the calculation time step is encrypted in the early and late time periods of the new construction classification cycle to obtain multiple encrypted time steps; The integration time step, calculation time step and encryption time step of each construction classification cycle are sorted to obtain the integration time step sequence.

4. The rockfill dam creep simulation analysis method based on implicit iteration according to claim 1, characterized in that: Substituting the initial values of the parameter vector and the applied load into the dam creep calculation formula and performing simulation calculations, the method to obtain the initial creep strain tensor is as follows: According to the creep characteristics of the rockfill dam simulation object, set Young's modulus, Poisson's ratio, parameter vector and continuous time; Discretize the continuous moments to obtain several time steps; For each time step, Young's modulus, Poisson's ratio and parameter vector are substituted into the dam creep calculation formula to obtain the creep strain increment corresponding to each time step; Based on the creep strain increment, the initial creep strain tensor is determined.

5. The rockfill dam creep simulation analysis method based on implicit iteration according to claim 1, characterized in that: The method for obtaining dam settlement data is as follows: Step 1: Determine the time difference between adjacent time steps based on the integrated time step sequence; Obtaining initial strain data of the rockfill dam, which includes initial creep stress tensor and initial strain tensor; Step 2: Based on the initial creep stress tensor and the time difference, the creep strain increment of a certain integration step is calculated using the Newton-Raphson iterative integration method. Step 3: Based on the creep strain increment of a certain integration step, the elastic strain increment of the current integration step is updated in real time to obtain a new elastic strain increment; Step 4: Calculate the unit internal force vector of the rockfill dam simulation object based on the new elastic strain increment, strain-displacement matrix, unit volume, and linear elastic stiffness matrix; Step 5, summarizing the unit internal force vectors into the overall internal force vector; Step 6: Check the convergence of the overall internal force vector. If converged, execute step 7. If not converged, reduce the time difference by half and execute step 2. Step 7: Obtain the strain tensor based on the creep strain increment, and obtain the dam displacement information through the strain-displacement matrix; Step 8: Based on the dam displacement information, the vertical displacement value of the dam is selected as the dam settlement data.

6. The rockfill dam creep simulation analysis method based on implicit iteration according to claim 5, characterized in that: The method for judging the convergence of the overall internal force vector is as follows: Obtaining the applied load and converting the applied load into an applied load vector; Calculate the difference between the global internal force vector and the applied load vector; Determine whether the difference satisfies the relative convergence criterion and the absolute convergence criterion, which includes the following: Setting a relative convergence benchmark value based on a relative threshold constant and an applied load vector; Based on the absolute threshold constant, set the absolute convergence benchmark value; When the difference is less than the relative convergence reference value, the relative convergence criterion is met. At this time, the absolute convergence criterion is not judged and the judgment result is convergence; When the difference is greater than the relative convergence reference value and less than the absolute convergence reference value, the result is convergence; When the difference is greater than the relative convergence reference value and the absolute convergence reference value, the result is judged as non-convergence.

7. The rockfill dam creep simulation analysis method based on implicit iteration according to claim 1, characterized in that: The method for obtaining dam settlement data is as follows: Step 1: Determine the time difference between adjacent time steps based on the integrated time step sequence; Obtaining initial strain data of the rockfill dam, which includes initial creep stress tensor and initial strain tensor; Step 2: Based on the initial creep stress tensor and the time difference, the creep strain increment of a certain integration step is calculated using the Newton-Raphson iterative integration method. Step 3, calculate the total strain increment based on the displacement increment and the strain displacement matrix; The displacement increment is a known quantity in the Newton-Raphson iterative integral, and the strain-displacement matrix consists of the shape functions of the mesh nodes and their derivatives; Step 4, subtract the total strain increment from the creep strain increment to obtain the elastic strain increment; Step 5: Calculate the unit internal force vector of the rockfill dam simulation object based on the elastic strain increment, the strain-displacement matrix, the unit volume, and the linear elastic stiffness matrix; Step 6, summarizing the unit internal force vectors into the overall internal force vector; Step 7: Check the convergence of the overall internal force vector. If converged, execute step 8. If not, reduce the time difference by half and execute step 2. Step 8: Obtain the strain tensor based on the creep strain increment, and obtain the dam displacement information through the strain-displacement matrix; Step 9: According to the dam displacement information, the vertical displacement value of the dam is screened out to obtain the dam settlement data.

8. A creep simulation analysis method for rockfill dams based on implicit iteration, characterized by: The following steps are involved: S1: Use the pre-built object generation unit, combined with the dam construction classification data and dam material information to create a rockfill dam simulation object; S2: Using the pre-built calculation model construction unit, a nonlinear elastic model and a creep empirical parameter model are established according to the rockfill dam simulation object; S3: Use pre-built solution strategy settings to create integration time step sequences and initial state variables based on nonlinear elastic models and creep empirical parameter models. S4: Using the pre-built implicit iterative calculation unit, the initial state variables are substituted into the nonlinear elastic model and the creep empirical parameter model to obtain the initial strain data of the rockfill dam; Then, the initial strain data of the rockfill dam is implicitly integrated according to the integration time step sequence to obtain the dam settlement value, completing the creep simulation analysis of the rockfill dam based on implicit iteration; The method for obtaining the initial strain data of the rockfill dam is as follows: Based on the creep characteristics of the rockfill dam simulation object, a dam creep calculation formula is constructed to describe the relationship between the creep strain tensor and the parameter vector to estimate the time-dependent deformation of the rockfill dam; Obtain the applied load of the rockfill dam to be simulated and analyzed, and set the initial value of the parameter vector; Substitute the initial values of the parameter vector and the applied load into the dam creep calculation formula, perform simulation calculations, and obtain the initial creep strain tensor; Based on the rockfill dam simulation object and nonlinear elastic algorithm, a nonlinear elastic calculation formula is constructed to describe the relationship between the rockfill dam parameter group, stress tensor, and strain tensor to estimate the instantaneous deformation of the rockfill dam; Set the initial value of the parameter group; Then, the initial values of the parameter group and the initial creep strain tensor are substituted into the nonlinear elastic calculation formula, and simulation calculation is performed to obtain the initial stress tensor; The initial creep stress tensor and initial strain tensor are summed up to obtain the initial strain data of the rockfill dam.

9. A rockfill dam creep simulation analysis system based on implicit iteration, 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 rockfill dam creep simulation analysis method based on implicit iteration according to any one of claims 1 to 8.

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