Method for calculating pipeline buckling strain and critical fault displacement under faulting

Abstract

The invention belongs to the technical field of petroleum and natural gas industries, and discloses a method for calculating pipeline buckling strain and critical fault displacement under faulting. The method comprises the following steps of: extracting a calculation result through finite element simulation and data analysis; carrying out dimensionless processing on parameters such as a wall thickness, a burial depth, an intersection angle between a pipeline and a fault surface, pipeline internal pressure, a soil compression modulus, soil cohesive force and critical fault displacement by combining a law of influences, on pipeline critical axial strain, of the parameters; and obtaining a critical compression strain regression formula and a critical fault displacement regression formula through multi-element linear regression analysis. According to the method, design strains of pipelines passing through fault areas X80 can be obtained through formula calculation and safety factors, theoretical support and a certain reference value are provided for the strain design standard-based establishment of the pipelines passing through the fault areas, and important reference basis and theoretical support are provided for the design, post-earthquake maintenance and safety analysis of fault buried heavy-caliber gas pipelines.

Description

technical field [0001] The invention belongs to the technical field of petroleum and natural gas industry, in particular to a method for calculating the buckling strain and critical fault displacement of pipelines under fault action. Background technique [0002] Active faults are widely distributed in my country, and long-distance oil and gas pipelines will pass through active fault areas. Most buried pipelines are subject to fracture failure due to permanent ground displacement caused by rupture of crustal rock formations. Under the action of fault dislocation, the pipeline is squeezed by the dislocation of the soil, and the section of the pipeline near the fault plane is greatly deformed. The sharply increased compressive strain leads to shell buckling of the pipeline, which makes the pipeline lose its pressure bearing capacity. In addition, large deformation is also an important cause of circumferential cracks in the pipe wall. Therefore, the study of the critical buckl...

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Problems solved by technology

[0005] Without comprehensive consideration of various influencing factors under the action of earthquake faults, the existing critical buckling strain prediction is not perfect, and cannot meet the needs of strain-based seismic design of pipelines crossing fault areas, and there is no empirically proposed fault corresponding to critical buckling of pipelines based on simulation results The displacement formula provides theoretical support for the safe maintenance of pipelines after earthquakes, resulting in large prediction errors and low prediction accuracy

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