Numerical Modeling of Mechanical Behavior for Buried Steel Pipelines Crossing Subsidence Strata

Area of Science:

• Geotechnical Engineering
• Mechanical Engineering
• Materials Science

Background:

• Buried steel pipelines are critical infrastructure susceptible to mechanical stress from ground subsidence.
• Understanding pipeline-soil interaction under large strain and inelastic conditions is essential for structural integrity.

Purpose of the Study:

• To investigate the mechanical behavior of buried steel pipelines crossing subsidence strata.
• To analyze the influence of various parameters on pipeline response under subsidence conditions.

Main Methods:

• Numerical simulation using the finite element method (FEM).
• Modeling nonlinear responses, large strain and displacement, inelastic material behavior, and pipeline-soil interface contact/friction.
• Parametric study including strata subsidence, diameter-thickness ratio, buried depth, internal pressure, friction coefficient, and soil properties.

Main Results:

• Maximum strain occurs at the outer transition subsidence section, leading to a concave cross-section.
• Increased strata subsidence and diameter-thickness ratio elevate out-of-roundness, longitudinal strain, and equivalent plastic strain.
• Greater buried depth reduces deflection, out-of-roundness, and strain; internal pressure and friction have minimal impact on deflection but affect out-of-roundness and strain.
• Soil properties significantly influence pipeline mechanical behavior.

Conclusions:

• Strata subsidence and pipeline geometry are primary drivers of mechanical stress.
• Pipeline design and maintenance strategies must consider soil properties and burial depth for optimal performance.
• The findings support the development of optimized designs and preventive maintenance for buried steel pipelines.