Design method and structure for slowing down frost heaving deformation of pipeline in frozen soil area
By laying an isolation and replacement pad and insulation material layer between the bottom of the pipe trench in the frozen soil area and the oil and gas pipeline, a heat insulation layer is formed, which solves the problem of frozen and swelling deformation of the pipeline in the frozen soil area, and achieves the effect of slowing down or eliminating frozen and swelling deformation, ensuring the safe operation of the pipeline.
Patent Information
- Application Number
- CN202311485339.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-09
- Publication Date
- 2025-05-09
AI Technical Summary
Pipes in frozen soil areas are prone to deformation and damage during the freezing and swelling process, resulting in the threat of the safe operation of the pipeline.
Dig a pipe trench in the frozen soil area, and lay an isolation filling pad and insulation material layer between the bottom of the pipe trench and the oil and gas pipeline to form a complete insulation layer to slow down the freezing and deformation of the pipeline.
By cutting off the moisture migration and ice analysis in the frozen soil near the pipeline area, it can effectively slow down or eliminate the frozen swelling and deformation of the pipeline in the frozen soil area and ensure the safe operation of the pipeline.
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Figure CN119962125A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present disclosure belong to the technical field of oil and gas pipeline design, and specifically relate to a design method and structure for alleviating frost heave deformation of pipelines in frozen soil areas. Background Art
[0002] The design of pipelines in permafrost areas has its own particularity. The operation of pipelines has a great impact on the hydrothermal state of frozen rock and soil around and along the pipeline. Negative temperature media can cause heat loss in the frozen and thawed soil around the pipeline, produce a freezing circle in the surrounding soil, and form strong frost heave, especially in areas with small-scale frost heave mounds and ice mounds with large frost heave deformation, which have a strong impact on pipeline safety; under the combined action of bending additional stress and pipeline oil and gas pressure, the yield stress of the steel pipe can be reached, and the steel pipe begins to enter the plastic yield stage, which will produce plastic deformation and lead to pipeline damage. Given that frost heave damage is one of the biggest threats to the safe operation of pipelines in permafrost areas, it is necessary to propose a design method to slow down the frost heave deformation of pipelines in permafrost areas during the pipeline design stage to avoid frost heave and ensure safe operation of pipelines. Summary of the invention
[0003] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a design method and structure for alleviating frost heave deformation of pipelines in frozen soil areas.
[0004] On the one hand, an embodiment of the present disclosure provides a design method for mitigating frost heave deformation of pipelines in frozen soil areas, including:
[0005] Digging a pipeline trench in the frozen soil area, the pipeline trench is used to accommodate oil and gas pipelines;
[0006] An isolation replacement cushion layer and a thermal insulation material layer are sequentially laid between the bottom of the trench and the oil and gas pipeline along the length direction of the trench;
[0007] The pipe trench is backfilled with backfill soil, so that a complete insulation layer is formed between the bottom of the pipe trench and the oil and gas pipeline, thereby alleviating the frost heave deformation of the oil and gas pipeline.
[0008] Optionally, the isolation replacement cushion layer is filled with filler that is insensitive to frost heave.
[0009] Optionally, the frost heave insensitive filler is prepared by using one or more of crushed stone soil with a fine particle content of less than 15 mm, gravel soil, and sand soil with a fine particle content of less than 5 mm.
[0010] Optionally, the thickness of the isolation replacement cushion layer is not less than 0.3m.
[0011] Optionally, the thermal insulation material layer is a geosynthetic foam thermal insulation material board.
[0012] Optionally, the geosynthetic foam insulation material board is a lightweight filling material, and the lightweight filling material is prepared by using one or more of rigid foam plastic foam, foam concrete and porous concrete.
[0013] Optionally, the thickness of the geosynthetic foam insulation material board is not less than 0.1m.
[0014] Optionally, the geosynthetic foam insulation material board extends beyond the outer diameter of the oil and gas pipeline by 0.4m to 0.6m on both sides along the radial direction of the oil and gas pipeline.
[0015] Optionally, the cross-section of the trench gradually increases in area from the bottom toward the top.
[0016] On the other hand, an embodiment of the present disclosure provides a structure for slowing down the frost heave deformation of a pipeline in a frozen soil area. The structure is obtained by adopting the design method for slowing down the frost heave deformation of a pipeline in a frozen soil area as described above. The structure includes:
[0017] Pipe trenches, dug in permafrost areas and used to house oil and gas pipelines;
[0018] An isolation replacement cushion layer is laid at the bottom of the trench along the length direction of the trench;
[0019] A thermal insulation material layer is laid between the isolation and replacement pad and the oil and gas pipeline along the length direction of the trench;
[0020] Backfill soil is used to backfill the trench.
[0021] The design method and structure for slowing down the frost heave deformation of pipelines in frozen soil areas in the embodiments of the present disclosure can cut off the migration of water and ice analysis in the frozen soil near the pipeline area, thereby slowing down or eliminating the frost heave deformation of pipelines in frozen soil areas while ensuring the laying and installation of the pipelines. The overall structure is simple, the construction is convenient, and it is reliable, stable, and economical. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A schematic flow chart of a design method for alleviating frost heave deformation of pipelines in frozen soil areas according to an embodiment of the present disclosure;
[0023] Figure 2 This is a schematic diagram of a structure for alleviating frost heave deformation of pipelines in frozen soil areas according to another embodiment of the present disclosure. DETAILED DESCRIPTION
[0024] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0025] like Figure 1As shown in the figure, a design method for mitigating the frost heave deformation of pipelines in permafrost areas is proposed to address the frost heave hazards that may be faced by long-distance oil and gas pipelines in permafrost areas.
[0026] Methods include:
[0027] S110. Digging a pipeline trench in the frozen soil area, wherein the pipeline trench is used to accommodate oil and gas pipelines.
[0028] Specifically, in this step, first, a trench for accommodating oil and gas pipelines is dug in the frozen soil area. Long-distance oil and gas pipelines are laid in the trench along the length direction of the trench, and the long-distance oil and gas pipelines are used to transport the required oil and gas. As an example, the cross-section of the trench gradually increases in area from the bottom toward the top, for example, the trench is set as a trapezoidal groove. Of course, the trench can also be set as a groove of other shapes besides the trapezoidal groove, and this embodiment does not impose specific restrictions on this. The trench configured in this way is convenient for laying the isolation replacement pad layer and the thermal insulation material layer that appear below, and can reduce the use of the isolation replacement pad layer and the thermal insulation material layer, reduce cost expenditure, and can also reduce the area between the bottom of the trench and the oil and gas pipeline, increasing the effect of heat insulation and heat preservation.
[0029] S120, laying an isolation replacement cushion layer and a thermal insulation material layer in sequence between the bottom of the trench and the oil and gas pipeline along the length direction of the trench.
[0030] Specifically, in this step, an isolation replacement pad is laid at the bottom of the trench along the length of the trench, and a thermal insulation material layer is laid on the isolation replacement pad along the length of the trench, and the oil and gas pipeline is supported on the thermal insulation material layer. This design can form a complete insulation layer between the bottom of the trench and the oil and gas pipeline, effectively reducing the frost heave effect of the frozen soil layer under the oil and gas pipeline.
[0031] Exemplarily, the isolation replacement pad is filled with frost-insensitive fillers, and the insulation material layer is a geosynthetic foam insulation material board. From the perspective of cutting off the water migration and ice analysis in the frozen soil near the pipeline area, by setting a geosynthetic foam insulation material board between the bottom of the trench and the oil and gas pipeline, and setting an isolation replacement pad at the same time, and replacing the frost-insensitive filler, it is possible to effectively cut off the water migration and ice analysis in the frozen soil near the pipeline area, so as to achieve the effect of effectively slowing down the frost heave deformation of the pipeline in the frozen soil area. The composite method of using geosynthetic foam insulation material boards and isolation replacement pads filled with frost-insensitive fillers fully integrates and utilizes the advantages of both, and the synergistic effect maximizes the efficacy, so as to slow down or eliminate the frost heave deformation of the pipeline in the frozen soil area while ensuring the laying and installation of the pipeline.
[0032] Exemplarily, the frost heave insensitive filler is prepared by using one or more of crushed stone soil with a fine particle content of less than 15 mm, gravel soil, and sand soil with a fine particle content of less than 5 mm. It should be noted that, based on the understanding of the frost heave mechanism and the interaction between pipes and soil in frozen soil areas, this embodiment designs a suitable frost heave insensitive filler, so as to effectively slow down the frost heave deformation of pipes in frozen soil areas through the composite effect of the isolation replacement cushion layer and the geosynthetic foam insulation material board.
[0033] As a specific example, the thickness of the isolation replacement pad is not less than 0.3m. Of course, the thickness of the isolation replacement pad can be calculated and determined according to the actual pipeline working conditions according to the following formula to design a suitable isolation replacement pad thickness to ensure that the bottom of the trench does not freeze. The calculation formula is as follows:
[0034]
[0035] Where: h m is the thickness of the isolation replacement cushion, h t is the frost heave of the frozen soil layer, Φ is the load correction coefficient, d is the particle size of the isolation and replacement cushion layer, and f is the average frost heave strength of the frozen soil.
[0036] Exemplarily, the geosynthetic foam insulation material board is a lightweight filling material, and the lightweight filling material is prepared by one or more of rigid foam plastic foam, foam concrete and porous concrete. As a specific example, the thickness of the geosynthetic foam insulation material board is not less than 0.1m. Of course, the thickness of the geosynthetic foam insulation material board can be calculated and determined according to the actual pipeline working conditions according to the following formula to design a suitable thickness of the geosynthetic foam insulation material board. The calculation formula is as follows:
[0037]
[0038] Where: h b is the thickness of geosynthetic foam insulation board, h t is the frost heave of the frozen soil layer, Φ is the load correction coefficient, K is the thermal conductivity of geosynthetic foam insulation material, and f is the average frost heave strength of the frozen soil.
[0039] Furthermore, the geosynthetic foam insulation material board exceeds the outer diameter of the oil and gas pipeline by 0.4m to 0.6m on both sides along the radial direction of the oil and gas pipeline. For example, in the radial direction of the oil and gas pipeline parallel to the geosynthetic foam insulation material board, the geosynthetic foam insulation material board exceeds the outer diameter of the oil and gas pipeline by 0.4m to 0.6m on both sides. As a specific example, the geosynthetic foam insulation material board exceeds the outer diameter of the oil and gas pipeline by 0.5m on both sides. It should be noted that the geosynthetic foam insulation material board replaces the backfill soil in contact with the bottom of the oil and gas pipeline, and the geosynthetic foam insulation material board directly contacts and supports the oil and gas pipeline, which can form an insulation layer in the bottom area of the pipeline, effectively reducing the frost heave effect of the soil layer under the bottom of the pipe.
[0040] S130, backfilling the pipe trench with backfill soil to form a complete insulation layer between the bottom of the pipe trench and the oil and gas pipeline, thereby alleviating the frost heave deformation of the oil and gas pipeline.
[0041] Specifically, in this step, after the isolation and replacement cushion layer, the insulation material layer and the oil and gas pipeline are laid in the trench, the trench is backfilled with backfill soil to complete the design scheme for slowing down the frost heave deformation of the pipeline in the frozen soil area. The complete insulation layer formed between the bottom of the trench and the oil and gas pipeline can effectively slow down the frost heave deformation of the oil and gas pipeline.
[0042] The design method for slowing down the frost heave deformation of pipelines in frozen soil areas in the embodiments of the present disclosure can effectively cut off the migration of moisture and ice analysis in the frozen soil near the pipeline area by designing an isolation replacement cushion layer and a thermal insulation material layer between the bottom of the trench and the oil and gas pipeline, thereby achieving the effect of effectively slowing down the frost heave deformation of pipelines in frozen soil areas. It can slow down or eliminate the frost heave deformation of pipelines in frozen soil areas while ensuring the laying and installation of pipelines. The overall structure is simple, the construction is convenient, and it is reliable, stable, and economical.
[0043] On the other hand, reference Figure 2 , an embodiment of the present disclosure provides a structure for slowing down the frost heave deformation of pipelines in frozen soil areas, and the structure is obtained by adopting the design method for slowing down the frost heave deformation of pipelines in frozen soil areas as described above. The specific steps of the design method for slowing down the frost heave deformation of pipelines in frozen soil areas can refer to the relevant records in the previous text, and will not be described in detail here. The structure includes: a trench 130 excavated in the frozen soil area 110 and used to accommodate the oil and gas pipeline 120. An isolation replacement pad 140 laid at the bottom of the trench 130 along the length direction of the trench 130. A thermal insulation material layer 150 laid between the isolation replacement pad 140 and the oil and gas pipeline 120 along the length direction of the trench 130, and backfill soil 160 for backfilling the trench 130.
[0044] The structure for slowing down the frost heave deformation of pipelines in frozen soil areas in the embodiments of the present disclosure can effectively cut off the migration of water and ice analysis in the frozen soil near the pipeline area through the isolation replacement cushion layer and the thermal insulation material layer designed between the bottom of the trench and the oil and gas pipeline, thereby achieving the effect of effectively slowing down the frost heave deformation of pipelines in frozen soil areas, and slowing down or eliminating the frost heave deformation of pipelines in frozen soil areas while ensuring the laying and installation of pipelines. The overall structure is simple, the construction is convenient, and it is reliable, stable, and economical.
[0045] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.
Claims
1. A design method for slowing down the frost heave deformation of pipelines in frozen soil areas, characterized in that: include: Digging a pipeline trench in the frozen soil area, the pipeline trench is used to accommodate oil and gas pipelines; An isolation replacement cushion layer and a thermal insulation material layer are sequentially laid between the bottom of the trench and the oil and gas pipeline along the length direction of the trench; The pipe trench is backfilled with backfill soil, so that a complete insulation layer is formed between the bottom of the pipe trench and the oil and gas pipeline, thereby alleviating the frost heave deformation of the oil and gas pipeline.
2. The design method for mitigating frost heave deformation of pipelines in frozen soil areas according to claim 1 is characterized in that: The isolation replacement cushion layer is filled with filler that is insensitive to frost heave.
3. The design method for mitigating frost heave deformation of pipelines in frozen soil areas according to claim 2 is characterized in that: The frost heave insensitive filler is prepared by using one or more of crushed stone soil with a fine particle content of less than 15 mm, gravel soil, and sand soil with a fine particle content of less than 5 mm.
4. The design method for mitigating frost heave deformation of pipelines in frozen soil areas according to claim 1 is characterized in that: The thickness of the isolation and replacement cushion layer is not less than 0.3m.
5. The design method for slowing down frost heave deformation of pipelines in frozen soil areas according to any one of claims 1 to 4, characterized in that: The thermal insulation material layer is a geosynthetic foam thermal insulation material board.
6. The design method for mitigating frost heave deformation of pipelines in frozen soil areas according to claim 5 is characterized in that: The geosynthetic foam insulation material board is a lightweight filling material, and the lightweight filling material is prepared by using one or more of rigid foam plastic foam, foam concrete and porous concrete.
7. The design method for mitigating frost heave deformation of pipelines in frozen soil areas according to claim 5 is characterized in that: The thickness of the geosynthetic foam insulation material board is not less than 0.1m.
8. The design method for mitigating frost heave deformation of pipelines in frozen soil areas according to claim 7 is characterized in that: The geosynthetic foam insulation material board extends beyond the outer diameter of the oil and gas pipeline by 0.4m to 0.6m on both sides along the radial direction of the oil and gas pipeline.
9. The design method for mitigating frost heave deformation of pipelines in frozen soil areas according to any one of claims 1 to 4, characterized in that: The cross-section of the pipe trench gradually increases in area from the bottom toward the top.
10. A structure for slowing down the frost heave deformation of pipelines in frozen soil areas, characterized in that: The structure is obtained by adopting the design method for slowing down the frost heave deformation of pipelines in frozen soil areas according to any one of claims 1 to 9, and the structure comprises: Pipe trenches, dug in permafrost areas and used to house oil and gas pipelines; An isolation replacement cushion layer is laid at the bottom of the trench along the length direction of the trench; A thermal insulation material layer is laid between the isolation and replacement pad and the oil and gas pipeline along the length direction of the trench; Backfill soil is used to backfill the trench.