A discrimination method and system for seepage of double-layer dam foundation

Abstract

The present invention discloses a method and system for discriminating the seepage of a double-layer dam foundation. The method includes: S1, obtaining the geological parameters of the double-layer dam to form a set of geological parameters; S2, constructing a seepage numerical model of the double-layer dam foundation to simulate the seepage field distribution at each grid node of the double-layer dam foundation and obtaining seepage field data; S3, calculating the seepage force of the grid node to determine the potential seepage failure area; S4, monitoring the changes in pore water pressure and seepage flow rate of preset monitoring points within the potential seepage failure area; S5, constructing a seepage failure discrimination model and outputting a seepage determination result; S6, performing hierarchical processing according to the determination result of seepage failure and outputting a graded seepage warning message through a seepage grading model. The present invention realizes the discrimination, real-time monitoring and graded early warning of the seepage failure of the double-layer dam foundation, and ensures the safety of the heterogeneous double-layer dam.

Description

Technical Field

[0001] The present invention relates to the technical field of dam seepage monitoring, and specifically to a method and system for discriminating seepage in a double-layer dam foundation Background Art

[0002] As an important part of water conservancy projects, the stability of the foundation of a dam is directly related to the safe operation of the entire water conservancy facility. Due to the differences in the properties of the upper and lower soil layers in a heterogeneous double-layer dam foundation, seepage failure is extremely likely to occur under seepage action, which in turn triggers risks such as dam piping and landslides, threatening the safety of the lives and property of the surrounding people and the stability of the ecological environment. Accurately discriminating the seepage failure situation of a heterogeneous double-layer dam foundation is crucial for taking effective preventive measures in advance and ensuring the safety of the dam. Therefore, it is of great significance to invent a reliable method for discriminating seepage failure in a heterogeneous double-layer dam foundation.

[0003] Traditional techniques for discriminating seepage failure in dam foundations mostly rely on empirical judgment and simple on-site observations. For example, by observing whether phenomena such as water seepage and sand gushing appear on the surface of the dam to judge whether seepage failure has occurred. The advantage of this method is that it is simple to operate and has a low cost, without the need for complex equipment and professional knowledge, and can make a preliminary judgment on obvious signs of seepage failure to a certain extent. However, its disadvantages are also extremely obvious. On the one hand, this method overly relies on human subjective experience and lacks scientific quantitative analysis, making it difficult to accurately judge potential seepage failure risks; on the other hand, it can only be discovered when seepage failure has developed to a certain extent and obvious external manifestations appear, unable to achieve early warning and unable to take timely measures to prevent the further development of the failure, posing a large safety hazard.

[0004] Existing technologies have made certain progress in discriminating seepage failure in dam foundations, and some have adopted numerical simulation techniques and monitoring means. Numerical simulation techniques estimate potential seepage failure areas by constructing simple seepage models and calculating the seepage field and seepage force. At the same time, sensors are used to monitor parameters such as pore water pressure and seepage flow rate inside the dam. These technologies have made obvious progress compared with traditional methods, can analyze seepage problems more deeply, discover some potential seepage failure areas in advance, and can obtain monitoring data in real time. However, existing technologies still have deficiencies. On the one hand, existing seepage models often do not adequately consider the complexity of heterogeneous double-layer dam foundations, and fail to accurately reflect the influence of the differences in the parameters of the upper and lower soil layers and their interaction on the seepage field, resulting in deviations in calculation results; on the other hand, the layout of monitoring points lacks systematicness and pertinence, making it difficult to comprehensively capture the seepage changes in the entire dam foundation, easily missing important seepage failure information, and affecting the accuracy and reliability of discrimination results.

[0005] Therefore, in view of the above problems, the present application proposes a method and system for discriminating seepage in the foundation of a double-layer dam, which solves the above-mentioned technical problems. Summary of the Invention

[0006] Based on the above, the present application proposes a method and system for discriminating seepage in the foundation of a double-layer dam. The method specifically includes the following steps:

[0007] S1. Obtain the geological parameters of the double-layer dam to form a set of geological parameters;

[0008] S2. According to the set of geological parameters, construct a seepage numerical model for the foundation of the double-layer dam. The seepage numerical model includes an upper-layer seepage numerical model and a lower-layer seepage numerical model. By setting different water head differences in the seepage numerical model, simulate the distribution of the seepage field at each grid node of the double-layer dam foundation, and obtain seepage field data;

[0009] S3. According to the seepage field data, calculate the seepage force at the grid nodes, and combine the soil shear strength indexes of the grid nodes to determine the potential seepage failure area;

[0010] S4. In the potential seepage failure area, set up preset monitoring points to monitor the changes in pore water pressure and seepage flow rate at the preset monitoring points;

[0011] S5. Construct a seepage failure discrimination model. When the change in pore water pressure or seepage flow rate at the monitoring point exceeds the preset threshold and the duration reaches the set time, it is determined that seepage failure has occurred in the monitoring area, and the seepage determination result is output;

[0012] S6. Perform grading processing according to the determination result of seepage failure, and output the graded seepage warning information through the seepage grading model.

[0013] Preferably, the geological parameters of the double-layer dam include upper-layer geological parameters and lower-layer geological parameters; the upper-layer geological parameters include upper-layer permeability coefficient, porosity, saturation, and soil thickness; the lower-layer geological parameters include lower-layer permeability coefficient, porosity, saturation, soil thickness, and compression modulus.

[0014] Preferably, the construction of the upper-layer seepage numerical model in S2 specifically includes:

[0015] Obtain the soil parameters of the tiny unit body of the upper-layer soil, and construct the seepage continuity equation. The formula is: , where is the spatial coordinate of the tiny unit body, is the time, is the upper-layer geological water head, is the upper-layer geological porosity, is the upper-layer geological saturation; obtain the upper-layer soil at The seepage velocity component in the direction, and the formula is: where are respectively the seepage velocity components of the upper soil layer in the direction,

[0016] Preferably, for the construction of the lower layer seepage numerical model in S2, it specifically includes:

[0017] Obtain the soil parameters of the micro - element body of the lower soil layer, and construct the seepage continuity equation, the formula is: where is the spatial coordinate of the micro - element body, is the time, is the groundwater head of the lower layer geology, is the porosity of the lower layer geology, is the degree of saturation of the lower layer geology; Obtain the seepage velocity component of the lower soil layer in the direction, and the formula is: where are respectively the seepage velocity components of the lower soil layer in the direction, is the permeability coefficient of the lower layer geology. The porosity of the lower soil layer is affected by compression deformation, and combined with the compression modulus for coupled solution, the formula is: where is the stress of the lower layer geology; By obtaining the seepage field of the lower micro - element body and performing continuous fitting of the micro - element body, a lower layer seepage numerical model is formed.

[0018] Preferably, couple the upper layer seepage numerical model with the lower layer seepage numerical model, set transition elements at the interface between the upper and lower layers, use dynamic loading technology to simulate the gradual change of the water head difference, capture multi - dimensional seepage information of grid nodes, and use distributed storage technology to store seepage data under different grid nodes and water head difference simulations in multiple associated storage units to obtain seepage field data.

[0019] Preferably, the grid nodes are obtained by the grid division crossing method, which specifically includes:

[0020] S2.1. Conduct geological exploration and structural analysis on the double - layer dam foundation to clarify the boundaries of the upper and lower soil layers, the changing areas of geological materials, and the existing weak parts;

[0021] S2.2. For the areas in the double-layer dam foundation where the seepage change is relatively gentle and the geological conditions are relatively uniform, larger-scale grids are used for division; in the areas where the seepage change is intense, the geological conditions are complex, the potential areas of seepage failure, and the parts with geological defects, smaller-scale grids are used for division;

[0022] S2.3. After grid division, through the grid connection method of gradual transition, the size change between adjacent grids is gradually reduced. Combining with the actual shape and boundary conditions of the dam foundation, grid division intersection is carried out to obtain grid nodes.

[0023] Preferably, in S3, according to the seepage field data obtained by simulation, the seepage force of grid nodes is calculated, and combined with the shear strength index of the soil mass at the grid nodes, the potential seepage failure area is determined, specifically including:

[0024] Obtain the seepage velocity of grid nodes , the unit weight of water and the porosity of the soil mass corresponding to the node , calculate the seepage force of grid nodes , the formula is: , where the seepage velocity is obtained from the seepage field data; obtain the friction angle , cohesion and effective stress of the soil mass at the grid nodes, calculate the shear strength of the soil mass, the formula is: , where the effective stress is obtained from the total stress and pore water pressure at the grid nodes, the formula is: ; obtain the safety factor of the grid nodes, the formula is: , if the safety factor of the grid node is less than the preset safety factor , it is determined as a potential seepage grid node. Through continuous screening, the obtained potential seepage grid nodes are networked to form a potential seepage failure area.

[0025] Preferably, in S5, an infiltration failure discrimination model is constructed, and the change of pore water pressure or seepage flow rate of the monitoring points is monitored in the potential infiltration failure area. If it exceeds the preset pore water pressure threshold or seepage flow rate change threshold and the duration reaches the set time, it is determined that the monitored area has infiltration failure and the infiltration determination result is output, specifically as follows:

[0026] Obtain the pore water pressure of the infiltration failure area at the monitoring points in the time , and the pore water pressure of the infiltration failure area at the initial moment is, the seepage flow rate is , the initial seepage flow rate is , the preset pore water pressure threshold in the seepage failure area is , the seepage flow rate threshold is , the set monitoring duration is , calculate the change rate of pore water pressure in the seepage failure area and the change rate of seepage flow rate , the formula is: , , construct a seepage failure discrimination function through the change rate of pore water pressure and the change rate of seepage flow pressure in the seepage failure area , the formula is: .

[0027] Preferably, the grading treatment is carried out according to the determination result of seepage failure, and the graded seepage warning information is output through the seepage grading model; the seepage grading model is constructed by accepting the seepage failure value output by the seepage failure discrimination model. If both the change rate of pore water pressure and the seepage flow pressure exceed the preset corresponding thresholds, it is a heavy-risk seepage failure. If either the change rate of pore water pressure or the seepage flow pressure exceeds the preset corresponding threshold, it is a medium-risk seepage failure. If neither the change rate of pore water pressure nor the seepage flow pressure exceeds the preset corresponding threshold, it is a low-risk seepage failure.

[0028] A seepage discrimination system applicable to the foundation of a double-layer dam, including a geological parameter acquisition module, a seepage simulation module, a mesh generation module, a monitoring module, a discrimination module, and a warning module:

[0029] The geological parameter acquisition module obtains the geological parameters of the double-layer dam, covering the upper geological parameters and the lower geological parameters, and forms a geological parameter set;

[0030] The seepage simulation module constructs an upper-layer seepage numerical model and a lower-layer seepage numerical model according to the parameters provided by the geological parameter acquisition module, couples the upper-layer and lower-layer seepage numerical models, and uses the dynamic loading technology to simulate the gradual change of the head difference to capture the multi-dimensional seepage information of the grid nodes;

[0031] The mesh generation module divides the grid of the double-layer dam foundation, connects adjacent grids through a gradual transition, and combines the shape and boundary conditions of the dam to perform mesh generation intersection to obtain grid nodes;

[0032] The monitoring module obtains the change of pore water pressure or seepage flow rate at the monitoring points within the seepage failure area through the monitoring points;

[0033] The discrimination module calculates the seepage force of grid nodes based on the seepage field data obtained by the seepage simulation module and the monitoring module, calculates the safety factor in combination with the soil shear strength index, determines the nodes with a safety factor less than the preset value as potential seepage grid nodes, forms a potential seepage failure area through continuous screening and networking, calculates the change rate of pore water pressure and the change rate of seepage flow, and determines whether seepage failure occurs in the monitoring area through the constructed seepage failure discrimination function, in combination with the preset threshold and the set time period, and outputs the seepage determination result;

[0034] The warning module receives the seepage determination result output by the monitoring and discrimination modules and performs grading processing on the determination result through the seepage grading model.

[0035] Compared with the prior art, the technical solution of the present application has the following technical effects:

[0036] The present invention constructs a double-layer dam foundation seepage numerical model including an upper-layer and a lower-layer seepage numerical model, and simulates the seepage field distribution in combination with different water head differences, solving the problem of difficult to accurately obtain the seepage field data of each grid node of the heterogeneous double-layer dam foundation. The technical effect of being able to comprehensively and accurately reflect the seepage field distribution of the double-layer dam foundation under different working conditions is obtained, providing a reliable data basis for subsequent analysis, helping to more deeply understand the seepage law, and improving the understanding of the seepage problem of the dam foundation.

[0037] The present invention adopts the technical solution of calculating the seepage force of grid nodes according to the seepage field data and determining the potential seepage failure area in combination with the soil shear strength index, solving the problem that it is difficult for traditional methods to accurately locate the potential seepage failure area of the heterogeneous double-layer dam foundation. Thus, the technical effect of being able to quickly and accurately identify the area where seepage failure may occur is obtained, facilitating the staff to carry out targeted monitoring work, reasonably allocate monitoring resources, take preventive measures in advance, effectively reduce the risk of seepage failure, and ensure the safety and stability of the dam.

[0038] The present invention uses the technical solution of presetting monitoring points in the potential seepage failure area, monitoring the changes in pore water pressure and seepage flow, and constructing a seepage failure discrimination model, solving the problem of being unable to timely and accurately judge whether seepage failure occurs in the monitoring area. Furthermore, the technical effect of being able to monitor the seepage failure situation in real time and quickly determine the occurrence of seepage failure once abnormal changes occur and reach the preset conditions is obtained, striving for valuable time for timely taking response measures, and enhancing the timeliness and accuracy of the dam safety warning.

[0039] By means of the technical solution of grading the determination results of seepage damage and outputting the graded seepage warning information through the seepage grading model, the present invention solves the problem that the seepage damage risk cannot be effectively evaluated and graded for early warning. Finally, the technical effect of clearly distinguishing the seepage damage risks of different degrees and providing intuitive and clear risk information for managers is obtained, which facilitates them to formulate corresponding countermeasures according to the risk levels, and improves the scientificity and effectiveness of the dam safety management.

[0040] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, so as to be implemented in accordance with the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following describes in detail with reference to the preferred embodiments of the present application and the accompanying drawings.

[0041] Those skilled in the art will understand the above and other purposes, advantages and features of the present application more clearly according to the following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0043] Figure 1 It is a flow chart of a method for discriminating seepage in a double-layer dam foundation according to the present invention;

[0044] Figure 2 It is a flow chart of grid division of a method for discriminating seepage in a double-layer dam foundation according to the present invention;

[0045] Figure 3 It is a structural diagram of a system for discriminating seepage in a double-layer dam foundation according to the present invention. Detailed Description of the Invention

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are part of the embodiments of this application, rather than all of them. In the following description, specific details such as specific configurations and components are provided only to assist in a comprehensive understanding of the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described here without departing from the scope and spirit of this application. Additionally, for the sake of clarity and conciseness, descriptions of known functions and structures are omitted in the embodiments.

[0047] It should be understood that the term "one embodiment" or "this embodiment" mentioned throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, the "one embodiment" or "this embodiment" that appears throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0048] In addition, this application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0049] The term "and / or" in this document is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, B exists alone, and both A and B exist simultaneously. The term " / and" in this document is a description of another association object relationship, indicating that two relationships can exist. For example, A / and B can represent: A exists alone, and both A and B exist. In addition, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0050] The term "at least one" in this document is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, at least one of A and B can represent: A exists alone, both A and B exist simultaneously, and B exists alone.

[0051] It should also be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include", or any other variant thereof are intended to cover non-exclusive inclusion.

[0052] Embodiment 1

[0053] This embodiment mainly describes a method for discriminating the seepage of a double-layer dam foundation, as Figure 1 shown, including the following steps:

[0054] S1. Obtain the geological parameters of the double-layer dam to form a geological parameter set;

[0055] S2. According to the geological parameter set, construct a seepage numerical model of the double-layer dam foundation, where the seepage numerical model includes an upper-layer seepage numerical model and a lower-layer seepage numerical model. By setting different head differences in the seepage numerical model, simulate the seepage field distribution at each grid node of the double-layer dam foundation to obtain seepage field data;

[0056] S3. According to the seepage field data, calculate the seepage force of the grid nodes, and combine the soil shear strength indexes of the grid nodes to determine the potential seepage failure area;

[0057] S4. In the potential seepage failure area, set preset monitoring points to monitor the changes in pore water pressure and seepage flow rate at the preset monitoring points;

[0058] S5. Construct a seepage failure discrimination model. When the change in pore water pressure or seepage flow rate at the monitoring point exceeds the preset threshold and the duration reaches the set time, determine that seepage failure occurs in the monitoring area and output the seepage determination result;

[0059] S6. Perform grading processing according to the determination result of seepage failure, and output the graded seepage warning information through the seepage grading model.

[0060] Furthermore, the geological parameters of the double-layer dam include upper-layer geological parameters and lower-layer geological parameters; the upper-layer geological parameters include upper-layer permeability coefficient, porosity, saturation, and soil thickness; the lower-layer geological parameters include lower-layer permeability coefficient, porosity, saturation, soil thickness, and compression modulus.

[0061] Furthermore, the construction of the upper-layer seepage numerical model in S2 specifically includes:

[0062] Obtain the soil parameters of the upper-layer soil microelement, and construct the seepage continuity equation, the formula is: , where is the spatial coordinate of the microelement, is the time, is the upper-layer geological water head, is the upper-layer geological porosity, is the upper-layer geological saturation; obtain the seepage velocity component of the upper-layer soil in the direction, the formula is: , where are respectively the seepage velocity components of the upper-layer soil in the direction, is the permeability coefficient of the upper layer of geology. By coupling and solving with the above formula, the seepage field of the upper-layer microelement is obtained, and through the continuous fitting of the microelements, the upper-layer seepage numerical model is formed.

[0063] Further, the construction of the lower-layer seepage numerical model in S2 specifically includes:

[0064] Obtain the soil parameters of the lower-layer soil microelement, and construct the seepage continuity equation. The formula is: , where is the spatial coordinate of the microelement, is the time, is the lower-layer geological water head, is the lower-layer geological porosity, is the lower-layer geological saturation; Obtain the seepage velocity component of the lower-layer soil in the direction. The formula is: , where are respectively the seepage velocity components of the lower-layer soil in the direction, is the lower-layer geological permeability coefficient. The porosity of the lower-layer soil is affected by compression deformation, and it is coupled and solved in combination with the compression modulus. The formula is: , where is the lower-layer geological stress; By obtaining the seepage field of the lower-layer microelement and performing continuous fitting of the microelements, the lower-layer seepage numerical model is formed.

[0065] Further, couple the upper-layer seepage numerical model with the lower-layer seepage numerical model, set transition elements at the interface between the upper and lower layers, use dynamic loading technology to simulate the gradual change of the water head difference, capture the multi-dimensional seepage information of the grid nodes, and use distributed storage technology to store the seepage data under different grid nodes and water head difference simulations in multiple associated storage units to obtain the seepage field data.

[0066] Further, as Figure 2 shown, the grid nodes are obtained through the grid division intersection method, which specifically includes:

[0067] S2.1. Conduct geological exploration and structural analysis on the double-layer dam foundation to clarify the boundaries of the upper and lower-layer soils, the changing areas of geological materials, and the existing weak parts;

[0068] S2.2. For the areas in the double-layer dam foundation where the seepage change is relatively gentle and the geological conditions are relatively uniform, use a larger-scale grid for division; in the areas where the seepage change is drastic, the geological conditions are complex, the potential areas of seepage failure, and the parts with geological defects, use a smaller-scale grid for division;

[0069] S2.3. After grid division, through a grid connection method with gradual transition, the size change between adjacent grids is gradually reduced. Combining the actual shape and boundary conditions of the dam foundation, grid division intersections are carried out to obtain grid nodes.

[0070] Furthermore, in the above-mentioned S3, according to the seepage field data obtained from the simulation, the seepage force of the grid nodes is calculated. Combining the soil shear strength indexes of the grid nodes, the potential seepage failure area is determined, specifically including:

[0071] Obtain the seepage velocity of the grid nodes , the unit weight of water and the porosity of the soil corresponding to the node , calculate the seepage force of the grid nodes . The formula is: , where the seepage velocity is obtained from the seepage field data; obtain the soil friction angle , cohesion and effective stress of the grid nodes, and calculate the soil shear strength . The formula is: , where the effective stress is obtained from the total stress and pore water pressure of the grid nodes. The formula is: ; obtain the safety factor of the grid nodes. The formula is: . If the safety factor of the grid node is less than the preset safety factor , it is determined as a potential seepage grid node. Through continuous screening, the obtained potential seepage grid nodes are networked to form a potential seepage failure area.

[0072] Furthermore, in the above-mentioned S5, an infiltration failure discrimination model is constructed. Monitor the change of pore water pressure or seepage flow rate at the monitoring points in the potential seepage failure area. If it exceeds the preset pore water pressure threshold or seepage flow rate change threshold and the duration reaches the set time, it is determined that the monitored area has suffered infiltration failure and the infiltration determination result is output. Specifically:

[0073] Obtain the pore water pressure of the monitoring points in the infiltration failure area at time . The pore water pressure at the initial moment in the infiltration failure area is . The seepage flow rate is . The initial seepage flow rate is . The preset pore water pressure threshold in the infiltration failure area is . The seepage flow rate threshold is . The set monitoring duration is and the change rate of seepage flow , and the formula is: , , a seepage failure discrimination function is constructed through the change rate of pore water pressure and the change rate of seepage flow pressure in the seepage failure area , and the formula is: .

[0074] Furthermore, the grading process is carried out according to the determination result of seepage failure, and the graded seepage warning information is output through the seepage grading model; the seepage grading model is constructed by accepting the seepage failure value output by the seepage failure discrimination model. If both the change rate of pore water pressure and the seepage flow pressure exceed the corresponding preset thresholds, it is a heavy-risk seepage failure. If either the change rate of pore water pressure or the seepage flow pressure exceeds the corresponding preset threshold, it is a medium-risk seepage failure. If neither the change rate of pore water pressure nor the seepage flow pressure exceeds the corresponding preset threshold, it is a low-risk seepage failure.

[0075] This embodiment details constructing a seepage numerical model by obtaining the geological parameters of the double-layer dam, simulating the seepage field distribution to obtain data, calculating the seepage force and shear strength to determine the potential failure area, monitoring the changes in pore water pressure and seepage flow and constructing a discrimination model, and grading the determination result to output warning information. It solves the problem that it is difficult to accurately discriminate and warn the seepage failure of the heterogeneous double-layer dam foundation, realizes the accurate positioning, real-time monitoring and grading warning of the seepage failure area, improves the accuracy and timeliness of the seepage failure discrimination of the dam, and effectively guarantees the safety of the dam.

[0076] Based on Embodiment 1, this embodiment describes coupling the upper-layer seepage numerical model and the lower-layer seepage numerical model, setting transition units at the interface between the upper and lower layers, using dynamic loading technology to simulate the gradual change of the water head difference, capturing multi-dimensional seepage information of grid nodes, and using distributed storage technology to store the seepage data under different grid nodes and water head difference simulations in multiple associated storage units to obtain the seepage field data. Specifically:

[0077] In the seepage analysis of heterogeneous double-layer dam foundations, the upper-layer seepage numerical model is coupled with the lower-layer seepage numerical model to simulate the seepage situation of the entire dam foundation. Due to different geological parameters of the upper and lower soil layers, there are differences in seepage characteristics. The coupling process is first based on their physical connection relationship, that is, the seepage continuity at the interface between the upper and lower soil layers. From the perspective of the mathematical model, the upper-layer seepage numerical model is obtained by establishing the seepage continuity equation for the tiny element of the upper soil layer and coupling and solving it in combination with the seepage velocity component formula; the same applies to the lower-layer model. When coupling, it is necessary to ensure the continuity of the water head and seepage velocity at the interface. For example, at the interface, the seepage velocity of the upper soil layer is equal to that of the lower soil layer in the vertical direction, and the water head values are also the same. This requires that during the calculation process, the seepage information at the interface obtained from the upper-layer model be transmitted to the lower-layer model, and vice versa.

[0078] An iterative algorithm is used to independently calculate the seepage fields of the upper and lower-layer models under the initial conditions. According to the relationship between the water head and seepage velocity at the interface, the parameters in the model, such as boundary conditions and initial values, are adjusted and calculated again. This process is continuously repeated until the water head and seepage velocity at the interface reach stability within a certain accuracy range, that is, the coupling of the upper and lower-layer seepage numerical models is achieved. This coupling method can comprehensively consider the interaction between the upper and lower soil layers and more realistically reflect the seepage situation of the entire dam foundation, providing a reliable model basis for accurately analyzing seepage failure subsequently.

[0079] During the coupling process of the upper and lower-layer seepage numerical models, setting transition elements at the interface between the upper and lower layers is an important means to solve the influence of the parameter differences of the upper and lower soil layers on seepage. Due to different geological parameters such as permeability coefficients and porosities of the upper and lower soil layers, seepage will undergo a sudden change when passing through the interface, resulting in inaccurate calculation results.

[0080] The purpose of setting transition elements is to alleviate this sudden change and enable seepage to transition smoothly. The size and shape of the transition elements need to be reasonably designed according to the characteristics of the upper and lower soil layers and the mesh division situation. The size of the transition elements should change gradually, transitioning from the mesh size of the upper soil layer to that of the lower soil layer to avoid discontinuous seepage at the interface. When determining the physical properties of the transition elements, the geological parameters of the upper and lower soil layers are comprehensively considered. For example, for the permeability coefficient, the weighted average method can be used to determine the equivalent permeability coefficient of the transition element according to the distance or volume ratio between the upper and lower soil layers and the transition element. In this way, the transition element has some characteristics of both the upper and lower soil layers, enabling seepage to gradually adapt to different soil conditions when passing through the interface.

[0081] The setting of the transition unit can also effectively reduce the errors in numerical calculations. In numerical simulations, grid discontinuities and parameter mutations are likely to cause numerical oscillations. The transition unit reduces the possibility of such oscillations by smoothing the seepage changes, improving the stability and accuracy of the calculation results. By reasonably setting the transition unit, the smooth transmission of seepage at the interface of the upper and lower soil layers is ensured, providing strong support for accurately simulating the seepage field of the entire dam foundation.

[0082] The dynamic loading technique is used to simulate the gradual change of the water head difference, reflecting the seepage effect on the heterogeneous double-layer dam foundation during actual operation. The water head difference between the upstream and downstream of the dam is not constant, but gradually changes with factors such as water level changes; the dynamic loading technique realizes the gradual change of the water head difference by gradually adjusting the water head boundary conditions in the seepage numerical model. In the initial stage, a relatively small water head difference is set to simulate the seepage situation of the dam under a certain initial state, and the corresponding seepage field data is calculated. Then, according to a certain time step and loading rate, the water head difference is gradually increased or decreased, and the seepage field is calculated again. This process is repeated continuously to simulate the continuous change of the water head difference over time.

[0083] The loading rate is determined according to the actual engineering situation and research purpose. If the loading rate is too fast, the detailed changes in the seepage field cannot be accurately captured; if the loading rate is too slow, the calculation cost and time will increase. Through multiple tests and comparisons, combined with engineering experience, the loading rate is determined.

[0084] During the simulation process, the dynamic loading technique is used to observe the changes in the seepage field in real time. As the water head difference gradually increases, the changing trends of seepage velocity and water head distribution parameters can be seen, as well as the influence of these changes on the potential seepage failure area. Using dynamic simulation can comprehensively understand the seepage characteristics of the dam foundation under different water head difference conditions.

[0085] During the seepage simulation of the heterogeneous double-layer dam foundation, a large amount of seepage data under different grid nodes and different water head differences are generated. The distributed storage technique is used to store them in multiple associated storage units; the distributed storage technique adopts a multi-node storage architecture and disperses the data in multiple storage units; during the seepage simulation, after the seepage data of each grid node is calculated, according to the preset storage rules, it is allocated to different storage units. For example, the storage location of the data can be determined through a specific algorithm based on information such as the grid node number and the size of the water head difference. This improves the storage capacity and scalability of the data. As the simulation scale increases, the data volume will continue to increase. The distributed storage technique can easily expand the storage capacity by adding storage nodes to meet the needs of data growth; the distributed storage technique enhances the reliability and fault tolerance of the data. Since the data is dispersed and stored on multiple nodes, even if a certain node fails, the data on other nodes can still be accessed normally without data loss.

[0086] This embodiment details the precise simulation of seepage in a heterogeneous double-layer dam foundation and the efficient processing of data. The model coupling ensures the consideration of the interaction between the upper and lower soil layers. The transition element mitigates the sudden change in seepage to improve the calculation accuracy. The dynamic loading simulates the gradual change of the water head difference to reflect the actual working conditions. The distributed storage technology efficiently manages the massive seepage data, making the seepage simulation more in line with the actual situation, accurately locating potential seepage failure areas, providing a reliable basis for the dam safety assessment and the formulation of protection measures, and effectively ensuring the safe and stable operation of the dam.

[0087] Embodiment 2

[0088] This embodiment details a discrimination system for seepage in a double-layer dam foundation, as Figure 3 shown, including a geological parameter acquisition module, a seepage simulation module, a mesh generation module, a monitoring module, a discrimination module, and an early warning module:

[0089] The geological parameter acquisition module obtains the geological parameters of the double-layer dam, covering the upper layer geological parameters and the lower layer geological parameters, and forms a set of geological parameters;

[0090] The seepage simulation module constructs an upper layer seepage numerical model and a lower layer seepage numerical model according to the parameters provided by the geological parameter acquisition module, couples the upper layer and lower layer seepage numerical models, and uses the dynamic loading technology to simulate the gradual change of the water head difference to capture the multi-dimensional seepage information of the grid nodes;

[0091] The mesh generation module divides the grid of the double-layer dam foundation, connects adjacent grids through gradual transition, and combines the dam shape and boundary conditions to perform mesh generation intersection to obtain grid nodes;

[0092] The monitoring module obtains the change in pore water pressure or seepage flow rate of the monitoring points within the seepage failure area through the monitoring points;

[0093] The discrimination module calculates the seepage force of the grid nodes according to the seepage field data obtained by the seepage simulation module and the monitoring module, calculates the safety factor in combination with the soil shear strength index, determines the nodes with a safety factor less than the preset value as potential seepage grid nodes, forms a potential seepage failure area through continuous screening and networking, calculates the change rate of pore water pressure and the change rate of seepage flow rate, and determines whether seepage failure occurs in the monitoring area through the constructed seepage failure discrimination function, in combination with the preset threshold and the set time duration, and outputs the seepage discrimination result;

[0094] The early warning module receives the seepage discrimination result output by the monitoring and discrimination modules and performs classification processing on the discrimination result through the seepage classification model.

[0095] This embodiment details a discrimination system for seepage failure of heterogeneous double-layer dam foundations, which can accurately collect geological parameters of double-layer dams, construct a high-precision seepage numerical model to simulate the seepage field, quickly lock potential seepage failure areas with the help of grid division and data analysis, monitor the changes in pore water pressure and seepage flow rate in real time, accurately determine whether seepage failure has occurred, and timely output hierarchical warning information, improving the accuracy and timeliness of dam seepage failure discrimination, effectively preventing dam safety accidents, ensuring the stable operation of water conservancy projects, reducing maintenance costs, and extending the service life of dams.

[0096] The above are only the preferred embodiments of the present invention, and it does not limit the protection scope of the present invention thereby. For those skilled in the art, the present invention can have various changes and modifications; within the spirit and principle of the present invention, any changes, modifications, substitutions, integrations, and parameter changes made to these embodiments by means of conventional substitutions or capable of achieving the same functions without departing from the principle and spirit of the present invention fall within the protection scope of the present invention.

Claims

1. A method for determining the permeability of a double-layer dam foundation, characterized in that: The following steps are involved: S1. Obtain geological parameters of the double-layer dam to form a geological parameter set; S2. According to the geological parameter set, a seepage numerical model of the double-layer dam foundation is constructed, wherein the seepage numerical model includes an upper layer seepage numerical model and a lower layer seepage numerical model. By setting different water head differences in the seepage numerical model, the seepage field distribution of the double-layer dam foundation at each grid node is simulated to obtain seepage field data; S3. Calculate the permeability of the grid nodes based on the seepage field data, and determine the potential permeability damage area by combining the soil shear strength index of the grid nodes; S4. In the potential seepage damage area, preset monitoring points are set to monitor the changes in pore water pressure and seepage volume at the preset monitoring points; S5. Construct a permeability damage discrimination model. When the pore water pressure or seepage volume change at the monitoring point exceeds a preset threshold and lasts for a set period of time, it is determined that permeability damage occurs in the monitoring area and the permeability judgment result is output; S6, performing classification processing according to the determination result of penetration damage, and outputting graded penetration warning information through a penetration classification model; In S3, the mesh node seepage force is calculated according to the simulated seepage field data, and the potential seepage damage area is determined in combination with the soil shear strength index of the mesh node, specifically: Get the seepage velocity of the grid node , water weight And the porosity of the soil corresponding to the node , calculate the mesh node penetration , the formula is: , where the seepage velocity Obtain soil friction angle at grid nodes through seepage field data acquisition; , Cohesion and effective stress , calculate the shear strength of soil , the formula is: , where the effective stress Total stress through mesh nodes and pore water pressure The formula is: ; Get the safety factor of the mesh node , the formula is: , if the grid node safety factor Less than the preset safety factor , determined as potential penetration grid nodes, and through continuous screening, the obtained potential penetration grid nodes are networked to form a potential penetration damage area.

2. A method for determining the permeability of a double-layer dam foundation according to claim 1, characterized in that: The double-layer dam geological parameters include upper geological parameters and lower geological parameters; the upper geological parameters include upper layer permeability, porosity, saturation and soil thickness; the lower geological parameters include lower layer permeability, porosity, saturation, soil thickness and compression modulus.

3. A method for determining permeability of a double-layer dam foundation according to claim 1, characterized in that: The construction of the S2 upper layer seepage numerical model specifically includes: The soil parameters of the micro-units of the upper soil layer are obtained, and the seepage continuity equation is constructed. The formula is: ,in is the spatial coordinate of the micro-unit, For time, is the upper geological head, is the upper geological porosity, is the geological saturation of the upper layer; The seepage velocity component in the direction is given by: ,in The upper soil layer is The seepage velocity component in the direction, is the geological permeability coefficient of the upper layer. The above formula is combined for coupling solution to obtain the seepage field of the upper micro-unit. Through continuous fitting of the micro-unit, the upper seepage numerical model is formed.

4. A method for determining permeability of a double-layer dam foundation according to claim 1, characterized in that: The construction of the S2 lower layer seepage numerical model specifically includes: The soil parameters of the micro-units of the lower soil layer are obtained, and the seepage continuity equation is constructed. The formula is: ,in is the spatial coordinate of the micro-unit, For time, is the lower geological head, is the underlying geological porosity, is the geological saturation of the lower layer; obtain the lower soil mass in The seepage velocity component in the direction is given by: ,in The lower soil is The seepage velocity component in the direction, is the geological permeability coefficient of the lower layer. The porosity of the lower soil layer is affected by the compression deformation. Combined with the compression modulus The coupled solution is: ,in is the geological stress of the lower layer; by obtaining the seepage field of the lower layer micro-units and performing continuous fitting of the micro-units, a numerical seepage model of the lower layer is formed.

5. A method for determining permeability of a double-layer dam foundation according to claim 1, 3 or 4, characterized in that: The upper seepage numerical model is coupled with the lower seepage numerical model, and a transition unit is set at the junction of the upper and lower layers. The dynamic loading technology is used to simulate the gradual change of the head difference and capture the multi-dimensional seepage information of the grid nodes. The distributed storage technology is used to store the seepage data under different grid nodes and head difference simulations in multiple associated storage units to obtain the seepage field data.

6. A method for determining permeability of a double-layer dam foundation according to claim 5, characterized in that: The grid nodes are obtained by grid division and intersection, specifically including: S2.

1. Conduct geological exploration and structural analysis on the double-layer dam foundation to identify the boundaries of the upper and lower soil layers, the changing areas of geological materials, and the existing weak points; S2.

2. For areas with relatively gentle seepage changes and relatively uniform geological conditions in the double-layer dam foundation, a larger scale grid is used for division; in areas with drastic seepage changes, complex geological conditions, potential areas of seepage damage, and areas with geological defects, a smaller scale grid is used for division; S2.

3. After meshing, the mesh connection method of gradual transition is used to gradually reduce the size change between adjacent meshes. Combined with the actual shape and boundary conditions of the dam foundation, mesh division and intersection are performed to obtain mesh nodes.

7. A method for determining permeability of a double-layer dam foundation according to claim 1, characterized in that: In S5, a permeability damage discrimination model is constructed to monitor the pore water pressure or seepage flow rate change of the monitoring point in the potential permeability damage area. If the pore water pressure threshold or seepage flow rate change threshold is exceeded and the duration reaches the set time, it is determined that permeability damage occurs in the monitoring area, and the permeability judgment result is output, which is specifically: Obtain the monitoring points in the penetration damage area at time Pore ​​water pressure in the seepage damage zone At the initial moment, the pore water pressure in the seepage damage zone is , the seepage rate is The initial seepage rate is , the preset pore water pressure threshold of the seepage damage zone is , the seepage threshold is , set the monitoring time to , calculate the pore water pressure change rate in the permeability damage zone and the seepage rate , the formula is: , The seepage damage discriminant function is constructed by the pore water pressure change rate and the seepage pressure change rate in the seepage damage zone. , the formula is: .

8. A method for determining permeability of a double-layer dam foundation according to claim 1 or 7, characterized in that: The method performs grading processing based on the judgment result of the seepage damage, and outputs graded seepage warning information through the seepage grading model; the seepage grading model is constructed by accepting the seepage damage value output by the seepage damage discrimination model, and if both the pore water pressure change rate and the seepage flow pressure exceed the preset corresponding thresholds, it is a severe dangerous seepage damage; if one of the pore water pressure change rate or the seepage flow pressure exceeds the preset corresponding threshold, it is a medium-risk seepage damage; if the pore water pressure change rate or the seepage flow pressure does not exceed the preset corresponding threshold, it is a low-risk seepage damage.

9. A permeability identification system for double-layer dam foundation, used to implement any one of the methods described in claims 1-8, characterized in that: It includes geological parameter acquisition module, seepage simulation module, grid division module, monitoring module, identification module and early warning module: The geological parameter acquisition module acquires geological parameters of the double-layer dam, including upper geological parameters and lower geological parameters, to form a geological parameter set; The seepage simulation module constructs an upper seepage numerical model and a lower seepage numerical model according to the parameters provided by the geological parameter acquisition module, couples the upper and lower seepage numerical models, uses dynamic loading technology to simulate the gradual change of water head difference, and captures multi-dimensional seepage information of grid nodes; The meshing module meshes the double-layer dam foundation, connects adjacent meshes through gradual transition, and meshes and crosses the meshes in combination with the dam shape and boundary conditions to obtain mesh nodes; The monitoring module obtains the change of pore water pressure or seepage volume at the monitoring point in the seepage damage area through the monitoring point; The discrimination module calculates the mesh node permeability according to the seepage field data obtained by the seepage simulation module and the monitoring module, calculates the safety factor in combination with the soil shear strength index, and determines the nodes with a safety factor less than a preset value as potential permeable mesh nodes. After continuous screening and networking, a potential permeability damage area is formed, and the pore water pressure change rate and the seepage flow change rate are calculated. Through the constructed permeability damage discrimination function, combined with the preset threshold and the set time, it is determined whether permeability damage occurs in the monitoring area, and the permeability determination result is output; The early warning module receives the infiltration determination result output by the monitoring and discrimination module, and performs classification processing on the determination result through the infiltration classification model.

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