A method and system for predicting seepage erosion characteristics of diaphragm wall inter-slot joint filling body

Abstract

The present application belongs to the technical field of concrete cutoff wall permeation stability evaluation, and specifically discloses a cutoff wall slot indirect joint filling body seepage erosion characteristic prediction method and system, which comprises obtaining concrete cutoff wall slot section joint three-dimensional geometric appearance data, extracting multiple parallel profiles according to the seepage direction in the slot section joint, and calculating the equivalent roughness coefficient of the slot section joint along the seepage direction; a critical hydraulic gradient model considering the interface roughness constraint factor and the grading correction term is established based on the equivalent roughness coefficient; when the actual hydraulic gradient is greater than the critical hydraulic gradient output by the critical hydraulic gradient model, an erosion model of the slot section joint filling body is established; according to the evolution result of the erosion model, a nonlinear equivalent permeability coefficient model in the erosion process is established, and then the cutoff wall slot indirect joint filling body seepage erosion characteristic is predicted. The present application solves the problems of insufficient geometry-erosion coupling, lack of dynamic evolution and insufficient seepage erosion coupling prediction of the existing method.

Description

Technical Field

[0001] This invention belongs to the technical field of permeability stability evaluation of concrete cut-off walls, specifically relating to a method and system for predicting the seepage erosion characteristics of the inter-joint filling body in the trench of a cut-off wall. Background Technology

[0002] Concrete cutoff walls are core seepage prevention components that block underground seepage and ensure the stability of engineering structures. Their construction requires a segmented casting process, inevitably resulting in joints at the contact surfaces of adjacent segments. The geometric characteristics (roughness, aperture) and the state of the internal filling material jointly control their seepage stability. Current research and engineering applications of concrete cutoff wall segment joints generally suffer from three major shortcomings: Insufficient Geometric-Erosion Coupling: Existing methods for evaluating seepage in trench joints of cut-off walls often rely on macroscopic indicators such as permeability coefficient and leakage rate, frequently treating the joints as equivalent to a continuous medium or ideal parallel fractures. This fails to adequately consider the coupling effect between the rough interface geometry and the erosion process of the filling medium. In actual trench joints, interface roughness, joint opening, and particle size distribution of the filling material collectively influence particle initiation, migration, blockage, and channel expansion. Evaluation based solely on a single equivalent permeability coefficient is insufficient to reflect the process of local seepage channels evolving from micro-seepage to concentrated leakage, potentially leading to inadequate assessment of seepage erosion risk.

[0003] Lack of dynamic evolution: Existing assessment models are mostly based on static geometric indicators, neglecting the migration and loss process of filling particles under high hydraulic gradients. This nonlinear evolution mechanism of "erosion-diameter expansion-instability" lacks description, making it difficult to predict the abrupt moment when the channel joint changes from local micro-seepage to overall failure.

[0004] Insufficient Coupled Prediction of Seepage-Erosion: Under high hydraulic gradients, the filling medium within the joints of the cut-off wall may experience fine particle loss, local channel expansion, and gradual erosion, leading to a continuous increase in joint permeability. Existing evaluation methods have not adequately incorporated interface roughness, crack aperture, and filling particle size distribution as coupled control factors into seepage-erosion analysis, making it difficult to quantitatively predict particle initiation thresholds, erosion development processes, and the deterioration patterns of permeability.

[0005] Therefore, there is an urgent need to propose a method for predicting the seepage erosion characteristics of the filler in the trench section of the anti-seepage wall based on interface roughness. This method should be able to calculate the equivalent roughness along the seepage direction based on three-dimensional geometric topography data, establish the critical hydraulic gradient criterion for the initiation of filler particles, describe the process of fine particle erosion and loss and the evolution of hydraulic aperture, and further predict the variation law of the equivalent permeability coefficient of the trench section joint, thereby providing technical support for the evaluation of seepage stability, construction quality control and service safety prediction of the anti-seepage wall trench section joint. Summary of the Invention

[0006] The purpose of this invention is to address the problems of insufficient geometric-erosion coupling, lack of dynamic evolution, and insufficient prediction of seepage-erosion coupling in existing methods. It proposes a method and system for predicting the seepage erosion characteristics of inter-groove joint filling bodies in anti-seepage walls, which is applicable to infrastructure projects in water conservancy, municipal engineering, transportation and other fields that rely on concrete anti-seepage walls for seepage control.

[0007] The technical solution of the present invention is as follows: Firstly, a method for predicting the seepage erosion characteristics of inter-joint filling bodies in anti-seepage wall trenches, comprising the following steps: Obtain three-dimensional geometric morphology data of the joints in the concrete anti-seepage wall trench; Based on the three-dimensional geometric topography data of the joints in the concrete anti-seepage wall, the seepage direction in the joints is determined. A preset number of parallel profiles are extracted from the elevation data of the joint wall along the seepage direction. Based on the roughness coefficient of each profile, the equivalent roughness coefficient of the joint along the seepage direction is calculated. An interface roughness constraint factor is established based on the equivalent roughness coefficient, and a critical hydraulic gradient model considering the interface roughness constraint factor and gradation correction term is established based on the force balance of representative soil particles in the trench joint filling body. When the actual hydraulic gradient is greater than the critical hydraulic gradient output by the critical hydraulic gradient model, an erosion model for the joint filling body of the channel section is established. Based on the evolution results of the erosion model, a nonlinear equivalent permeability coefficient model is established for the erosion process; Based on a nonlinear equivalent permeability coefficient model of the erosion process, the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench are predicted.

[0008] As a preferred option, the formula for calculating the equivalent roughness coefficient is:

[0009] in, Indicates the direction of seepage within the groove section. Indicates the groove joint along the seepage direction The equivalent roughness coefficient, Indicates the number of cross sections. Indicates the direction of seepage The root mean square slope of the r-th profile is used to characterize the degree of undulation of the fracture wall along the actual seepage direction. The calculation formula is:

[0010] in, The number of sampling points on each profile. Let be the elevation of the crack wall at the location corresponding to the k-th sampling point on the r-th profile. Let be the elevation of the fracture wall at the (k+1)th sampling point on the r-th profile. Let be the distance coordinates along the seepage direction of the k-th sampling point on the r-th profile. Let be the distance coordinates of the (k+1)th sampling point along the seepage direction on the r-th profile.

[0011] Preferably, the formula for calculating the interface roughness constraint factor is:

[0012] in, This represents the interface roughness constraint factor. Represents the equivalent roughness coefficient. For the dimensionless parameter to be calibrated, This is the equivalent roughness angle; Grading correction item The calculation formula is:

[0013] in, The coefficient of non-uniformity, and A dimensionless parameter characterizing the gradation-enhanced bite effect, Indicates the mechanical aperture of the crack in the groove section. Indicates the reference mechanical opening, used to compare the actual mechanical opening of the joint. Perform dimensionless processing. This indicates the particle size corresponding to a cumulative pass rate of 60%. This indicates the particle size corresponding to a cumulative pass rate of 10%. This represents the logarithmic function with the natural base.

[0014] As a preferred option, the formula for the critical hydraulic gradient model is:

[0015] in, Indicates the critical hydraulic gradient. Indicates particle density, This indicates the density of water. Indicates the seepage drag coefficient. Indicates the coefficient of friction between particles. Indicates overlying pressure. This indicates the contact stress within the particle itself. Indicates the gravity coefficient. This indicates the particle size corresponding to a cumulative percentage of fine particles in the soil reaching 50%. This represents the interface roughness constraint factor. It is a graded correction term.

[0016] As a preferred option, the erosion model for the joint filler of the trench section is as follows:

[0017]

[0018] in, This represents the fine-grained erosion rate per unit joint area at time t. Indicates the erosion coefficient. and The coefficient is dimensionless. The initial hydraulic opening, Indicates the mechanical aperture of the crack in the groove section. This represents the initial fine particle content. Indicates particle density, This represents the initial mass concentration. This indicates the particle size corresponding to a cumulative pass rate of 50%. The change of hydraulic opening over time, This represents the actual hydraulic gradient. Indicates the critical hydraulic gradient. Represents the integral variable. This indicates the pore throat's hindering effect on fine particle loss. Indicates particle density, This indicates the initial porosity of the filling material.

[0019] As a preferred option, the nonlinear equivalent permeability coefficient model in the erosion process is obtained by coupling the linear equivalent permeability coefficient modified by the interface roughness and the Forchheimer inertia coefficient. Linear equivalent permeability coefficient with interface roughness correction The calculation formula is:

[0020] in, This indicates the density of water. Indicates the gravity coefficient. The change of hydraulic opening over time, The dynamic viscosity of water. and This is a dimensionless correction factor; Forchheimer inertia coefficient The calculation formula is:

[0021] in, This represents the actual hydraulic gradient. Forchheimer's empirical constant, This represents the linear equivalent permeability coefficient after interface roughness correction.

[0022] As a preferred option, the nonlinear equivalent permeability coefficient model for the erosion process is as follows:

[0023] in, It represents the nonlinear equivalent permeability coefficient during the erosion process.

[0024] The beneficial effects of this invention are: 1. A complete closed-loop mechanism prediction system has been established. This invention uses the surface roughness (JRC) of the joint in the anti-seepage wall trench as an input parameter to quantitatively describe the entire process of "critical hydraulic gradient criterion - fine-grained erosion evolution - nonlinear permeability coefficient prediction", forming a complete mechanism chain from roughness input to leakage output, which makes up for the shortcomings of existing methods that only make empirical estimations and lack mechanism depth.

[0025] 2. A multi-mechanism control model for the seepage erosion process based on roughness was established for the first time. This invention explicitly introduces the JRC (Judge's Ratio) into the critical hydraulic gradient criterion and permeability coefficient model using the Barton equivalent dilatation angle tan(JRC), and further analyzes the evolution of hydraulic aperture. Indirect regulation of erosion rate comprehensively characterizes the physical regulation effect of roughness on the entire process of seepage erosion at the joint.

[0026] 3. Introducing the Forchheimer nonlinear seepage framework. Unlike the traditional cubic law, which is limited to laminar flow, this invention employs the Darcy-Forchheimer nonlinear seepage equation and calculates... The explicit determination of the flow regime range makes the model applicable to the entire flow regime range, including laminar flow, transition zone and inertial-dominated zone, which better matches the actual seepage conditions of the joints of the anti-seepage wall.

[0027] 4. The model parameters have clear physical meaning and strong engineering operability. The input parameters required by the model (JRC, mechanical opening, gradation characteristics, initial fine particle content, etc.) can all be obtained through field measurements or conventional tests, without the need for complex inversion and multi-parameter calibration. It can directly serve engineering practices such as leakage risk assessment of seepage barrier joints, construction quality feedback control, and service life prediction.

[0028] Secondly, a system for predicting the seepage erosion characteristics of inter-joint filling bodies in anti-seepage wall trenches includes: The first module is used to acquire three-dimensional geometric morphology data of the joints in the concrete anti-seepage wall trench. The second module is used to determine the seepage direction in the joint of the concrete anti-seepage wall based on the three-dimensional geometric topography data of the joint. It extracts multiple parallel profiles from the wall elevation data of the joint along the seepage direction and calculates the equivalent roughness coefficient of the joint along the seepage direction based on the roughness coefficient of each profile. The third module is used to establish the interface roughness constraint factor based on the equivalent roughness coefficient, and to establish a critical hydraulic gradient model considering the interface roughness constraint factor and the gradation correction term based on the force balance of representative soil particles in the trench joint filling body. The fourth module is used to establish an erosion model for the trench joint filler when the actual hydraulic gradient is greater than the critical hydraulic gradient output by the critical hydraulic gradient model. The fifth module is used to establish a nonlinear equivalent permeability coefficient model in the erosion process based on the evolution results of the erosion model. The sixth module is used to predict the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench based on the nonlinear equivalent permeability coefficient model in the erosion process.

[0029] Thirdly, a non-transitory computer-readable storage medium is provided that stores computer instructions for causing a computer to perform the method as described in the first aspect. Attached Figure Description

[0030] Figure 1 The diagram shows a flowchart of a method for predicting the seepage erosion characteristics of a joint filling body in a seepage-proof wall trench, as provided in Embodiment 1 of the present invention.

[0031] Figure 2 The diagram shows a method for calculating the roughness of the groove joint interface provided in Embodiment 2 of the present invention.

[0032] Figure 3 The diagram shown is a force analysis diagram of the erosion particles provided in Embodiment 2 of the present invention.

[0033] Figure 4 The diagram shown is a schematic diagram of the experimental apparatus provided in Embodiment 2 of the present invention.

[0034] Figure 5 The figure shows the soil particle size distribution curve provided in Embodiment 2 of the present invention.

[0035] Figure 6 The diagram shown is a schematic diagram of the groove joint interface R1 provided in Embodiment 2 of the present invention.

[0036] Figure 7 The diagram shown is a schematic diagram of the groove joint interface R2 provided in Embodiment 2 of the present invention.

[0037] Figure 8 The diagram shown is a schematic diagram of the groove joint interface R3 provided in Embodiment 2 of the present invention.

[0038] Figure 9 The diagram shown is a diagram of the test process (before the test) provided in Embodiment 2 of the present invention.

[0039] Figure 10 The diagram shown is a test process diagram provided in Embodiment 2 of the present invention (fine particles begin to be lost).

[0040] Figure 11 The diagram shown is a test process diagram (loss stabilization) provided in Embodiment 2 of the present invention.

[0041] Figure 12 The figure shows the critical hydraulic gradient fitting curve provided in Embodiment 2 of the present invention.

[0042] Figure 13 The figure shows the test results and model fitting curves for the groove joint interface R1 provided in Embodiment 2 of the present invention under multi-stage hydraulic gradient loading.

[0043] Figure 14 The figure shows the test results and model fitting curves for the groove joint interface R2 provided in Embodiment 2 of the present invention under multi-stage hydraulic gradient loading.

[0044] Figure 15 The figure shows the test results and model fitting curves for the groove joint interface R3 provided in Embodiment 2 of the present invention under multi-stage hydraulic gradient loading.

[0045] Figure 16 The figure shows the fitting curve of the equivalent permeability coefficient model corresponding to the groove joint interface R1 provided in Embodiment 2 of the present invention.

[0046] Figure 17 The figure shows the fitting curve of the equivalent permeability coefficient model corresponding to the groove joint interface R2 provided in Embodiment 2 of the present invention.

[0047] Figure 18 The figure shows the fitting curve of the equivalent permeability coefficient model corresponding to the groove joint interface R3 provided in Embodiment 2 of the present invention. Detailed Implementation

[0048] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary and are intended to illustrate the principles and spirit of the invention, and are not intended to limit the scope of the invention.

[0049] Example 1: A method for predicting the seepage erosion characteristics of jointed filling bodies in cutoff wall trenches is proposed. Using the joint roughness coefficient JRC as the core input parameter, and through the coupled solution of the critical hydraulic gradient criterion, the fine-grained erosion evolution equation, and the nonlinear permeability coefficient model, it achieves quantitative prediction of the entire process of joint seepage erosion initiation conditions, evolution process, and permeability performance degradation. This provides a theoretical basis and engineering method for the permeability stability assessment and service life prediction of cutoff walls. Figure 1 As shown, the method for predicting the seepage erosion characteristics of the joint filling body in the anti-seepage wall trench specifically includes the following steps: S1. Obtain the three-dimensional geometric morphology data of the joints in the concrete anti-seepage wall trench; S2. Based on the three-dimensional geometric topography data of the joint of the concrete anti-seepage wall, determine the seepage direction in the joint, extract a preset number of parallel profiles from the elevation data of the joint wall along the seepage direction, and calculate the equivalent roughness coefficient of the joint along the seepage direction based on the roughness coefficient of each profile. S3. Based on the equivalent roughness coefficient, establish the interface roughness constraint factor, and based on the force balance of representative soil particles in the trench joint filling body, establish a critical hydraulic gradient model considering the interface roughness constraint factor and gradation correction term. S4. When the actual hydraulic gradient is greater than the critical hydraulic gradient output by the critical hydraulic gradient model, establish an erosion model for the joint filling body of the trench section; S5. Based on the evolution results of the erosion model, establish a nonlinear equivalent permeability coefficient model in the erosion process; S6. Based on the nonlinear equivalent permeability coefficient model in the erosion process, predict the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench.

[0050] In this embodiment, step S1 specifically includes: Three-dimensional laser scanning was used to acquire the three-dimensional morphology of the contact surface samples of adjacent trench sections of the concrete cutoff wall, obtaining spatial coordinate point cloud data of the trench joint surface. The spatial coordinate point cloud data was then denoised, registered, resampled, and smoothed to establish a three-dimensional geometric model of the trench joint. The scanning accuracy of the three-dimensional laser scanner should be no less than 0.1 mm.

[0051] In this embodiment, step S2 specifically includes: Determine the seepage direction within the groove section, denoted as . Along the seepage direction Profile extraction was performed on the elevation data of the crack wall surface in the groove section, and a total of [data missing] were extracted. 10 parallel sections, each section containing Sampling points. Extracted along the seepage direction. The roughness coefficients of the parallel cross sections are taken as the arithmetic mean to obtain the equivalent roughness coefficient of the groove section along the seepage direction. :

[0052] in, seepage direction The root mean square slope of the r-th profile is used to characterize the degree of undulation of the fracture wall along the actual seepage direction. The specific calculation formula is as follows:

[0053] Let be the elevation of the crack wall at the location corresponding to the k-th sampling point on the r-th profile. Let be the elevation of the fracture wall at the (k+1)th sampling point on the r-th profile. Let be the distance coordinates along the seepage direction of the k-th sampling point on the r-th profile. Let be the distance coordinate along the seepage direction of the (k+1)th sampling point on the r-th profile. Equivalent roughness coefficient. The coefficients 32.2 and 32.47 in the calculation formula are derived from empirical relationships. This formula digitizes ten standard roughness profiles and then uses JRC and root mean square slope to calculate the roughness. The result was obtained by log-linear least squares regression fitting, where 32.2 is the intercept of the regression line and 32.47 is the slope of the regression line. This is a recognized method in rock mechanics for quantitatively characterizing joint roughness. Based on this, this invention introduces the seepage direction... Multi-section averaging is performed along this direction to obtain an equivalent roughness coefficient that is consistent with the seepage erosion direction and is statistically stable.

[0054] The roughness of the joint interface in the trench section is anisotropic, and the direction of the roughness must be consistent with the direction of seepage. The parallel profile extracted from the joint interface in the trench section and the spacing between points on the profile are 0.5 mm, and the sampling interval is also within the applicable range of the Tse-Cruden formula.

[0055] In this embodiment, step S3 specifically includes: The forces acting on a representative soil particle in the joint filler of the trench section include seepage driving forces. Effective gravity interparticle friction and interface roughness constraint force The critical condition for particle initiation is that the driving force equals the resistance force:

[0056] The physical definition of friction is the product of the coefficient of friction and the normal contact force, where the normal contact force is equal to the contact stress. (dimension Pa) multiplied by the projected contact area of ​​the particle ( (dimension m²), therefore The dimensionless quantity is N, and , , Consistent.

[0057] seepage driving force The calculation method is as follows:

[0058] in, The seepage drag coefficient is... This refers to the density of water, expressed in kg / m³. 3 , This is the gravity coefficient, with units of m / s². 2 , This represents the actual hydraulic gradient. Indicates soil particle size. Seepage drag coefficient. The drag coefficient is an empirical parameter in fluid mechanics that characterizes the strength of the drag effect of a fluid on particles. Its value depends on factors such as particle shape, surface characteristics, and flow regime. In engineering practice, it is usually selected based on empirical ranges or determined through experimental calibration. For natural sand and gravel backfill particles, under low Reynolds number seepage conditions at the joints of cut-off walls, this coefficient is generally in the range of 1 to 10. This invention comprehensively considers the actual working conditions of approximately spherical backfill particles and a certain degree of surface roughness, and refers to the empirical value rules of the drag coefficient in fluid mechanics, taking... =5.5 is used as a representative empirical value. This value is within a generally accepted reasonable range and can reflect the actual magnitude of the seepage drag effect on the filling particles. In specific engineering applications, it can also be further calibrated and corrected through the indoor rough filling fracture seepage erosion test described in step S6 of this invention to adapt to the actual characteristics of different filling media.

[0059] Actual hydraulic gradient It is one of the core fundamental concepts in seepage mechanics that describes the driving force of seepage. It is defined as the head loss per unit seepage path along the seepage direction, i.e., the head difference between the upstream and downstream of the joint. With seepage path length The ratio, This can be obtained directly through on-site or indoor tests. Specifically, head difference... The seepage path length is obtained from the water level monitoring upstream and downstream of the cutoff wall or from the actual measurement of the piezometer installed. The actual hydraulic gradient is obtained by dividing the difference between the on-site design and construction conditions. Therefore... It is a fundamental quantity in seepage mechanics that has a clear concept and can be directly obtained from experiments, and its value has no uncertainty.

[0060] Effective gravity The calculation method is as follows:

[0061] in, Particle density, in kg / m³ 3 .

[0062] interparticle friction The calculation method is as follows:

[0063] in, The coefficient of friction between particles. The overburden pressure is expressed in Pa. This refers to the contact stress of the particle itself, expressed in Pa. The calculation method is as follows:

[0064] in, Reference contact stress, in Pa. For the porosity of the filling medium, For the mechanical aperture of the crack, and For the parameters to be calibrated, This indicates the particle size corresponding to a cumulative pass rate of 50%.

[0065] Interface roughness constraint The calculation method is as follows:

[0066] in, Roughness constraint factor This indicates that geometric engagement must be overcome before the particles can start moving. The calculation method is as follows:

[0067] in, For the dimensionless parameter to be calibrated, This is the equivalent roughness angle, measured in rad.

[0068] Critical hydraulic gradient The calculation formula is:

[0069] in, This refers to the particle size corresponding to a cumulative percentage of fine particles in the soil reaching 50%, expressed in meters (m). This is a graded adjustment term; To represent the force balance of a single particle, a gradation correction term is introduced. This indicates that soil particles of different sizes fill and interlock with each other, resulting in enhanced strength. The calculation method is as follows:

[0070] in, The coefficient of non-uniformity, and A dimensionless parameter characterizing the gradation-enhanced bite effect, Indicates the mechanical aperture of the crack in the groove section. Indicates the reference mechanical opening, used to compare the actual mechanical opening of the joint. Dimensionless processing can be performed by taking the median aperture from the test conditions or the representative aperture from the engineering design. This indicates the particle size corresponding to a cumulative pass rate of 60%. This indicates the particle size corresponding to a cumulative pass rate of 10%. This represents the logarithmic function with the natural base.

[0071] In this embodiment, in step S4, when > When erosion occurs in the cracks, the erosion rate of the fine-grained erosion rate, i.e., the erosion model of the joint filler in the trench section, is expressed as:

[0072] in, Let be the fine-grained erosion rate per unit joint area at time t, expressed in kg / (m²·s). This is the erosion coefficient, expressed in seconds. -1 , and The coefficient is dimensionless. The initial hydraulic opening, This indicates the particle size corresponding to a cumulative pass rate of 50%. This represents the initial fine particle content. The change of hydraulic opening over time, The calculation formula is:

[0073] in, This indicates the initial porosity of the filling material.

[0074] Erosion coefficient in erosion rate model Nonlinear coefficients and These are all parameters characterizing the erosion kinetics of the filling medium, which cannot be directly derived from theory and must be determined by regression calibration of measured data through indoor seepage erosion tests. In Example 2 of this invention, a complete calibration method is provided: Seepage erosion tests are conducted under nine conditions with three different interface roughnesses and three different crack openings. Hydraulic gradients are applied progressively, and the evolution curves of fine-grained erosion loss and permeability coefficient are monitored in real time. The measured data are then substituted into the erosion rate model for nonlinear least-squares regression to determine the values ​​of the aforementioned parameters.

[0075] Initial hydraulic opening The calculation formula is:

[0076] In this embodiment, in step S5, the nonlinear equivalent permeability coefficient model during the erosion process is:

[0077] in, This represents the nonlinear equivalent permeability coefficient during the erosion process. The linear equivalent permeability coefficient is corrected for interface roughness. This is the Forchheimer inertia coefficient. The flow rate decreases as the hydraulic gradient increases, indicating that the inertial loss caused by the increase in flow velocity increases, further damaging the equivalent permeability of the fracture. This is the fundamental difference between nonlinear seepage flow and Darcy flow. Equivalent roughness coefficient The fact that JRC affects both linear and nonlinear terms indicates that it increases both viscous drag and inertial loss.

[0078] Linear equivalent permeability coefficient with interface roughness correction The calculation formula is:

[0079] in, The dynamic viscosity of water (1.0 × 10⁻⁶) 3 Pa·s), and This is a dimensionless correction factor.

[0080] Forchheimer inertia coefficient The calculation formula is:

[0081] in, It is the Forchheimer empirical constant.

[0082] when When it approaches 0, Degenerate into The Darcy flow reverts; when JRC approaches 0, Degenerate into The linear term regresses to the cube law; when When it approaches infinity, Degenerate into The seepage flow is entirely driven by inertia.

[0083] The present invention also includes model testing and parameter calibration steps. To verify the engineering applicability of the established critical hydraulic gradient criterion, erosion evolution equation and nonlinear permeability coefficient model, and to calibrate the relevant parameters involved in the model, an indoor rough fissure seepage erosion model test was carried out. By applying hydraulic gradients step by step and monitoring the erosion loss and permeability coefficient evolution curves in real time, the values ​​of each parameter were obtained by inversion.

[0084] Example 2: Based on Example 1, this embodiment of the invention takes the filling of cracks in the trench section of a concrete anti-seepage wall as the research object, setting three types of interface roughness and three different crack openings, forming a total of nine test conditions. The geometric morphology of the crack wall surface in the trench section is obtained through three-dimensional scanning, and the equivalent roughness is calculated along the seepage direction. In conjunction with seepage erosion tests, the critical hydraulic gradient for the initiation of filling particles, the fine particle erosion process, the evolution of hydraulic aperture, and the change of equivalent permeability coefficient were predicted and parameters were calibrated.

[0085] This embodiment takes the concrete anti-seepage wall of a water conservancy project as the application scenario. The dam foundation cover layer of this project is mainly composed of silty clay and gravel, with abundant groundwater, which imposes strict requirements on the anti-seepage performance of the trench joints.

[0086] First, test samples of the joints of the trench sections with different interface roughness were prepared. Then, a three-dimensional model of the actual joints of the trench sections was obtained by scanning after concrete pouring.

[0087] The second step is to establish a geometric characteristic parameter system for the trench joints. The seepage direction within the trench joints is determined, denoted as... Along the seepage direction Profile extraction was performed on the elevation data of the joint wall surface of the trench section, and a total of [data missing] were extracted. 10 parallel sections, each section containing Sampling points. Extracted along the seepage direction. The roughness coefficients of the parallel cross sections are taken as the arithmetic mean to obtain the equivalent roughness coefficient of the groove section along the seepage direction. :

[0088] in, seepage direction The root mean square slope of the r-th profile is used to characterize the degree of undulation of the joint surface of the trench section along the actual seepage direction.

[0089] The third step is to establish a critical hydraulic gradient model for the joint filler in the trench section. Based on the force process of a representative soil particle in the joint filler, the critical condition for particle initiation is that the driving force equals the resistance force, and the critical hydraulic gradient is determined. Represented as:

[0090] in, and (kg / m 3 These represent particle density and water density, respectively. The seepage drag coefficient is... The coefficient of friction between particles. (Pa) represents the overlying pressure. (Pa) represents the contact stress of the particle itself. (m / s 2 ) is the gravity coefficient. (m) represents the particle size corresponding to a cumulative percentage of fine particles in the soil reaching 50%. Roughness constraint factor It is a graded correction term.

[0091] The fourth step is to establish an erosion model of the joint filler in the trench sections. When > At that time, erosion occurred at the joints of the trench sections, and the fine-grained erosion rate was expressed as:

[0092] in, (kg / (m²·s)) represents the fine-grained erosion rate per unit joint area at time t. The erosion coefficient (s) -1 ), and The coefficient is dimensionless. The initial hydraulic opening, This represents the initial fine particle content. This represents the change in hydraulic opening over time.

[0093] The fifth step is to establish an equivalent permeability coefficient model for the joint filling body of the trench section. Based on S3 and S4, the nonlinear equivalent permeability coefficient model for the erosion process is as follows:

[0094] in, The linear equivalent permeability coefficient is corrected for interface roughness. This is the Forchheimer inertia coefficient.

[0095] Model tests and parameter calibration. To verify the engineering applicability of the established critical hydraulic gradient criterion, erosion evolution equation, and nonlinear permeability coefficient model, and to calibrate the relevant parameters involved in the model, indoor rough fissure seepage erosion model tests were conducted. By applying hydraulic gradients step by step and monitoring the erosion loss and permeability coefficient evolution curves in real time, the values ​​of each parameter were obtained through inversion.

[0096] Based on the above prediction method, preparations were made for the corresponding concrete trench filling seepage erosion model test and the determination of basic parameters. Figure 2 This diagram illustrates the calculation method for the interface roughness of the channel section. First, a geometric three-dimensional model is established through three-dimensional scanning. The direction of the parallel section is determined according to the seepage direction, and the roughness in the JRC direction is calculated. Finally, the arithmetic mean is taken as the equivalent interface roughness.

[0097] To evaluate the particle initiation conditions of the trench backfill under seepage, stress analysis was performed on the erodible particles, such as... Figure 3 As shown, erosion of fine particles only occurs when the seepage driving force equals the interparticle friction, buoyancy, and interfacial roughness resistance. Figure 4 The diagram shows the test apparatus for seepage erosion of the filling material in the trench section. Each set of plates is made of transparent resin and is assembled with bolts. The test was conducted according to the following test steps: (1) Assembly and sealing: The trench section joint model with a natural rough surface was assembled and fixed with high-strength bolts; in order to eliminate preferential tributaries and ensure reliable lateral sealing, waterproof gaskets were carefully arranged along the boundary and silicone rubber sealant was applied. (2) Filling and saturation: Quartz sand mixture was filled into the trench section joint. Then, the filling material was compacted by gradually tightening the bolts until the target porosity was reached; after compaction, the top cover was lowered to the set initial opening degree using a precision screw mechanism and the opening degree was locked to keep it constant throughout the test; then, the outlet valve of the upstream water tank was opened to gradually saturate the test chamber with a very small flow rate, thereby minimizing the air trapped inside and avoiding premature internal erosion. (3) Staged loading: The hydraulic gradient is applied by stepwise increasing method; the hydraulic gradient is increased to the next stage only when the loss of fine particles under the current hydraulic gradient has completely stabilized and no longer increases. (4) Particle collection: The water-filling mixture is weighed and counted in the downstream collection device to obtain the response characteristics of the mass loss of filling material under the loading conditions. The imaging device can record in real time the movement process of the filling material inside the fracture under hydraulic conditions and the formation process of the flow channel.

[0098] Figure 5The quartz sand particle size distribution curve used in this embodiment of the invention is shown. The concrete trench joint was prepared by cutting the anti-seepage wall on site and then by fine cutting indoors. The sample size of the trench joint is 100mm×100mm×20mm. Before the test, the interface of the trench was subjected to three-dimensional laser scanning with a laser scanning accuracy of 0.01mm. Figure 6 , Figure 7 and Figure 8 This is a schematic diagram of the interface of the groove section used for the sample.

[0099] In the experiment of this embodiment, the particle size distribution parameters of the filling were determined by standard sieve analysis, and the particle size corresponding to the cumulative volume fractions of 10%, 30%, and 60% was determined. =0.315mm =0.50mm =1.35mm, based on which the uniformity coefficient is calculated. 4.27. Curvature Coefficient =0.59; Particle density The value is taken as 2650 kg / m³; based on the test conditions, The value is 2.5 mm; the sample porosity is 0.34; and the seepage drag coefficient is... The value is 5.5; interparticle friction coefficient Based on experience, a value of 0.6 is chosen; water density The value is taken as 1000 kg / m³; overburden pressure The value is 0; the gravity coefficient is 9.81 m / s². =0.45mm. For the non-cohesive quartz sand filling body involved in this invention, the interparticle contact stress that fine particles need to overcome when initiating at the pore scale is approximately Pa, which can be taken as 0.45mm in engineering. =5Pa is used as a typical value. The test conditions are shown in Table 1.

[0100] Table 1. Test conditions for seepage erosion of the trench filling body

[0101] Figure 9 , Figure 10 and Figure 11 This diagram illustrates the process of an internal erosion test induced by seepage. It shows the evolution of the filling medium inside the joint of the trench section from the initial loss to the point of erosion stabilization. Parameter calibration was then performed, and the final coefficient values ​​were obtained. =4.16, =33.15, =0.19, =3.60, =36.80, model fit coefficient R²=0.9945, see Figure 12 .

[0102] Figure 13 , Figure 14 and Figure 15 The evolution curves and fitting results of fine particle loss rate versus time under multi-stage hydraulic gradients are presented, and the final coefficient values ​​are determined. =1.03×10 -2 , =0.66, =0.06, =0.13, model fit coefficient R²=0.9769, the fit effect is very good.

[0103] Figure 16 , Figure 17 and Figure 18 The relationship between the equivalent permeability coefficient and the hydraulic gradient in this embodiment is given, where the fitting coefficient is... , =0.39, =29.88, model fit coefficient R²=0.9473, good fit effect.

[0104] Through the above implementation methods, a complete technical chain can be formed, encompassing "equivalent roughness input—critical hydraulic gradient criterion—fine-grained erosion evolution—hydraulic aperture update—nonlinear equivalent permeability coefficient prediction—leakage capacity evaluation." This embodiment can verify the predictive ability of the method of the present invention for the initiation conditions, evolution process, and permeability performance degradation law of seepage erosion in the filling body of the anti-seepage wall trench joints. It can provide quantitative basis for the evaluation of seepage stability, construction quality control, and service safety prediction of anti-seepage wall trench joints.

[0105] Example 3: Based on Example 1, this embodiment of the invention provides a system for predicting the seepage erosion characteristics of jointed filling bodies in anti-seepage wall trenches. This system can be used to implement the method for predicting the seepage erosion characteristics of jointed filling bodies in anti-seepage wall trenches as described in the preceding embodiments. The system includes: The first module is used to acquire three-dimensional geometric morphology data of the joints in the concrete anti-seepage wall trench. The second module is used to determine the seepage direction in the joint of the concrete anti-seepage wall based on the three-dimensional geometric topography data of the joint. It extracts a preset number of parallel profiles from the wall elevation data of the joint along the seepage direction and calculates the equivalent roughness coefficient of the joint along the seepage direction based on the roughness coefficient of each profile. The third module is used to establish the interface roughness constraint factor based on the equivalent roughness coefficient, and to establish a critical hydraulic gradient model considering the interface roughness constraint factor and the gradation correction term based on the force balance of representative soil particles in the trench joint filling body. The fourth module is used to establish an erosion model for the trench joint filler when the actual hydraulic gradient is greater than the critical hydraulic gradient output by the critical hydraulic gradient model. The fifth module is used to establish a nonlinear equivalent permeability coefficient model in the erosion process based on the evolution results of the erosion model. The sixth module is used to predict the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench based on the nonlinear equivalent permeability coefficient model in the erosion process.

[0106] According to embodiments of the present invention, the present invention also provides an electronic device, a readable storage medium, and a computer program product.

[0107] In an exemplary embodiment, an electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method as described in Embodiment 1 above.

[0108] In an exemplary embodiment, the readable storage medium may be a non-transitory computer-readable storage medium storing computer instructions for causing the computer to perform the method described in Embodiment 1 above.

[0109] In an exemplary embodiment, the computer program product includes a computer program that, when executed by a processor, implements the method described in Embodiment 1 above.

[0110] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0111] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0112] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0113] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with embodiments of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0114] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact via communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other. Servers can be cloud servers, servers in distributed systems, or servers incorporating blockchain technology.

[0115] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A method for predicting the seepage erosion characteristics of inter-joint filling bodies in anti-seepage wall trenches, characterized in that, Includes the following steps: Obtain three-dimensional geometric morphology data of the joints in the concrete anti-seepage wall trench; Based on the three-dimensional geometric topography data of the joints in the concrete anti-seepage wall, the seepage direction in the joints is determined. A preset number of parallel profiles are extracted from the elevation data of the joint wall along the seepage direction. Based on the roughness coefficient of each profile, the equivalent roughness coefficient of the joint along the seepage direction is calculated. An interface roughness constraint factor is established based on the equivalent roughness coefficient, and a critical hydraulic gradient model considering the interface roughness constraint factor and gradation correction term is established based on the force balance of representative soil particles in the trench joint filling body. When the actual hydraulic gradient is greater than the critical hydraulic gradient output by the critical hydraulic gradient model, an erosion model for the joint filling body of the channel section is established. Based on the evolution results of the erosion model, a nonlinear equivalent permeability coefficient model is established for the erosion process; Based on a nonlinear equivalent permeability coefficient model of the erosion process, the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench are predicted.

2. The method for predicting the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench according to claim 1, characterized in that, The formula for calculating the equivalent roughness coefficient is: in, Indicates the direction of seepage within the groove section. Indicates the groove joint along the seepage direction The equivalent roughness coefficient, Indicates the number of cross sections. Indicates the direction of seepage The root mean square slope of the r-th profile is used to characterize the degree of undulation of the fracture wall along the actual seepage direction. The calculation formula is: in, The number of sampling points on each profile. Let be the elevation of the crack wall at the location corresponding to the k-th sampling point on the r-th profile. Let be the elevation of the fracture wall at the (k+1)th sampling point on the r-th profile. Let be the distance coordinates along the seepage direction of the k-th sampling point on the r-th profile. Let be the distance coordinates of the (k+1)th sampling point along the seepage direction on the r-th profile.

3. The method for predicting the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench according to claim 1, characterized in that, The formula for calculating the interface roughness constraint factor is: in, This represents the interface roughness constraint factor. Represents the equivalent roughness coefficient. For the dimensionless parameter to be calibrated, This is the equivalent roughness angle; Grading correction item The calculation formula is: in, The coefficient of non-uniformity, and A dimensionless parameter characterizing the gradation-enhanced bite effect, Indicates the mechanical aperture of the crack in the groove section. Indicates the reference mechanical opening, used to compare the actual mechanical opening of the joint. Perform dimensionless processing. This indicates the particle size corresponding to a cumulative pass rate of 60%. This indicates the particle size corresponding to a cumulative pass rate of 10%. This represents the logarithmic function with the natural base.

4. The method for predicting the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench according to claim 1, characterized in that, The formula for the critical hydraulic gradient model is: in, Indicates the critical hydraulic gradient. Indicates particle density, This indicates the density of water. Indicates the seepage drag coefficient. Indicates the coefficient of friction between particles. Indicates overlying pressure. This indicates the contact stress within the particle itself. Indicates the gravity coefficient. This indicates the particle size corresponding to a cumulative percentage of fine particles in the soil reaching 50%. This represents the interface roughness constraint factor. It is a graded correction term.

5. The method for predicting the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench according to claim 1, characterized in that, The erosion model of the joint filler in the trench section is as follows: in, This represents the fine-grained erosion rate per unit joint area at time t. Indicates the erosion coefficient. and The coefficient is dimensionless. The initial hydraulic opening, Indicates the mechanical aperture of the crack in the groove section. This represents the initial fine particle content. Indicates particle density, This represents the initial mass concentration. This indicates the particle size corresponding to a cumulative pass rate of 50%. The change of hydraulic opening over time, This represents the actual hydraulic gradient. Indicates the critical hydraulic gradient. Represents the integral variable. This indicates the pore throat's hindering effect on fine particle loss. Indicates particle density, This indicates the initial porosity of the filling material.

6. The method for predicting the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench according to claim 1, characterized in that, The nonlinear equivalent permeability coefficient model for the erosion process is obtained by coupling the linear equivalent permeability coefficient modified by the interface roughness and the Forchheimer inertia coefficient. Linear equivalent permeability coefficient with interface roughness correction The calculation formula is: in, This indicates the density of water. Indicates the gravity coefficient. The change of hydraulic opening over time, The dynamic viscosity of water. and This is a dimensionless correction factor; Forchheimer inertia coefficient The calculation formula is: in, This represents the actual hydraulic gradient. Forchheimer's empirical constant, This represents the linear equivalent permeability coefficient after interface roughness correction.

7. The method for predicting the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench according to claim 6, characterized in that, The nonlinear equivalent permeability coefficient model for the erosion process is as follows: in, It represents the nonlinear equivalent permeability coefficient during the erosion process.

8. A system for predicting the seepage erosion characteristics of inter-joint filling bodies in anti-seepage wall trenches, characterized in that, include: The first module is used to acquire three-dimensional geometric morphology data of the joints in the concrete anti-seepage wall trench. The second module is used to determine the seepage direction in the joint of the concrete anti-seepage wall based on the three-dimensional geometric topography data of the joint. It extracts a preset number of parallel profiles from the wall elevation data of the joint along the seepage direction and calculates the equivalent roughness coefficient of the joint along the seepage direction based on the roughness coefficient of each profile. The third module is used to establish the interface roughness constraint factor based on the equivalent roughness coefficient, and to establish a critical hydraulic gradient model considering the interface roughness constraint factor and the gradation correction term based on the force balance of representative soil particles in the trench joint filling body. The fourth module is used to establish an erosion model for the trench joint filler when the actual hydraulic gradient is greater than the critical hydraulic gradient output by the critical hydraulic gradient model. The fifth module is used to establish a nonlinear equivalent permeability coefficient model in the erosion process based on the evolution results of the erosion model. The sixth module is used to predict the seepage erosion characteristics of the inter-joint filling body in the anti-seepage wall trench based on the nonlinear equivalent permeability coefficient model in the erosion process.

9. A non-transitory computer-readable storage medium storing computer instructions, characterized in that, The computer instructions are used to cause the computer to perform the method according to any one of claims 1-7.

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