An experimental method and apparatus for simulating the deformation of buried pipelines.

Abstract

This invention relates to the technical field of long-distance oil and gas pipelines, and particularly to an experimental method and apparatus for simulating the deformation of buried pipelines. The method includes the following steps: controlling different stress conditions on the buried pipeline using an experimental apparatus to simulate the stress conditions of the buried pipeline under different scenarios; collecting mechanical parameters under different scenarios, including stress-strain values ​​and displacement changes; establishing a zoned deformation model of the buried pipeline, which includes a pipeline deformation curve model for the settlement zone and a soil spring model for the non-settlement zone; calculating the ultimate strain and circumferential stress based on the pipeline's stress balance and stress-strain relationship; determining the failure criteria; and evaluating the remaining strength of the deformed parts. This invention aims to solve the technical problem of the lack of existing methods and apparatus for simulating the deformation of buried pipelines.

Description

Technical Field

[0001] This invention relates to the technical field of long-distance oil and gas pipelines, and in particular to an experimental method and apparatus for simulating the deformation of buried pipelines. Background Technology

[0002] Pipelines, as the primary means of transporting oil and gas resources, offer convenience but also present safety challenges. Long-distance pipelines are buried underground, and due to the compressibility of the soil, they undergo varying degrees of settlement over time. This geological settlement leads to stress redistribution in buried pipelines, causing damage such as bending, localized buckling, cracking, and fracture. Furthermore, changes in the load on the overlying soil or the presence of significant external forces can induce large deformations in the pipeline, shortening its lifespan and causing oil and gas leaks. In severe cases, this can even lead to dangerous accidents such as fires and explosions, posing a significant threat to life and property safety, social stability, and the natural environment.

[0003] Therefore, it is necessary to propose an experimental method and apparatus for simulating the deformation of buried pipelines to test and analyze the effects of different settlement and topographic effects on the mechanical behavior and performance of buried oil and gas pipelines. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an experimental method and apparatus for simulating the deformation of buried pipelines, which aims to solve the technical problem that there is no method and apparatus for simulating the deformation of buried pipelines in the prior art.

[0005] To achieve the above objectives, in a first aspect, the present invention proposes an experimental method for simulating the deformation of buried pipelines, comprising the following steps:

[0006] S1. By using experimental equipment to control different stress conditions on buried pipelines, the stress conditions of buried pipelines under different scenarios are simulated.

[0007] S2. Collect mechanical parameters under different scenarios, including stress and strain values ​​and displacement changes;

[0008] S3. Establish a zoned deformation model for buried pipelines. The zoned deformation model includes a pipeline deformation curve model for the settlement zone and a soil spring model for the non-settlement zone. Calculate the ultimate strain and circumferential stress based on the pipeline's force balance and stress-strain relationship, determine the failure criteria, and evaluate the remaining strength of the deformed parts.

[0009] Preferably, the establishment of the partition deformation model includes:

[0010] Determine the pipeline deformation curve in the settlement area based on the boundary conditions;

[0011] The non-settlement area is simplified into a soil spring model, where the yield stress of the soil spring is determined based on the unit weight of the fill soil, the pipe radius, and the soil parameters.

[0012] Based on the generalized Hooke's law, the strain value is converted into a stress value, and the failure criterion is determined by combining the extreme value of the radial deformation of the pipeline, the ultimate compressive strain, and the ultimate tensile strain.

[0013] Preferably, the assessment of the remaining strength of the deformed portion includes:

[0014] The allowable compressive strain and allowable tensile strain of the pipeline are calculated based on strain theory.

[0015] The remaining life of uniform and localized corrosion in straight pipe sections is calculated based on the remaining wall thickness ratio and corrosion rate.

[0016] Preferably, the experimental apparatus includes a main structure, a hydraulic loading and control system, and a data acquisition and processing system; the main structure is used to fix the buried pipeline, the hydraulic loading and control system is used to apply different forces to the buried pipeline, and the data acquisition and processing system is used to collect and process data of the buried pipeline under different force conditions.

[0017] Preferably, the steps for controlling different stress conditions of the buried pipeline in S1 include the following:

[0018] S01. The geological settlement of the overlying soil of the buried pipeline is simulated by a hydraulic loading and control system to explore the deformation of the pipeline under different settlement amounts of the overlying soil. Simulated stones are placed at the bottom of the experimental pipeline specimen under the action of the overlying soil settlement to simulate the deformation of the bottom of the pipeline under external force.

[0019] S02. Select pipe materials for buried pipelines of different diameters and investigate the stress situation under the action of different pipe materials;

[0020] S03. Under a specific pipe material and diameter, buried pipes with different wall thicknesses are selected to simulate the deformation of the pipes under external forces.

[0021] S04. Inject high-pressure and / or high-temperature fluid into the buried pipeline to simulate the pressure inside the pipeline;

[0022] S05. Release the soil at the bottom of the buried pipeline and simulate the deformation of the buried pipeline under different settlement of the bottom soil.

[0023] S06. By changing the burial angle of the pipeline test specimen, repeat S01-S05 to test the deformation of the buried pipeline.

[0024] To achieve the above objectives, in a second aspect, the present invention proposes an experimental apparatus for simulating the deformation of buried pipelines, used in the experimental method for simulating the deformation of buried pipelines described in the first aspect. The experimental apparatus includes a main structure, a hydraulic loading and control system, and a data acquisition and processing system. The main structure is used to fix the buried pipeline; the hydraulic loading and control system is used to apply different forces to the buried pipeline; and the data acquisition and processing system is used to collect and process data of the buried pipeline under different force conditions.

[0025] Preferably, the main structure consists of a pipeline test specimen, a soil covering the pipeline, a simulated soil layer at the bottom of the pipeline, and a soil release port. The hydraulic loading and control system comprises a hydraulic pump station, a control system, hydraulic pipelines, a pressure application port, and a natural gas / oil injection port. The data acquisition and processing system consists of a stress-strain sensor, a displacement sensor, sensor test leads, a data acquisition terminal, a test lead serial port, a test lead sealing plug, a transmission interface, a data analysis and processing module, and a visualization module.

[0026] Preferably, the soil covering the pipeline and the simulated soil at the bottom of the pipeline are one or more of sand, clay, and silty clay.

[0027] Preferably, the stress-strain sensors are attached to the outer wall of the pipe test specimen and are evenly distributed along the clockwise direction of the pipe wall. The displacement sensors are also attached to the outer wall of the pipe test specimen and are evenly distributed along the clockwise direction of the pipe wall. The stress-strain sensors and displacement sensors are arranged alternately. One end of the test lead is connected to the stress-strain sensor and the displacement sensor respectively, and the other end is connected to the data acquisition terminal through the test lead series port. The test lead series port is completely sealed with a test lead sealing plug. The data acquisition terminal is used to receive stress-strain and displacement data during the experiment. The deformation of the specimen is captured by the strain sensor and the displacement sensor and stored on the data acquisition device.

[0028] Preferably, the data acquisition terminal includes a data acquisition layer, a data transmission layer, and a back-end data processing service layer. The data acquisition layer includes a stress-strain sensor, a displacement sensor, a data acquisition card, and a test lead serial port. The data transmission layer includes test leads and a transmission interface. The back-end data processing service layer provides real-time services and data analysis. The data analysis includes a real-time data acquisition analysis module, a data batch processing module, a machine learning module, and a visualization module. The visualization module mainly includes a real-time chart module and a data storage module.

[0029] Compared with existing technologies, the beneficial effects of the experimental method and apparatus for simulating the deformation of buried pipelines provided by this invention are as follows:

[0030] This study aims to test and analyze the mechanical behavior and performance impact of buried oil and gas pipelines under different settlement and topographic effects, and to predict the lifespan of buried pipelines. The mechanical performance research of this buried pipeline can provide scientific theoretical guidance for the safe operation of buried pipelines.

[0031] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an experimental method using an experimental device that can be used to simulate the deformation of buried pipelines.

[0033] Figure 2 This is a schematic diagram of the settlement zone and non-settlement zone of a buried pipeline.

[0034] Figure 3 It is a model diagram that can be used to simulate the settlement and deformation of buried pipelines.

[0035] Figure 4 It is a data acquisition and analysis system for simulating the settlement and deformation of buried pipelines, and is a visual analysis diagram.

[0036] Figure 5 This is an analysis diagram of axial strain.

[0037] Figure 6 This is a schematic diagram of the first type of release mechanism.

[0038] Figure 7 This is the main view of another release mechanism.

[0039] Figure 8 yes Figure 7 Sectional view of AA.

[0040] In the diagram: 1. Sensor test lead; 2. Pipeline test specimen; 3. Overlying soil on the pipeline; 4. Pressure application port; 5. Stress-strain sensor; 6. Displacement sensor; 7. Natural gas / oil injection port; 8. Test lead series port; 9. Soil release port; 10. Simulated rock; 11. Simulated soil at the bottom of the pipeline; 100. Release mechanism; 101. Rotating disk; 102. Fixed disk; 103. Toothed disk; 104. Hollow notch; 105. Sealing ring; 106. Ball bearing; 107. Sliding cone. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0042] In the description of this invention, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to or indirectly connected to the other element.

[0043] In the description of this invention, it should be noted that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0044] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] See Figure 1 and Figure 2This invention provides an experimental device for simulating the deformation of buried pipelines, comprising three subsystems: a main structure of a simulation experimental chamber, a hydraulic loading and control system, and a data acquisition and processing system. The main structure of the simulation experimental chamber consists of a pipeline test specimen 2, soil covering the pipeline 3, and simulated soil at the bottom of the pipeline 11. The hydraulic loading and control system consists of a hydraulic pump station, a control system, hydraulic pipelines, pipe joints, a pressure valve, and a pressure application port 4. The data acquisition and processing system consists of a displacement sensor 6, a stress-strain sensor 5, sensor test leads 1, test lead sealing plugs, and a data acquisition terminal.

[0046] Furthermore, the simulation experimental chamber includes an external cavity structure. The pipeline experimental specimen 2 is welded onto a fixed base to fix the pipeline experimental specimen. The fixed base is equipped with a test lead series port 8 and a natural gas / oil injection port 7. The test lead series port 8 is used to lead out the test leads of the stress strain sensor and displacement sensor through the test lead series port 8 and connect them to an external data acquisition device. The natural gas / oil injection port 7 is used to inject high-temperature and high-pressure fluid into the chamber during the experimental test to create internal pressure.

[0047] Furthermore, the different types of simulated soil are mainly divided into two types: the overlying soil 3 of the pipeline test specimen and the simulated soil 11 at the bottom of the pipeline. The overlying soil 3 is used to simulate the overlying soil of buried oil and gas pipelines. The soil type can be sand, clay, silty clay, etc. The simulated soil 11 at the bottom of the pipeline mainly serves as the original soil of the pipeline. The soil type can also be clay, silty clay, sand, etc. The original soil of the pipeline needs to be continuously compacted during the experiment. The original soil at the bottom of the pipeline can contain granular gravel, stones, etc., to simulate the external force at the bottom of the buried pipeline.

[0048] The pressure application port 4 applies pressure during the experiment using an external hydraulic loading and control system; different levels of pressure are applied to the overlying soil of the pipeline test specimen to simulate the geological settlement of the overlying soil 3, thereby realizing the stress on the pipeline test specimen 2.

[0049] The stress-strain sensor 5 is attached to the outer wall of the pipe test specimen 2 and is evenly arranged along the clock direction of the pipe wall. The displacement sensor 6 is attached to the outer wall of the pipe test specimen 2 and is evenly arranged along the clock direction of the pipe wall. The stress-strain sensor 5 and the displacement sensor 6 are arranged in a cross pattern to facilitate more comprehensive and complete data acquisition.

[0050] Furthermore, one end of the sensor test lead 1 is connected to the stress-strain sensor 5 and the displacement sensor 6 respectively, and the other end is connected to the data acquisition terminal through the test lead series port 8. The stress and deformation of the pipeline test specimen 2 can be obtained by processing the data on the data acquisition device. Those skilled in the art will understand that when using the present invention to conduct mechanical testing on the pipeline test specimen 2, stress and pipeline and soil parameters are used as preset parameters. By setting different parameters, the deformation mechanism of the pipeline test specimen 2 under different influencing factors is explored, thereby determining its failure mechanism and evaluating the remaining strength of the buried pipeline test specimen 2.

[0051] Furthermore, the data acquisition terminal is mainly used to collect data from the stress-strain sensor 5 and the displacement sensor 6. During the experiment, the sensor data is transmitted to the data acquisition terminal through the sensor test lead 1 and the test lead serial port 8.

[0052] The present invention also proposes an experimental method for simulating the deformation of buried pipelines, using the above-mentioned experimental apparatus.

[0053] S1. By using experimental equipment to control different stress conditions on buried pipelines, the stress conditions of buried pipelines under different scenarios are simulated.

[0054] The steps for controlling different stress conditions of buried pipelines in S1 include:

[0055] S01. The geological settlement of the overlying soil of the buried pipeline is simulated by a hydraulic loading and control system to explore the deformation of the pipeline under different settlement amounts of the overlying soil. Simulated stones are placed at the bottom of the experimental pipeline specimen under the action of the overlying soil settlement to simulate the deformation of the bottom of the pipeline under external force.

[0056] Specifically, the pressure application port 4 of the hydraulic loading system was used to simulate the geological settlement of the overlying soil 3 of the buried pipeline, and the deformation of the pipeline test specimen 2 under different settlement amounts of the overlying soil (soil settlement amounts of 5mm, 10mm, 15mm, 20mm, 25mm, and 30mm) was investigated. In addition, if a simulated stone 10 is placed at the bottom of the pipeline test specimen 2 under the settlement of the overlying soil 3 of the buried pipeline, the deformation of the bottom of the pipeline test specimen 2 under the action of external force can be simulated.

[0057] S02. Select buried pipelines of different diameters and investigate the stress under different pipe materials.

[0058] Specifically, the pipe material for the pipeline test specimen 2 can be a specific type of steel with different pipe diameters (355mm, 457mm, 508mm, 610mm, etc.) to investigate the stress under different pipe materials.

[0059] S03. Under a specific pipe material and diameter, buried pipes with different wall thicknesses are selected to simulate the deformation of the pipes under external forces.

[0060] Specifically, for a specific pipe material and pipe diameter (L415M pipe diameter is 457mm), different pipe test specimens 2 with different wall thicknesses (6mm, 7mm, 8mm, 9mm, 10mm, 11mm, etc.) were selected to simulate the deformation of the pipe under external force.

[0061] S04. Inject high-pressure and / or high-temperature fluid into the buried pipeline to simulate the effect of internal pressure.

[0062] Specifically, during the above-mentioned experimental simulation process, high-pressure and / or high-temperature fluids (gas / oil) can be injected into the pipeline experimental specimen 2 through the natural gas / oil injection port 7 to simulate the internal pressure of the pipeline.

[0063] S05. Release the soil at the bottom of the buried pipeline and simulate the deformation of the buried pipeline under different amounts of soil settlement at the bottom.

[0064] Specifically, the soil at the bottom of the buried pipeline is released through the soil release port 9 to simulate the deformation of the buried pipeline test specimen 2 under different amounts of bottom soil settlement (settlement amounts of 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, and 40mm).

[0065] Furthermore, the soil at the bottom of the buried pipeline is released, and pressurized or high-temperature natural gas or oil is injected into the pipeline test specimen 2 through the natural gas / oil injection port 7 to simulate the dynamic response mechanism and deformation of the pipeline under the combined action of internal pressure and external force.

[0066] S06. By changing the burial angle of pipe test specimen 2, repeat S01-S05 to test the buried pipeline.

[0067] Deformation status.

[0068] Specifically, by changing the burial angle of the pipeline test specimen 2 (the angle with the plane is 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, etc.), the deformation of the buried pipeline test specimen 2 is further tested under the above steps S01, S02, S03 and S04.

[0069] S2. Collect mechanical parameters under different scenarios, including stress and strain values ​​and displacement changes.

[0070] S3. Establish a zoned deformation model for buried pipelines. The zoned deformation model includes a pipeline deformation curve model for the settlement zone and a soil spring model for the non-settlement zone. Calculate the ultimate strain and circumferential stress based on the pipeline's force balance and stress-strain relationship, determine the failure criteria, and evaluate the remaining strength of the deformed parts.

[0071] The establishment of the partition deformation model includes:

[0072] Determine the pipeline deformation curve in the settlement area based on the boundary conditions;

[0073] The non-settlement area is simplified into a soil spring model, where the yield stress of the soil spring is determined based on the unit weight of the fill soil, the pipe radius, and the soil parameters.

[0074] Based on the generalized Hooke's law, the strain value is converted into a stress value, and the failure criterion is determined by combining the extreme value of the radial deformation of the pipeline, the ultimate compressive strain, and the ultimate tensile strain.

[0075] The assessment of the remaining strength of the deformed parts includes: calculating the allowable compressive strain and allowable tensile strain of the pipeline based on strain theory; and calculating the remaining life of the straight pipe section under uniform and localized corrosion based on the remaining wall thickness ratio and corrosion rate.

[0076] Specifically, based on the mechanical parameters, the strain value can be converted into a stress value according to the generalized Hooke's law; the mechanism of pipeline deformation induced by geological subsidence can be revealed, the critical failure pressure can be identified, and the remaining strength of the deformed part of the buried pipeline can be assessed.

[0077] See Figure 2 and Figure 3 , Figure 2 This is a schematic diagram showing the settlement and deformation of the pipeline. Figure 3 The red area in the middle indicates the stress phenomenon of the pipeline due to geological subsidence. The red area indicates that the stress is more obvious than other parts. If the subsidence is increased, the pipeline will deform.

[0078] In the above embodiment steps, it should be noted that the deformation calculation of the pipeline test specimen 2 includes the following steps:

[0079] like Figure 3 As shown, the deformation calculation of the pipeline test specimen in the settlement zone is as follows:

[0080]

[0081] Based on the boundary conditions, the pipe deformation curve in the settlement region can be obtained as follows:

[0082]

[0083] The deformation of the pipeline test specimen in the non-settlement zone can be regarded as a soil spring model, and its calculation is as follows:

[0084]

[0085]

[0086] In the formula: —Spring damping; — Yield stress of soil spring, MPa; —The most elastic displacement of the soil spring model, m (value range 0.1~0.15D); —Unit weight of fill soil, kN / m³ 3 ; —Radius of the buried pipeline, in meters.

[0087] Based on the force balance and stress-strain relationship of the pipeline, substituting the boundary conditions, we can obtain:

[0088]

[0089] According to the "Code for Design of Gas Transmission Pipeline Engineering" (GB 50251-2015), the radial deformation of gas transmission pipelines must meet the following requirements.

[0090]

[0091]

[0092] Ultimate strain values:

[0093]

[0094] In the formula: - Maximum horizontal deformation of the steel pipe, m; D - Outer diameter of the steel pipe, m; Z - Deformation hysteresis coefficient of the steel pipe, taken as 1.5; K - Subgrade coefficient; W - Total vertical load acting on a unit length of pipe, N / m; - Average diameter of steel pipe, m; E - Elastic modulus of steel, N / m 2 I - Moment of inertia per unit tube length, m 4 / m; -Soil deformation modulus, N / m 2 . —Critical compressive strain during pipe buckling; t —Pipe wall thickness, m; —Critical tensile strain for pipe fracture; —Minimum yield strength, MPa.

[0095] The value of circumferential stress varies with the internal pressure:

[0096]

[0097] Pipeline failure criteria based on strain theory:

[0098]

[0099] In the formula: —Pipe compression strain; —Pipe tensile strain; —Permissible compressive strain for pipelines; —Allowable tensile strain generated during pipeline operation; —Safety factor.

[0100] The formula for predicting the remaining service life of uniform and localized corrosion in straight pipe sections is as follows:

[0101]

[0102] .

[0103] In the formula: R L — Remaining lifespan, in years (a); C rate —Expected corrosion rate, in millimeters per year (mm / a); t mm —Measured average wall thickness of the pipe, in millimeters (mm); t min —Minimum wall thickness requirement for pipes, in millimeters (mm); R t —The remaining wall thickness ratio can be obtained from the remaining strength assessment; M t —Fourier factor; λ—shell parameter, RSF a —Allowable residual strength factor; S —Measured axial length of local metal loss, in millimeters (mm); P —Pipe operating pressure (MPa); D —Pipe outer diameter (mm); F —Design factor; — Welding coefficient; —Minimum yield strength of the pipe (MPa); t —Temperature reduction factor; when the temperature is less than 120℃, the value of t is 1.0.

[0104] Experiments were conducted using the above model; see reference [link / reference]. Figure 4 and Figure 5 The pipe has a diameter of 457 mm and a wall thickness of 7.2 mm. The geological settlement is 20 mm. The data obtained from the settlement deformation analysis are the maximum, minimum, and average radial, circumferential, and axial stresses in the settlement area. Figure 5 It contains the axial deformation data of the settlement area, and the specific graphical interface for displaying the simulation parameters required by the visualization interface. Regularities can be derived from multiple settlement simulations.

[0105] The data acquisition and processing system for simulating buried pipeline deformation of the present invention uses the above-mentioned method for processing. To facilitate the acquisition and analysis of experimental data, a complete modular experimental data acquisition and analysis system based on the experimental simulation platform was built. Experimental parameters were set and simulation analysis was performed using the pipeline deformation simulation experimental platform.

[0106] The example uses a specific pipe material and diameter (L415M pipe diameter is 457mm) as an example. The pipe wall thickness is 6mm. The soil width, length and height parameters are input to simulate the soil layer. The soil material interface of the soil layer is set to a variable parameter running script. Soil density, elastic modulus input interface, Poisson's ratio, cohesion, internal friction angle and pipe-soil friction coefficient are set respectively. The pipe material is set with elastic modulus input interface, yield strength input interface, tensile strength input interface, Poisson's ratio and other parameters.

[0107] Further, the settlement area is set. This analysis system uses the middle area of ​​the soil as the experimental simulation area and sets the settlement start point, settlement end point, transition amount, and soil displacement settlement amount.

[0108] Furthermore, to make the simulation effect closer to the actual situation, a medium is placed inside the pipeline, and the medium has parameters such as density, internal pressure, and operating temperature;

[0109] Connect the hardware interface and terminal analysis system. Stress-strain sensors and displacement sensors required for the data acquisition layer are installed closely along the pipeline, and connected to the serial port via sensor test leads. After setting the experimental parameters, start the experimental simulation equipment platform and issue analysis task commands. The backend data processing service layer provides real-time services and data analysis, builds data models, receives commands from the experimental equipment client, and initiates real-time batch data analysis through the real-time data channel.

[0110] The data analysis mainly consists of a real-time data acquisition and analysis module, a batch data processing module, a machine learning module, and a visualization module. Clicking "Run Script" allows the machine learning module to read the collected data from the database, perform analytical operations, analyze and save the real-time data, and click the "Results" command to obtain the data analysis results.

[0111] The terminal analysis system's visualization module performs charting and data saving operations based on real-time analysis results. The main charting modules include deformation cloud maps, and real-time React + WebSocket chart sets for parameters such as radial stress, circumferential stress, axial stress, deflection, displacement changes, and strain.

[0112] The following are some of the Python modular execution scripts for the data acquisition and analysis processing system in this example:

[0113] # ---- Basic Information ----

[0114] 'model_name': 'Pipe_Soil_Settlement_Model',

[0115] 'job_name': 'Pipe_Soil_Settlement_Model',

[0116] # ---- Geometric Parameter Settings ----

[0117] 'pipe_length': 50.0,

[0118] 'pipe_od_mm': 457,

[0119] 'pipe_thickness_mm': 6,

[0120] 'burial_depth': 12,

[0121] 'soil_width': 5.0,

[0122] 'soil_height': 20.0,

[0123] # ---- Pipe Material Interface Settings ----

[0124] 'pipe_steel_grade': 'L415M',

[0125] 'use_steel_grade_preset': True,

[0126] 'pipe_density': 7800.0,

[0127] 'pipe_E_GPa': 210.0,

[0128] 'pipe_nu': 0.3,

[0129] 'pipe_yield_stress_MPa': 450.0,

[0130] 'pipe_tensile_strength_MPa': 535.0,

[0131] 'pipe_alpha': 1.2e-5,

[0132] # ---- Soil Material Interface (Mohr-Coulomb) ----

[0133] 'soil_type': 'custom',

[0134] 'use_soil_type_preset': False,

[0135] 'soil_density': 1400.0,

[0136] 'soil_E': 33.0e6,

[0137] 'soil_E_MPa': 33.0,

[0138] 'soil_nu': 0.37,

[0139] 'soil_c': 24600.0,

[0140] 'soil_c_kPa': 24.6,

[0141] 'soil_phi': 26.0,

[0142] 'soil_dilation': 0.0,

[0143] 'use_mohr_coulomb': True,

[0144] …………

[0145] # ---- Visualization Module ----

[0146] def _zone_cn(zone):

[0147] if zone == 'settlement':

[0148] return 'settlement zone'

[0149] if zone == 'nearby':

[0150] return 'neighborhood area'

[0151] return str(zone)

[0152] def _metric_cn(metric):

[0153] mapping = {

[0154] 'deflection_U2': 'deflection',

[0155] 'deflection_U_mag': 'Deformation result (displacement)',

[0156] 'sigma_axial': 'axial stress'

[0157] 'sigma_hoop': 'circumferential stress',

[0158] 'sigma_radial': 'radial stress',

[0159] 'axial_strain': 'axial strain',

[0160] }

[0161] return mapping.get(metric, str(metric))

[0162] The above examples represent a partial solution to the Python script in the visualization module.

[0163] Example 2:

[0164] Based on Example 1, in order to further improve the accuracy of different settlement amounts of the bottom soil, a release mechanism 100 is added to the soil release port 9 to control the accuracy of soil release. The soil is released from the soil release port 9 after passing through the release mechanism 100.

[0165] See Figure 6 The release mechanism 100 includes a rotating disk 101 and a fixed disk 102, with a toothed disk 103 mounted on the rotating disk 101. The rotating disk 101 is a circular disk, and the fixed disk 102 is also a circular disk corresponding to the rotating disk 101. The rotating disk 101 is divided into four sections, each being a quarter circle. Each quarter circle has a hollow notch 104, while the remaining portion is solid. A sealing ring 105 is positioned corresponding to the hollow notch 104. The sealing ring 105 has a certain degree of elasticity and sealing performance. The sealing ring 105 is higher than the solid portion of the rotating disk 101 and effectively seals the release port. Similar to the test lead sealing plug in Embodiment 1, a seal is required at this location. Atmospheric moisture and temperature affect the pressure of the bottom soil and the release process. For example, excessive moisture can cause the soil at the release port to condense, making release difficult. The hollow notch 104 and the sealing convex ring 105 are diagonally opposite each other, which can increase the sealing area, making the isolation area larger and the sealing effect better.

[0166] The fixed plate 102 corresponds to the rotating plate 101, and is also divided into four equal parts. Each part is a quarter circle, with a notch in the quarter circle and the rest being solid.

[0167] After the soil from the rotating disk 101 aligns with the hollow notch 104 at the soil release port 9, the soil enters the hollow notch 104. As the rotating disk 101 continues to rotate, the hollow notch 104 moves away from the soil release port 9 and slowly aligns with the notch on the fixed disk 102, releasing the soil. At this point, the soil release port 9 is blocked again by the sealing ring 105. The amount of soil released by the rotating disk 101 each time is constant, and the size of the hollow notch 104 allows for better adjustment of the release accuracy. Different numbers of rotations provide a better understanding of the release volume.

[0168] In an alternative embodiment, the gear 103 is driven by meshing with a gear driven by a motor. See also Figure 7 and Figure 8 To reduce friction, ball bearings 106 are provided on the outer periphery above and / or below the rotating disk 101. During the rotation of the gear disk, the upper and lower contact points of the rotating disk 101 are connected by ball bearings 106. No hard friction occurs during rotation; instead, rolling friction occurs, making it easier for the rotating disk 101 to rotate.

[0169] In an optional embodiment, see [reference] Figure 7 and Figure 8 A sliding cone 107 is provided inside the sealing ring 105. The sliding cone 107 is pyramidal in shape, preferably a square pyramid. Since the soil will be compacted during the experiment, a larger opening is needed to allow the soil to fall during the release process. By rotating the disk 101 to drive the sliding cone 107 to rotate, the sliding cone 107 slides the soil, making the contact point loose and easier to release. This allows the opening of the soil release port 9 to be smaller, and the corresponding hollow notch 104 can also be smaller, resulting in less soil being released and higher precision.

[0170] One or more sliding cones 107 can be provided, depending on the actual scenario. A recess is provided on the surface of the rotating disk 101, and the sliding cone 107 is positioned within the recess. The sliding cone 107 is made of a rigid material and generally does not protrude above the upper surface of the solid part of the rotating disk 101 or the upper surface of the ball bearing 106, preventing the sliding cone 107 from scratching other surfaces during the rotation of the rotating disk 101. The recess is relatively small, allowing for pre-calculation of the capacity, and generally has little impact on the test pressure.

[0171] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An experimental method for simulating the deformation of buried pipelines, characterized in that, Includes the following steps: S1. By using experimental equipment to control different stress conditions on buried pipelines, the stress conditions of buried pipelines under different scenarios are simulated. S2. Collect mechanical parameters under different scenarios, including stress and strain values ​​and displacement changes; S3. Establish a zoned deformation model for buried pipelines. The zoned deformation model includes a pipeline deformation curve model for the settlement zone and a soil spring model for the non-settlement zone. Calculate the ultimate strain and circumferential stress based on the pipeline's force balance and stress-strain relationship, determine the failure criteria, and evaluate the remaining strength of the deformed parts. The assessment of the remaining strength of the deformed portion includes: The allowable compressive strain and allowable tensile strain of the pipeline are calculated based on strain theory. The remaining life of uniform and localized corrosion in straight pipe sections is calculated based on the remaining wall thickness ratio and corrosion rate. The formula for predicting the remaining service life of uniform and localized corrosion in straight pipe sections is as follows: ； ； In the formula: R L For remaining lifetime; C rate t represents the expected corrosion rate. mm The measured average wall thickness of the pipeline; t min Minimum required wall thickness for the pipe; R t The remaining wall thickness ratio is obtained from the remaining strength assessment; M t λ is the Fourier factor; λ is the shell parameter. RSF a S is the allowable residual strength factor; S is the measured axial length of local metal loss; P is the pipeline operating pressure; D is the pipe outer diameter; F is the design factor. The welding coefficient; t represents the minimum yield strength of the pipe; t is the temperature reduction factor; when the temperature is less than 120℃, the value of t is 1.

0. The steps for controlling different stress conditions of buried pipelines in S1 include: S01. The geological settlement of the overlying soil of the buried pipeline was simulated by a hydraulic loading and control system to investigate the deformation of the pipeline under different settlement amounts of the overlying soil. Simulated stones were placed at the bottom of the experimental pipeline specimen under the action of external force to simulate the deformation of the bottom of the pipeline under the action of external force. S02. Select pipe materials for buried pipelines of different diameters and investigate the stress situation under the action of different pipe materials; S03. Under a specific pipe material and diameter, buried pipes with different wall thicknesses are selected to simulate the deformation of the pipes under external forces. S04. Inject high-pressure and / or high-temperature fluid into the buried pipeline to simulate the pressure inside the pipeline; S05. Soil is released from the bottom of the buried pipeline through the soil release port. A release mechanism is added to the soil release port to control the accuracy of soil release. The soil is released from the soil release port after passing through the release mechanism, simulating the deformation of the buried pipeline under different settlement of the bottom soil. The release mechanism includes a rotating disk and a fixed disk. The rotating disk is equipped with a toothed disc. The rotating disk is divided into four sections, each of which is a 1 / 4 circle. One of the 1 / 4 circles is a hollow notch, and the rest are solid. A sealing convex ring is also provided at the position corresponding to the hollow notch. A sliding cone is provided inside the sealing convex ring. The fixed disk is corresponding to the rotating disk and is divided into four sections, each of which is a 1 / 4 circle. One of them is a notch, and the rest are solid. The soil enters the hollow notch after it corresponds to the soil release port. The rotating disk continues to rotate, causing the hollow notch to leave the soil release port and correspond to the notch of the fixed disk to release the soil. At the same time, the soil release port is sealed by the sealing convex ring. S06. By changing the burial angle of the pipeline test specimen 2, repeat S01-S05 to test the deformation of the buried pipeline.

2. The experimental method for simulating the deformation of buried pipelines as described in claim 1, characterized in that, The establishment of the buried pipeline zonal deformation model includes: Determine the pipeline deformation curve in the settlement area based on the boundary conditions; The non-settlement area is simplified into a soil spring model, where the yield stress of the soil spring is determined based on the unit weight of the fill soil, the pipe radius, and the soil parameters. Based on the generalized Hooke's law, the strain value is converted into a stress value, and the failure criterion is determined by combining the extreme value of the radial deformation of the pipeline, the ultimate compressive strain, and the ultimate tensile strain.

3. The experimental method for simulating the deformation of buried pipelines as described in claim 1, characterized in that, The experimental setup includes a main structure, a hydraulic loading and control system, and a data acquisition and processing system. The main structure is used to fix the buried pipeline, the hydraulic loading and control system is used to apply different forces to the buried pipeline, and the data acquisition and processing system is used to collect and process data of the buried pipeline under different stress conditions.

4. An experimental apparatus for simulating the deformation of buried pipelines, characterized in that, The experimental method for simulating the deformation of buried pipelines according to any one of claims 1-3, wherein the experimental apparatus comprises a main structure, a hydraulic loading and control system, and a data acquisition and processing system; the main structure is used to fix the buried pipeline, the hydraulic loading and control system is used to apply different forces to the buried pipeline, and the data acquisition and processing system is used to collect and process data of the buried pipeline under different stress conditions; the main structure consists of a pipeline experimental specimen, soil covering the pipeline, simulated soil at the bottom of the pipeline, and a soil release port; the hydraulic loading and control system consists of a hydraulic pump station, a control system, hydraulic pipelines, a pressure application port, and a natural gas / oil injection port; a release mechanism is added to the soil release port to control the accuracy of soil release, and the soil is released from the soil... The soil is released after passing through the release mechanism. The release mechanism includes a rotating disk and a fixed disk. The rotating disk is equipped with a toothed disc and is divided into four sections, each of which is a quarter circle. One of the quarter circles is hollow with a notch, and the rest is solid. A sealing ring is also provided at the position corresponding to the hollow notch, and a sliding cone is provided inside the sealing ring. The fixed disk is corresponding to the rotating disk and is also divided into four sections, each of which is a quarter circle. One of the sections is notched, and the rest is solid. The soil enters the hollow notch after it corresponds to the soil release port. The rotating disk continues to rotate, causing the hollow notch to leave the soil release port and align with the notch on the fixed disk to release the soil. At the same time, the soil release port is sealed by the sealing ring. Simultaneously, simulated stones are placed at the bottom of the experimental pipe specimen.

5. The experimental apparatus for simulating the deformation of buried pipelines as described in claim 4, characterized in that, The data acquisition and processing system consists of a stress-strain sensor, a displacement sensor, sensor test leads, a data acquisition terminal, a test lead serial port, a test lead sealing plug, a transmission interface, a data analysis and processing module, and a visualization module.

6. The experimental apparatus for simulating the deformation of buried pipelines as described in claim 5, characterized in that, The soil covering the pipeline and the simulated soil at the bottom of the pipeline are one or more of sand, clay, and silty clay.

7. The experimental apparatus for simulating the deformation of buried pipelines as described in claim 6, characterized in that, The stress-strain sensors are attached to the outer wall of the pipe test specimen and are evenly distributed along the clockwise direction of the pipe wall. The displacement sensors are also attached to the outer wall of the pipe test specimen and are evenly distributed along the clockwise direction of the pipe wall. The stress-strain sensors and displacement sensors are arranged alternately. One end of the test lead is connected to the stress-strain sensor and the displacement sensor respectively, and the other end is connected to the data acquisition terminal through the test lead series port. The test lead series port is completely sealed with a test lead sealing plug. The data acquisition terminal is used to receive stress-strain and displacement data during the experiment. The deformation of the specimen is captured by the strain sensor and the displacement sensor and stored on the data acquisition terminal.

8. The experimental apparatus for simulating the deformation of buried pipelines as described in claim 7, characterized in that, The data acquisition terminal includes a data acquisition layer, a data transmission layer, and a back-end data processing service layer. The data acquisition layer includes a stress-strain sensor, a displacement sensor, a data acquisition card, and a test lead serial port. The data transmission layer includes test leads and a transmission interface. The back-end data processing service layer provides real-time services and data analysis. The data analysis includes a real-time data acquisition analysis module, a data batch processing module, a machine learning module, and a visualization module. The visualization module includes a real-time chart module and a data storage module.

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