A submarine pipeline overall buckling experiment device and an experiment method thereof

Abstract

This application discloses a test apparatus for the overall buckling of a subsea pipeline, comprising: a test tank, wherein the test tank has first through holes penetrating the sidewalls of the test tank at both ends in the axial direction, and the test pipeline is placed inside the test tank; an axial pressure device, wherein two sets of the axial pressure device are respectively disposed at both ends in the length direction of the test tank, the axial pressure device corresponding to the first through holes, and the axial pressure device is used to apply an axial load to the test pipeline inside the test tank through the first through holes; and a monitoring component, wherein the monitoring component is equally spaced in the middle part of the test pipeline, the monitoring component including dynamic and static strain sensors and / or tensile and compressive force sensors, used to collect the deformation of the test pipeline and the soil resistance during the deformation process of the test pipeline in real time.

Description

Technical Field

[0001] This application relates to the field of overall buckling test technology for subsea pipelines and indoor model test of pipe-soil interaction, specifically to an overall buckling test device and test method for subsea pipelines. Background Technology

[0002] To improve crude oil transportation efficiency, subsea pipelines typically operate at temperatures exceeding 100°C and pressures reaching up to 10 MPa. Under the combined loads of high temperature and high pressure, the pipeline expands, generating enormous axial forces. Due to the constraint of the seabed soil, the pipeline cannot deform freely, leading to overall buckling instability, cracking, and even failure. To ensure the long-term safe and stable operation of the pipeline after laying, it is necessary to determine the loads the pipeline can withstand and the constraint forces of the seabed soil during the pipeline design phase, which requires conducting corresponding indoor model experiments. Current experiments often treat the axial loads the pipeline can withstand and the pipe-soil interaction in a relatively isolated manner, only studying one aspect. Furthermore, the pipe-soil interaction tests only measure the soil constraint forces under straight pipeline motion, which differs significantly from the actual buckling amplitude of 5 to 20 times the pipe diameter under bending conditions. Therefore, further improving the overall buckling experimental device for subsea pipelines and the pipe-soil interaction testing methods is of great significance for ensuring the in-situ stability and service safety of the pipeline.

[0003] Application content

[0004] The purpose of this application is to provide a test device and method for the overall buckling test of subsea pipelines, the specific technical solution of which is as follows:

[0005] An experimental apparatus for testing the overall buckling of a subsea pipeline includes: an experimental water tank, wherein first through holes penetrating the sidewalls of the experimental water tank are provided at both ends in the axial direction, and an experimental pipeline is placed inside the experimental water tank; an axial pressure device, wherein two sets of axial pressure devices are respectively provided at both ends in the length direction of the experimental water tank, the axial pressure devices corresponding to the first through holes, and the axial pressure devices are used to apply axial load to the experimental pipeline inside the experimental water tank through the first through holes; and a monitoring component, wherein the monitoring component is equally spaced in the middle part of the experimental pipeline, the monitoring component including dynamic and static strain sensors and / or tensile and compressive force sensors, for real-time acquisition of the deformation of the experimental pipeline and the soil resistance during the deformation process of the experimental pipeline.

[0006] It also includes a through pipe section, which is configured as a hollow tube and passes through the first through hole.

[0007] The axial pressurization device includes: a flange, comprising a front flange facing the experimental water tank and a rear flange facing away from the experimental water tank, the front flange and the rear flange being connected together by mounting bolts, the front flange having a second through hole, the front flange being connected to the through pipe section by a connector, the through pipe section corresponding to the second through hole; and a thrust assembly, comprising a thrust rod and a thrust plate, the thrust plate being disposed between the front flange and the rear flange, the thrust plate moving axially along the experimental water tank under the drive of an external drive device, one end of the thrust rod being fixed to the thrust plate, and the other end of the thrust rod passing through the second through hole and the through pipe section to transmit load to the experimental pipe inside the experimental water tank.

[0008] The axial pressurizing device applies a load to the experimental pipe in the experimental water tank through a pipe fixing assembly. The pipe fixing assembly includes a pressure plate and a connecting pipe. The side of the pressure plate facing the axial pressurizing device is fixed to the thrust rod, and the side of the pressure plate facing the experimental pipe is fixed to the connecting pipe. The connecting pipe is used to clamp or release the experimental pipe.

[0009] The experimental tank is equipped with a sand discharge hole at the bottom to clean up the seabed soil left after the experiment.

[0010] A method for testing the overall buckling critical load of a subsea pipeline, using the aforementioned overall buckling test equipment for subsea pipelines, includes: S1, installing the two ends of the test pipeline onto connecting pipes located at both ends, and then laying seabed soil to a predetermined depth in the test tank; S2, installing monitoring components at equal intervals in the middle of the test pipeline to monitor the deformation of the test pipeline in real time; S3, activating an external drive device to drive an axial pressure device, gradually increasing the thrust to push the pressure plate onto the test pipeline with an axial load; S4, analyzing the overall buckling critical axial load of the test pipeline based on the deformation data returned by the monitoring components in S2.

[0011] A method for testing the interaction between a pipe and soil, using the aforementioned overall buckling test equipment for a subsea pipeline, includes: M1, installing the two ends of the test pipeline onto connecting pipes at both ends, and then laying seabed soil to a predetermined depth in the test tank; M2, installing monitoring components at equal intervals in the middle of the test pipeline to monitor the soil resistance during the deformation process of the test pipeline in real time; M3, activating an external drive device to drive an axial pressure device, gradually increasing the thrust to push the pressure plate onto the test pipeline with an axial load; M4, using an external camera to monitor the overall buckling deformation process of the test pipeline and the deformation and failure process data of the seabed soil / sand and gravel in real time; M5, analyzing the overall buckling deformation amount of the test pipeline and the failure mode and magnitude of the soil resistance based on the soil resistance data transmitted back in M2 and the overall buckling deformation process and deformation and failure process data of the seabed soil / sand and gravel transmitted back in M4.

[0012] The beneficial effects of this application are as follows: The overall buckling test device and pipe-soil interaction test method for subsea pipelines can control the pipeline burial depth through the scale lines in the test trench. By placing the thrust rod inside the test trench through a through-pipe section, errors that may be caused by the constraint of the test trench during pipeline buckling deformation can be reduced. The external motor drive of the axial pressurization device can gradually increase the pressure and monitor the pressure loading changes in real time. The critical deformation point of overall pipeline buckling can be detected through dynamic and static strain gauges. The soil resistance variation law of different bending sections during pipeline buckling deformation can be tested through tensile and compressive sensors. The buckling deformation trajectory of the pipeline and the deformation and failure mode of the soil can be monitored through an external camera. This application has the advantages of simple structure, convenient operation, and the ability to simulate the real overall buckling deformation process of subsea pipelines and measure the soil resistance variation law of different buckling sections of the pipeline, thereby deriving a more reliable theoretical model of pipe-soil interaction and providing a basis for the in-situ stability design of pipelines. The overall buckling test apparatus and pipe-soil interaction test method for subsea pipelines proposed in this application can be used not only for lateral buckling tests of subsea pipelines, but also for heave buckling and pipe-soil interaction tests of subsea pipelines. The structure is reasonably designed, has good stability and is easy to implement, which greatly improves the accuracy and reliability of the overall buckling model test of subsea pipelines.

[0013] Instruction manual illustrations

[0014] Figure 1 This is a schematic diagram of the structure of the overall buckling test equipment for the subsea pipeline in this application when one side is transparent;

[0015] Figure 2 This is a schematic diagram of the axial pressurization device in this application;

[0016] Figure 3 This is a schematic diagram of the pipe fixing assembly structure in this application;

[0017] Among them: 1-Experimental water tank, 101-Bracket, 102-Through pipe section, 103-Sand discharge hole, 2-Axial pressurization device, 201-Flange, 202-Thrust rod, 203-Thrust plate, 204-Fastening bolt, 205-Connector, 206-Mounting bolt, 3-Pressure plate, 4-Pipe fixing assembly, 401-Connecting pipe, 402-Threaded ring, 403-Locking mechanism, 404-Locking bolt, 5-Experimental pipe, 6-Monitoring assembly. Specific Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0019] An experimental apparatus for testing the overall buckling of a subsea pipeline includes: an experimental water tank 1, wherein the experimental water tank 1 has first through holes penetrating the sidewalls of the experimental water tank 1 at both ends in the axial direction, and an experimental pipeline 5 is placed inside the experimental water tank 1; an axial pressure device 2, wherein the axial pressure device 2 is configured as two sets and respectively disposed at both ends in the length direction of the experimental water tank 1, the axial pressure device 2 corresponding to the first through holes, and the axial pressure device 2 is used to apply an axial load to the experimental pipeline 5 inside the experimental water tank 1 through the first through holes; and a monitoring component 6, wherein the monitoring component 6 is equally spaced at the middle part of the experimental pipeline 5, and the monitoring component 6 includes dynamic and static strain sensors and / or tensile and compressive force sensors, used to collect the deformation of the experimental pipeline 5 and the soil resistance during the deformation process of the experimental pipeline 5 in real time. The subsea pipeline overall buckling test apparatus and pipe-soil interaction testing method disclosed in this application can control the pipeline burial depth through the scale lines in the test trench. The thrust rod 202 is placed inside the test trench via the through-pipe section 102, reducing errors that may be caused by the constraints of the test trench during pipeline buckling deformation. Pressure can be gradually increased and monitored in real time through an external motor-driven axial pressure device 2. The critical deformation point of overall pipeline buckling can be detected through dynamic and static strain gauges. The soil resistance variation law at different bending sections during pipeline buckling deformation can be tested through tensile and compressive sensors. The buckling deformation trajectory of the pipeline and the deformation and failure mode of the soil can be monitored through an external camera. This application features a simple structure, convenient operation, and the ability to effectively simulate the real overall buckling deformation process of subsea pipelines and measure the soil resistance variation law at different buckling sections, thereby deriving a more reliable theoretical model of pipe-soil interaction and providing a basis for the in-situ stability design of pipelines. The overall buckling test apparatus and pipe-soil interaction testing method for subsea pipelines disclosed in this application can be used not only for lateral buckling tests of subsea pipelines, but also for heave buckling and pipe-soil interaction tests. The apparatus features a reasonable structural design, good stability, and ease of implementation, significantly improving the accuracy and reliability of overall buckling model experiments for subsea pipelines. In practical use, the experimental water tank is supported by bracket 101.

[0020] It also includes a through pipe section 102, which is configured as a hollow tube and passes through the first through hole.

[0021] The axial pressurizing device 2 includes: a flange 201, which includes a front flange facing the experimental water tank 1 and a rear flange facing away from the experimental water tank 1. The front flange and the rear flange are connected together by mounting bolts 206. The front flange is provided with a second through hole and is connected to the through pipe section 102 by a connector 205. The through pipe section 102 corresponds to the second through hole. A thrust assembly includes a thrust rod 202 and a thrust plate 203. The thrust plate 203 is disposed between the front flange and the rear flange. The thrust plate 203 moves axially along the experimental water tank 1 under the drive of an external drive device. One end of the thrust rod 202 is fixed to the thrust plate 203, and the other end of the thrust rod 202 passes through the second through hole and the through pipe section 102 to transmit load to the experimental pipe 5 inside the experimental water tank 1. In actual use, the thrust rod is fixed to the thrust plate by fastening bolts 204.

[0022] The axial pressurizing device 2 applies a load to the experimental pipe 5 in the experimental water tank 1 through the pipe fixing assembly 4. The pipe fixing assembly 4 includes a pressure plate 3 and a connecting pipe 401. The side of the pressure plate 3 facing the axial pressurizing device 2 is fixed to the thrust rod 202, and the side of the pressure plate 3 facing the experimental pipe 5 is fixed to the connecting pipe 401. The connecting pipe 401 is used to clamp or release the experimental pipe 5. In actual use, the connecting pipe 401 is provided with a circular tube-shaped groove and three openable threaded rings 402 connected to it, as well as a locking mechanism 403 and a locking bolt 404. During installation, the locking mechanism 403 is first loosened by the locking bolt 404, the experimental pipe 5 is inserted into the circular tube-shaped groove, and then the locking mechanism 403 is tightened by the locking bolt 404.

[0023] The experimental water tank 1 is equipped with a sand discharge hole 103 at the bottom, which is used to clean up the seabed soil left after the experiment.

[0024] A method for testing the overall buckling critical load of a subsea pipeline, using the aforementioned subsea pipeline overall buckling test equipment, includes: S1, installing the two ends of the test pipeline 5 onto connecting pipes 401 located at both ends, and then laying seabed soil to a predetermined depth in the test tank 1; S2, installing monitoring components 6 at equal intervals in the middle of the test pipeline 5 to monitor the deformation of the test pipeline 5 in real time; S3, activating the external drive device to drive the axial pressure device 2, gradually increasing the thrust so that the thrust rod 202 pushes the pressure plate 3 to apply an axial load to the test pipeline 5; S4, analyzing the overall buckling critical axial load of the test pipeline 5 based on the deformation data transmitted back by the monitoring components 6 in S2.

[0025] A method for testing the interaction between a pipe and soil, using the aforementioned overall buckling test equipment for a subsea pipeline, includes: M1, installing the two ends of the experimental pipeline 5 onto connecting pipes 401 located at both ends, and then laying seabed soil to a predetermined depth in the experimental water tank 1; M2, installing monitoring components 6 at equal intervals in the middle of the experimental pipeline 5 to monitor the soil resistance during the deformation process of the experimental pipeline 5 in real time; M3, activating an external drive device to drive the axial pressure device 2, gradually increasing the thrust so that the thrust rod 202 pushes the pressure plate 3 to apply an axial load to the experimental pipeline 5; M4, using an external camera to monitor the overall buckling deformation process of the experimental pipeline 5 and the deformation and failure process data of the seabed soil / sand and gravel in real time; M5, analyzing the overall buckling deformation amount and the failure mode and magnitude of the soil resistance of the experimental pipeline 5 based on the soil resistance during the deformation process of the experimental pipeline 5 transmitted back in M2 and the overall buckling deformation process and deformation and failure process data of the seabed soil / sand and gravel transmitted back in M4.

Claims

1. A test apparatus for the overall buckling of a subsea pipeline, characterized in that, include: Experimental water tank (1), the experimental water tank (1) has a first through hole through the side wall of the experimental water tank (1) at both ends in the axial direction, and the experimental pipe (5) is placed in the experimental water tank (1); A through pipe section (102) is configured as a hollow tube and passes through the first through hole; An axial pressure device (2) is provided, consisting of two sets located at both ends of the experimental water tank (1) along its length. The axial pressure device (2) corresponds to the first through hole and is used to apply an axial load to the experimental pipe (5) within the experimental water tank (1) through the first through hole. The axial pressure device (2) includes a flange (201) and a thrust assembly. The flange (201) includes a front flange facing the experimental water tank (1) and a rear flange facing away from the experimental water tank (1). The front flange and the rear flange are connected together by mounting bolts (206). A second thrust assembly is provided on the front flange. The front flange is connected to the through pipe section (102) via a connector (205), and the through pipe section (102) corresponds to the second through hole; the thrust assembly includes a thrust rod (202) and a thrust plate (203), the thrust plate (203) is disposed between the front flange and the rear flange, the thrust plate (203) moves axially along the experimental water tank (1) under the drive of an external drive device, one end of the thrust rod (202) is fixed to the thrust plate (203), and the other end of the thrust rod (202) passes through the second through hole and the through pipe section (102) to transmit the load to the experimental pipe (5) in the experimental water tank (1); The monitoring component (6) is arranged at equal intervals in the middle part of the experimental pipe (5). The monitoring component (6) includes dynamic and static strain sensors and tensile and compressive strain sensors, which are used to collect the deformation of the experimental pipe (5) and the soil resistance during the deformation process of the experimental pipe (5) in real time.

2. The overall buckling test equipment for subsea pipelines as described in claim 1, characterized in that, The axial pressurizing device (2) applies a load to the experimental pipe (5) in the experimental water tank (1) through the pipe fixing assembly (4). The pipe fixing assembly (4) includes a pressure plate (3) and a connecting pipe. The pressure plate (3) is fixed to the thrust rod (202) on the side facing the axial pressurizing device (2) and to the connecting pipe on the side facing the experimental pipe (5). The connecting pipe is used to clamp or release the experimental pipe (5).

3. The overall buckling test equipment for subsea pipelines as described in claim 1, characterized in that, The experimental water tank (1) is equipped with a sand discharge hole (103) at the bottom for cleaning the seabed soil left after the experiment.

4. A method for testing the critical buckling load of a subsea pipeline, using the subsea pipeline overall buckling test equipment as described in any one of claims 1-3, characterized in that, include: S1. Install the two ends of the experimental pipe (5) onto the connecting pipes set at both ends, and then lay seabed soil of a preset depth into the experimental water tank (1). S2. Install the monitoring components (6) at equal intervals in the middle of the experimental pipe (5) to monitor the deformation of the experimental pipe (5) in real time. S3. Start the external drive device to drive the axial pressure device (2), and gradually increase the thrust so that the thrust rod (202) pushes the pressure plate (3) to apply axial load to the experimental pipeline (5); S4. Analyze the overall buckling critical axial load of the experimental pipeline (5) based on the deformation data returned by the monitoring component (6) in S2.

5. A method for testing pipe-soil interaction, using the overall buckling test equipment for subsea pipelines as described in any one of claims 1-3, characterized in that, include: M1. Install the two ends of the experimental pipe (5) onto the connecting pipes set at both ends, and then lay seabed soil of a preset depth into the experimental water tank (1). M2. Install the monitoring components (6) at equal intervals in the middle of the experimental pipe (5) to monitor the soil resistance during the deformation process of the experimental pipe (5) in real time. M3. Start the external drive device to drive the axial pressure device (2), and gradually increase the thrust so that the thrust rod (202) pushes the pressure plate (3) to apply axial load to the experimental pipeline (5); M4. Use an external camera to monitor the overall buckling deformation process of the experimental pipeline (5) and the deformation and failure process of the seabed soil / sand and gravel in real time. M5. Based on the soil resistance during the deformation process of the experimental pipeline (5) transmitted back in M2 and the data on the overall buckling deformation process and seabed soil / gravel deformation and failure process of the experimental pipeline (5) transmitted back in M4, analyze the overall buckling deformation amount and the failure mode and magnitude of the soil resistance of the experimental pipeline (5).

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