Inter-bar force function determination method oriented to horizontal bar fraction limit equilibrium method

Abstract

The invention relates to an inter-bar force function determination method oriented to a horizontal bar division limit equilibrium method. The method comprises the following steps: establishing a database; establishing a finite element calculation model and analyzing; calculating resultant force of tangential force and normal force of the strip edge of the horizontal strip block; and determining an inter-bar force function. The method has the advantages that the artificial intelligence technology is ingeniously introduced, the difference between a fitting equation calculation result and a finite element simulation analysis result is regarded as a residual error, and then a model capable of predicting residual error data is constructed; according to an output result of the model, a tangential force obtained through calculation of a fitting equation is corrected, a high-precision inter-bar force function equation in the horizontal bar limit equilibrium method is finally obtained, the method can be widely applied to various slip plane situations, and the calculation process is remarkably simplified.

Description

Technical Field

[0001] The invention belongs to the field of rock and soil mechanics, and in particular relates to a method for determining an inter-strip force function for a horizontal strip limit equilibrium method. Background Art

[0002] The horizontal strip limit equilibrium method divides the slope into horizontal strips. Compared with the vertical strip method, it can more accurately consider the differences in material properties between soil strips and the non-uniform distribution of pore water pressure. When dealing with complex engineering conditions such as heterogeneous slope rock and soil media, seismic force effects, and reservoir water level fluctuations, the horizontal strip limit equilibrium method can usually produce a more reliable safety factor.

[0003] However, in the field of horizontal strip limit equilibrium method, there is a lack of unified standards for the functional relationship between the inter-strip tangential force and the inter-strip normal force. Some horizontal strip limit equilibrium methods still use the inter-strip force function of the vertical strip method, which not only makes the calculation process cumbersome and complicated, but also limits the popularization and application of this method, making it difficult for researchers to refer to it.

[0004] In view of this, it is urgent to propose a method for determining the inter-strip force function for the horizontal strip limit equilibrium method, which is applicable to a variety of slip surface situations and simplifies the calculation process to solve the problems existing in the existing technology. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for determining the inter-strip force function for the horizontal strip limit equilibrium method.

[0006] The method for determining the inter-strip force function for the horizontal strip limit equilibrium method comprises the following steps:

[0007] Step 1: Establish a database: Establish a typical profile geological model;

[0008] Step 2: Establish finite element calculation model and analysis: Based on the above typical section geological model, construct a finite element mesh model, apply gravity load to the finite element mesh model, and then perform finite element calculation to obtain the model stress field distribution;

[0009] Step 3: Calculate the resultant tangential and normal forces of the horizontal strips: set a stress path for each horizontal strip, and extract the tangential force data, normal force data and path length of all unit nodes on the path;

[0010] Step 4: Determine the inter-strip force function: Fit the tangential force and normal force data to obtain a fitting equation, construct a prediction model for the difference between the tangential force calculated by the fitting equation and the finite element calculation, and correct the fitting equation to obtain the inter-strip force function.

[0011] Preferably, in step 2, each stratum in the profile geological model is set as an ideal elastic material, and the elastic modulus of each stratum is set to 120 GPa.

[0012] Preferably, in step three, according to the formula F=P·L, the tangential stress and normal stress of the horizontal bar are converted into the resultant tangential force and the resultant normal force, where F is the resultant force, P is the average stress of all unit nodes on the path, and L is the stress path length.

[0013] Preferably, in step 4, the tangential force and normal force data of all slopes are obtained, and nonlinear curve fitting is performed on the tangential force and normal force data to obtain a fitting equation; and the difference between the tangential force calculated by the fitting equation and the tangential force calculated by the finite element method is calculated.

[0014] Preferably, in step four, the difference between the tangential force calculated by the fitting equation and the tangential force calculated by the finite element method is used as the output variable, and a prediction model for the output variable is constructed in combination with artificial intelligence technology; the prediction model is used to output the predicted value of the difference between the tangential force calculated by the fitting equation and the tangential force calculated by the finite element method, and the tangential force calculated by the fitting equation is corrected.

[0015] Preferably, the inter-strip force function obtained after correction of the fitting equation is used for the horizontal strip limit equilibrium method.

[0016] The beneficial effects of the present invention are:

[0017] The method for determining the inter-strip force function for the horizontal strip limit equilibrium method proposed in the present invention first constructs a slope database, and uses finite element simulation software to accurately analyze and obtain the tangential force and normal force data of each horizontal strip; then, a nonlinear curve fitting method is used to obtain a fitting equation; on this basis, artificial intelligence technology is cleverly introduced, and the difference between the calculation result of the fitting equation and the finite element simulation analysis result is regarded as a residual, and then a model that can predict these residual data is constructed; through the output result of the model, the tangential force calculated by the fitting equation is corrected, and finally a high-precision inter-strip force function equation in the horizontal strip limit equilibrium method is obtained, which is not only widely applicable to a variety of slip surface situations, but also significantly simplifies the calculation process, providing a novel and accurate method for determining the inter-strip force function for researchers. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the flow chart of the method for determining the inter-strip force function;

[0019] Figure 2 Draw slope division diagrams for programming procedures;

[0020] Figure 3 This is a schematic diagram of stress extraction from finite element analysis software;

[0021] Figure 4 for Figure 3 A schematic diagram of the enlarged area in the middle;

[0022] Figure 5 Plot the tangential force before and after correction of the fitted equation. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0024] Embodiment 1

[0025] As an example, Figure 1 As shown, in order to determine the functional relationship between the inter-strip tangential force and the inter-strip normal force in the horizontal strip limit equilibrium method, and then improve the accuracy of the safety factor calculated by the horizontal strip limit equilibrium method when dealing with complex engineering conditions such as non-homogeneous slope rock and soil media, seismic force influence and reservoir water level fluctuation. This patent proposes a method for determining the inter-strip force function of the horizontal strip limit equilibrium method based on numerical simulation analysis and artificial intelligence technology. This method relies on extensive slope case simulation analysis to establish the functional relationship between the inter-strip tangential force and the inter-strip normal force that is generally applicable in the horizontal strip limit equilibrium method. The horizontal strip limit equilibrium method constructed based on this functional relationship has a safety factor that is more in line with the actual situation, thereby greatly enhancing the reliability and practicality of engineering calculations.

[0026] The method for determining the inter-strip force function for the horizontal strip limit equilibrium method comprises the following steps:

[0027] Step 1: Establish a database: Collect numerous slope cases, organize data including geometric shape, geological landforms, topography, stratum lithology, and physical and mechanical parameters of rock and soil bodies, and establish a typical profile geological model.

[0028] Step 2: Based on the typical profile geological model mentioned above, a finite element calculation model is constructed. Assuming that each stratum is an ideal elastic material, the stratum elastic modulus of each layer is set to 120 GPa, and then the finite element stress calculation is carried out.

[0029] Step 3: Calculate the tangential and normal force of the horizontal strip: According to the finite element stress calculation results, each horizontal strip is set as a stress path, the number of unit nodes on all paths and the stress magnitude of each unit node are determined, and the tangential and normal stresses of the unit nodes on all paths and their true distances are extracted. The tangential and normal stresses of the horizontal strip are converted into the tangential force resultant and the normal force resultant.

[0030] Step 4: Determine the inter-strip force function: Repeat step 3 to obtain the data of all slope tangential forces and normal forces, and use the nonlinear curve fitting method to process these data to obtain the fitting equation. On the basis of comprehensively considering the parameters such as slope size, strip length and position, deadweight and sliding surface inclination, the difference between the tangential force calculated by the fitting equation and the tangential force obtained by finite element analysis is used as the output variable. Combined with artificial intelligence technology, a prediction model for this variable is constructed. Subsequently, the tangential force calculated by the fitting equation is corrected according to the variable prediction value output by the prediction model, so as to achieve high-precision optimization of the inter-strip force function equation in the horizontal strip limit equilibrium method.

[0031] Embodiment 2

[0032] As another embodiment, this embodiment 2 proposes, based on the embodiment 1, a more specific method for determining the inter-strip force function for the horizontal strip limit equilibrium method:

[0033] Step 1: Establish a database: Collect a large number of slope examples, and organize geological models containing physical and mechanical parameters such as bulk density, Young's modulus, Poisson's ratio, cohesion, and internal friction angle as a database for slope analysis. Use data processing software to divide the coordinate data of the slope surface and the sliding surface into n horizontal strips according to user needs. By interpolating the slope coordinate data, the slope is divided into equal distances to determine the length of the horizontal strips and their spatial positions; in this embodiment, by using the Python platform, a code specifically for data processing is written. The code can flexibly divide the slope into n horizontal strips according to different n values. Subsequently, the code will read and obtain the spatial coordinate information of each horizontal strip one by one, and the visualization results are as follows. Figure 2 This step aims to locate the spatial position of each horizontal bar when constructing the finite element mesh model, and then accurately extract the stress value of each horizontal bar in the finite element calculation model.

[0034] Step 2: Establishment and analysis of finite element calculation model: According to the above-mentioned typical profile geological model, a finite element mesh model is constructed, such as Abaqus, Flac, Geo-Studio, Anasys, etc., and fine meshing is performed to determine the spatial position of the horizontal strips; it is assumed that each stratum is an ideal elastic material, and the elastic modulus of each stratum is uniformly set to 120GPa, so that the model is close to a rigid body. After completing these settings, finite element stress calculation is immediately carried out. In the present embodiment, a finite element mesh model is constructed in the Abaqus software, and the elastic modulus of each stratum is uniformly set to 120GPa. Subsequently, according to the spatial coordinates of the horizontal strips obtained by fine processing of the Python code in step one, the specific spatial position of each horizontal strip is accurately locked in the finite element calculation model. This operation is intended to ensure that the stress magnitude of each horizontal strip can be accurately determined in the finite element calculation model, and then the finite element stress calculation is carried out.

[0035] Step 3: Calculate the tangential force and normal force of the horizontal strip: According to the finite element stress calculation results, set the stress path for the horizontal strip to determine the number of unit nodes on the stress path and the stress magnitude of each unit node. Then, extract and save the tangential stress and normal stress values ​​of all unit nodes on these paths, and simultaneously record the specific length of each path. The data extraction diagram in the finite element stress calculation is as follows: Figure 3 and Figure 4 As shown. According to the mechanical formula F = P·L, the tangential stress of the horizontal bar is converted into the tangential force resultant. Where F is the resultant force, P is the average stress of all unit nodes on the selected path, and L is the length of the selected path. Similarly, the calculation of the normal force resultant of the horizontal bar also follows this method.

[0036] Step 4: Determine the inter-strip force function: Repeat step 3 continuously to obtain a large amount of tangential force and normal force data of the slope, and use the nonlinear curve fitting method to process these data to obtain the fitting equation. On the basis of comprehensively considering multiple parameters such as slope size, horizontal strip length, spatial position of horizontal strips, deadweight of horizontal strips, and the angle between the sliding surface and the horizontal direction, the difference between the tangential force calculated by the fitting equation and the tangential force calculated by the finite element method is used as the output variable, and artificial intelligence technology is used to construct a prediction model for the variable. Subsequently, the trained prediction model is used to output the predicted value of the variable. Subsequently, for a single slope instance, the calculated tangential force values ​​calculated by the fitting equation before and after correction, the predicted tangential force predicted by the prediction model, and the actual tangential force value obtained by finite element analysis are integrated. Subsequently, these data are plotted into an intuitive curve graph, such as Figure 5 As shown, the purpose is to clearly show the changing trend of the tangential force before and after correction.

[0037] from Figure 5It can be seen that after the fitting equation is obtained by the nonlinear curve fitting method, the tangential force calculated by the fitting equation still has a certain error compared with the tangential force calculated by the finite element method. After correction by the method proposed in the present invention, the predicted value is greatly close to the actual value, and a better result is achieved, thereby realizing high-precision optimization of the inter-strip force function equation in the horizontal strip limit equilibrium method.

[0038] It should be noted that the parts in this embodiment that are the same or similar to those in the first embodiment can be referenced to each other and will not be described in detail in this application.

[0039] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

Claims

1. A method for determining the inter-strip force function for the horizontal strip limit equilibrium method, characterized in that: The following steps are involved: Step 1: Establish a database: Establish a typical profile geological model; Step 2: Establish finite element calculation model and analysis: Based on the above typical section geological model, construct a finite element mesh model, apply gravity load to the finite element mesh model, and then perform finite element calculation to obtain the model stress field distribution; Step 3: Calculate the resultant tangential and normal forces of the horizontal strips: set a stress path for each horizontal strip, and extract the tangential force data, normal force data and path length of all unit nodes on the path; Step 4: Determine the inter-strip force function: Fit the tangential force and normal force data to obtain a fitting equation, construct a prediction model for the difference between the tangential force calculated by the fitting equation and the finite element calculation, and correct the fitting equation to obtain the inter-strip force function.

2. The method for determining the inter-strip force function for the horizontal strip limit equilibrium method according to claim 1, characterized in that: In step 2, each stratum in the profile geological model is set as an ideal elastic material, and the elastic modulus of each stratum is set to 120 GPa.

3. The method for determining the inter-strip force function for the horizontal strip limit equilibrium method according to claim 1, characterized in that: In step 3, the tangential stress and normal stress of the horizontal bar are converted into the tangential force resultant and the normal force resultant according to the formula F = P·L, where F is the resultant force, P is the average stress of all unit nodes on the path, and L is the stress path length.

4. The method for determining the inter-strip force function for the horizontal strip limit equilibrium method according to claim 1, characterized in that: In step 4, the tangential force and normal force data of all slopes are obtained, and nonlinear curve fitting is performed on the tangential force and normal force data to obtain a fitting equation; the difference between the tangential force calculated by the fitting equation and the tangential force calculated by the finite element method is calculated.

5. The method for determining the inter-strip force function for the horizontal strip limit equilibrium method according to claim 4, characterized in that: In step 4, the difference between the tangential force calculated by the fitting equation and the tangential force calculated by the finite element method is taken as the output variable, and a prediction model for the output variable is constructed in combination with artificial intelligence technology; the prediction model is used to output the predicted value of the difference between the tangential force calculated by the fitting equation and the tangential force calculated by the finite element method, and the tangential force calculated by the fitting equation is corrected.

6. The method for determining the inter-strip force function for the horizontal strip limit equilibrium method according to claim 1, characterized in that: The inter-strip force function obtained after correction using the fitting equation is used for the horizontal strip limit equilibrium method.

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