Method and device for determining strain of a pipeline under the action of a fault and pipeline design system

Abstract

The application discloses a kind of determination method, device and pipeline design system of pipeline strain under fault action.The method comprises: establishing pipeline mechanics calculation model, pipeline mechanics calculation model includes multiple units, unit is used to calculate the interaction of soil layer and pipeline near position under corresponding position of pipeline strain;Adjust the influence factor variable, build the finite element model corresponding to the influence factor variable to pipeline mechanics calculation model, obtain multiple finite element models;According to each finite element model, the axial displacement and axial strain of the corresponding position of all units are calculated in turn, to obtain multiple sets of fitting data, a set of fitting data corresponds to one finite element model;According to multiple sets of fitting data, fitting is carried out, to obtain tensile strain fitting formula and compressive strain fitting formula;According to tensile strain fitting formula and compressive strain fitting formula, the tensile strain of pipeline and the compressive strain of pipeline under reverse strike-slip fault action are calculated, solve the technical problem that pipeline strain under fault action is difficult to accurately calculate.

Description

Technical Field

[0001] This invention relates to the field of pipeline design, and more specifically, to a method, apparatus, computer-readable storage medium, processor, and pipeline design system for determining pipeline strain under fault conditions. Background Technology

[0002] Major pipeline projects inevitably cross active faults. For example, a certain large-scale key project that has been completed has a total length of 8,485 km. The pipeline passes through a considerable area of ​​strong earthquakes and 11 active faults, two of which are reverse strike-slip faults. Therefore, how to ensure the safety of the pipeline under the action of reverse strike-slip faults is a key issue in pipeline construction. Accurately predicting and analyzing the pipeline strain under the action of reverse strike-slip faults is one of its core contents.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This invention provides a method, apparatus, computer-readable storage medium, processor, and pipeline design system for determining pipeline strain under fault action, solving the technical problem that existing technologies struggle to accurately calculate pipeline strain under fault action.

[0005] According to one aspect of the present invention, a method for determining pipeline strain under fault action is provided, comprising: establishing a pipeline mechanical calculation model, the pipeline mechanical calculation model comprising multiple elements, the elements being used to calculate the pipeline strain at corresponding positions under the interaction between the soil layer near the fault and the pipeline, the positions in the pipeline corresponding to different elements being different; adjusting influencing factor variables, constructing the pipeline mechanical calculation model into finite element models corresponding to the influencing factor variables, obtaining multiple finite element models, the influencing factor variables including at least pipeline burial depth, crossing angle, dislocation amount, and crack width; sequentially calculating the axial displacement and axial strain at corresponding positions of all elements according to each finite element model, obtaining multiple sets of fitting data, each set of fitting data corresponding to one finite element model, each set of fitting data including the value of the influencing factor variables, the corresponding position of the element, the axial displacement, and the axial strain; fitting the multiple sets of fitting data to obtain tensile strain fitting formulas and compressive strain fitting formulas; calculating the pipeline tensile strain and pipeline compressive strain under strike-slip fault action according to the tensile strain fitting formulas and the compressive strain fitting formulas.

[0006] Optionally, a pipeline mechanics calculation model is established, including: establishing a pipe element model, wherein the pipe element model includes multiple first elements and multiple second elements, each of the first and second elements simulating a soil spring; the multiple first elements corresponding one-to-one with pipe positions evenly distributed within a first pipe segment; the multiple second elements corresponding one-to-one with pipe positions evenly distributed within a second pipe segment; the first pipe segment being a pipe within a first predetermined distance from the fault; the second pipe segment being a pipe within a second predetermined distance from the first pipe segment; and the spacing between the first and second pipe segments being different; establishing a fixed boundary shell unit. The meta-model, the fixed boundary shell element model includes multiple third elements, each simulating multiple soil springs. Some of these soil springs are connected to the inner wall of the pipe, while the remaining soil springs are connected to the outer wall of the pipe. Each of the multiple third elements corresponds one-to-one with a pipe position evenly distributed within a third pipe segment. The third pipe segment is a pipe within a predetermined distance from the fault. The spacing between the third pipe segment and the first pipe segment is different, and the spacing between the third pipe segment and the second pipe segment is different. A pipe-shell coupling model is established, including multiple fourth elements and multiple fifth elements. The fourth elements simulate multiple... The soil springs are described above. Of the multiple soil springs, some are connected to the inner wall of the pipe, and the remaining are connected to the outer wall of the pipe. The fifth unit simulates one soil spring. Multiple fourth units correspond one-to-one with equally spaced pipe positions within the fourth pipe segment. Multiple fifth units correspond one-to-one with equally spaced pipe positions within the fifth pipe segment. The fourth pipe segment is a pipe whose distance from the fault is less than or equal to a fourth predetermined distance. The fifth pipe segment is a pipe whose minimum distance from the fourth pipe segment is less than or equal to a fifth predetermined distance. The spacing between the fourth and fifth pipe segments is different. An equivalent spring boundary model is established. The model includes multiple sixth units and multiple seventh units. The sixth units simulate multiple soil springs, some of which are connected to the inner wall of the pipe, while the remaining soil springs are connected to the outer wall of the pipe. The seventh unit simulates one soil spring. The multiple sixth units correspond one-to-one with the pipe positions that are evenly distributed within the sixth pipe segment. The seventh units are connected one-to-one with the sixth units. The sixth pipe segment is a pipe within a predetermined distance from the fault that is less than or equal to a sixth predetermined distance. The corresponding verification axial displacement and verification axial strain are calculated based on the pipe unit model, the fixed boundary shell unit model, the pipe-shell coupling model, and the equivalent spring boundary model.The verified axial displacement is compared with the corresponding actual axial displacement, and the verified axial strain is compared with the actual verified axial strain to obtain an accuracy rate. The accuracy rate is the ratio of a first quantity and a second quantity. The first quantity is the number of combinations of qualified verified axial displacements and qualified verified axial strains, and the second quantity is the total number of combinations of verified axial displacements and verified axial strains. A qualified verified axial displacement is a verified axial displacement whose error with the corresponding actual axial displacement is less than a first predetermined error, and a qualified verified axial strain is a verified axial strain whose error with the corresponding actual axial displacement is less than a second predetermined error. The model corresponding to the highest accuracy rate is determined as the pipeline mechanics calculation model.

[0007] Optionally, the axial displacement and axial strain at the corresponding positions of all the elements are calculated sequentially according to each of the finite element models to obtain multiple sets of fitting data, including: a calculation step, calculating the horizontal displacement component, horizontal lateral displacement component, and vertical displacement component of the pipe at the corresponding positions according to the finite element model, wherein the direction of the vertical displacement component is parallel to the vertical direction, and the directions of the horizontal displacement component and the horizontal lateral displacement component are perpendicular to the vertical direction, and the directions of the horizontal displacement component and the horizontal lateral displacement component are perpendicular to each other; a simulation step, inputting the horizontal displacement component, the horizontal lateral displacement component, and the vertical displacement component into Abaqus software to obtain the axial displacement and the axial strain; adjusting the influencing factor variables, and repeating the calculation step and the simulation step at least once to obtain multiple sets of fitting data.

[0008] Optionally, the formula for calculating the horizontal displacement component of the pipeline is as follows: The horizontal lateral displacement component is The vertical displacement component is Where β is the crossing angle, The fault dip angle δ s δ represents the horizontal displacement of the fault. p The vertical displacement of the fault is given.

[0009] Optionally, δp is positive when the fault is a normal fault, negative when the fault is a reverse fault, positive when the fault is a right-lateral strike-slip fault, and negative when the fault is a left-lateral strike-slip fault.

[0010] Optionally, multiple sets of the fitted data are input into 1stOpt software for fitting to obtain the tensile strain fitting formula and the compressive strain fitting formula, wherein the tensile strain fitting formula is: The compressive strain fitting formula is as follows: Where s is the maximum displacement of the pipeline under fault action, h is the pipeline burial depth, D is the pipe diameter, c is the clay cohesion, t is the trench depth, b is the trench bottom width, m is the sand friction angle, n is the clay friction angle, and u is the trench slope.

[0011] According to another aspect of the present invention, a device for determining pipeline strain under fault action is also provided, comprising: a building unit for building a pipeline mechanical calculation model, the pipeline mechanical calculation model comprising multiple units, the units being used to calculate the pipeline strain at corresponding locations under the interaction between the soil layer near the fault and the pipeline, the different locations in the pipeline corresponding to different units; and an adjustment unit for adjusting influencing factor variables, constructing the pipeline mechanical calculation model into finite element models corresponding to the influencing factor variables, obtaining multiple finite element models, the influencing factor variables including at least pipeline burial depth, crossing angle, dislocation amount, and crack width; A calculation unit is used to sequentially calculate the axial displacement and axial strain of all the corresponding positions of the elements according to each of the finite element models, and obtain multiple sets of fitting data. Each set of fitting data corresponds to one finite element model. Each set of fitting data includes the value of the influencing factor variable, the corresponding position of the element, the axial displacement, and the axial strain. A fitting unit is used to fit the multiple sets of fitting data to obtain a tensile strain fitting formula and a compressive strain fitting formula. A second calculation unit is used to calculate the pipeline tensile strain and pipeline compressive strain under the action of the reverse strike-slip fault according to the tensile strain fitting formula and the compressive strain fitting formula.

[0012] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform any of the methods described.

[0013] According to another aspect of the present invention, a processor is also provided, the processor being configured to run a program, wherein the program, when running, executes any of the methods described herein.

[0014] According to another aspect of the present invention, a pipeline design system is also provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including methods for performing any one of the methods described.

[0015] In this embodiment of the invention, the method for determining pipeline strain under the aforementioned fault action firstly involves establishing a pipeline mechanical calculation model, which includes multiple elements. These elements are used to calculate the pipeline strain at corresponding locations under the interaction between the soil layer near the fault and the pipeline. Different elements correspond to different locations within the pipeline. Then, the influencing factor variables are adjusted, and the pipeline mechanical calculation model is constructed into a finite element model corresponding to the influencing factor variables, resulting in multiple finite element models. The influencing factor variables include at least the pipeline burial depth, crossing angle, dislocation amount, and crack width. Subsequently, the axial displacement and axial strain at the corresponding locations of all elements are calculated sequentially based on each finite element model, resulting in multiple sets of fitting data. Each set of fitting data corresponds to one finite element model, and each set of fitting data includes the value of the influencing factor variables, the corresponding location of the element, the axial displacement, and the axial strain. Then, the fitting data is fitted to obtain tensile strain fitting formulas and compressive strain fitting formulas. Finally, the tensile strain and compressive strain of the pipeline under the action of the reverse strike-slip fault are calculated based on the tensile strain fitting formulas and the compressive strain fitting formulas. The regression formulas for tensile and compressive strain of pipelines under the action of reverse strike-slip faults constructed by this method enable pipeline designers to easily calculate the pipeline strain under the action of reverse strike-slip faults based on relevant parameters such as pipeline and fault. This simplifies the pipeline strain analysis process, improves work efficiency, and solves the technical problem that existing technologies cannot accurately calculate pipeline strain under the action of faults. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0017] Figure 1 This is a flowchart of a method for determining pipeline strain under faulting according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a pipe unit model according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of a fixed boundary shell element model according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of a shell-and-tube coupling model according to an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of an equivalent spring boundary model according to an embodiment of the present invention;

[0022] Figure 6This is a schematic diagram of a pipeline model that crosses a strike-slip fault according to an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of a device for determining pipeline strain under faulting according to an embodiment of the present invention;

[0024] Figure 8 This is a schematic diagram showing the relationship between the tensile strain fitting formula calculation results and the finite element operation results according to Embodiment 1 of the present invention;

[0025] Figure 9 This is a schematic diagram showing the relationship between the calculation results of the compressive strain fitting formula and the finite element operation results according to Embodiment 1 of the present invention;

[0026] Figure 10 This is a schematic diagram showing the relationship between the calculation results of the fitting formula according to Embodiment 1 of the present invention and the actual working condition data. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] As mentioned in the background section, existing technologies struggle to accurately calculate pipeline strain under reverse strike-slip fault conditions. To address this issue, in a typical embodiment of this application, a method, apparatus, computer-readable storage medium, processor, and pipeline design system for determining pipeline strain under fault conditions are provided.

[0030] According to an embodiment of this application, a method for determining pipeline strain under fault action is provided.

[0031] Figure 1 This is a flowchart of a method for determining pipeline strain under fault action according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0032] Step S101: Establish a pipeline mechanics calculation model. The pipeline mechanics calculation model includes multiple elements. The elements are used to calculate the pipeline strain at the corresponding location under the interaction between the soil layer near the fault and the pipeline. Different elements correspond to different locations in the pipeline.

[0033] Step S102: Adjust the influencing factor variables and construct the above pipeline mechanics calculation model into a finite element model corresponding to the above influencing factor variables to obtain multiple above finite element models. The above influencing factor variables include at least pipeline burial depth, crossing angle, dislocation amount and crack width.

[0034] Step S103: Calculate the axial displacement and axial strain of all the above-mentioned elements at the corresponding positions according to each of the above-mentioned finite element models in sequence to obtain multiple sets of fitting data. Each set of the above-mentioned fitting data corresponds to one of the above-mentioned finite element models. Each set of the above-mentioned fitting data includes the value of the above-mentioned influencing factor variable, the corresponding position of the above-mentioned element, the above-mentioned axial displacement and the above-mentioned axial strain.

[0035] Step S104: Fit multiple sets of the above-mentioned fitting data to obtain the tensile strain fitting formula and the compressive strain fitting formula.

[0036] Step S105: Calculate the pipeline tensile strain and pipeline compressive strain under the action of the reverse strike-slip fault according to the above tensile strain fitting formula and the above compressive strain fitting formula.

[0037] In the method for determining pipeline strain under the aforementioned fault action, firstly, a pipeline mechanical calculation model is established, comprising multiple elements. These elements are used to calculate the pipeline strain at corresponding locations under the interaction between the soil layer near the fault and the pipeline. Different elements correspond to different locations within the pipeline. Then, the influencing factor variables are adjusted, and the pipeline mechanical calculation model is constructed into finite element models corresponding to these variables, resulting in multiple finite element models. The influencing factor variables include at least pipeline burial depth, crossing angle, dislocation amount, and crack width. Next, the axial displacement and axial strain at corresponding locations of all elements are calculated sequentially based on each finite element model, yielding multiple sets of fitted data. Each set of fitted data corresponds to one finite element model, and each set includes the values ​​of the influencing factor variables, the corresponding locations of the elements, the axial displacement, and the axial strain. Then, the multiple sets of fitted data are fitted to obtain tensile strain and compressive strain fitting formulas. Finally, the tensile strain and compressive strain of the pipeline under the action of a reverse strike-slip fault are calculated using the tensile strain and compressive strain fitting formulas. The regression formulas for tensile and compressive strain of pipelines under the action of reverse strike-slip faults constructed by this method enable pipeline designers to easily calculate the pipeline strain under the action of reverse strike-slip faults based on relevant parameters such as pipeline and fault. This simplifies the pipeline strain analysis process, improves work efficiency, and solves the technical problem that existing technologies cannot accurately calculate pipeline strain under the action of faults.

[0038] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0039] In one embodiment of this application, establishing a pipeline mechanics calculation model includes: establishing a pipe element model, wherein the pipe element model includes multiple first elements and multiple second elements, each of the first and second elements simulating a soil spring; the multiple first elements corresponding one-to-one with pipe positions evenly distributed within a first pipe segment; the multiple second elements corresponding one-to-one with pipe positions evenly distributed within a second pipe segment; the first pipe segment being a pipe within a first predetermined distance from the fault; the second pipe segment being a pipe within a second predetermined distance from the first pipe segment; and the spacing between the first and second pipe segments being different; establishing a solid... A fixed-boundary shell element model is established, comprising multiple third elements that simulate multiple soil springs. Some of these soil springs are connected to the inner wall of the pipe, while the remaining soil springs are connected to the outer wall. Each of the third elements corresponds one-to-one with a pipe section within a third pipe segment, where the distance from the fault is less than or equal to a predetermined third distance. The spacing between the third pipe segment and the first pipe segment is different, and the spacing between the third pipe segment and the second pipe segment is also different. A pipe-shell coupling model is then established, comprising multiple fourth and fifth elements. The fourth element model... Multiple soil springs are simulated, with some connected to the inner wall of the pipe and the remaining connected to the outer wall. The fifth unit simulates one soil spring. Multiple fourth units correspond one-to-one with equally spaced pipe positions within the fourth pipe segment, and multiple fifth units correspond one-to-one with equally spaced pipe positions within the fifth pipe segment. The fourth pipe segment is within a fourth predetermined distance from the fault, and the fifth pipe segment is within a fifth predetermined distance from the fourth pipe segment. The spacing between the fourth and fifth pipe segments is different. An equivalent spring boundary model is established. The boundary model includes multiple sixth elements and multiple seventh elements. The sixth elements simulate multiple soil springs, some of which are connected to the inner wall of the pipe, while the remaining soil springs are connected to the outer wall of the pipe. The seventh element simulates one soil spring. The multiple sixth elements correspond one-to-one with the pipe positions that are evenly distributed within the sixth pipe segment. The seventh elements are connected one-to-one with the sixth elements. The sixth pipe segment is the pipe within a predetermined distance from the fault. The corresponding verification axial displacement and verification axial strain are calculated based on the pipe element model, the fixed boundary shell element model, the pipe-shell coupling model, and the equivalent spring boundary model.The verified axial displacement is compared with the corresponding actual axial displacement, and the verified axial strain is compared with the actual verified axial strain to obtain the accuracy rate. The accuracy rate is the ratio of a first quantity and a second quantity. The first quantity is the number of combinations of qualified verified axial displacement and qualified verified axial strain, and the second quantity is the total number of combinations of verified axial displacement and verified axial strain. The qualified verified axial displacement is the verified axial displacement whose error with the corresponding actual axial displacement is less than a first predetermined error, and the qualified verified axial strain is the verified axial strain whose error with the corresponding actual axial displacement is less than a second predetermined error. The model corresponding to the highest accuracy rate is determined as the pipeline mechanics calculation model. Specifically, in the model establishment, the pipeline and soil spring are simulated by bending pipe elements and Jointc elements respectively. To accurately describe the pipeline deformation, a densification element method is used to set one element at a 0.1m interval within 100m at both ends of the fault region, and one element at a 1m interval on each side 1000m away from the fault region, forming a pipe element model, such as... Figure 2 As shown, the pipeline is divided into elements every 0.4m along its axial direction, with 24 nodes cut circumferentially. Each node has a soil spring, and they are connected using Jointc elements to simulate the triaxial soil spring stiffness, forming a fixed boundary shell element model. Figure 3 As shown, the pipeline within 100m of the fault region is modeled using shell elements. 24 elements are cut circumferentially, and one element is placed at 0.4m intervals along the axial direction to form a coupled pipe-shell model. Figure 4 As shown, pipe sections far from the fault zone can be simulated using the command: Spring, thus replacing the pipe with a spring. The equivalent spring model is as follows: Figure 5 As shown, the shell unit is 100m long, and 24 units are arranged in the circumferential direction to connect the spring units. One unit is arranged in the axial direction of the pipe at intervals of 0.4m.

[0040] A comparative analysis of the four models revealed several differences in results. When the crossing angle and dislocation amount of the pipeline across the fault varied, the results for the maximum and minimum axial strain of the pipeline were relatively close, with the fixed-boundary shell element model showing a more conservative approach. When the pipeline crossing angle was less than 90° and the dislocation amount was 4m, the axial and bending strain values ​​obtained by the pipe element and shell element models were similar. When the pipeline crossing angle was equal to 90°, the axial strain results of the two models were similar, but the maximum axial strain values ​​obtained by the shell element model were all larger. In terms of computational efficiency, to ensure the accuracy of the calculation results, the equivalent spring boundary and the pipe-shell coupling model could significantly reduce computational costs. However, the former required an additional increase in pipe length to ensure the applicability of the boundary when the fault dislocation amount was large. The pipe element model was suitable for large-scale calculations. Compared with other models, the pipe-shell coupling model had higher computational efficiency, stronger applicability, and relatively conservative calculation results in the seismic design of pipelines across faults. The shell-tube coupled model, located far from the fault region, uses pipe elements for modeling. The pipe ends of the pipe elements serve as control points to constrain the shell elements, ensuring that each node only undergoes rigid movement with the control points and that this behavior is transmitted to the shell element boundaries. This reduces the number of elements and lowers computational costs. Through comparative analysis, considering applicability, result accuracy, and computational cost, the shell-tube coupled element model is selected to establish the cross-fault mechanical calculation model.

[0041] In one embodiment of this application, the axial displacement and axial strain of all the corresponding positions of the above-mentioned elements are calculated sequentially according to each of the above-mentioned finite element models to obtain multiple sets of fitting data, including: a calculation step, calculating the horizontal displacement component, horizontal lateral displacement component and vertical displacement component of the pipe at the corresponding positions according to the above-mentioned finite element models, wherein the direction of the vertical displacement component is parallel to the vertical direction, and the directions of the horizontal displacement component and the horizontal lateral displacement component are respectively perpendicular to the vertical direction, and the directions of the horizontal displacement component and the horizontal lateral displacement component are perpendicular to each other; a simulation step, inputting the horizontal displacement component, the horizontal lateral displacement component and the vertical displacement component into Abaqus software to obtain the axial displacement and the axial strain; adjusting the above-mentioned influencing factor variables, and repeating the above-mentioned calculation step and the above-mentioned simulation step at least once to obtain multiple sets of the above-mentioned fitting data. Specifically, by controlling for a single variable, finite element models were established for different pipeline burial depths of 0.8m, 1.2m, 1.6m, and 2.0m, respectively. Four sets of fitting data were obtained. The calculation results show that as the pipeline burial depth increases, the maximum axial displacement decreases, while the maximum axial strain increases. The axial displacement and axial strain of the pipeline change significantly near the fault. The maximum tensile displacement of the pipeline is located at -2.5m, which is 0.078m; the maximum compressive displacement of the pipeline is located at 0.5m, which is -0.038m; the maximum tensile strain of the pipeline is located at 1.2m, with a strain value of 2.02%; and the maximum compressive strain of the pipeline is located at -0.6m, with a strain value of -0.48%. Overall, the pipeline failure location, i.e., the extreme strain value, is mainly located within 2.5m on both sides of the fault center. Finite element models were established under different pipeline crossing angles of 50°, 60°, 70°, and 80°, and four sets of fitting data were obtained. The calculation results show that as the pipeline crossing angle increases, the maximum values ​​of axial displacement and axial compressive strain decrease significantly, while the maximum value of axial tensile strain remains almost unchanged. This indicates that compressive strain is more sensitive to the crossing angle, and a larger crossing angle can effectively reduce the maximum values ​​of pipeline axial displacement and axial compressive strain. Finite element models were also established under different fault dislocation conditions of 0.7m, 1.0m, 1.3m, and 1.6m, and four sets of fitting data were obtained. The calculation results show that as the dislocation amount increases, the maximum values ​​of pipeline axial displacement and axial strain also increase. This is because the shear and tensile forces of the surrounding soil on the pipeline increase, thereby increasing the pipeline axial displacement and strain. The maximum value of tensile strain increases significantly with the increase of dislocation amount, while the maximum value of compressive strain remains basically unchanged.This fully demonstrates that under the influence of large dislocations, tensile deformation and failure are the main manifestations of pipelines crossing faults. Finite element models were established under different crack widths of 0.1m, 0.4m, 0.7m, and 1.0m, and four sets of fitting data were obtained. The calculation results show that the crack width has a certain impact on the maximum axial displacement of the pipeline, but has almost no impact on the maximum compressive displacement and axial strain. Overall, a larger crack width can effectively reduce the mechanical parameters of pipelines crossing faults.

[0042] In one embodiment of this application, the formula for calculating the horizontal displacement component of the pipeline is as follows: The above-mentioned horizontal lateral displacement components are The above vertical displacement components are Where β is the crossing angle, The fault dip angle δ s δ represents the horizontal displacement of the aforementioned fault. p This represents the vertical displacement of the aforementioned fault. Specifically, as shown... Figure 6 As shown, the pipeline fault region is represented by ELBOW elements, while the remaining pipe sections are represented by PIPE elements. The ELBOW elements employ full-shell integration in the circumferential direction, which can describe complex pipeline deformations and is suitable for solving problems such as ellipticization, torsion, and warping of pipeline cross-sections. PSI elements are used to simulate pipe-soil interaction, with the soil spring stiffness of the PSI elements determined by the three-dimensional pipe-soil contact analysis model. Equivalent boundary conditions are introduced, constraining displacement in the X direction at the left and right ends of the model, and applying symmetric constraints to the symmetry plane. By applying displacement load conditions to the PSI elements and internal pressure loads to the ELBOW elements, the pipeline mechanical calculation model considering trench parameters can be determined, thus yielding the aforementioned calculation formulas.

[0043] In one embodiment of this application, δp is positive when the fault is a normal fault, negative when the fault is a reverse fault, positive when the fault is a right-lateral strike-slip fault, and negative when the fault is a left-lateral strike-slip fault. Specifically, different methods are used to determine the values ​​for different faults, and these methods can further ensure the accuracy of the displacement component calculations.

[0044] In one embodiment of this application, fitting multiple sets of the above-mentioned fitting data to obtain a tensile strain fitting formula and a compressive strain fitting formula includes: inputting the multiple sets of the fitting data into 1stOpt software for fitting to obtain the tensile strain fitting formula and the compressive strain fitting formula, wherein the tensile strain fitting formula is... The compressive strain fitting formula is as follows: Where s is the maximum displacement of the pipeline under fault action, h is the pipeline burial depth, D is the pipe diameter, c is the clay cohesion, t is the trench depth, b is the trench bottom width, m is the sand friction angle, n is the clay friction angle, and u is the trench slope. Specifically, to verify the accuracy of the pipeline strain regression formula, based on the geological survey data of the actual project, 40 sets of actual pipeline strain data were compared and analyzed with the calculation results of the fitted formula. The maximum strain error was 3.986%, and the minimum strain error was 0.011915%. The comparative analysis showed that the trend of the fitted calculation results and the actual working condition data were the same, indicating that the fitted formula had a high degree of fit and could be used for pipeline strain calculation under fault action.

[0045] This application also provides a device for determining pipeline strain under fault action. It should be noted that the device for determining pipeline strain under fault action provided in this application can be used to execute the method for determining pipeline strain under reverse strike-slip fault action provided in this application. The following describes the device for determining pipeline strain under fault action provided in this application.

[0046] Figure 7 This is a schematic diagram of a device for determining pipeline strain under fault action according to an embodiment of this application. Figure 7 As shown, the device includes:

[0047] Element 10 is established to establish a pipeline mechanics calculation model. The pipeline mechanics calculation model includes multiple elements. The elements are used to calculate the pipeline strain at the corresponding location under the interaction between the soil layer near the fault and the pipeline. Different elements correspond to different locations in the pipeline.

[0048] Adjustment unit 20 is used to adjust the influencing factor variables and construct the above pipeline mechanics calculation model into a finite element model corresponding to the above influencing factor variables, thereby obtaining multiple above finite element models. The above influencing factor variables include at least pipeline burial depth, crossing angle, dislocation amount and crack width.

[0049] The first calculation unit 30 is used to calculate the axial displacement and axial strain of all the above-mentioned units at the corresponding positions according to each of the above-mentioned finite element models in sequence, and obtain multiple sets of fitting data. Each set of the above-mentioned fitting data corresponds to one of the above-mentioned finite element models. Each set of the above-mentioned fitting data includes the value of the above-mentioned influencing factor variable, the corresponding position of the above-mentioned unit, the above-mentioned axial displacement and the above-mentioned axial strain.

[0050] Fitting unit 40 is used to fit multiple sets of the above-mentioned fitting data to obtain tensile strain fitting formula and compressive strain fitting formula.

[0051] The second calculation unit 50 is used to calculate the pipeline tensile strain and pipeline compressive strain under the action of the reverse strike-slip fault according to the above tensile strain fitting formula and the above compressive strain fitting formula.

[0052] In the method for determining pipeline strain under the aforementioned fault action, firstly, a pipeline mechanical calculation model is established, comprising multiple elements. These elements are used to calculate the pipeline strain at corresponding locations under the interaction between the soil layer near the fault and the pipeline. Different elements correspond to different locations within the pipeline. Then, the influencing factor variables are adjusted, and the pipeline mechanical calculation model is constructed into finite element models corresponding to these variables, resulting in multiple finite element models. The influencing factor variables include at least pipeline burial depth, crossing angle, dislocation amount, and crack width. Next, the axial displacement and axial strain at corresponding locations of all elements are calculated sequentially based on each finite element model, yielding multiple sets of fitted data. Each set of fitted data corresponds to one finite element model, and each set includes the values ​​of the influencing factor variables, the corresponding locations of the elements, the axial displacement, and the axial strain. Then, the multiple sets of fitted data are fitted to obtain tensile strain and compressive strain fitting formulas. Finally, the tensile strain and compressive strain of the pipeline under the action of a reverse strike-slip fault are calculated using the tensile strain and compressive strain fitting formulas. The device constructs regression formulas for pipeline tensile and compressive strain under reverse strike-slip fault action, enabling pipeline designers to easily calculate pipeline strain under reverse strike-slip fault action based on relevant parameters such as pipeline and fault. This simplifies the pipeline strain analysis process, improves work efficiency, and solves the technical problem that existing technologies cannot accurately calculate pipeline strain under fault action.

[0053] In one embodiment of this application, the aforementioned establishment unit includes a first establishment module, a second establishment module, a third establishment module, a fourth establishment module, a first calculation module, a second calculation module, and a determination module. The first establishment module is used to establish a pipe unit model, which includes multiple first units and multiple second units. Each first unit and each second unit simulates a soil spring. The multiple first units correspond one-to-one with equally spaced pipe positions within a first pipe segment, and the multiple second units correspond one-to-one with equally spaced pipe positions within a second pipe segment. The first pipe segment is a pipe within a distance of less than or equal to a first predetermined distance from the fault, and the second pipe segment is a pipe within a distance of less than or equal to the first pipe segment. The minimum distance between the segments is less than or equal to the second predetermined distance for the pipeline. The spacing between the first pipeline segment and the second pipeline segment is different. The second establishment module is used to establish a fixed boundary shell element model. The fixed boundary shell element model includes multiple third elements. The third elements simulate multiple soil springs. Among the multiple soil springs, some of the soil springs are connected to the inner wall of the pipeline, and the remaining soil springs are connected to the outer wall of the pipeline. The multiple third elements correspond one-to-one with the pipeline positions that are evenly distributed within the third pipeline segment. The third pipeline segment is a pipeline whose distance from the fault is less than or equal to the third predetermined distance. The spacing between the third pipeline segment and the first pipeline segment is different. The spacing between the second pipe segment is different; the third module is used to establish a pipe-shell coupling model, which includes multiple fourth units and multiple fifth units. The fourth units simulate multiple soil springs, some of which are connected to the inner wall of the pipe, and the remaining soil springs are connected to the outer wall of the pipe. The fifth unit simulates one soil spring. The multiple fourth units correspond one-to-one with the pipe positions distributed at equal intervals within the fourth pipe segment, and the multiple fifth units correspond one-to-one with the pipe positions distributed at equal intervals within the fifth pipe segment. The fourth pipe segment is the pipe within a predetermined distance from the fault, and the fifth pipe segment is the pipe within the minimum distance from the fourth pipe segment. The distance between the fourth and fifth pipe segments is less than or equal to the fifth predetermined distance. The fourth establishment module is used to establish an equivalent spring boundary model. The equivalent spring boundary model includes multiple sixth units and multiple seventh units. The sixth unit simulates multiple soil springs. Among the multiple soil springs, some of the soil springs are connected to the inner wall of the pipe, and the remaining soil springs are connected to the outer wall of the pipe. The seventh unit simulates one soil spring. The multiple sixth units correspond one-to-one with the pipe positions that are evenly distributed within the sixth pipe segment. The seventh unit is connected one-to-one with the sixth unit. The sixth pipe segment is a pipe whose distance from the fault is less than or equal to the sixth predetermined distance.The first calculation module is used to calculate the corresponding verification axial displacement and verification axial strain based on the pipe unit model, the fixed boundary shell unit model, the pipe-shell coupling model, and the equivalent spring boundary model. The second calculation module is used to compare the verification axial displacement with the corresponding actual axial displacement and the verification axial strain with the actual verification axial strain to obtain an accuracy rate. The accuracy rate is the ratio of a first quantity and a second quantity. The first quantity is the number of combinations of qualified verification axial displacement and qualified verification axial strain, and the second quantity is the total number of combinations of verification axial displacement and verification axial strain. The qualified verification axial displacement is the verification axial displacement whose error with the corresponding actual axial displacement is less than a first predetermined error, and the qualified verification axial strain is the verification axial strain whose error with the corresponding actual axial displacement is less than a second predetermined error. The determining module is used to determine the model corresponding to the highest accuracy rate as the pipeline mechanics calculation model. Specifically, in the model building, pipe and soil spring are simulated by bending pipe elements and Jointc elements respectively. In order to accurately describe the pipe deformation, the method of densification of elements is used to set one element at a interval of 0.1m within 100m at both ends of the fault area, and one element at a interval of 1m at 1000m on both sides away from the fault area, to form a pipe element model, such as; Figure 2 As shown, the pipeline is divided into elements every 0.4m along its axial direction, with 24 nodes cut circumferentially. Each node has a soil spring, and they are connected using Jointc elements to simulate the triaxial soil spring stiffness, forming a fixed boundary shell element model. Figure 3 As shown, the pipeline within 100m of the fault region is modeled using shell elements. 24 elements are cut circumferentially, and one element is placed at 0.4m intervals along the axial direction to form a coupled pipe-shell model. Figure 4 As shown, pipe sections far from the fault zone can be simulated using the command: Spring, thus replacing the pipe with a spring. The equivalent spring model is as follows: Figure 5 As shown, the shell unit is 100m long, and 24 units are arranged in the circumferential direction to connect the spring units. One unit is arranged in the axial direction of the pipe at intervals of 0.4m.

[0054] A comparative analysis of the four models revealed several differences in results. When the crossing angle and dislocation amount of the pipeline across the fault varied, the results for the maximum and minimum axial strain of the pipeline were relatively close, with the fixed-boundary shell element model showing a more conservative approach. When the pipeline crossing angle was less than 90° and the dislocation amount was 4m, the axial and bending strain values ​​obtained by the pipe element and shell element models were similar. When the pipeline crossing angle was equal to 90°, the axial strain results of the two models were similar, but the maximum axial strain values ​​obtained by the shell element model were all larger. In terms of computational efficiency, to ensure the accuracy of the calculation results, the equivalent spring boundary and the pipe-shell coupling model could significantly reduce computational costs. However, the former required an additional increase in pipe length to ensure the applicability of the boundary when the fault dislocation amount was large. The pipe element model was suitable for large-scale calculations. Compared with other models, the pipe-shell coupling model had higher computational efficiency, stronger applicability, and relatively conservative calculation results in the seismic design of pipelines across faults. The shell-tube coupled model, located far from the fault region, uses pipe elements for modeling. The pipe ends of the pipe elements serve as control points to constrain the shell elements, ensuring that each node only undergoes rigid movement with the control points and that this behavior is transmitted to the shell element boundaries. This reduces the number of elements and lowers computational costs. Through comparative analysis, considering applicability, result accuracy, and computational cost, the shell-tube coupled element model is selected to establish the cross-fault mechanical calculation model.

[0055] In one embodiment of this application, the first calculation unit includes a third calculation module, a simulation module, and a repetition module. The third calculation module performs calculation steps, calculating the horizontal displacement component, horizontal lateral displacement component, and vertical displacement component of the pipe at the corresponding position based on the finite element model. The direction of the vertical displacement component is parallel to the vertical direction, and the directions of the horizontal displacement component and the horizontal lateral displacement component are perpendicular to the vertical direction, respectively. The simulation module performs simulation steps, inputting the horizontal displacement component, the horizontal lateral displacement component, and the vertical displacement component into Abaqus software to obtain the axial displacement and the axial strain. The repetition module adjusts the influencing factor variables and repeats the calculation steps and the simulation steps at least once to obtain multiple sets of the fitted data. Specifically, by controlling for a single variable, finite element models were established for different pipeline burial depths of 0.8m, 1.2m, 1.6m, and 2.0m, respectively. Four sets of fitting data were obtained. The calculation results show that as the pipeline burial depth increases, the maximum axial displacement decreases, while the maximum axial strain increases. The axial displacement and axial strain of the pipeline change significantly near the fault. The maximum tensile displacement of the pipeline is located at -2.5m, which is 0.078m; the maximum compressive displacement of the pipeline is located at 0.5m, which is -0.038m; the maximum tensile strain of the pipeline is located at 1.2m, with a strain value of 2.02%; and the maximum compressive strain of the pipeline is located at -0.6m, with a strain value of -0.48%. Overall, the pipeline failure location, i.e., the extreme strain value, is mainly located within 2.5m on both sides of the fault center. Finite element models were established under different pipeline crossing angles of 50°, 60°, 70°, and 80°, and four sets of fitting data were obtained. The calculation results show that as the pipeline crossing angle increases, the maximum values ​​of axial displacement and axial compressive strain decrease significantly, while the maximum value of axial tensile strain remains almost unchanged. This indicates that compressive strain is more sensitive to the crossing angle, and a larger crossing angle can effectively reduce the maximum values ​​of pipeline axial displacement and axial compressive strain. Finite element models were also established under different fault dislocation conditions of 0.7m, 1.0m, 1.3m, and 1.6m, and four sets of fitting data were obtained. The calculation results show that as the dislocation amount increases, the maximum values ​​of pipeline axial displacement and axial strain also increase. This is because the shear and tensile forces of the surrounding soil on the pipeline increase, thereby increasing the pipeline axial displacement and strain. The maximum value of tensile strain increases significantly with the increase of dislocation amount, while the maximum value of compressive strain remains basically unchanged.This fully demonstrates that under the influence of large dislocations, tensile deformation and failure are the main manifestations of pipelines crossing faults. Finite element models were established under different crack widths of 0.1m, 0.4m, 0.7m, and 1.0m, and four sets of fitting data were obtained. The calculation results show that the crack width has a certain impact on the maximum axial displacement of the pipeline, but has almost no impact on the maximum compressive displacement and axial strain. Overall, a larger crack width can effectively reduce the mechanical parameters of pipelines crossing faults.

[0056] In one embodiment of this application, the formula for calculating the horizontal displacement component of the pipeline is as follows: The above-mentioned horizontal lateral displacement components are The above vertical displacement components are Where β is the crossing angle, The fault dip angle δ s δ represents the horizontal displacement of the aforementioned fault. p This represents the vertical displacement of the aforementioned fault. Specifically, as shown... Figure 6 As shown, the pipeline fault region is represented by ELBOW elements, while the remaining pipe sections are represented by PIPE elements. The ELBOW elements employ full-shell integration in the circumferential direction, which can describe complex pipeline deformations and is suitable for solving problems such as ellipticization, torsion, and warping of pipeline cross-sections. PSI elements are used to simulate pipe-soil interaction, with the soil spring stiffness of the PSI elements determined by the three-dimensional pipe-soil contact analysis model. Equivalent boundary conditions are introduced, constraining displacement in the X direction at the left and right ends of the model, and applying symmetric constraints to the symmetry plane. By applying displacement load conditions to the PSI elements and internal pressure loads to the ELBOW elements, the pipeline mechanical calculation model considering trench parameters can be determined, thus yielding the aforementioned calculation formulas.

[0057] In one embodiment of this application, δp is positive when the fault is a normal fault, negative when the fault is a reverse fault, positive when the fault is a right-lateral strike-slip fault, and negative when the fault is a left-lateral strike-slip fault. Specifically, different methods are used to determine the values ​​for different faults, and these methods can further ensure the accuracy of the displacement component calculations.

[0058] In one embodiment of this application, the fitting unit is used to input multiple sets of fitting data into 1stOpt software for fitting, to obtain the tensile strain fitting formula and the compressive strain fitting formula, wherein the tensile strain fitting formula is: The compressive strain fitting formula is as follows: Where s is the maximum displacement of the pipeline under fault action, h is the pipeline burial depth, D is the pipe diameter, c is the clay cohesion, t is the trench depth, b is the trench bottom width, m is the sand friction angle, n is the clay friction angle, and u is the trench slope. Specifically, to verify the accuracy of the pipeline strain regression formula, based on the geological survey data of the actual project, 40 sets of actual pipeline strain data were compared and analyzed with the calculation results of the fitted formula. The maximum strain error was 3.986%, and the minimum strain error was 0.011915%. The comparative analysis showed that the trend of the fitted calculation results and the actual working condition data were the same, indicating that the fitted formula had a high degree of fit and could be used for pipeline strain calculation under fault action.

[0059] This application also provides a pipeline design system, including: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include methods for performing any of the above-described methods.

[0060] The aforementioned pipeline design system includes one or more processors, a memory, and one or more programs. The programs are stored in the memory and configured to be executed by the processors. Each program includes a method for performing one of the aforementioned techniques. The pipeline design system constructs regression formulas for tensile and compressive strain in pipelines under reverse strike-slip fault action. This allows pipeline designers to easily calculate pipeline strain under reverse strike-slip fault action based on relevant parameters such as pipeline and fault parameters. This simplifies the pipeline strain analysis process, improves work efficiency, and solves the technical problem of accurately calculating pipeline strain under fault action using existing technologies.

[0061] Example 1

[0062] Taking a natural gas pipeline as a reference, the pipeline steel grade is X80, and the basic parameters are: outer diameter 1219mm, wall thickness 22mm. The Ramberg-Osgood constitutive model is adopted, and its parameters are determined by fitting the material's true stress-strain curve obtained from tensile tests, resulting in α = 15.94 and N = 15.95. The cross-sectional dimensions are 1219mm × 18.4mm, the elastic modulus is 210GPa, the Poisson's ratio is 0.3, the design pressure is 10MPa, the pipe yield strength is 555MPa, the temperature difference is 45℃, and the burial depth is 1.2m. The soil characteristics are silty clay with an elastic modulus of 25MPa, an internal friction angle of 22°, a friction coefficient of 0.3, and a unit weight of 20kN / m3. Sand is used as the backfill soil for the pipe trench, with an internal friction angle of 35°. The fault type is a reverse strike-slip fault with a dip angle of 70°, a cross-fault angle of 62°, a horizontal fault displacement of 4m, a vertical fault displacement of 1.7m, and a crack width of 0.1m. The ultimate resistance and displacement parameters of the triaxial soil spring are shown in Table 1, and the fault displacement is shown in Table 2.

[0063] Table 1

[0064] direction <![CDATA[Ultimate resistance / (kN·m -1 )]]> Displacement / mm Axial spring 40 3 Lateral spring 430 96 Vertically upward 52 27 Vertically downward 2360 122

[0065] Table 2

[0066] Fault parameters Δx Δy Δz numerical values 1.36 -1.6 -3.8

[0067] The comparison between the results of the fitting formulas for tensile and compressive strain and the results of finite element calculations is as follows: Figure 8 and Figure 9 As shown in Table 3, the parameters for judging the fitting results are as follows. It can be seen from the table that the mean square error and the sum of squared residuals are close to 0, and the correlation coefficient and the square of the correlation coefficient are close to 1, indicating that the fitting results are accurate and the fitting formula has good precision.

[0068] Table 3

[0069] Comparison parameters Root mean square Sum of Squares of Residuals Correlation coefficient Square of the correlation coefficient Tensile strain <![CDATA[0.91×10 -3 ]]> 3.6536 0.9945 0.9891 Compressive strain 2.2724 2.2204 0.9974 0.9950

[0070] To verify the accuracy of the pipeline strain regression formula, based on the geological survey data of the natural gas pipeline project, the actual strain data of the pipeline was compared and analyzed with the calculation results of the fitted formula. The analysis results are as follows: Figure 10 As shown, the maximum strain error is 3.986%, and the minimum strain error is 0.011915%. The comparative analysis shows that the fitting calculation results and the actual working condition data have the same trend. The fitting formula has a high degree of fit and can be used for pipeline strain calculation under fault action.

[0071] The device for determining pipeline strain under the aforementioned fault action includes a processor and a memory. The aforementioned establishment unit, adjustment unit, first calculation unit, fitting unit, and second calculation unit are all stored in the memory as program units. The processor executes the aforementioned program units stored in the memory to achieve the corresponding functions.

[0072] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured, and adjusting kernel parameters can address the technical challenge of accurately calculating pipeline strain under reverse strike-slip fault conditions, a problem that is difficult to solve with existing technologies.

[0073] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0074] This invention provides a computer-readable storage medium including a stored program, wherein the program, when running, controls the device containing the computer-readable storage medium to execute the method.

[0075] This invention provides a processor for running a program, wherein the program executes the method described above when it runs.

[0076] This invention provides a device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps:

[0077] Step S101: Establish a pipeline mechanics calculation model. The pipeline mechanics calculation model includes multiple elements. The elements are used to calculate the pipeline strain at the corresponding location under the interaction between the soil layer near the fault and the pipeline. Different elements correspond to different locations in the pipeline.

[0078] Step S102: Adjust the influencing factor variables and construct the above pipeline mechanics calculation model into a finite element model corresponding to the above influencing factor variables to obtain multiple above finite element models. The above influencing factor variables include at least pipeline burial depth, crossing angle, dislocation amount and crack width.

[0079] Step S103: Calculate the axial displacement and axial strain of all the above-mentioned elements at the corresponding positions according to each of the above-mentioned finite element models in sequence to obtain multiple sets of fitting data. Each set of the above-mentioned fitting data corresponds to one of the above-mentioned finite element models. Each set of the above-mentioned fitting data includes the value of the above-mentioned influencing factor variable, the corresponding position of the above-mentioned element, the above-mentioned axial displacement and the above-mentioned axial strain.

[0080] Step S104: Fit multiple sets of the above-mentioned fitting data to obtain the tensile strain fitting formula and the compressive strain fitting formula.

[0081] Step S105: Calculate the pipeline tensile strain and pipeline compressive strain under the action of the reverse strike-slip fault according to the above tensile strain fitting formula and the above compressive strain fitting formula.

[0082] The devices mentioned in this article can be servers, PCs, tablets, mobile phones, etc.

[0083] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0084] Step S101: Establish a pipeline mechanics calculation model. The pipeline mechanics calculation model includes multiple elements. The elements are used to calculate the pipeline strain at the corresponding location under the interaction between the soil layer near the fault and the pipeline. Different elements correspond to different locations in the pipeline.

[0085] Step S102: Adjust the influencing factor variables and construct the above pipeline mechanics calculation model into a finite element model corresponding to the above influencing factor variables to obtain multiple above finite element models. The above influencing factor variables include at least pipeline burial depth, crossing angle, dislocation amount and crack width.

[0086] Step S103: Calculate the axial displacement and axial strain of all the above-mentioned elements at the corresponding positions according to each of the above-mentioned finite element models in sequence to obtain multiple sets of fitting data. Each set of the above-mentioned fitting data corresponds to one of the above-mentioned finite element models. Each set of the above-mentioned fitting data includes the value of the above-mentioned influencing factor variable, the corresponding position of the above-mentioned element, the above-mentioned axial displacement and the above-mentioned axial strain.

[0087] Step S104: Fit multiple sets of the above-mentioned fitting data to obtain the tensile strain fitting formula and the compressive strain fitting formula.

[0088] Step S105: Calculate the pipeline tensile strain and pipeline compressive strain under the action of the reverse strike-slip fault according to the above tensile strain fitting formula and the above compressive strain fitting formula.

[0089] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0090] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units described above can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0091] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0092] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0093] If the aforementioned integrated units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining pipeline strain under fault action, characterized in that, include: A pipeline mechanics calculation model is established, which includes multiple elements. Each element is used to calculate the pipeline strain at the corresponding location under the interaction between the soil layer and the pipeline near the fault. Different elements correspond to different locations in the pipeline. By adjusting the influencing factor variables, the pipeline mechanics calculation model is constructed into a finite element model corresponding to the influencing factor variables, resulting in multiple finite element models. The influencing factor variables include at least pipeline burial depth, crossing angle, dislocation amount, and crack width. The axial displacement and axial strain of all the corresponding positions of the elements are calculated sequentially according to each of the finite element models to obtain multiple sets of fitting data. Each set of fitting data corresponds to one finite element model. Each set of fitting data includes the value of the influencing factor variable, the corresponding position of the element, the axial displacement, and the axial strain. Based on the fitting data from multiple sets, the fitting formulas for tensile strain and compressive strain are obtained. Calculate the pipeline tensile strain and pipeline compressive strain under the action of the reverse strike-slip fault according to the tensile strain fitting formula and the compressive strain fitting formula; The tensile strain fitting formula and the compressive strain fitting formula are obtained by fitting multiple sets of the aforementioned fitting data, including: inputting the multiple sets of the aforementioned fitting data into 1stOpt software for fitting, and obtaining the tensile strain fitting formula and the compressive strain fitting formula, wherein the tensile strain fitting formula is... The compressive strain fitting formula is as follows: Where s is the maximum displacement of the pipeline under fault action, h is the pipeline burial depth, D is the pipe diameter, c is the clay cohesion, t is the trench depth, b is the trench bottom width, m is the sand friction angle, n is the clay friction angle, and u is the trench slope.

2. The method according to claim 1, characterized in that, Establish a pipeline mechanics calculation model, including: A pipe unit model is established, which includes multiple first units and multiple second units. Each first unit and each second unit simulates a soil spring. The multiple first units correspond one-to-one with the pipe positions distributed at equal intervals within a first pipe segment, and the multiple second units correspond one-to-one with the pipe positions distributed at equal intervals within a second pipe segment. The first pipe segment is a pipe within a first predetermined distance from the fault, and the second pipe segment is a pipe within a second predetermined distance from the first pipe segment. The spacing between the first pipe segment and the second pipe segment is different. A fixed boundary shell element model is established, which includes multiple third elements. Each third element simulates multiple soil springs. Among the multiple soil springs, some soil springs are connected to the inner wall of the pipe, and the remaining soil springs are connected to the outer wall of the pipe. The multiple third elements correspond one-to-one with the pipe positions that are equally spaced within a third pipe segment. The third pipe segment is a pipe whose distance from the fault is less than or equal to a third predetermined distance. The spacing between the third pipe segment and the first pipe segment is different, and the spacing between the third pipe segment and the second pipe segment is different. A pipe-shell coupling model is established, comprising multiple fourth units and multiple fifth units. Each fourth unit simulates multiple soil springs, some of which are connected to the inner wall of the pipe, while the remaining soil springs are connected to the outer wall of the pipe. Each fifth unit simulates one soil spring. The multiple fourth units correspond one-to-one with the equally spaced pipe positions within a fourth pipe segment, and the multiple fifth units correspond one-to-one with the equally spaced pipe positions within a fifth pipe segment. The fourth pipe segment is a pipe whose distance from the fault is less than or equal to a fourth predetermined distance, and the fifth pipe segment is a pipe whose minimum distance from the fourth pipe segment is less than or equal to a fifth predetermined distance. The spacing between the fourth and fifth pipe segments is different. An equivalent spring boundary model is established, comprising multiple sixth elements and multiple seventh elements. The sixth elements simulate multiple soil springs, some of which are connected to the inner wall of the pipe, while the remaining soil springs are connected to the outer wall of the pipe. The seventh element simulates one soil spring. The multiple sixth elements correspond one-to-one with the pipe positions that are evenly distributed within the sixth pipe segment. The seventh elements are connected one-to-one with the sixth elements. The sixth pipe segment is a pipe within a predetermined distance from the fault that is less than or equal to the sixth predetermined distance. The corresponding verification axial displacement and verification axial strain are calculated based on the tube element model, the fixed boundary shell element model, the tube-shell coupling model, and the equivalent spring boundary model. The verified axial displacement is compared with the corresponding actual axial displacement, and the verified axial strain is compared with the actual verified axial strain to obtain an accuracy rate. The accuracy rate is the ratio of a first quantity and a second quantity. The first quantity is the number of combinations of qualified verified axial displacements and qualified verified axial strains, and the second quantity is the total number of combinations of verified axial displacements and verified axial strains. The qualified verified axial displacement is the verified axial displacement whose error with the corresponding actual axial displacement is less than a first predetermined error, and the qualified verified axial strain is the verified axial strain whose error with the corresponding actual axial displacement is less than a second predetermined error. The model corresponding to the highest accuracy rate is determined as the pipeline mechanics calculation model.

3. The method according to claim 1, characterized in that, The axial displacement and axial strain at the corresponding positions of all the elements are calculated sequentially according to each of the finite element models, resulting in multiple sets of fitting data, including: The calculation steps involve calculating the horizontal displacement component, horizontal lateral displacement component, and vertical displacement component of the pipe at the corresponding position based on the finite element model. The direction of the vertical displacement component is parallel to the vertical direction, and the directions of the horizontal displacement component and the horizontal lateral displacement component are perpendicular to the vertical direction, respectively. Furthermore, the direction of the horizontal displacement component and the direction of the horizontal lateral displacement component are perpendicular to each other. In the simulation step, the horizontal displacement component, the horizontal lateral displacement component, and the vertical displacement component of the pipeline are input into the Abaqus software to obtain the axial displacement and the axial strain. Adjust the influencing factor variables, and repeat the calculation and simulation steps at least once to obtain multiple sets of fitted data.

4. The method according to claim 3, characterized in that, The formula for calculating the horizontal displacement component of the pipeline is as follows: The horizontal lateral displacement component is The vertical displacement component is Where β is the crossing angle, δ is the fault dip angle. s δ represents the horizontal displacement of the fault. p The vertical displacement of the fault is given.

5. The method according to claim 4, characterized in that, In the case that the fault is a normal fault, δ p If the value is positive, then δ is positive when the fault is a reverse fault. p When the fault is negative, δ is negative if the fault is a right-lateral strike-slip fault. s If the value is positive, then when the fault is a left-lateral strike-slip fault, δ s It is a negative value.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method of any one of claims 1 to 5.

7. A processor, characterized in that, The processor is used to run a program, wherein the program executes the method of any one of claims 1 to 5 when it runs.

8. A pipeline design system, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising methods for performing any one of claims 1 to 5.

Images