Flood discharge dam crack simulation prediction and stability analysis method and device

Abstract

The invention discloses a flood discharge dam crack simulation prediction and stability analysis method and a flood discharge dam crack simulation prediction and stability analysis device, relates to the field of water conservancy projects, and aims to realize comprehensive analysis and stability prediction of crack causes. According to the method, a nonlinear finite element model of the flood discharge dam section downstream facade crack is established, loads such as self weight, temperature, water pressure, sand pressure, uplift pressure and valve thrust are applied to the model, then flood discharge dam construction, water storage and whole-process simulation calculation of operation are conducted, then the crack initiation and expansion process of the flood discharge dam section downstream facade crack is inverted, and the flood discharge dam section downstream facade crack is obtained. And performing corresponding repair processing on the crack, evaluating the state of the processed crack through analogue simulation, and analyzing the expansion stability of the crack. According to the method, various influence factors are more comprehensively considered, more accurate crack cause analysis is provided, and the method has the advantages of being efficient, accurate, high in stability, high in controllability, low in detection cost and the like.

Description

Technical Field

[0001] The invention relates to the field of water conservancy engineering, and in particular to a method and a device for simulation prediction and stability analysis of cracks in a spillway dam. Background Art

[0002] With the continuous development of water conservancy projects, concrete spillway dams, as an important water conservancy facility, are widely used in the regulation and management of water resources. However, during its long-term operation, cracks often appear on the dam body due to the influence of various external loads. These cracks not only affect the integrity and safety of the dam body, but may also lead to serious leakage and structural failure. Therefore, it is particularly important to accurately analyze and predict the causes and development trends of dam surface cracks.

[0003] In recent years, the crack formation analysis method based on finite element full-process simulation technology has gradually attracted attention. This method can comprehensively simulate the formation and expansion process of cracks by establishing a three-dimensional finite element model of the spillway dam and comprehensively considering multiple loads such as deadweight, temperature, water pressure, and sand pressure, providing a scientific basis for the safety assessment of the spillway dam.

[0004] Although the finite element method has certain advantages in crack analysis, there are still relatively few studies on the cause analysis of dam surface cracks in current technology, and the technical means used in most studies have certain limitations. Specifically, traditional crack analysis methods mainly rely on empirical formulas and simple mechanical models, which often cannot fully consider the heterogeneity of concrete and complex load effects. In addition, many studies only focus on the impact of a single factor on cracks, and lack in-depth analysis of crack behavior under the combined action of multiple factors. This one-sided analysis method not only reduces the accuracy of crack prediction, but also makes the understanding of the causes of cracks incomplete. Therefore, a more systematic and precise analysis method is urgently needed to improve the efficiency and reliability of crack cause analysis. Summary of the invention

[0005] The object of the present invention is to provide a method and device for simulation prediction and stability analysis of cracks in a spillway dam to address all or part of the above-mentioned problems, so as to achieve a comprehensive analysis of the causes of cracks and stability prediction.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for simulation prediction and stability analysis of cracks in a spillway dam, comprising:

[0008] S1. Simulate the cracks on the downstream facade of the spillway dam by presetting nonlinear contact units at the crack locations, and establish a nonlinear finite element model of the cracks on the downstream facade of the spillway dam;

[0009] S2. Apply at least two loads of deadweight, temperature, water pressure, sand pressure, uplift pressure and valve thrust to the model;

[0010] S3. Simulate the whole process of spillway dam construction, water storage and operation:

[0011] Based on the monitoring data of the construction, water storage and operation process of the spillway dam, the nonlinear finite element full-process simulation analysis method is adopted to simulate the concrete pouring process, hydration and heating process, hardening process, longitudinal joint grouting process, water cooling, surface insulation measures, temperature change process, reservoir water level change process according to the actual construction progress of the spillway dam, and simulate the temperature field and stress field of the whole process of the spillway dam construction, water storage and operation;

[0012] S4, based on the simulation calculation results of step S3, with the goal of minimizing the difference between the simulation calculation value and the monitoring data of the temperature and deformation of the spillway dam body, inverse the crack initiation and expansion process of the vertical cracks on the downstream side of the spillway dam section;

[0013] S5. According to the analysis results of the crack initiation and expansion process in step S4, the crack is repaired accordingly, the state of the crack after treatment is evaluated through simulation, and the expansion stability of the crack is analyzed.

[0014] Further, step S1 includes:

[0015] S1.1. Collect the size and material information of the spillway dam and use nonlinear finite element tools to establish a three-dimensional geometric model of the spillway dam;

[0016] S1.2, use contact elements to simulate cracks;

[0017] S1.3. The initial strength of the initial crack is the concrete body strength.

[0018] Furthermore, in step S3, simulating the concrete pouring process includes:

[0019] The spillway is divided into grids, and each unit is sorted according to the pouring order. The corresponding units are gradually activated to simulate the pouring of concrete, and the self-weight of the activated units is used as the load increment. It is assumed that the concrete of each unit will gradually harden and creep with age after pouring, and the hydration heat will gradually dissipate.

[0020] After each unit of concrete is poured, the time is divided into multiple time steps, and the temperature field and stress field of the spillway dam are calculated in time sequence at each time step;

[0021] The simulated joint grouting process includes:

[0022] Grout the expansion joints between the dam sections and the cast blocks in sequence to connect the dam sections and the cast blocks into a whole;

[0023] Goodman elements with tensile strength are used to simulate expansion joints, and discontinuous deformation analysis methods are introduced into finite elements to simulate the opening and closing states of expansion joints;

[0024] Simulate the layered and block-by-layer jump unit pouring of concrete and the layered and staged joint grouting, track the stress change, opening and closing process of each Goodman unit and the change of the opening of the expansion joint. When the relevant grouting area meets the grouting requirements and the joint grouting is carried out, lock the current opening of each expansion joint, use the current opening as the thickness of the Goodman unit, fill the Goodman unit with grouting material, set the corresponding material parameters, and give the tensile and shear strengths according to the following formula:

[0025]

[0026] Where i is the expansion joint identifier, δ i is the opening of the expansion joint, are the normal and shear stiffness of the expansion joint, respectively; E and μ are the elastic modulus and Poisson's ratio of the grouting material, respectively;

[0027] Simulated water cooling includes:

[0028] The equivalent simulation method is used to simulate the heat removed by water cooling to calculate the concrete temperature;

[0029] Simulated surface insulation includes:

[0030] Surface insulation is simulated by changing the surface heat dissipation coefficient, where the surface heat dissipation coefficient β0 when the concrete surface is exposed is calculated by the following formula:

[0031] β0=23.9+14.50v n ,

[0032] In the formula, v n is the wind speed;

[0033] Surface heat dissipation coefficient β when the concrete surface is equipped with an insulation board s Calculated by the following formula:

[0034]

[0035] In the formula, h i is the thickness of insulation board i, λ i is the thermal conductivity coefficient of insulation board i;

[0036] The simulated water storage operation process includes:

[0037] Before water storage, the temperature field and stress field models are established by simulating the construction, temperature control and material hydration and hardening processes. After water storage begins, water pressure is simulated by applying triangular surface loads on the upstream and downstream surfaces of the spillway, and vertical upward surface loads are applied on the dam foundation interface to simulate uplift pressure. During the water storage process, the temperature boundary conditions of the upstream dam surface change from air temperature boundary conditions to water temperature boundary conditions for the surface of the rising water level, while the water level change area alternates between air temperature boundary conditions and water temperature boundary conditions.

[0038] In the process of simulating the temperature field and stress field of the spillway dam, the temperature boundary condition is set according to the measured temperature or the multi-year average monthly temperature, and the influence of solar radiation heat is simulated by adding a temperature increment based on the set temperature.

[0039] Furthermore, in step S4, the initiation and propagation process of cracks on the downstream facade of the spillway dam section is inverted, including the inversion of thermal parameters of the spillway dam concrete and bedrock, and the inversion of mechanical parameters of the spillway dam concrete and bedrock.

[0040] Furthermore, the inversion of thermal parameters of spillway concrete and bedrock includes:

[0041] With the goal of minimizing the difference between the simulation value and the monitoring data of the temperature and deformation of the spillway dam body, the thermal conductivity, specific heat and adiabatic temperature rise parameters of concrete in different partitions of the spillway dam body are obtained by inversion; in the simulation process, the adiabatic temperature rise of the spillway dam body during the construction period and the temperature rise after joint grouting are simulated using the following formula:

[0042]

[0043] Where Q(τ) represents the adiabatic temperature rise at the concrete age τ, α1 and α2 are the adiabatic temperature rise parameters of the dam body and joints after grouting, τ is the concrete age, Q1 and Q2 are the final adiabatic temperature rise values ​​of the spillway dam concrete and grouting materials, respectively.

[0044] Furthermore, the inversion of the mechanical parameters of the spillway dam concrete and bedrock includes:

[0045] Based on the monitoring data of the deformation of the spillway dam, the water pressure components of each measuring point obtained by regression were used, and the finite element simulation analysis method was used. Only the hydrostatic pressure was considered to simulate the deformation of the dam body under different elastic moduli of concrete. The calculated deformation was compared with the water pressure deformation component obtained by multivariate regression of the deformation monitoring data. With the goal of minimizing the error between the simulation calculation value and the water pressure deformation component, the optimal elastic modulus of the concrete and bedrock of the spillway dam was determined by inversion.

[0046] During the simulation calculation, the following formula is used to simulate the elastic modulus hardening process of concrete:

[0047]

[0048] Where E(τ) and E0 are the elastic modulus and final elastic modulus of the dam concrete at age τ, respectively; α and β are the elastic modulus growth rate parameters of the concrete, respectively.

[0049] Furthermore, in step S5, the state after crack treatment is evaluated through simulation and the stability under extreme climate conditions is analyzed.

[0050] Furthermore, the evaluation of the state of the crack after treatment and the analysis of the stability under extreme climate conditions by simulation include:

[0051] Select the climate data of the lowest temperature period in history as the temperature parameter of the simulation; use the temperature parameter to simulate the crack state within the predetermined normal operation time after the crack treatment; compare the state before and after the crack treatment in winter and the state before and after the crack treatment in summer to analyze the expansion stability of the crack under temperature changes in different seasons; and,

[0052] The simulation simulates the crack state after removing the insulation board and performing crack treatment in winter to analyze the expansion stability of the cracks under extreme low temperature conditions after treatment.

[0053] The present invention also provides a spillway dam crack simulation prediction and stability analysis device, comprising a processor and a storage medium, wherein the processor runs a computer program stored in the storage medium to execute the above-mentioned spillway dam crack simulation prediction and stability analysis method.

[0054] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0055] The present invention establishes a detailed nonlinear finite element model and comprehensively considers loads such as deadweight, temperature, water pressure, and sand pressure to achieve a comprehensive analysis and prediction of the causes of cracks. The present invention introduces nonlinear contact units in the identification of crack extension, more accurately simulates the open-closed state and extension process of cracks, and focuses on the prediction of the state after crack treatment, especially the stability analysis under extreme climatic conditions, to provide technical support for the safe management of spillway dams. Compared with traditional methods, the present invention can more comprehensively consider various influencing factors, provide more accurate crack cause analysis, and has the advantages of high efficiency, accuracy, high stability, strong controllability, and low detection cost. It can effectively guide engineering practice and provide a scientific basis for the safe management of spillway dams. Through this new technical means, the causes of cracks on the dam surface of spillway dams can be better understood and predicted, providing more reliable technical support for the design, construction and maintenance of spillway dams. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0057] Figure 1 It is a flow chart of the flood spillway dam crack simulation prediction and stability analysis method proposed in the embodiment of the present application.

[0058] Figure 2 It is a simulation diagram of cracks in the spillway dam in the embodiment of the present application.

[0059] Figure 3 It is a comparison diagram of summer cracking and winter cracking during the construction period of the spillway dam in the embodiment of the present application.

[0060] Figure 4 It is a process line diagram of the crack opening degree at an elevation of 353m of the spillway crack in the embodiment of the present application.

[0061] Figure 5 This is a graph of measured data of the spillway temperature in the embodiment of the present application.

[0062] Figure 6 This is a comparison diagram before and after grouting treatment of cracks in the spillway dam in winter in an embodiment of the present application.

[0063] Figure 7 This is a diagram of the crack status of the spillway dam after summer crack grouting treatment in the embodiment of the present application.

[0064] Figure 8 This is a diagram of the crack state after the insulation board of the spillway dam is removed in the embodiment of the present application. DETAILED DESCRIPTION

[0065] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0066] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0067] In response to the problems of cause analysis and stability assessment of cracks in spillway dams in water conservancy projects, the embodiment of the present application proposes a method for simulation prediction and stability analysis of cracks in spillway dams, aiming to address the limitations of crack cause analysis in the prior art, especially in considering the influence of multiple loads, simulating the crack development process, and evaluating crack stability under extreme climatic conditions.

[0068] In some embodiments, Figure 1 As shown in FIG. 1 , the simulation prediction and stability analysis method of the spillway dam crack includes the following steps:

[0069] S1. The cracks on the downstream facade of the spillway are simulated by presetting nonlinear contact units at the crack locations, and a nonlinear finite element model of the cracks on the downstream facade of the spillway is established.

[0070] As a feasible implementation method, the step includes:

[0071] S1.1. Collect the size and material information of the spillway dam and use nonlinear finite element tools to establish a three-dimensional geometric model of the spillway dam.

[0072] In this sub-step, the geometric dimensions and material properties of the spillway dam can be collected from the engineering construction data, including the elastic modulus and tensile strength of the concrete. The three-dimensional geometric model of the spillway dam is established using existing nonlinear finite element tools, such as Figure 2 shown.

[0073] S1.2. Use contact elements to simulate cracks.

[0074] For the contact problem describing cracks, in addition to satisfying the basic equations, boundary conditions and initial conditions, the contact conditions on the contact surface must also be satisfied, including: contact displacement conditions, contact force conditions, contact state conditions, etc.

[0075] S1.3. The initial strength of the initial crack is the concrete body strength.

[0076] If the stress exceeds the tensile strength of concrete, the crack will open automatically, and the tensile stress borne by the concrete unit will be transferred to other concrete units. The expansion after local cracking will take into account the principles of fracture mechanics. After the crack is generated, it will automatically open and close iteratively as the stress changes.

[0077] S2. Apply at least two loads of deadweight, temperature, water pressure, sand pressure, uplift pressure and valve thrust to the model.

[0078] This application is aimed at a comprehensive analysis of the impact of various loads on crack formation, so the simulated loads include various types. Based on the detection results of cracks on the downstream facade of the spillway section, this step involves applying various loads to the finite element model to simulate actual working conditions. These loads include deadweight, temperature changes, water pressure, sand pressure, uplift pressure, and gate thrust.

[0079] 1) Self-weight load: According to the actual pouring progress of the spillway dam, the self-weight load of the model is simulated to ensure that the load distribution is consistent with the actual construction status.

[0080] 2) Temperature load: Using temperature monitoring data, through the simulation inversion of the entire process of construction, water storage and operation, the temperature load is obtained to reflect the impact of ambient temperature changes on the dam body. Figure 3The figure shows a comparison of summer cracking and winter cracking during the spillway dam construction period. The left side is a schematic diagram of the summer cracking range, and the right side is a schematic diagram of the winter cracking range. States "0" and "1" are both open states, state "2" is a bonding state, and state "3" is a bonding state after grouting. It can be clearly seen that temperature affects the cracking range.

[0081] 3) Water pressure load: simulate the actual downstream water level changes by applying surface loads on the upstream and downstream surfaces of the spillway to simulate the effect of water pressure.

[0082] 4) Silt load: A surface load is applied to the upstream surface of the spillway to simulate the pressure of silt on the dam body. The silt elevation is set at 300 meters to reflect the actual silt situation.

[0083] 5) Uplift pressure: According to the design requirements, a vertical upward surface load is applied to the interface between the dam and the foundation to simulate the influence of uplift pressure on the dam body.

[0084] 6) Gate thrust: When the surface and middle gates are blocking water, the gate thrust is simulated by applying concentrated force at the gate support to ensure that the impact of the gate on the dam body is accurately simulated.

[0085] By applying the above loads, it can be ensured that the model can accurately reflect the various loads borne by the spillway in actual operation, and provide accurate load conditions for the subsequent inversion of crack initiation and propagation processes. Figure 4 The figure shows the crack opening process line diagram of the spillway crack at an elevation of 353m. It can be seen that the crack opening changes periodically. Figure 5 From the measured temperature data of the middle spillway dam, it can be seen that the temperature data of the spillway dam also presents periodic changes. Therefore, there is reason to suspect that the factors causing the periodic changes in the crack opening may be the various loads mentioned above.

[0086] S3. Simulate the entire process of construction, water storage and operation of the spillway dam: Based on the monitoring data of the construction, water storage and operation of the spillway dam, adopt the nonlinear finite element simulation analysis method of the entire process. According to the actual construction progress of the spillway dam, simulate the concrete pouring process, hydration and heating process, hardening process, longitudinal joint grouting process, water cooling, surface insulation measures, temperature change process, reservoir water level change process, and simulate the temperature field and stress field of the entire process of construction, water storage and operation of the spillway dam.

[0087] In some feasible implementations, the step includes:

[0088] 1) The simulated concrete pouring process includes:

[0089] The pouring of concrete for the spillway dam is done in layers, blocks and bins according to the dam sections. When each bin is poured, the deadweight of the concrete in that bin will act on the poured concrete structure (including the foundation). Therefore, in this process, the spillway dam is divided into grids, each grid corresponds to a bin of concrete, and each divided unit is sorted according to the pouring order (using SAPTIS software, etc.), and the corresponding units are gradually activated to simulate the pouring of concrete, forming a step-by-step calculated grid model, and the deadweight of the activated units is used as the load increment. The calculation method for the deadweight load of the simulated pouring unit is:

[0090]

[0091] In the formula, represents the pressure change of the ith node on element e, N represents the shape function matrix, Δv represents the volume change vector, and Ω represents the domain of element e.

[0092] After pouring, concrete gradually hardens with age, which is manifested by the continuous increase of elastic modulus, strength and other parameters with age. The heat of cement hydration is continuously dissipated, which together with the boundary temperature causes the temperature change of the dam body. The concrete poured at different times gradually undergoes creep deformation. These changes affect both the stiffness matrix and the calculated load. Therefore, during the simulation, it is set that each unit concrete gradually hardens and gradually undergoes creep deformation with age after pouring, and the hydration heat is gradually dissipated.

[0093] After each unit concrete is poured, the time is divided into multiple time steps, and the temperature field and stress field of the spillway dam are calculated in time sequence at each time step. In each step of the calculation, the stiffness matrix and load array to be calculated need to be modified by considering the above factors.

[0094] 2) The simulated joint grouting process includes:

[0095] In practice, concrete is poured in sections, with expansion joints between sections and between cast blocks. Therefore, during simulation, the expansion joints between sections and cast blocks are grouted in sequence to connect the sections and blocks of concrete into a whole. For example, the longitudinal joints of a gravity dam must be grouted before the reservoir is filled with water.

[0096] During the simulation, the Goodman unit with tensile strength is used to simulate the expansion joint, and the discontinuous deformation analysis method (proposed by Shi Genhua, referred to as the DDA method) is introduced into the finite element to simulate the open-closed state of the expansion joint. Under normal circumstances, the expansion joint is in a closed state just after the concrete is poured. With the hydration heat, the concrete temperature rises, the concrete expands and deforms, and the joint is continuously compressed, that is, the compressive stress on the joint surface continues to increase. After the temperature reaches the peak value, with natural heat dissipation or artificial cooling, the normal stress on the joint surface gradually decreases, and the compression is converted to tension. When the tensile stress on the joint surface is greater than the tensile strength of the joint, the joint opens.

[0097] Simulate the layered and block-by-layer jump unit pouring of concrete and the layered and staged joint grouting, track the stress change, opening and closing process of each Goodman unit and the change of the opening of the expansion joint. When the temperature of the relevant grouting area meets the grouting requirements and the joint grouting is carried out, lock the current opening of each expansion joint, use the current opening as the thickness of the Goodman unit, fill the Goodman unit with grouting material, set the corresponding material parameters, and give the tensile and shear strengths according to the following formula:

[0098]

[0099] Where i is the expansion joint identifier, δ i is the opening of the expansion joint, are the normal and shear stiffness of the expansion joint respectively; E and μ are the elastic modulus and Poisson's ratio of the grouting material respectively. Due to the different pouring seasons, stress conditions and temperature changes of concrete in different parts, the opening and closing of the corresponding parts show different change rules.

[0100] 3) Simulated water cooling includes:

[0101] The equivalent simulation method is used to simulate the heat removed by water cooling to calculate the concrete temperature. The equivalent simulation method was proposed by Zhu Bofang. This method averages the cooling effect of water in the control range of each water pipe, uses a semi-analytical solution of water cooling, calculates the heat removed by water cooling, and then solves the concrete temperature.

[0102] 4) Simulated surface insulation includes:

[0103] Surface insulation is simulated by changing the surface heat dissipation coefficient, where the surface heat dissipation coefficient β0 when the concrete surface is exposed is calculated by the following formula:

[0104] β0=23.9+14.50v n ,

[0105] In the formula, v n is the wind speed.

[0106] Surface heat dissipation coefficient β when the concrete surface is equipped with an insulation board s Calculated by the following formula:

[0107]

[0108] In the formula, h i is the thickness of insulation board i, λ i is the thermal conductivity coefficient of insulation board i.

[0109] The spillway dam targeted by the embodiment of the present application adopts a phased water storage strategy. Once the spillway dam reaches a certain height and has initial water retaining capacity, it begins to store water to achieve power generation benefits in advance. The water load increment in each phase is only borne by the part of the dam body that has completed joint grouting, which is significantly different from the stress state of the entire dam body when it is filled with water at one time. Therefore, it is necessary to simulate the high dam.

[0110] 5) The simulated water storage operation process includes:

[0111] Before water storage, the temperature field and stress field models are established by simulating the construction, temperature control and material hydration and hardening process, in which the temperature field affects the stress field as a load. After water storage begins, the water pressure is simulated by applying triangular surface loads on the upstream and downstream surfaces of the spillway, and vertical upward (triangular) surface loads are applied to the dam foundation interface to simulate uplift pressure; the temperature boundary conditions of the upstream dam surface during the water storage process change from air temperature boundary conditions to water temperature boundary conditions for the surface of the water level rising part, while the water level change area alternates between air temperature boundary conditions and water temperature boundary conditions.

[0112] In the process of simulating the temperature and stress fields of the spillway dam (i.e. simulating the entire construction to operation process), the changes in gas phase hydrological conditions are also considered. The temperature boundary conditions are set according to the measured temperature or the multi-year monthly average temperature, and the influence of solar radiation heat is simulated by adding a temperature increment to the set temperature. This simulation method can more accurately reflect the actual working conditions and provide a scientific basis for the safety assessment of the spillway dam.

[0113] S4. Based on the simulation calculation results of step S3, the initiation and expansion process of the cracks on the downstream vertical surface of the spillway dam section is inverted with the goal of minimizing the difference between the simulation calculation value and the monitoring data of the temperature and deformation of the spillway dam body.

[0114] In some embodiments, step S4 includes inversion of thermal parameters of spillway dam concrete and bedrock, and inversion of mechanical parameters of spillway dam concrete and bedrock. This step aims to minimize the difference between the simulation calculation value and the monitoring data of the temperature and deformation of the spillway dam body, invert the thermal parameters of spillway dam concrete and bedrock, and the mechanical parameters of spillway dam concrete and bedrock, analyze the crack propagation path and rate based on the inversion data, determine the main influencing factors of crack propagation, so as to give corresponding crack treatment opinions and perform corresponding crack treatment.

[0115] As a feasible implementation method, the inversion of thermal parameters of spillway concrete and bedrock includes:

[0116] With the goal of minimizing the difference between the simulation value and the monitoring data of the temperature and deformation of the spillway dam body, the thermal conductivity, specific heat and adiabatic temperature rise parameters of concrete in different partitions of the spillway dam body are obtained by inversion; in the simulation process, the adiabatic temperature rise of the spillway dam body during the construction period and the temperature rise after joint grouting are simulated using the following formula:

[0117]

[0118] Where Q(τ) represents the adiabatic temperature rise at the concrete age τ, α1 and α2 are the adiabatic temperature rise parameters of the dam body and joints after grouting, τ is the concrete age, Q1 and Q2 are the final adiabatic temperature rise values ​​of the spillway dam concrete and grouting materials, respectively.

[0119] As another feasible approach, the inversion of the mechanical parameters of the spillway dam concrete and bedrock includes:

[0120] Based on the monitoring data of the deformation of the spillway dam, the water pressure components of each measuring point obtained by regression were used, and the finite element simulation analysis method was used. Only the hydrostatic pressure was considered to simulate the deformation of the dam body under different elastic moduli of concrete. The calculated deformation was compared with the water pressure deformation component obtained by multivariate regression of the deformation monitoring data. With the goal of minimizing the error between the simulation calculation value and the water pressure deformation component, the optimal elastic modulus of the concrete and bedrock of the spillway dam was determined by inversion.

[0121] During the simulation calculation, the following formula is used to simulate the elastic modulus hardening process of concrete:

[0122]

[0123] Where E(τ) and E0 are the elastic modulus and final elastic modulus of the dam concrete at age τ, respectively; α and β are the elastic modulus growth rate parameters of the concrete, respectively.

[0124] This step is based on step S3 and the design parameters and test parameters of the spillway dam body and bedrock materials. According to the dam body temperature and deformation monitoring data, SAPTIS software is used to simulate and feedback the temperature field and deformation field (i.e., stress field) of the spillway dam section during construction, water storage, and operation. The objective function is to minimize the difference between the calculated value and the monitored value, and the key thermal and mechanical parameters of the dam body and bedrock are obtained by inversion. The inversion parameters are used to simulate and calculate the initiation and expansion process of the vertical cracks downstream of the spillway dam section. By comparing the simulation results with the actual monitoring data, the accuracy of the model is verified, and the crack expansion path and rate are analyzed.

[0125] S5. According to the analysis results of the crack initiation and expansion process in step S4, the crack is repaired accordingly, the state of the crack after treatment is evaluated through simulation, and the expansion stability of the crack is analyzed.

[0126] This step is intended to predict the state of the crack after treatment and analyze its expansion stability. Based on the analysis results of the aforementioned step S4, combined with the analysis of the causes of the cracks, crack treatment suggestions are proposed, such as epoxy grouting and other treatments. Through simulation prediction and analysis, the state of the crack after treatment is evaluated, especially the stability under extreme climatic conditions. Focus on the behavior of cracks under extreme low temperature conditions to evaluate the effectiveness of the treatment measures. Therefore, in some embodiments, this step evaluates the state of the crack after treatment through simulation simulation and analyzes the stability under extreme climatic conditions.

[0127] As a feasible implementation method, the step includes:

[0128] 1) Select the climate data of the lowest temperature period in history as the temperature parameter for simulation; use the temperature parameter to simulate the crack state within the predetermined normal operation time after crack treatment; by comparing the state before and after crack treatment in winter and the state before and after crack treatment in summer, analyze the expansion stability of cracks under temperature changes in different seasons. Figure 6 , Figure 7 As shown, Figure 6 The left side shows the state before winter crack grouting, and the right side shows the state after winter crack grouting. Figure 7 This is the state of the cracks after grouting in summer.

[0129] 2) Simulate the crack state after removing the insulation board and treating the cracks in winter, such as Figure 8 As shown in the figure, the expansion stability of cracks after treatment under extreme low temperature conditions is analyzed. After the insulation board is removed, when encountering extreme low temperatures in winter, there is a risk of cracking on the surface of the cracks on the downstream facade of the dam.

[0130] Through step S5, the opening and closing states of the cracks under temperature changes in different seasons and the stability of the cracks under extreme low temperature conditions after treatment can be determined, thereby providing scientific decision-making support for the management and maintenance of the spillway dam cracks.

[0131] The embodiment of the present application also proposes a spillway dam crack simulation prediction and stability analysis device, including a processor and a storage medium, wherein the processor runs a computer program stored in the storage medium to execute the spillway dam crack simulation prediction and stability analysis method of the above embodiment.

[0132] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A method for simulation prediction and stability analysis of spillway cracks, characterized in that: include: S1. Simulate the cracks on the downstream facade of the spillway dam by presetting nonlinear contact units at the crack locations, and establish a nonlinear finite element model of the cracks on the downstream facade of the spillway dam; S2. Apply at least two loads of deadweight, temperature, water pressure, sand pressure, uplift pressure and valve thrust to the model; S3. Simulate the whole process of spillway dam construction, water storage and operation: Based on the monitoring data of the construction, water storage and operation process of the spillway dam, the nonlinear finite element full-process simulation analysis method is adopted to simulate the concrete pouring process, hydration and heating process, hardening process, longitudinal joint grouting process, water cooling, surface insulation measures, temperature change process, reservoir water level change process according to the actual construction progress of the spillway dam, and simulate the temperature field and stress field of the whole process of the spillway dam construction, water storage and operation; S4, based on the simulation calculation results of step S3, with the goal of minimizing the difference between the simulation calculation value and the monitoring data of the temperature and deformation of the spillway dam body, inverse the crack initiation and expansion process of the vertical cracks on the downstream side of the spillway dam section; S5. According to the analysis results of the crack initiation and expansion process in step S4, the crack is repaired accordingly, the state of the crack after treatment is evaluated through simulation, and the expansion stability of the crack is analyzed.

2. The method for simulation prediction and stability analysis of spillway dam cracks according to claim 1, characterized in that: Step S1 includes: S1.

1. Collect the size and material information of the spillway dam and use nonlinear finite element tools to establish a three-dimensional geometric model of the spillway dam; S1.2, use contact elements to simulate cracks; S1.

3. The initial strength of the initial crack is the concrete body strength.

3. The method for simulation prediction and stability analysis of spillway dam cracks according to claim 2, characterized in that: In step S3, the simulation of concrete pouring process includes: The spillway is divided into grids, and each unit is sorted according to the pouring order. The corresponding units are gradually activated to simulate the pouring of concrete, and the self-weight of the activated units is used as the load increment. It is assumed that the concrete of each unit will gradually harden and creep with age after pouring, and the hydration heat will gradually dissipate. After each unit of concrete is poured, the time is divided into multiple time steps, and the temperature field and stress field of the spillway dam are calculated in time sequence at each time step; The simulated joint grouting process includes: Grout the expansion joints between the dam sections and the cast blocks in sequence to connect the dam sections and the cast blocks into a whole; Goodman elements with tensile strength are used to simulate expansion joints, and discontinuous deformation analysis methods are introduced into finite elements to simulate the opening and closing states of expansion joints; Simulate the layered and block-by-layer jump unit pouring of concrete and the layered and staged joint grouting, track the stress change, opening and closing process of each Goodman unit and the change of the opening of the expansion joint. When the relevant grouting area meets the grouting requirements and the joint grouting is carried out, lock the current opening of each expansion joint, use the current opening as the thickness of the Goodman unit, fill the Goodman unit with grouting material, set the corresponding material parameters, and give the tensile and shear strengths according to the following formula: Where i is the expansion joint identifier, δ i is the opening of the expansion joint, are the normal and shear stiffness of the expansion joint, respectively; E and μ are the elastic modulus and Poisson's ratio of the grouting material, respectively; Simulated water cooling includes: The equivalent simulation method is used to simulate the heat removed by water cooling to calculate the concrete temperature; Simulated surface insulation includes: Surface insulation is simulated by changing the surface heat dissipation coefficient, where the surface heat dissipation coefficient β0 when the concrete surface is exposed is calculated by the following formula: β0＝23.9+14.50v n ， In the formula, v n is the wind speed; Surface heat dissipation coefficient β when the concrete surface is equipped with an insulation board s Calculated by the following formula: In the formula, h i is the thickness of the insulation board i, λ i is the thermal conductivity coefficient of insulation board i; The simulated water storage operation process includes: Before water storage, the temperature field and stress field models are established by simulating the construction, temperature control and material hydration and hardening processes. After water storage begins, water pressure is simulated by applying triangular surface loads on the upstream and downstream surfaces of the spillway, and vertical upward surface loads are applied on the dam foundation interface to simulate uplift pressure. During the water storage process, the temperature boundary conditions of the upstream dam surface change from air temperature boundary conditions to water temperature boundary conditions for the surface of the rising water level, while the water level change area alternates between air temperature boundary conditions and water temperature boundary conditions. In the process of simulating the temperature field and stress field of the spillway dam, the temperature boundary condition is set according to the measured temperature or the multi-year average monthly temperature, and the influence of solar radiation heat is simulated by adding a temperature increment based on the set temperature.

4. The method for simulation prediction and stability analysis of spillway dam cracks according to claim 1, characterized in that: In step S4, the initiation and propagation process of cracks on the downstream facade of the spillway dam section is inverted, including the inversion of thermal parameters of the spillway dam concrete and bedrock, and the inversion of mechanical parameters of the spillway dam concrete and bedrock.

5. The method for simulation prediction and stability analysis of spillway dam cracks according to claim 4, characterized in that: Inversion of thermal parameters of spillway concrete and bedrock, including: With the goal of minimizing the difference between the simulation value and the monitoring data of the temperature and deformation of the spillway dam body, the thermal conductivity, specific heat and adiabatic temperature rise parameters of concrete in different partitions of the spillway dam body are obtained by inversion; in the simulation process, the adiabatic temperature rise of the spillway dam body during the construction period and the temperature rise after joint grouting are simulated using the following formula: Where Q(τ) represents the adiabatic temperature rise at the concrete age τ, α1 and α2 are the adiabatic temperature rise parameters of the dam body and joints after grouting, τ is the concrete age, Q1 and Q2 are the final adiabatic temperature rise values ​​of the spillway dam concrete and grouting materials, respectively.

6. The method for simulation prediction and stability analysis of spillway dam cracks according to claim 4, characterized in that: Inversion of the mechanical parameters of the spillway dam concrete and bedrock, including: Based on the monitoring data of the deformation of the spillway dam, the water pressure components of each measuring point obtained by regression were used, and the finite element simulation analysis method was used. Only the hydrostatic pressure was considered to simulate the deformation of the dam body under different elastic moduli of concrete. The calculated deformation was compared with the water pressure deformation component obtained by multivariate regression of the deformation monitoring data. With the goal of minimizing the error between the simulation calculation value and the water pressure deformation component, the optimal elastic modulus of the concrete and bedrock of the spillway dam was determined by inversion. During the simulation calculation, the following formula is used to simulate the elastic modulus hardening process of concrete: Where E(τ) and E0 are the elastic modulus and final elastic modulus of the dam concrete at age τ, respectively; α and β are the elastic modulus growth rate parameters of the concrete, respectively.

7. The method for simulation prediction and stability analysis of spillway dam cracks according to claim 1, characterized in that: In step S5, the state after crack treatment is evaluated through simulation and the stability under extreme climate conditions is analyzed.

8. The method for simulation prediction and stability analysis of spillway dam cracks according to claim 7, characterized in that: The simulation is used to evaluate the state of cracks after treatment and analyze the stability under extreme climate conditions, including: Select the climate data of the lowest temperature period in history as the temperature parameter of the simulation; use the temperature parameter to simulate the crack state within the predetermined normal operation time after the crack treatment; compare the state before and after the crack treatment in winter and the state before and after the crack treatment in summer to analyze the expansion stability of the crack under temperature changes in different seasons; and, The simulation simulates the crack state after removing the insulation board and performing crack treatment in winter to analyze the expansion stability of the cracks under extreme low temperature conditions after treatment.

9. A device for simulation prediction and stability analysis of cracks in a spillway dam, comprising a processor and a storage medium, characterized in that: The processor runs the computer program stored in the storage medium to execute the flood spillway crack simulation prediction and stability analysis method as described in any one of claims 1-8.

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