Penetration discrimination method and system suitable for double-layer dam foundation

Abstract

The invention discloses a penetration discrimination method and system suitable for a double-layer dam foundation, and the method comprises the steps: S1, obtaining the geological parameters of a double-layer dam, and forming a geological parameter set; s2, constructing a seepage numerical model of the double-layer dam foundation, simulating the seepage field distribution condition of the double-layer dam foundation at each grid node, and obtaining seepage field data; s3, grid node seepage force is calculated, and a potential seepage failure area is determined; s4, monitoring pore water pressure and seepage flow changes of the preset monitoring points in the potential seepage failure area; s5, constructing a seepage failure judgment model, and outputting a seepage judgment result; and S6, performing grading processing according to the judgment result of seepage failure, and outputting grade seepage early warning information through a seepage grading model. According to the method, judgment, real-time monitoring and graded early warning of seepage damage of the double-layer dam foundation are achieved, and the safety of the heterogeneous double-layer dam is guaranteed.

Description

Technical Field

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

[0002] As an important part of water conservancy projects, the stability of the foundation of the dam is directly related to the safe operation of the entire water conservancy facility. Due to the difference in the properties of the upper and lower layers of soil, the foundation of a heterogeneous double-layer dam is very prone to seepage damage under the action of seepage, which in turn causes dangerous situations such as dam pipe bursts and landslides, threatening the safety of life and property of the surrounding people and the stability of the ecological environment. Accurately identifying the seepage damage of the foundation of a heterogeneous double-layer dam is crucial to taking effective protective measures in advance and ensuring the safety of the dam. Therefore, it is of great significance to invent a reliable method for identifying the seepage damage of the foundation of a heterogeneous double-layer dam.

[0003] Traditional technologies for identifying seepage damage to dam foundations rely on empirical judgment and simple on-site observations. For example, by observing whether water seepage, sand, and other phenomena appear on the surface of the dam, it is possible to determine whether seepage damage has occurred. The advantages of this method are simple operation, low cost, no need for complex equipment and professional knowledge, and the ability to make preliminary judgments on obvious signs of seepage damage to a certain extent. However, its disadvantages are also extremely significant. On the one hand, this method relies too much on people's subjective experience, lacks scientific quantitative analysis, and is difficult to accurately judge the potential risk of seepage damage; on the other hand, it can only be discovered when the seepage damage has developed to a certain extent and obvious external manifestations appear. Early warning cannot be achieved, and timely measures cannot be taken to prevent further development of damage, posing a major safety hazard.

[0004] Existing technologies have made some progress in the identification of seepage damage in dam foundations, and some of them have adopted numerical simulation technology and monitoring methods. Numerical simulation technology estimates the potential seepage damage area by constructing a simple seepage model, calculating the seepage field and seepage force. At the same time, sensors are used to monitor parameters such as pore water pressure and seepage volume inside the dam. These technologies have made significant progress compared to traditional methods. They can analyze seepage problems more deeply, discover some potential seepage damage areas in advance, and obtain monitoring data in real time. However, existing technologies still have shortcomings. On the one hand, existing seepage models often fail to take into account the complexity of heterogeneous double-layer dam foundations, and fail to accurately reflect the differences in soil parameters between the upper and lower layers and the impact of interaction on the seepage field, resulting in deviations in the calculation results; on the other hand, the layout of monitoring points lacks systematicity and pertinence, making it difficult to fully capture the seepage changes of the entire dam foundation, and it is easy to miss important seepage damage information, affecting the accuracy and reliability of the identification results.

[0005] Therefore, in order to solve the above problems, this application proposes a permeability identification method and system suitable for double-layer dam foundation, which solves the above-mentioned technical problems. Summary of the invention

[0006] Based on the above content, this application proposes a method and system for judging the permeability of a double-layer dam foundation, which specifically includes the following steps:

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

[0008] 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;

[0009] 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;

[0010] 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;

[0011] 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;

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

[0013] Preferably, 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.

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

[0015] 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.

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

[0017] 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 at 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 and is solved by coupling with the compression modulus. The formula 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.

[0018] Preferably, the upper layer seepage numerical model is coupled with the lower layer seepage numerical model, a transition unit is set at the junction of the upper and lower layers, dynamic loading technology is used to simulate the gradual change of head difference, and the multi-dimensional seepage information of grid nodes is captured. 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.

[0019] Preferably, the grid nodes are obtained by grid division and intersection, specifically including:

[0020] 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;

[0021] 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;

[0022] 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.

[0023] Preferably, the S3 calculates the mesh node permeability according to the simulated seepage field data, and determines the potential seepage damage area in combination with the soil shear strength index of the mesh node, which specifically includes:

[0024] 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 grid node safety factor , 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.

[0025] Preferably, 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:

[0026] Obtain the pore water pressure in the seepage damage zone at the monitoring point in the seepage damage zone at time 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: .

[0027] Preferably, the judgment result of the seepage damage is graded and the graded seepage warning information is outputted through the seepage grading model; the seepage grading model is constructed by accepting the seepage damage value outputted by the seepage damage discrimination model; if both the pore water pressure change rate and the seepage flow pressure exceed the preset corresponding threshold values, 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 value, 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 value, it is a low risk seepage damage.

[0028] A permeability identification system for double-layer dam foundation, including a geological parameter acquisition module, a seepage simulation module, a grid division module, a monitoring module, a identification module and an early warning module:

[0029] 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;

[0030] 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;

[0031] 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;

[0032] 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;

[0033] 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;

[0034] 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.

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

[0036] The present invention solves the problem of difficulty in accurately obtaining seepage field data of each grid node of a non-homogeneous double-layer dam foundation by constructing a double-layer dam foundation seepage numerical model including upper and lower seepage numerical models, and simulating seepage field distribution by combining different head differences. The technical effect of being able to comprehensively and accurately reflect the seepage field distribution of a double-layer dam foundation under different working conditions is obtained, providing a reliable data basis for subsequent analysis, helping to gain a deeper understanding of the seepage law, and improving the level of awareness of the seepage problem of the dam foundation.

[0037] The present invention adopts a technical solution that calculates the grid node permeability based on the seepage field data and determines the potential seepage damage area in combination with the soil shear strength index, solving the problem that the traditional method is difficult to accurately locate the potential seepage damage area of ​​the heterogeneous double-layer dam foundation. As a result, the technical effect of being able to quickly and accurately identify the area where seepage damage may occur is achieved, which facilitates the staff to carry out targeted monitoring work, reasonably allocate monitoring resources, take protective measures in advance, effectively reduce the risk of seepage damage, and ensure the safety and stability of the dam.

[0038] The present invention uses a technical solution of presetting monitoring points in the potential seepage damage area, monitoring the changes in pore water pressure and seepage volume, and constructing a seepage damage discrimination model, which solves the problem of being unable to timely and accurately determine whether seepage damage has occurred in the monitoring area. As a result, the technical effect of being able to monitor the seepage damage in real time and quickly determine the occurrence of seepage damage once abnormal changes occur and the preset conditions are met is obtained, which buys precious time for timely taking countermeasures and enhances the timeliness and accuracy of dam safety warning.

[0039] The present invention solves the problem of being unable to effectively evaluate and grade the risk of seepage damage by using a technical solution that grades the results of seepage damage determination and outputs graded seepage warning information through a seepage grading model. Ultimately, the technical effect of being able to clearly distinguish different degrees of seepage damage risks and provide managers with intuitive and clear risk information is achieved, making it easier for them to formulate corresponding response strategies based on risk levels, thereby improving the scientificity and effectiveness of dam safety management.

[0040] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings as follows.

[0041] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF 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 drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0043] Figure 1 This is a flow chart of a method for determining the permeability of a double-layer dam foundation according to the present invention;

[0044] Figure 2 A grid division flow chart of a method for judging the permeability of a double-layer dam foundation according to the present invention;

[0045] Figure 3 This is a structural diagram of a permeability discrimination system suitable for a double-layer dam foundation according to the present invention. DETAILED DESCRIPTION

[0046] To make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all of the embodiments. In the following description, specific details such as specific configuration and components are provided only to help fully understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and brevity, the description of known functions and structures is omitted in the embodiment.

[0047] It should be understood that the references to "one embodiment" or "this embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present application. Therefore, the references to "one embodiment" or "this embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

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

[0049] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" in this article describes another type of association object relationship, indicating that there can be two relationships. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0050] The term "at least one" in this article is merely a description of the association relationship of associated objects, indicating that there may be three relationships. For example, at least one of A and B can mean: A exists alone, A and B exist at the same time, and B exists alone.

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

[0052] Example 1

[0053] This embodiment mainly describes a method for judging the permeability of a double-layer dam foundation. Figure 1 As shown, the following steps are included:

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

[0055] 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;

[0056] 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;

[0057] 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;

[0058] 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;

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

[0060] Furthermore, 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.

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

[0062] 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.

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

[0064] 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 at 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 and is solved by coupling with the compression modulus. The formula 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.

[0065] Furthermore, the upper layer seepage numerical model is coupled with the lower layer seepage numerical model, 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, the multi-dimensional seepage information of the grid nodes is captured, and 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.

[0066] Further, if Figure 2 As shown, the grid nodes are obtained by grid division and intersection, which specifically includes:

[0067] 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;

[0068] 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;

[0069] 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.

[0070] Furthermore, in S3, the seepage force of the grid nodes 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 grid nodes, which specifically includes:

[0071] 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 grid node safety factor , 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.

[0072] Furthermore, 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:

[0073] Obtain the pore water pressure in the seepage damage zone at the monitoring point in the seepage damage zone at time 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: .

[0074] Furthermore, the judgment result of the seepage damage is graded and the graded seepage warning information is outputted through the seepage grading model; the seepage grading model is constructed by accepting the seepage damage value outputted by the seepage damage discrimination model; if both the pore water pressure change rate and the seepage flow pressure exceed the preset corresponding threshold values, it is a severe dangerous seepage damage; if either the pore water pressure change rate or the seepage flow pressure exceeds the preset corresponding threshold values, 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 values, it is a low risk seepage damage.

[0075] This embodiment describes in detail how to construct a seepage numerical model by acquiring the geological parameters of a double-layer dam, simulate the distribution of the seepage field to obtain data, calculate the permeability and shear strength to determine the potential damage area, monitor the changes in pore water pressure and seepage volume and build a discrimination model, and output warning information based on the judgment results in a graded manner. This solves the problem that it is difficult to accurately distinguish and warn of seepage damage in the foundation of a heterogeneous double-layer dam, realizes accurate positioning, real-time monitoring and graded warning of the seepage damage area, improves the accuracy and timeliness of the judgment of seepage damage in the dam, and effectively ensures the safety of the dam.

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

[0077] In the seepage analysis of the heterogeneous double-layer dam foundation, the upper seepage numerical model is coupled with the lower seepage numerical model to simulate the seepage of the entire dam foundation. Due to the different geological parameters, the seepage characteristics of the upper and lower soils are different. The coupling process is first based on the physical connection between the two, that is, the seepage continuity of the upper and lower soils at the interface. From the perspective of the mathematical model, the upper seepage numerical model is obtained by establishing the seepage continuity equation for the micro-unit of the upper soil, and coupling and solving it with the seepage velocity component formula; the lower model is the same; when coupling, it is necessary to ensure that the water head and seepage velocity at the interface are continuous. For example, at the interface, the seepage velocity of the upper soil is equal to the seepage velocity of the lower soil in the vertical direction, and the water head value is also the same. This requires that during the calculation process, the seepage information at the interface calculated by the upper model is passed to the lower model, and vice versa.

[0078] An iterative algorithm is used to independently calculate the seepage fields of the upper and lower models under 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 repeated until the water head and seepage velocity at the interface are stable within a certain accuracy range, thus achieving the coupling of the upper and lower seepage numerical models. This coupling method can comprehensively consider the interaction between the upper and lower soil layers, more realistically reflect the seepage conditions of the entire dam foundation, and provide a reliable model basis for the subsequent accurate analysis of seepage damage.

[0079] In the process of coupling the upper and lower seepage numerical models, setting a transition unit at the interface between the upper and lower layers is an important means to solve the influence of the difference in soil parameters between the upper and lower layers on the seepage. Due to the differences in geological parameters such as permeability and porosity between the upper and lower layers, the seepage will change suddenly when passing through the interface, which leads to inaccurate calculation results.

[0080] The setting of the transition unit is to ease this mutation and enable a smooth transition of seepage. The size and shape of the transition unit need to be reasonably designed according to the characteristics of the upper and lower soil layers and the grid division. The size of the transition unit should change gradually, gradually transitioning from the grid size of the upper soil layer to the grid size of the lower soil layer to avoid discontinuity of seepage at the interface. When determining the physical properties of the transition unit, the geological parameters of the upper and lower soil layers are considered comprehensively. For example, for the permeability coefficient, the weighted average method can be used to determine the equivalent permeability coefficient of the transition unit based on the distance or volume ratio between the upper and lower soil layers and the transition unit; in this way, the transition unit has both some characteristics of the upper soil layer and some characteristics of the lower soil layer, so that the seepage can gradually adapt to different soil conditions when passing through the interface.

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

[0082] Dynamic loading technology is used to simulate the gradual change of head difference, reflecting the seepage effect on the foundation of the heterogeneous double-layer dam during actual operation. The head difference between the upstream and downstream of the dam is not constant, but gradually changes with factors such as water level changes; dynamic loading technology realizes the gradual change of head difference by gradually adjusting the head boundary conditions in the seepage numerical model. In the initial stage, a smaller head difference is set to simulate the seepage of the dam in a certain initial state, and the corresponding seepage field data is calculated. Then, according to a certain time step and loading rate, the 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 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 details of the changes in the seepage field cannot be accurately captured; if the loading rate is too slow, the calculation cost and time will increase. The loading rate is determined through multiple tests and comparisons combined with engineering experience.

[0084] During the simulation, dynamic loading technology is used to observe the changes in the seepage field in real time. As the head difference gradually increases, the change trend of the seepage velocity and head distribution parameters can be seen, as well as the impact of these changes on the potential seepage damage area. Dynamic simulation is used to more fully understand the seepage characteristics of the dam foundation under different head difference conditions.

[0085] In the process of seepage simulation of heterogeneous double-layer dam foundation, a large amount of seepage data under different grid nodes and different head difference simulations are generated, and distributed storage technology is used to store them in multiple associated storage units; distributed storage technology adopts a multi-node storage architecture to store data in multiple storage units in a distributed manner; when performing seepage simulation, the seepage data of each grid node is allocated to different storage units according to the preset storage rules after the calculation is completed. For example, the storage location of the data can be determined by a specific algorithm based on information such as the number of the grid node and the size of the head difference. The capacity and scalability of data storage are improved. As the scale of simulation increases, the amount of data will continue to increase. Distributed storage technology can easily expand the storage capacity by adding storage nodes to meet the needs of data growth; distributed storage technology enhances the reliability and fault tolerance of data. Since the data is stored in multiple nodes in a distributed manner, even if a node fails, the data on other nodes can still be accessed normally without causing data loss.

[0086] This embodiment describes in detail the precise simulation and efficient data processing of seepage in the heterogeneous double-layer dam foundation. Model coupling ensures that the interaction between the upper and lower soil layers is taken into account. The transition unit mitigates the sudden change in seepage to improve the calculation accuracy. Dynamic loading simulates the gradual change of head difference to reflect the actual working conditions. Distributed storage technology efficiently manages massive seepage data, making the seepage simulation more realistic and accurately locating potential seepage damage areas, providing a reliable basis for dam safety assessment and formulation of protective measures, and effectively ensuring the safe and stable operation of the dam.

[0087] Example 2

[0088] This embodiment describes in detail a permeability determination system applicable to a double-layer dam foundation. Figure 3 As shown, it includes geological parameter acquisition module, seepage simulation module, grid division module, monitoring module, identification module and early warning module:

[0089] 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;

[0090] 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;

[0091] 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;

[0092] 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;

[0093] 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;

[0094] 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.

[0095] This embodiment describes in detail a non-homogeneous double-layer dam foundation seepage damage identification system, which can accurately collect the geological parameters of the double-layer dam, construct a high-precision seepage numerical model to simulate the seepage field, and quickly lock potential seepage damage areas with the help of grid division and data analysis. It monitors the changes in pore water pressure and seepage volume in real time, accurately determines whether seepage damage occurs, and outputs graded warning information in a timely manner, thereby improving the accuracy and timeliness of dam seepage damage identification, 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 preferred embodiments of the present invention, which do not limit the scope of protection of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any changes, modifications, replacements, integrations and parameter changes to these embodiments within the spirit and principles of the present invention through conventional substitutions or without departing from the principles and spirit of the present invention fall within the scope of protection 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. Perform graded processing according to the determination result of penetration damage, and output graded penetration warning information through a penetration grading model.

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 tiny 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 tiny 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 at 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 S3, the seepage force of the grid nodes 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 grid nodes, which specifically includes: 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 grid node safety factor , 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.

8. The method for determining the 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: .

9. A method for determining permeability of a double-layer dam foundation according to claim 1 or 8, 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.

10. A permeability identification system for double-layer dam foundation, 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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