CN117077496A - Safety evaluation method for pipeline containing corrosion defects under landslide effect - Google Patents
Safety evaluation method for pipeline containing corrosion defects under landslide effect Download PDFInfo
- Publication number
- CN117077496A CN117077496A CN202311329010.5A CN202311329010A CN117077496A CN 117077496 A CN117077496 A CN 117077496A CN 202311329010 A CN202311329010 A CN 202311329010A CN 117077496 A CN117077496 A CN 117077496A
- Authority
- CN
- China
- Prior art keywords
- landslide
- pipeline
- model
- body model
- soil body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000007547 defect Effects 0.000 title claims abstract description 71
- 238000005260 corrosion Methods 0.000 title claims abstract description 66
- 230000007797 corrosion Effects 0.000 title claims abstract description 60
- 238000011156 evaluation Methods 0.000 title claims abstract description 37
- 230000000694 effects Effects 0.000 title claims description 11
- 239000002689 soil Substances 0.000 claims abstract description 92
- 230000009471 action Effects 0.000 claims abstract description 32
- 238000006073 displacement reaction Methods 0.000 claims description 51
- 238000000034 method Methods 0.000 claims description 46
- 239000000463 material Substances 0.000 claims description 3
- 238000005192 partition Methods 0.000 claims description 3
- 230000008569 process Effects 0.000 description 14
- 238000004364 calculation method Methods 0.000 description 9
- 239000007789 gas Substances 0.000 description 8
- 238000004088 simulation Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000005422 blasting Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000037237 body shape Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 239000013598 vector Substances 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/18—Network design, e.g. design based on topological or interconnect aspects of utility systems, piping, heating ventilation air conditioning [HVAC] or cabling
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T17/00—Three dimensional [3D] modelling, e.g. data description of 3D objects
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2113/00—Details relating to the application field
- G06F2113/14—Pipes
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/23—Dune restoration or creation; Cliff stabilisation
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Geometry (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- General Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Computer Graphics (AREA)
- Software Systems (AREA)
- Pit Excavations, Shoring, Fill Or Stabilisation Of Slopes (AREA)
Abstract
The application discloses a safety evaluation method of a pipeline containing corrosion defects under the action of landslide, which comprises the steps of obtaining on-site landslide parameters; establishing a finite element model of a landslide body-soil body-corrosion defect-containing pipeline; and loading the finite element model, and evaluating whether the pipeline containing the corrosion defect is invalid or not based on a pipeline failure criterion. The application aims to provide a safety evaluation method for a pipeline containing corrosion defects under the action of landslide, so as to solve the problems of single safety evaluation method, easy distortion of evaluation results and the like of the pipeline containing corrosion defects under the action of landslide in the prior art, realize more scientific and reasonable evaluation of the pipeline containing corrosion defects under the action of landslide, improve evaluation accuracy, reduce potential safety hazards, ensure property and life safety of people along the line and the like.
Description
Technical Field
The application relates to the field of long oil and gas pipelines, in particular to a safety evaluation method of a pipeline containing corrosion defects under the action of landslide.
Background
As one of five transportation modes of oil and gas, the pipeline transportation has the advantages of small loss, strong continuity, stable operation, convenient management, safety, reliability and the like, and nearly 100% of natural gas and more than 85% of petroleum in the whole world are transported through long-distance transportation pipelines. With the population growth and the economic development, the energy demand is continuously increased, and the pipeline construction is rapidly developed. The pipeline can pass through different landform areas in the laying process, especially in areas where geological disasters are likely to occur, and soil body movements such as landslide, earthquake, fault, frozen soil, settlement and the like can lead the pipeline to be in a complex loading state, thus having great threat to the safe use of the pipeline. The landslide is one of common geological disasters affecting the safety of the pipeline, when the pipeline in the area where the landslide occurs forms an inner corrosion defect due to the service life or transportation medium and the like, the residual strength of the pipeline is lower, once the landslide disaster occurs, the safety operation of the pipeline is affected, the pollution of soil and underground water is caused, and the explosion accident occurs when the landslide disaster occurs, so that the life and property safety of people is endangered. Therefore, failure analysis of the pipeline containing the corrosion defects under the action of landslide is particularly important.
In the prior art, a great deal of researches are carried out on the influence of landslide and corrosion defects on the performance of the pipeline, but the strength of the pipeline containing the corrosion defects under the action of the landslide is less researched, and along with the service life of the pipeline and the development of an underground pipe network, the loaded condition becomes a real problem to be solved in the oil and gas pipeline in the landslide area. In addition, in the prior art, for pipeline mechanics analysis under landslide action, a conventional cuboid model is adopted to model soil body and landslide body, and great difference exists between the soil body and actual working conditions on site, so that evaluation result distortion is easy to cause.
Disclosure of Invention
The application aims to provide a safety evaluation method for a pipeline containing corrosion defects under the action of landslide, so as to solve the problems of single evaluation method, easy distortion of evaluation results and the like of the pipeline containing corrosion defects under the action of landslide in the prior art, realize more scientific and reasonable evaluation of the pipeline containing corrosion defects under the action of landslide, improve evaluation accuracy, reduce potential safety hazards, ensure property and life safety of people along the line and the like.
The application is realized by the following technical scheme:
the safety evaluation method of the pipeline containing the corrosion defects under the landslide effect comprises the following steps:
acquiring on-site landslide parameters;
establishing a finite element model of a landslide body-soil body-corrosion defect-containing pipeline;
and loading the finite element model, and evaluating whether the pipeline containing the corrosion defect is invalid or not based on a pipeline failure criterion.
Aiming at the problems that the safety evaluation method of a pipeline with corrosion defects under the action of landslide in the prior art is single, the evaluation result is easy to distort and the like, the application provides the safety evaluation method of the pipeline with corrosion defects under the action of landslide. And then establishing a finite element model of the landslide body-soil body-corrosion-defect-containing pipeline based on the on-site landslide parameters, and carrying out loading simulation on the established model to obtain a mechanical analysis result of the corrosion-defect-containing pipeline, and evaluating whether the corrosion-defect-containing pipeline fails or not according to a pipeline failure criterion based on the mechanical analysis result.
It can be seen that the method can carry out limited evaluation on whether the long oil and gas pipeline containing corrosion defects fails under the sliding action, is favorable for quickly judging whether the buried pipeline has potential safety hazards after landslide occurs, and further provides more scientific and reasonable decision basis for an administrator of oil and gas transportation, and is convenient for quickly making subsequent treatment measures after landslide occurs.
The method for establishing the finite element model of the landslide body-soil body-corrosion defect-containing pipeline comprises the following steps:
establishing a three-dimensional rectangular coordinate system by taking the axial direction of the pipeline as a Z axis, the vertical direction as a Y axis and the transverse direction as an X axis;
establishing a pipeline model containing corrosion defects;
establishing a landslide body model, wherein the upper edge and the lower edge of the landslide body model are arc-shaped, and the upper end and the lower end of the upper edge are respectively overlapped with the upper end and the lower end of the lower edge;
establishing a soil body model, wherein the soil body model is low at the front and high at the rear, a groove for assembling the landslide body model is reserved on the soil body model, and the contact surface of the soil body model and the landslide body model is in a circular arc shape matched with the lower edge of the landslide body model;
material properties are respectively assigned to the pipeline model, the landslide body model and the soil body model;
and assembling the pipeline model, the landslide body model and the soil body model, enabling the pipeline model to pass through the landslide body model, enabling the landslide body model to be positioned on the soil body model, setting boundary conditions and dividing grids.
The distribution of corrosion defects on the pipeline belongs to data acquired earlier in the pipeline operation process, and belongs to known data in the application, so that the modeling process of the pipeline model is only required to adopt a common modeling process of the pipeline with the corrosion defects, and details are omitted here.
Unlike conventional cuboid-shaped soil and landslide models are:
the top surface and the bottom surface of the landslide body model are both formed by arc curved surfaces, and the upper end and the lower end of the upper edge are respectively overlapped with the upper end and the lower end of the lower edge, so that the landslide body model is formed by enclosing two arc curved surfaces;
the soil body model is in a shape with a low front part and a high rear part, and the contact surface of the soil body model and the landslide body model, namely the top surface of the soil body model is in a circular arc shape matched with the lower edge of the landslide body model.
The inventor finds that the traditional cuboid landslide body model and soil body model are simple and convenient in the model building process, but do not conform to the actual working condition of landslide, are unfavorable for considering the influence of site factors such as landslide inclination and the like, and easily lead to lower model accuracy and distortion of a final evaluation result. The analysis is that the landslide displacement loading distance of the conventional square landslide pipeline model is generally selected to be 5 times of the pipe diameter, and a longer distance is reserved for reducing the influence of soil in front of the pipeline on the deformation of the pipeline, so that the problem of selection of the landslide displacement loading distance and the problem of interference of soil in front of the model on the stress strain of the pipeline are caused. The application creatively improves and optimizes the shapes of the landslide body model and the soil body model, so that the interaction surface between the landslide body and the soil body is in a certain radian; the upper surface of the landslide body is also in a certain radian, the influence of vegetation, implementation and other heavy objects on the landslide body is considered, the model is ensured to be relatively simple and convenient to build, the actual situation of landslide occurrence is more met, the follow-up calculation result is more practical and more accurate, meanwhile, the influence of site factors such as landslide inclination angle and the like can be more conveniently considered, and the failure evaluation result of a pipeline with corrosion defects under the action of the landslide is more accurate and reliable; the method omits the problem of selecting the loading distance of the square landslide pipeline model in landslide displacement, and simultaneously avoids the influence of soil in front of the square landslide pipeline model on the stress strain of the pipeline.
Further, the lower edge of the landslide body model takes the central angle as A 1 Radius ofR 1 Is a circular arc of (2);
the upper edge of the landslide body model takes the central angle as A 2 Radius ofR 2 Is a circular arc of (2);
wherein: a is that 1 =55°~65°；R 1 =L；A 2 =40°~50°；LThe maximum linear distance between the upper edge and the lower edge of the landslide body model;
。
the scheme limits the specific shapes of the upper edge and the lower edge of the landslide body model, wherein the central angle corresponding to the lower edge of the landslide body is within the range of 55-65 degrees, and can be consistent with most actual landslide conditions; the central angle corresponding to the upper edge of the landslide body is relatively smaller, and the value is taken in the range of 40-50 degrees, so that the weight interference of the vegetation and the like can be simulated in a reasonable range; wherein the central angle A 1 、A 2 The specific values of (2) may be empirically determined within the respective interval.
In addition, the scheme also provides a general determination method for the specific circular arc radiuses of the upper edge and the lower edge of the landslide body model, and the landslide body model determined by the method can meet the general simulation evaluation of pipeline failure after landslide body modeling.
Wherein in the actual operation process, the maximum linear distance between the upper edge and the lower edge of the landslide body modelLThe maximum landslide thickness in the on-site landslide parameter can be characterized.
Furthermore, the front side surface and the rear side surface of the soil body model are parallel to each other, the height of the front side surface is lower than that of the rear side surface, and the bottom surface of the soil body model is perpendicular to the front side surface and the rear side surface.
Wherein the person skilled in the art will understand that the front side refers to the side facing in the downhill direction and the rear side refers to the side facing in the uphill direction.
Further, along the axial direction of the pipeline model: the length of the soil body model is greater than 10 times of the outer diameter of the pipeline model, and the length of the landslide body model is smaller than or equal to the length of the soil body model. The scheme can ensure that landslide only occurs in partial areas of soil, and ensure that the boundary effect of the pipeline is eliminated.
Further, the method for setting boundary conditions and dividing grids comprises the following steps:
setting one end of the pipeline model as a completely fixed constraint, setting a contact mode of hard contact and penalty function between the pipeline model and the soil body model, and setting the bottom surface of the soil body model as a completely fixed constraint; setting the two side surfaces of the soil body model to be completely fixed and restrained along the Z-axis direction;
dividing grids of the pipeline model, the landslide body model and the soil body model by adopting eight-node linear hexahedral units respectively, and encrypting the grids in a side distribution mode in the region where the landslide body model acts on the pipeline model, the region where the landslide body model acts on the soil body model, the region where the soil body model contacts with the landslide body model, the region where the pipeline model contacts with the landslide body model and the region where the pipeline model contacts with the soil body model;
dividing the pipeline model into three layers of grids along the radial direction, and carrying out partition treatment on corrosion defects on the pipeline model.
When the landslide body is divided into grids, the upper bottom and the lower bottom of the landslide body are provided with relatively narrow approximately wedge-shaped parts, so that the landslide body is divided by adopting the grid mainly comprising hexahedrons, and the grid encryption treatment is carried out at the contact part of the landslide body and the pipeline in a side distribution mode due to obvious change of displacement stress and the like of the contact part of the landslide body and the pipeline.
The soil body is the most complex entity in the whole landslide process, and because the contact surface is more, the unique area is bigger, so the contact position adopts the mode of side distribution to encrypt the grid, and simultaneously, in order to eliminate the boundary effect, the proper grid encryption is also carried out in the length direction of the soil body.
It should be understood by those skilled in the art that the "grid encryption method of" side-by-side "refers to a method of dividing a region where fine division of a grid is required, and setting the number of units and the size of the dimension on the sides of the region.
The application adopts an extension surface segmentation mode to divide the rear end of the defect and the pipeline into sections, adopts a multi-point segmentation mode to divide the two sides of the defect and the pipeline into sections, and simultaneously divides the pipeline into three layers along the radial direction in order to ensure the accuracy of the calculation of the corrosion defect.
Further, the method for loading the finite element model comprises the following steps:
applying normal operation internal pressure before landslide occurs in the pipeline model;
tangential displacement is applied to the landslide body based on the on-site landslide parameter.
Wherein, tangential displacement of any point on the landslide body is synthesized by X-direction displacement and Y-direction displacement, so that C is formed 2 = C 1 2 + C 2 2 The method comprises the steps of carrying out a first treatment on the surface of the Wherein C is tangential displacement of any point on the landslide body, C 1 For X displacement of this point, C 2 For the Y displacement of this point.
Preferably, the X-axis is displaced by C 1 Applied by the following formula:
；
preferably, the Y-position is C 2 Applied by the following formula:
；
wherein:Ais the actual measured landslide displacement;Bis the actual measured landslide width;xis an X-direction coordinate;βis the actual measured landslide angle.
The traditional loading mode of the external force of the pipeline under the action of the landslide is considered as the transverse loading in the horizontal direction, and the traditional linear loading mode cannot be adopted because of the arc-shaped structural design of the landslide body model and the soil body model. In order to overcome the problem, the application also enables the transverse displacement and the longitudinal displacement applied to the landslide body to be parabolic, so that a more accurate and reasonable tangential parabolic line can be obtained according to different adaptability of the actual landslide width and displacement, and the landslide process is simulated by utilizing the displacement of the landslide body in the tangential direction, so that the simulation result is more fit with the actual situation, and the final evaluation result is more accurate and reliable. Therefore, the parabolic loading mode of the scheme omits the distance of the transition region section of the square landslide pipeline, so that the calculation time and the calculation efficiency of the model are greatly saved, and the real situation in the landslide process can be clearly and conveniently represented.
In addition, in some existing square landslide pipeline models, landslide displacement adopts a quadratic/quartic parabolic form of a transverse landslide, so that when the landslide occurs, longitudinal stress, strain and displacement of soil and a pipeline cannot be simulated, and therefore the load loading mode of the conventional square landslide pipeline has great defects.
Compared with the prior art, the application has the following advantages and beneficial effects:
1. the safety evaluation method for the pipeline with the corrosion defect under the action of the landslide can carry out limited evaluation on whether the long oil and gas pipeline with the corrosion defect fails under the action of the sliding, is favorable for quickly judging whether the buried pipeline has potential safety hazards after the landslide occurs, further provides a more scientific and reasonable decision basis for an administrator of oil and gas transportation, and is convenient for quickly making subsequent treatment measures after the landslide occurs.
2. According to the safety evaluation method for the pipeline containing the corrosion defects under the landslide effect, the shapes of the landslide body model and the soil body model are improved and optimized, so that the interaction surface between the landslide body and the soil body is in a certain radian; the upper surface of the landslide body is also in a certain radian, the influence of vegetation, implementation and other heavy objects on the landslide body is considered, the actual condition of landslide occurrence is more met while the model is relatively simple and convenient to build, the follow-up calculation result is more practical and accurate, meanwhile, the influence of site factors such as landslide inclination angle and the like can be more conveniently considered, and the failure evaluation result of the pipeline with the corrosion defects under the action of the landslide is more accurate and reliable.
3. According to the safety evaluation method for the pipeline containing the corrosion defects under the landslide effect, which is disclosed by the application, more accurate and reasonable tangential loading parabolic line type is obtained according to the difference of the actual landslide width and displacement, and the landslide process is simulated by utilizing the displacement of the landslide body in the tangential direction, so that the simulation result is more fit with the actual situation, and the final evaluation result is more accurate and reliable.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:
FIG. 1 is a schematic diagram of a landslide mass model according to an embodiment of the present application;
FIG. 2 is a schematic view of a soil model according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a landslide body-soil body-corrosion-defect-containing pipeline model in accordance with an embodiment of the present application;
FIG. 4 is a schematic diagram showing the effects of the loaded vehicle according to an embodiment of the present application;
FIG. 5 is a stress cloud of a pipe with corrosion defects in an embodiment of the application.
In the drawings, the reference numerals and corresponding part names:
1-landslide mass model, 2-soil mass model and 3-pipeline model containing corrosion defects.
Detailed Description
For the purpose of making apparent the objects, technical solutions and advantages of the present application, the present application will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present application and the descriptions thereof are for illustrating the present application only and are not to be construed as limiting the present application.
Example 1
A safety evaluation method for a pipeline containing corrosion defects under landslide action comprises the following steps:
acquiring on-site landslide parameters;
establishing a finite element model of a landslide body-soil body-corrosion defect-containing pipeline;
and loading the finite element model, and evaluating whether the pipeline containing the corrosion defect is invalid or not based on a pipeline failure criterion.
The method for establishing the finite element model of the landslide body-soil body-corrosion defect-containing pipeline comprises the following steps:
establishing a three-dimensional rectangular coordinate system by taking the axial direction of the pipeline as a Z axis, the vertical direction as a Y axis and the transverse direction as an X axis;
establishing a pipeline model containing corrosion defects;
establishing a landslide body model as shown in fig. 1, wherein the upper edge and the lower edge of the landslide body model 1 are arc-shaped, and the upper end and the lower end of the upper edge are respectively overlapped with the upper end and the lower end of the lower edge;
establishing a soil body model as shown in fig. 2, wherein the soil body model 2 is low at the front and high at the rear, a groove for assembling the landslide body model is reserved on the soil body model, and the contact surface of the soil body model and the landslide body model is in a circular arc shape matched with the lower edge of the landslide body model;
material properties are respectively assigned to the pipeline model, the landslide body model and the soil body model;
and assembling the pipeline model, the landslide body model and the soil body model to obtain a landslide body-soil body-finite element model of the pipeline with the corrosion defects shown in figure 3, enabling the pipeline model 3 with the corrosion defects to pass through the landslide body model, enabling the landslide body model to be positioned on the soil body model, setting boundary conditions and dividing grids.
Example 2
A safety evaluation method for a pipeline containing corrosion defects under the action of landslide, based on the embodiment 1,
in the modeling process of the embodiment, the following steps are adopted:
the lower edge of the landslide body model takes the central angle as A 1 Radius ofR 1 Is a circular arc of (2);
the upper edge of the landslide body model takes the central angle as A 2 Radius ofR 2 Is a circular arc of (2);
wherein: a is that 1 =55°~65°；R 1 =L；A 2 =40°~50°；LThe maximum linear distance between the upper edge and the lower edge of the landslide body model;
。
the front side surface and the rear side surface of the soil body model are parallel to each other, the height of the front side surface is lower than that of the rear side surface, and the bottom surface of the soil body model is perpendicular to the front side surface and the rear side surface.
Along the axial direction of the pipeline model: the length of the soil body model is greater than 10 times of the outer diameter of the pipeline model, and the length of the landslide body model is smaller than or equal to the length of the soil body model.
The method for setting the boundary conditions and dividing the grids comprises the following steps:
setting one end of the pipeline model as a completely fixed constraint, setting a contact mode of hard contact and penalty function between the pipeline model and the soil body model, and setting the bottom surface of the soil body model as a completely fixed constraint; setting the two side surfaces of the soil body model to be completely fixed and restrained along the Z-axis direction;
dividing grids of the pipeline model, the landslide body model and the soil body model by adopting eight-node linear hexahedral units respectively, and encrypting the grids in a side distribution mode in the region where the landslide body model acts on the pipeline model, the region where the landslide body model acts on the soil body model, the region where the soil body model contacts with the landslide body model, the region where the pipeline model contacts with the landslide body model and the region where the pipeline model contacts with the soil body model;
dividing the pipeline model into three layers of grids along the radial direction, and carrying out partition treatment on corrosion defects on the pipeline model.
The method for loading the finite element model in the embodiment comprises the following steps:
applying normal operation internal pressure before landslide occurs in the pipeline model;
applying tangential displacement to the landslide body based on the on-site landslide parameter; wherein, tangential displacement of any point on the landslide body is synthesized by X-direction displacement and Y-direction displacement, so that C is formed 2 = C 1 2 + C 2 2 The method comprises the steps of carrying out a first treatment on the surface of the Wherein C is tangential displacement of any point on the landslide body, C 1 For X displacement of this point, C 2 For the Y displacement of this point.
X-displacement C 1 Applied by the following formula:
；
y-displacement C 2 Applied by the following formula:
；
wherein:Ais the actual measured landslide displacement;Bis the actual measured landslide width;xis an X-direction coordinate;βis the actual measured landslide angle.
Example 3
Based on the evaluation method described in example 2, this example will be described by taking a certain long-distance natural gas pipeline as an example. The long gas pipeline adopts a buried paving mode. Wherein, the pipeline is made of X80 steel, the pipe diameter is 1016mm, the wall thickness of the pipeline is 22mm, and the operating pressure is 7MPa; the length of the corrosion defect was 15% of the pipe diameter, i.e. 492.3mm, the depth was 30% of the pipe thickness, i.e. 76.2mm, and the width was 10 °.
Because the pipeline structure is symmetrical and the load is symmetrical, the modeling adopts a 1/2 model symmetrical about the Z axis so as to save the calculation time.
The following pre-assumptions were made during modeling in this embodiment:
(1) The mechanical property of the pipeline weld joint is the same as that of the parent metal;
(2) The interface between the pipeline and the soil body adopts the contact attribute of limited slip;
(3) The corrosion defect is represented by a defect with equal wall thickness;
(4) The landslide effect is simulated by respectively applying horizontal displacement and vertical displacement and synthesizing tangential displacement of a landslide body through vectors, and the distribution of the horizontal displacement and the vertical displacement adopts a fitted quadratic polynomial.
The pipe failure criterion used in this embodiment is the fourth strength theory in the stress failure criterion, that is, the pipe is considered to fail when the allowable stress is reached with the normal form equivalent stress of the pipe. The loaded action effect of the embodiment is shown in fig. 4, and the stress cloud diagram of the pipeline with the corrosion defect obtained through simulation is shown in fig. 5.
In order to verify the effectiveness of the model of the pipeline with corrosion defects in the landslide body, simulation verification is carried out according to known pipeline blasting experimental data, and table 1 shows the comparison results of the blasting experimental data, the simulation blasting data and the calculation of various standards. It can be seen that the simulation result is not quite different from the extreme pressure result obtained by other methods, which indicates that the accuracy of the corrosion defect-containing pipeline model in the embodiment is extremely high. Failure evaluation of a pipeline containing corrosion defects under the landslide action can be performed by the method.
It will be appreciated by those skilled in the art that "DNVRP-F101" in Table 1 refers to the Norwegian class society for corrosion-defective pipelines under only internal and longitudinal compressive stresses, "0.85dl" refers to the further revised RSTRENG0.85dl effective area method of the U.S. department of transportation for B31G assessment, and "B31G" refers to the American society of mechanical Engineers evaluation criteria for calculating the ultimate load carrying capacity and maximum allowable safe operating pressure of a corrosion-defective pipeline.
TABLE 1
Experiments prove that compared with the modeling mode of a conventional square landslide pipeline, the method adopts the arc-shaped landslide body shape, and the problem that a longer distance is reserved for reducing the influence of soil in front of the pipeline on the pipeline deformation is solved because the landslide displacement loading distance of the conventional square landslide pipeline model is generally 5 times the pipe diameter, and the problem of selecting the landslide displacement loading distance of the square landslide pipeline model is omitted, and meanwhile, the influence of the soil in front of the square landslide pipeline model on the pipeline stress strain is avoided.
In addition, the landslide displacement adopts a parabolic loading mode, so that the distance of a transition region section of the square landslide pipeline is omitted, the calculation time and the calculation efficiency of a model are greatly saved, and the real situation in the landslide process can be clearly and conveniently represented. In the traditional square landslide pipeline model, landslide displacement adopts a secondary/quartic parabolic form of a transverse landslide, so that when the landslide cannot be generated, the longitudinal stress, strain and displacement of soil and a pipeline cannot be simulated, and therefore the load loading mode of the traditional square landslide pipeline has great defects.
It should be noted that in this document, terms such as "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the application, and is not meant to limit the scope of the application, but to limit the application to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the application are intended to be included within the scope of the application.
Claims (10)
1. The safety evaluation method of the pipeline containing the corrosion defects under the landslide effect is characterized by comprising the following steps:
acquiring on-site landslide parameters;
establishing a finite element model of a landslide body-soil body-corrosion defect-containing pipeline;
and loading the finite element model, and evaluating whether the pipeline containing the corrosion defect is invalid or not based on a pipeline failure criterion.
2. The method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide according to claim 1, wherein the method for establishing a finite element model of a landslide body-soil body-pipeline containing corrosion defects comprises the following steps:
establishing a three-dimensional rectangular coordinate system by taking the axial direction of the pipeline as a Z axis, the vertical direction as a Y axis and the transverse direction as an X axis;
establishing a pipeline model containing corrosion defects;
establishing a landslide body model, wherein the upper edge and the lower edge of the landslide body model are arc-shaped, and the upper end and the lower end of the upper edge are respectively overlapped with the upper end and the lower end of the lower edge;
establishing a soil body model, wherein the soil body model is low at the front and high at the rear, a groove for assembling the landslide body model is reserved on the soil body model, and the contact surface of the soil body model and the landslide body model is in a circular arc shape matched with the lower edge of the landslide body model;
material properties are respectively assigned to the pipeline model, the landslide body model and the soil body model;
and assembling the pipeline model, the landslide body model and the soil body model, enabling the pipeline model to pass through the landslide body model, enabling the landslide body model to be positioned on the soil body model, setting boundary conditions and dividing grids.
3. The method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide according to claim 2, wherein,
the lower edge of the landslide body model takes the central angle as A 1 Radius ofR 1 Is a circular arc of (2);
the upper edge of the landslide body model takes the central angle as A 2 Radius ofR 2 Is a circular arc of (2);
wherein: a is that 1 =55°~65°；R 1 =L；A 2 =40°~50°；LThe maximum linear distance between the upper edge and the lower edge of the landslide body model;
。
4. the method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide according to claim 2, wherein the front side surface and the rear side surface of the soil body model are parallel to each other, the height of the front side surface is lower than that of the rear side surface, and the bottom surface of the soil body model is perpendicular to both the front side surface and the rear side surface.
5. The method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide according to claim 2, wherein the axial direction of the pipeline model is as follows: the length of the soil body model is greater than 10 times of the outer diameter of the pipeline model, and the length of the landslide body model is smaller than or equal to the length of the soil body model.
6. The method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide according to claim 2, wherein the method for setting boundary conditions and dividing grids comprises the following steps:
setting one end of the pipeline model as a completely fixed constraint, setting a contact mode of hard contact and penalty function between the pipeline model and the soil body model, and setting the bottom surface of the soil body model as a completely fixed constraint; setting the two side surfaces of the soil body model to be completely fixed and restrained along the Z-axis direction;
dividing grids of the pipeline model, the landslide body model and the soil body model by adopting eight-node linear hexahedral units respectively, and encrypting the grids in a side distribution mode in the region where the landslide body model acts on the pipeline model, the region where the landslide body model acts on the soil body model, the region where the soil body model contacts with the landslide body model, the region where the pipeline model contacts with the landslide body model and the region where the pipeline model contacts with the soil body model;
dividing the pipeline model into three layers of grids along the radial direction, and carrying out partition treatment on corrosion defects on the pipeline model.
7. The method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide according to any one of claims 1 to 6, wherein the method for loading the finite element model comprises the following steps:
applying normal operation internal pressure before landslide occurs in the pipeline model;
tangential displacement is applied to the landslide body based on the on-site landslide parameter.
8. Safety of pipelines with corrosion defects under landslide action according to claim 7The evaluation method is characterized in that tangential displacement of any point on the landslide body is synthesized by X-direction displacement and Y-direction displacement, so that C is obtained 2 = C 1 2 + C 2 2 The method comprises the steps of carrying out a first treatment on the surface of the Wherein C is tangential displacement of any point on the landslide body, C 1 For X displacement of this point, C 2 For the Y displacement of this point.
9. The method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide of claim 8, wherein the displacement in the X direction is C 1 Applied by the following formula:
；
wherein:Ais the actual measured landslide displacement;Bis the actual measured landslide width;xis the X-direction coordinate.
10. The method for evaluating the safety of a pipeline containing corrosion defects under the action of landslide of claim 8, wherein the displacement C in Y direction is 2 Applied by the following formula:
；
wherein:Ais the actual measured landslide displacement;Bis the actual measured landslide width;xis an X-direction coordinate;βis the actual measured landslide angle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311329010.5A CN117077496B (en) | 2023-10-16 | 2023-10-16 | Safety evaluation method for pipeline containing corrosion defects under landslide effect |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311329010.5A CN117077496B (en) | 2023-10-16 | 2023-10-16 | Safety evaluation method for pipeline containing corrosion defects under landslide effect |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117077496A true CN117077496A (en) | 2023-11-17 |
| CN117077496B CN117077496B (en) | 2024-01-23 |
Family
ID=88717455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311329010.5A Active CN117077496B (en) | 2023-10-16 | 2023-10-16 | Safety evaluation method for pipeline containing corrosion defects under landslide effect |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117077496B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101667326A (en) * | 2008-09-03 | 2010-03-10 | 中国石油天然气股份有限公司 | Method and system for monitoring and warning influence of landslide on pipeline |
| CN101667328A (en) * | 2008-09-03 | 2010-03-10 | 中国石油天然气股份有限公司 | Method and system for monitoring and warning pipeline landslide surface displacement and method for constructing system |
| CN205841999U (en) * | 2016-04-27 | 2016-12-28 | 大连理工大学 | A kind of submarine landslide district oil and gas pipes with new type section |
| CN113935204A (en) * | 2020-07-13 | 2022-01-14 | 中国石油化工股份有限公司 | Pipeline corrosion defect evaluation method and device |
| CN115374677A (en) * | 2022-09-03 | 2022-11-22 | 西南石油大学 | Method for evaluating safety of pipeline with crack defects under landslide geological disaster |
-
2023
- 2023-10-16 CN CN202311329010.5A patent/CN117077496B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101667326A (en) * | 2008-09-03 | 2010-03-10 | 中国石油天然气股份有限公司 | Method and system for monitoring and warning influence of landslide on pipeline |
| CN101667328A (en) * | 2008-09-03 | 2010-03-10 | 中国石油天然气股份有限公司 | Method and system for monitoring and warning pipeline landslide surface displacement and method for constructing system |
| CN205841999U (en) * | 2016-04-27 | 2016-12-28 | 大连理工大学 | A kind of submarine landslide district oil and gas pipes with new type section |
| CN113935204A (en) * | 2020-07-13 | 2022-01-14 | 中国石油化工股份有限公司 | Pipeline corrosion defect evaluation method and device |
| CN115374677A (en) * | 2022-09-03 | 2022-11-22 | 西南石油大学 | Method for evaluating safety of pipeline with crack defects under landslide geological disaster |
Non-Patent Citations (5)
| Title |
|---|
| ZHU XIANXIANG: "Limit load prediction analysis of X80 pipeline containing corrosion in mountainous landslide section", 《GEOENERGY SCIENCE AND ENGINEERING》, vol. 229, no. 2023, pages 1 - 15 * |
| 张瑶瑶: "滑坡对含腐蚀缺陷输气管道应力的影响", 《腐蚀与防护》, vol. 43, no. 3, pages 1 - 4 * |
| 王小龙: "含缺陷海底管道压溃压力和止屈效率分析", 《中国优秀硕士学位论文全文数据库 工程科技 Ⅰ辑》, no. 02, pages 019 - 1110 * |
| 王立航;孙萍萍;: "基于有限元法单点腐蚀缺陷分析", 油气田地面工程, no. 12, pages 100 - 101 * |
| 臧雪瑞: "深层圆弧滑坡作用下埋地管道有限元模型研究", 《能源化工》, vol. 41, no. 01, pages 65 - 70 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117077496B (en) | 2024-01-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Han et al. | Failure pressure analysis of the pipe with inner corrosion defects by FEM | |
| O’Rourke et al. | Underground lifeline system performance during the Canterbury earthquake sequence | |
| Teng et al. | An adaptively refined XFEM with virtual node polygonal elements for dynamic crack problems | |
| Lin et al. | Fatigue growth prediction of internal surface cracks in pressure vessels | |
| Zhang et al. | Complex variable solution for twin tunneling-induced ground movements considering nonuniform convergence pattern | |
| CN109344490A (en) | A kind of ocean platform based on BRANN model fires risk analysis method | |
| Wang et al. | On lateral buckling of subsea pipe-in-pipe systems | |
| Rashidov et al. | Seismic Behavior of Underground Polymer Piping with Variable Interaction Coefficients. | |
| CN117077496B (en) | Safety evaluation method for pipeline containing corrosion defects under landslide effect | |
| Khademi Zahedi et al. | Investigating peak stresses in fitting and repair patches of buried polyethylene gas pipes | |
| Marache et al. | Characterization and reconstruction of a rock fracture surface by geostatistics | |
| Liu et al. | Slope stability analysis based on a multigrid method using a nonlinear 3D finite element model | |
| Azad et al. | A numerical simulation of thermo-mechanical behavior of a single fracture in porous rock | |
| Zhu et al. | Limit load prediction analysis of X80 pipeline containing corrosion in mountainous landslide section | |
| Lv et al. | Experimental and finite-element studies of buried pipes connected by a bellow Joint under Cyclic Shear Loading | |
| Hu et al. | Reliability analysis of marine risers with narrow and long corrosion defects under combined loads | |
| Brown et al. | Coupled Eulerian-Lagrangian methods for earth penetrating weapon applications | |
| CN110765684A (en) | Parameterized modeling method for W-shaped elastic strip | |
| Li et al. | Mechanical simulation and electrochemical corrosion in a buried pipeline with corrosion defects situated in permafrost regions | |
| Khoramishad et al. | Finite element analysis of a semi-elliptical external crack in a buried pipe | |
| Zhang et al. | Numerical study on mechanism responses of submarine pipeline impacted by bar-shaped falling object | |
| Yang et al. | Dynamic response and safety analysis of polyethylene pipeline under rockfall conditions | |
| Zhang et al. | Soil-structure interaction and failure analyses of steel water pipelines with welded joints | |
| Chen et al. | Study on burst pressure of subsea pipelines with asymmetrical corrosion defects | |
| Sun et al. | Statistical Analysis of Underground Pipeline Typical Accidents and Numerical Simulation Research |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |