Mechanical response of buried X70 pipelines rolled by heavy-duty vehicles

Abstract

[Objective] With the ongoing urbanization in China, the frequency of heavy-duty vehicles traversing buried pipelines is steadily increasing. Therefore, it is of paramount importance to investigate the mechanical response patterns of buried pipelines subjected to heavyduty vehicle rolling in order to ensure the safety of oil and gas pipelines. [Methods] Field tests were conducted to investigate the rolling of heavy-duty vehicles on a buried X70 pipeline. Strain gauge technology was employed to gather pipeline response data and summarize the response patterns of soil pressure and axial stress. Additionally, an ABAQUS software-based finite element simulation model was established to simulate the soil-pipeline interaction using a nonlinear contact model. The vehicle load was simplified as the dead load of a moving plane source, and a DLOAD subprogram was developed to implement the loading. Subsequently, simulations were conducted based on the test conditions. [Results] The results demonstrated a negligible deviation between the simulated and tested values of the additional axial stress in the pipeline. Furthermore, the simulated distribution patterns of soil pressure and axial stress aligned with those observed in the tests, thus the response patterns of soil pressure and axial stress were verified. Based on the verified finite element model, the impact of six parameters, i.e.,vehicle load, vehicle speed, pipe diameter, pipe wall thickness, fill height, and pipeline internal pressure, on the axial stress of the pipeline was explored through simulation by employing a single-variable approach. [Conclusion] The topsoil pressure and axial stress at the section beneath the crawler belts on both sides are higher than those at the central section. Conversely, the bottom axial stress is lower than that at the central section. Augmenting the pipe diameter, pipe wall thickness, or fill height can diminish the additional axial stress induced by vehicle rolling on the pipeline. However, altering the vehicle speed and pipeline internal pressure does not yield significant effects on the axial stress.The obtained mechanical response patterns of the buried pipeline can be used as a reference for evaluating the safety margin of pipelines under heavy-duty vehicle rolling.

Keywords

• buried pipeline
• vehicle rolling
• field test
• finite element simulation
• mechanical response