Method and system for evaluating anti-seepage performance of dam foundation curtain under seepage corrosion effect

Abstract

The invention belongs to the technical field of hydraulic structure engineering, and relates to a dam foundation curtain anti-seepage performance evaluation method and system under the action of seepage corrosion, and the method comprises the steps: drawing a hydropower station dam engineering riverbed cross section geometric model, and carrying out the mesh generation of the geometric model to obtain a calculation model; constructing a dam foundation anti-seepage curtain corrosion degradation analysis initial model; coupling a seepage field, a calcium ion transport field and a corrosion field in the dam foundation anti-seepage curtain corrosion degradation analysis initial model by utilizing the calculation model to obtain a permeability coefficient, porosity and a diffusion coefficient; updating parameters to obtain a dam foundation anti-seepage curtain corrosion degradation analysis updating model; whether the permeability coefficient, the porosity and the diffusion coefficient converge or not is judged, and if yes, the anti-seepage curtain structure calcium ion concentration, the solid-phase calcium concentration and the water head corresponding to the parameters are output; evaluating the anti-seepage performance of the dam foundation curtain; and otherwise, carrying out coupling solution on the analysis updating model by utilizing a calculation model. The technical problem of inaccurate calculation results in the prior art is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic structure engineering, and in particular relates to a method and system for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution. Background Art

[0002] Grout curtain is an anti-seepage structure commonly used in hydropower stations to reduce the seepage pressure and leakage of dam foundation, prevent or reduce the penetration of groundwater in the foundation, prevent the foundation from seepage damage, and improve the anti-seepage capacity of the dam foundation. It plays a vital role in ensuring the safe and economical operation of hydropower stations. Under the action of long-term reservoir water seepage, the physical and chemical properties of the grouting curtain change due to the action of environmental water, resulting in the decomposition and release of solid calcium in the concrete material, resulting in increased porosity and reduced anti-seepage performance, that is, the phenomenon of seepage dissolution occurs. The concrete anti-seepage structures of many hydropower stations that have been put into operation at home and abroad (such as Fengman Hydropower Station, Banqiao Hydropower Station, etc.) have serious leakage and calcium precipitation due to seepage dissolution, and the anti-seepage performance is significantly reduced. Therefore, studying the anti-seepage capacity dissolution and degradation of hydropower station anti-seepage structures, especially dam foundation grouting curtains, is of great significance to the safe and economical operation of hydropower stations and the durability evaluation of anti-seepage structures.

[0003] At present, the research on the degradation law of the anti-seepage performance of anti-seepage curtains under the action of seepage dissolution mostly adopts experimental research and numerical simulation calculation. In terms of experimental research, the concrete materials of the anti-seepage curtain or the samples taken from the drilling holes are usually used to prepare concrete samples, and the evolution law of the permeability characteristics of the samples under the action of seepage dissolution is studied using the hydraulic concrete seepage dissolution test system. However, the experimental research method is not only cumbersome, time-consuming and labor-intensive, but also highly dependent on operators and test equipment. In addition, due to environmental factors, there are differences between the experimental measurement results and the actual dissolution and degradation of the anti-seepage curtain. In addition, in terms of numerical simulation calculation, the existing simulation calculation of the anti-seepage performance of the anti-seepage curtain is mostly for contact dissolution without seepage effect. In the simulation calculation and analysis of the evolution law of the permeability coefficient considering the seepage effect, it is mostly based on empirical formulas, ignoring the influence of solid phase calcium decomposition on the pore structure of the anti-seepage curtain. The calculation results are not accurate and cannot truly reflect the degradation of the anti-seepage performance of the anti-seepage curtain. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution, so as to solve the technical problem that the prior art ignores the influence of solid-phase calcium decomposition on the pore structure of the anti-seepage curtain and the calculation results are inaccurate.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present application proposes a method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution, comprising:

[0007] Draw the geometric model of the riverbed section of the hydropower station dam project, and mesh the geometric model to obtain the calculation model;

[0008] Obtain the permeability coefficient, porosity and calcium ion concentration of cement-based materials in the service water environment of the actual hydropower station dam project anti-seepage curtain; construct a dam foundation anti-seepage curtain dissolution degradation analysis model based on the permeability coefficient, porosity and calcium ion concentration in the service water environment;

[0009] The initial parameters and boundary conditions of the dam foundation anti-seepage curtain dissolution degradation analysis model are set to obtain the initial model for the dam foundation anti-seepage curtain dissolution degradation analysis;

[0010] The computational model is used to couple the seepage field, calcium ion migration field and dissolution field in the initial model of the dam foundation anti-seepage curtain dissolution degradation analysis to obtain the permeability coefficient, porosity and diffusion coefficient; the dam foundation anti-seepage curtain dissolution degradation analysis model is updated based on the permeability coefficient, porosity and diffusion coefficient, and the updated model of the dam foundation anti-seepage curtain dissolution degradation analysis is obtained;

[0011] Determine whether the permeability coefficient, porosity and diffusion coefficient converge. If converged, output the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure corresponding to the above parameters; evaluate the anti-seepage performance of the dam foundation curtain based on the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure; if not converged, use the calculation model to couple and solve the update model of the dam foundation anti-seepage curtain dissolution degradation analysis.

[0012] Preferably, the method comprises obtaining the permeability coefficient, porosity and calcium ion concentration in the service water environment of the cement-based material of the anti-seepage curtain of the actual hydropower station dam project; constructing a dam foundation anti-seepage curtain dissolution degradation analysis model according to the permeability coefficient, porosity and calcium ion concentration in the service water environment, and the dam foundation anti-seepage curtain dissolution degradation analysis model includes a water seepage equation, a calcium ion migration equation and a solid phase calcium decomposition equation.

[0013] Preferably, the water seepage equation is:

[0014]

[0015] The calcium ion transport equation is:

[0016]

[0017] The solid phase calcium decomposition equation is:

[0018]

[0019] Among them, θ is the porosity of cement-based materials after dissolution; ρ is the density of the solution; t is the dissolution time; u is the flow velocity vector of the solution in the pores; is the Hamiltonian operator; Q mis the source term; k is the permeability coefficient; g is the gravitational acceleration; p is the pore water pressure; J ion is the calcium ion transmission flux; D is the effective diffusion coefficient of calcium ions in the solution after the cement-based material is dissolved; α is the dispersivity; D e is the diffusion coefficient of calcium ions in cement-based materials; C s is the solid phase calcium concentration in cement-based materials; C ion is the concentration of calcium ions; C OH is the hydroxide ion concentration in the pore solution; m and K sp are the kinetic index and the solubility product constant of CH respectively; λ is the reaction kinetic coefficient.

[0020] Preferably, the initial parameters and boundary conditions of the dam foundation anti-seepage curtain dissolution degradation analysis model are set to obtain the dam foundation anti-seepage curtain dissolution degradation analysis initial model, which specifically includes:

[0021] For the anti-seepage curtain at the dam foundation, the upstream side of the power station dam and the upstream side of the bedrock are set as the upstream head boundary, the downstream side of the power station dam and the top of the downstream side of the bedrock are set as the downstream head boundary, and the downstream of the power station dam is set as the seepage boundary in the middle of the upstream and downstream head elevations. The initial calcium ion concentration of the anti-seepage curtain is taken as the saturated concentration according to the construction mix ratio of its cement-based materials, and the initial calcium ion concentration of the bedrock is set as 0;

[0022] The boundary conditions of the water seepage equation are set as:

[0023]

[0024] The boundary conditions of the calcium ion transport equation are set as:

[0025]

[0026] Where p is the pore water pressure; ρ is the density of the solution; g is the acceleration of gravity; n is the normal direction outside the boundary surface; u is the velocity vector of the solution in the pore; q is the known seepage flux on the boundary; H0 is the initial water head; H b is the external pressure head; H is the external internal boundary head; z is the elevation of the calculation point; R b is the external conductivity, 1 / s, R b =k s / L,k s is the saturated permeability coefficient, L is the coupling length scale; n is the normal direction outside the boundary surface; C ion is the concentration of calcium ions; k t is the calcium ion transfer coefficient between pore water and ambient water; D ion is the effective diffusion coefficient of calcium ions; q1 is the known diffusion flux on the boundary; C0 is the concentration of calcium ions in the ambient water; is the Hamiltonian operator.

[0027] Preferably, the method of coupling the seepage field, calcium ion migration field and dissolution field in the initial model for analyzing the dissolution degradation of the dam foundation anti-seepage curtain by using a computational model specifically includes:

[0028] In the process of cement-based material dissolution, the seepage field and the dissolution field are coupled with each other. The control equation of the seepage dissolution process of cement-based materials of the dam foundation anti-seepage curtain is expressed as follows:

[0029]

[0030] The coupling relationship between seepage field and calcium ion transport field is expressed by water seepage equation, calcium ion transport equation and solid phase calcium decomposition equation;

[0031] Wherein, θ is the porosity of cement-based materials after dissolution; ρ is the density of the solution; t is the dissolution time; is the Hamiltonian operator; k is the permeability coefficient; g is the gravitational acceleration; p is the pore water pressure; I is the gravity vector; Q m is the source term; C ion is the concentration of calcium ions; λ is the reaction kinetic coefficient; C OH is the hydroxide ion concentration in the pore solution; m and K sp are the kinetic index and the solubility product constant of CH, respectively; D e is the diffusion coefficient of calcium ions in cement-based materials; α is the dispersivity.

[0032] Preferably, the permeability coefficient, porosity and diffusion coefficient are obtained as follows:

[0033] The porosity is:

[0034]

[0035] The permeability coefficient is:

[0036]

[0037] The diffusion coefficient is:

[0038]

[0039] Where θ is the porosity of cement-based materials after dissolution; θ0 is the initial porosity of cement-based materials; M CH is the molar mass of CH; ρ CH is the density of CH; C s0 is the initial solid calcium concentration of cement-based materials; C s is the solid phase calcium concentration in cement-based materials; is the volume fraction of cement matrix in cement-based materials, In concrete is the volume fraction of gravel in concrete, is the volume fraction of sand in concrete; β is the maximum hydration degree of cement-based materials; w / c is the water-cement ratio, k0 is the initial permeability coefficient; D e is the diffusion coefficient of calcium ions in the pore solution; D0 is the diffusion coefficient of calcium ions in the aqueous solution; H(x) is the heaviside function.

[0040] Preferably, the cross-sectional geometric model of the riverbed of the hydropower station dam project is drawn by AutoCAD, and imported into COMSOL numerical analysis software to perform mesh division of the geometric model to obtain a computational model.

[0041] In the second aspect, the present application proposes a system for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution, comprising:

[0042] A computational model building unit is used to draw a geometric model of the riverbed cross section of a hydropower station dam project and to perform meshing of the geometric model to obtain a computational model;

[0043] The analysis model building unit is used to obtain the permeability coefficient, porosity and calcium ion concentration of cement-based materials in the service water environment of the actual hydropower station dam project anti-seepage curtain; the dam foundation anti-seepage curtain dissolution degradation analysis model is constructed based on the permeability coefficient, porosity and calcium ion concentration in the service water environment;

[0044] A processing unit is used to set initial parameters and boundary conditions for the dam foundation anti-seepage curtain dissolution degradation analysis model, so as to obtain an initial model for the dam foundation anti-seepage curtain dissolution degradation analysis;

[0045] An updating calculation unit is used to couple the seepage field, calcium ion migration field and dissolution field in the initial model of the dam foundation anti-seepage curtain dissolution degradation analysis by using the calculation model to obtain the permeability coefficient, porosity and diffusion coefficient; the dam foundation anti-seepage curtain dissolution degradation analysis model is updated according to the permeability coefficient, porosity and diffusion coefficient to obtain the updated model of the dam foundation anti-seepage curtain dissolution degradation analysis;

[0046] The judgment unit is used to judge whether the permeability coefficient, porosity and diffusion coefficient converge. If converged, the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure corresponding to the above parameters are output; the anti-seepage performance of the dam foundation curtain is evaluated according to the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure; if not converged, the calculation model is used to couple and solve the update model of the dam foundation anti-seepage curtain dissolution degradation analysis.

[0047] In the third aspect, the present application proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution as described in any one of the above items when executing the computer program.

[0048] In a fourth aspect, the present application proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution as described in any of the above items.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] This application is different from the traditional conventional geometric model construction method. It realizes the rapid construction of geometric models and meshes the geometric models to obtain calculation models, solving the problems of cumbersome operation and low efficiency in the conventional process of drawing and constructing geometric models using COMSOL numerical analysis software. This application realizes the coupling solution of the seepage field and dissolution field of the dam foundation anti-seepage curtain using the coefficient-type partial differential equations in the seepage module, dilute material transfer module, and mathematical module in the calculation model, solving the existing dam foundation anti-seepage curtain dissolution simulation, lacking the change in the porosity of cement-based materials caused by dissolution, resulting in changes in its seepage field, and the reaction of the seepage field to the dissolution field, and cannot accurately analyze and evaluate the long-term evolution law of the anti-seepage performance of the dam foundation anti-seepage curtain, and can realize the long-term service performance evaluation of the dam foundation anti-seepage curtain under different hydraulic gradients considering the effect of seepage dissolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0052] Figure 1 is a flow chart of the method of the present invention;

[0053] Figure 2 This is an analysis flow chart of analyzing the anti-seepage performance of the dam foundation anti-seepage curtain based on COMSOL software according to an embodiment of the present invention;

[0054] Figure 3 4 is a comparison chart of simulation test results of an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0058] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0059] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0060] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0062] See also Figure 1 The present application discloses a method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution, comprising:

[0063] S1: Draw the geometric model of the riverbed section of the hydropower station dam project, and perform meshing of the geometric model to obtain the calculation model;

[0064] S2: Obtain the permeability coefficient, porosity and calcium ion concentration of cement-based materials in the service water environment of the actual hydropower station dam project anti-seepage curtain; construct a dam foundation anti-seepage curtain dissolution degradation analysis model based on the permeability coefficient, porosity and calcium ion concentration in the service water environment;

[0065] S3: setting initial parameters and boundary conditions for the dam foundation anti-seepage curtain dissolution degradation analysis model to obtain the dam foundation anti-seepage curtain dissolution degradation analysis initial model;

[0066] S4: Using the computational model, the seepage field, calcium ion migration field and dissolution field in the initial model of the dam foundation anti-seepage curtain dissolution degradation analysis are coupled to obtain the permeability coefficient, porosity and diffusion coefficient; the dam foundation anti-seepage curtain dissolution degradation analysis model is updated according to the permeability coefficient, porosity and diffusion coefficient to obtain the updated model of the dam foundation anti-seepage curtain dissolution degradation analysis;

[0067] S5: Determine whether the permeability coefficient, porosity and diffusion coefficient converge. If converged, output the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure corresponding to the above parameters; evaluate the anti-seepage performance of the dam foundation curtain according to the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure; if not converged, use the calculation model to couple and solve the update model of the dam foundation anti-seepage curtain dissolution degradation analysis.

[0068] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a calculation method for predicting the anti-seepage performance of a grouting curtain of a hydropower station under the action of seepage dissolution, which solves the calculation problem of predicting the service performance of hydraulic concrete anti-seepage structures during the process of seepage dissolution, and is of great significance for predicting the deterioration of the anti-seepage performance of concrete structures that have been serving in a water environment for a long time and for evaluating their service life.

[0069] In order to solve the above technical problems, the present invention provides a method for analyzing the deterioration of the anti-seepage curtain anti-seepage capacity of a hydropower station dam foundation under the action of seepage dissolution, the method comprising the following steps:

[0070] Determine the permeability coefficient, porosity and other parameter values ​​of cement-based materials for anti-seepage curtains in actual hydropower station dam projects, and obtain the calcium ion concentration in its service water environment;

[0071] The AutoCAD computer-aided design software was used to draw the typical cross-sectional geometric model of the riverbed section of the hydropower station dam project, and then the COMSOL numerical analysis software was imported to perform meshing of the geometric model;

[0072] Constructing a dam foundation anti-seepage curtain dissolution degradation analysis model, wherein the dam foundation anti-seepage curtain dissolution degradation analysis model includes a water seepage equation, a calcium ion migration equation, and a solid phase calcium decomposition equation;

[0073] The initial parameters and boundary conditions of the dam foundation anti-seepage curtain dissolution degradation analysis model were set; the seepage field, calcium ion migration field and dissolution field were coupled and solved using the coefficient-type partial differential equations in the seepage module, dilute material transfer module and mathematical module in the COMSOL numerical analysis software;

[0074] The water head, calcium ion concentration, solid phase calcium concentration, etc. of the entire model are calculated.

[0075] Furthermore, the water seepage equation is:

[0076] The pore water flow behavior in cement-based materials is described by Darcy's law:

[0077]

[0078] Where: θ is the porosity of cement-based materials after dissolution; ρ is the density of the solution, usually 1000 kg / m 3 ; t is the dissolution time; u is the velocity vector of the solution in the pore, m / s; is the Hamiltonian operator; Q m is the source term; k is the permeability coefficient, m / s; g is the gravitational acceleration, m / s 2 ; p is the pore water pressure, MPa.

[0079] The seepage equation of cement-based materials can be expressed as follows in the three types of boundary conditions of COMSOL numerical analysis software: constant head boundary, constant flux boundary and permeable layer boundary:

[0080]

[0081] Where: H b is the water head, m; n is the normal direction outside the boundary surface; q is the known seepage flux on the boundary, kg / (m 2 ·s); H b is the external pressure head, m; H is the external internal boundary head, m; z is the elevation of the calculation point, m; R b is the external conductivity, 1 / s, R b =k s / L,k s is the saturated permeability, m / s, and L is the coupling length scale, m.

[0082] Furthermore, the calcium ion migration equation of the cement-based material of the dam foundation anti-seepage curtain is:

[0083]

[0084] Where: J ion is the calcium ion transmission flux; D is the effective diffusion coefficient of calcium ions in the solution after the cement-based material is dissolved; α is the dispersivity; D e is the diffusion coefficient of calcium ions in cement-based materials.

[0085] Furthermore, the constant flux boundary condition and the ion exchange boundary condition in the calcium ion transport equation are expressed as:

[0086]

[0087] Where: n is the normal direction outside the boundary surface; C ion is the concentration of calcium ions, mol / m 3 ;k t is the calcium ion transfer coefficient between pore water and ambient water, m / s; D ion is the effective diffusion coefficient of ions, m / s; q1 is the known diffusion flux on the boundary; C0 is the concentration of calcium ions in the ambient water, mol / m 3 .

[0088] Further, the solid phase calcium decomposition model is:

[0089]

[0090] Where: C s is the solid phase calcium concentration in cement-based materials, mol / m 3 ; C OH is the hydroxide ion concentration in the pore solution, C OH =2C ion +C OH,0 , C OH,0 is the initial concentration of hydroxide ions in the pore solution; m and K sp are the kinetic index and the solubility product constant of CH, respectively. m can be taken as 4.5, K sp It can be taken as 4.68×10 3 mol 3 / m 9 ; λ is the reaction kinetic coefficient, which is 1×10 -5 mol / (m 3 ·s).

[0091] Furthermore, the setting of initial parameters and boundary conditions for the dam foundation anti-seepage curtain dissolution degradation analysis model includes:

[0092] For the dam foundation anti-seepage curtain, the upstream side of the power station dam and the upstream side of the bedrock are set as the upstream head boundary, the downstream side of the power station dam and the top of the downstream side of the bedrock are set as the downstream head boundary, and the downstream of the power station dam is set as the seepage boundary in the middle of the upstream and downstream head elevations. The initial calcium ion concentration of the anti-seepage curtain is taken as the saturated concentration according to the construction mix ratio of its cement-based materials, and the initial calcium ion concentration of the bedrock is set to 0.

[0093] The coefficient-type partial differential equation in the mathematical module of COMSOL numerical analysis software is used to couple the seepage field and the dissolution field. The coupling analysis process is as follows:

[0094] Under the action of a certain hydraulic gradient seepage water pressure and calcium ion concentration difference, the solid phase calcium of the cement-based material of the hydropower station dam foundation anti-seepage curtain will continue to decompose, which will cause the porosity of the anti-seepage curtain structure to increase, resulting in an increase in the permeability coefficient of the cement-based material, which in turn affects the seepage field of the anti-seepage curtain structure. The change in the seepage field will further promote the migration of the anti-seepage curtain solute, that is, the seepage field and the dissolution field are mutually coupled during the dissolution process of the cement-based material. The control equation for the seepage dissolution process of the cement-based material of the dam foundation anti-seepage curtain can be expressed as follows:

[0095]

[0096] Furthermore, the control equations of the coupling analysis model of the seepage field and dissolution field of the dam foundation anti-seepage curtain are a group of strongly coupled nonlinear equations. The seepage field and solute migration field use the seepage equation, calcium ion migration equation and solid phase calcium decomposition equation. The coupling relationship between different equations can be established through source terms, boundary conditions, material parameters, etc. During the seepage and dissolution process of cement-based materials, the evolution law of porosity can be described based on the initial porosity and the amount of solid phase calcium dissolution, specifically:

[0097]

[0098] Where: θ0 is the initial porosity of cement-based materials; M CH is the molar mass of CH; ρ CH is the density of CH; C s0 is the initial solid phase calcium concentration of cement-based materials; is the volume fraction of cement matrix in cement-based materials, In concrete is the volume fraction of gravel in concrete, is the volume fraction of sand in concrete; β is the maximum hydration degree of cement-based materials, which can be referred to the empirical formula in the literature β=0.239+0.745tanh[3.62(r wc -0.095)] value; r wc is the water-cement ratio.

[0099] The evolution law of permeability coefficient during the seepage dissolution of cement-based materials of dam foundation anti-seepage curtain is described by Kozeny-Carman equation:

[0100]

[0101] Furthermore, the diffusivity of calcium ions in cement-based materials directly affects the solid phase calcium decomposition rate and decomposition process. During the dissolution process, the diffusion coefficient can be expressed as a function of porosity and can be described by the van Eijk diffusion coefficient evolution model:

[0102]

[0103] Where: D e is the diffusion coefficient of calcium ions in the pore solution, m / s; D0 is the diffusion coefficient of calcium ions in the aqueous solution, taken as 1×10 -9 m 2 / s; H(x) is the heaviside function.

[0104] In summary, this application is different from the traditional conventional geometric model construction method. It realizes the rapid construction of geometric models based on AutoCAD computer-aided drawing software, and imports COMSOL numerical analysis software for gridding, solving the problems of cumbersome operation and low efficiency in the conventional process of drawing and constructing geometric models using COMSOL numerical analysis software. This application realizes the coupling solution of the seepage field and dissolution field of the dam foundation anti-seepage curtain by using the coefficient-type partial differential equations in the seepage module, dilute material transfer module, and mathematical module in COMSOL numerical analysis software, solving the existing dam foundation anti-seepage curtain dissolution simulation, lacking the change in the porosity of cement-based materials caused by dissolution, resulting in changes in its seepage field, and the reaction of the seepage field to the dissolution field, and cannot accurately analyze and evaluate the long-term evolution law of the anti-seepage performance of the dam foundation anti-seepage curtain, and can realize the long-term service performance evaluation of the dam foundation anti-seepage curtain under different hydraulic gradients considering the effect of seepage dissolution.

[0105] The present application also discloses an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution described in any one of the above items are implemented.

[0106] The present application also discloses a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the steps of the method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution described in any one of the above are implemented.

[0107] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0108] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0109] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0111] 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 relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution, characterized in that: include: Draw the geometric model of the riverbed section of the hydropower station dam project, and mesh the geometric model to obtain the calculation model; Obtain the permeability coefficient, porosity and calcium ion concentration of cement-based materials in the service water environment of the actual hydropower station dam project anti-seepage curtain; construct a dam foundation anti-seepage curtain dissolution degradation analysis model based on the permeability coefficient, porosity and calcium ion concentration in the service water environment; The initial parameters and boundary conditions of the dam foundation anti-seepage curtain dissolution degradation analysis model are set to obtain the initial model for the dam foundation anti-seepage curtain dissolution degradation analysis; The computational model is used to couple the seepage field, calcium ion migration field and dissolution field in the initial model of the dam foundation anti-seepage curtain dissolution degradation analysis to obtain the permeability coefficient, porosity and diffusion coefficient; the dam foundation anti-seepage curtain dissolution degradation analysis model is updated based on the permeability coefficient, porosity and diffusion coefficient, and the updated model of the dam foundation anti-seepage curtain dissolution degradation analysis is obtained; Determine whether the permeability coefficient, porosity and diffusion coefficient converge. If converged, output the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure corresponding to the above parameters; evaluate the anti-seepage performance of the dam foundation curtain based on the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure; if not converged, use the calculation model to couple and solve the update model of the dam foundation anti-seepage curtain dissolution degradation analysis.

2. The method for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution according to claim 1 is characterized in that: The method obtains the permeability coefficient, porosity and calcium ion concentration in the service water environment of the cement-based material of the actual hydropower station dam project anti-seepage curtain; and constructs a dam foundation anti-seepage curtain dissolution degradation analysis model according to the permeability coefficient, porosity and calcium ion concentration in the service water environment. The dam foundation anti-seepage curtain dissolution degradation analysis model includes a water seepage equation, a calcium ion migration equation and a solid phase calcium decomposition equation.

3. The method for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution according to claim 2 is characterized in that: The water seepage equation is: The calcium ion transport equation is: The solid phase calcium decomposition equation is: Among them, θ is the porosity of cement-based materials after dissolution; ρ is the density of the solution; t is the dissolution time; u is the flow velocity vector of the solution in the pores; is the Hamiltonian operator; Q m is the source term; k is the permeability coefficient; g is the gravitational acceleration; p is the pore water pressure; J ion is the calcium ion transmission flux; D is the effective diffusion coefficient of calcium ions in the solution after the cement-based material is dissolved; α is the dispersivity; D e is the diffusion coefficient of calcium ions in cement-based materials; C s is the solid phase calcium concentration in cement-based materials; C ion is the concentration of calcium ions; C OH is the hydroxide ion concentration in the pore solution; m and K sp are the kinetic index and the solubility product constant of CH respectively; λ is the reaction kinetic coefficient.

4. The method for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution according to claim 3 is characterized in that: The initial parameters and boundary conditions of the dam foundation anti-seepage curtain dissolution degradation analysis model are set to obtain the dam foundation anti-seepage curtain dissolution degradation analysis initial model, which specifically includes: For the anti-seepage curtain at the dam foundation, the upstream side of the power station dam and the upstream side of the bedrock are set as the upstream head boundary, the downstream side of the power station dam and the top of the downstream side of the bedrock are set as the downstream head boundary, and the downstream of the power station dam is set as the seepage boundary in the middle of the upstream and downstream head elevations. The initial calcium ion concentration of the anti-seepage curtain is taken as the saturated concentration according to the construction mix ratio of its cement-based materials, and the initial calcium ion concentration of the bedrock is set as 0; The boundary conditions of the water seepage equation are set as: The boundary conditions of the calcium ion transport equation are set as: Where p is the pore water pressure; ρ is the density of the solution; g is the acceleration of gravity; n is the normal direction outside the boundary surface; u is the velocity vector of the solution in the pore; q is the known seepage flux on the boundary; H0 is the initial water head; H b is the external pressure head; H is the external internal boundary head; z is the elevation of the calculation point; R b is the external conductivity, 1 / s, R b =k s / L,k s is the saturated permeability coefficient, L is the coupling length scale; n is the normal direction outside the boundary surface; C ion is the concentration of calcium ions; k t is the calcium ion transfer coefficient between pore water and ambient water; D ion is the effective diffusion coefficient of calcium ions; q1 is the known diffusion flux on the boundary; C0 is the concentration of calcium ions in the ambient water; is the Hamiltonian operator.

5. The method for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution according to claim 3 is characterized in that: The method of using the computational model to couple the seepage field, calcium ion migration field and dissolution field in the initial model for analyzing the dissolution degradation of the dam foundation anti-seepage curtain specifically includes: In the process of cement-based material dissolution, the seepage field and the dissolution field are coupled with each other. The control equation of the seepage dissolution process of cement-based materials of the dam foundation anti-seepage curtain is expressed as follows: The coupling relationship between seepage field and calcium ion transport field is expressed by water seepage equation, calcium ion transport equation and solid phase calcium decomposition equation; Wherein, θ is the porosity of cement-based materials after dissolution; ρ is the density of the solution; t is the dissolution time; is the Hamiltonian operator; k is the permeability coefficient; g is the gravitational acceleration; p is the pore water pressure; I is the gravity vector; Q m is the source term; C ion is the concentration of calcium ions; λ is the reaction kinetic coefficient; C OH is the hydroxide ion concentration in the pore solution; m and K sp are the kinetic index and the solubility product constant of CH, respectively; D e is the diffusion coefficient of calcium ions in cement-based materials; α is the dispersivity.

6. The method for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution according to claim 5 is characterized in that: The permeability coefficient, porosity and diffusion coefficient are obtained as follows: The porosity is: The permeability coefficient is: The diffusion coefficient is: Where θ is the porosity of cement-based materials after dissolution; θ0 is the initial porosity of cement-based materials; M CH is the molar mass of CH; ρ CH is the density of CH; C s0 is the initial solid calcium concentration of cement-based materials; C s is the solid phase calcium concentration in cement-based materials; is the volume fraction of cement matrix in cement-based materials, In concrete is the volume fraction of gravel in concrete, is the volume fraction of sand in concrete; β is the maximum hydration degree of cement-based materials; w / c is the water-cement ratio, k0 is the initial permeability coefficient; D e is the diffusion coefficient of calcium ions in the pore solution; D0 is the diffusion coefficient of calcium ions in the aqueous solution; H(x) is the heaviside function.

7. The method for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution according to claim 1 is characterized in that: The cross-sectional geometric model of the riverbed of the hydropower station dam project is drawn by AutoCAD, and is imported into COMSOL numerical analysis software to perform mesh division of the geometric model to obtain a calculation model.

8. A system for evaluating the anti-seepage performance of dam foundation curtain under the action of seepage dissolution, characterized in that: include: A computational model building unit is used to draw a geometric model of the riverbed cross section of a hydropower station dam project and to perform meshing of the geometric model to obtain a computational model; The analysis model building unit is used to obtain the permeability coefficient, porosity and calcium ion concentration of cement-based materials in the service water environment of the actual hydropower station dam project anti-seepage curtain; the dam foundation anti-seepage curtain dissolution degradation analysis model is constructed based on the permeability coefficient, porosity and calcium ion concentration in the service water environment; A processing unit is used to set initial parameters and boundary conditions for the dam foundation anti-seepage curtain dissolution degradation analysis model, so as to obtain an initial model for the dam foundation anti-seepage curtain dissolution degradation analysis; An updating calculation unit is used to couple the seepage field, calcium ion migration field and dissolution field in the initial model of the dam foundation anti-seepage curtain dissolution degradation analysis by using the calculation model to obtain the permeability coefficient, porosity and diffusion coefficient; the dam foundation anti-seepage curtain dissolution degradation analysis model is updated according to the permeability coefficient, porosity and diffusion coefficient to obtain the updated model of the dam foundation anti-seepage curtain dissolution degradation analysis; The judgment unit is used to judge whether the permeability coefficient, porosity and diffusion coefficient converge. If converged, the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure corresponding to the above parameters are output; the anti-seepage performance of the dam foundation curtain is evaluated according to the calcium ion concentration, solid calcium concentration and water head of the anti-seepage curtain structure; if not converged, the calculation model is used to couple and solve the update model of the dam foundation anti-seepage curtain dissolution degradation analysis.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the method for evaluating the anti-seepage performance of a dam foundation curtain under the action of seepage dissolution as described in any one of claims 1 to 7.

Images