Novel Remediation for Buried Pipelines under Ground Deformation

• Author / Creator

  Ilozumba, Eziolu SI

• Buried pipeline systems often transverse regions with a wide variety of soil types, geological conditions, or regions of varying seismicity, exposing these buried infrastructures to severe geohazards that pose a significant amount of risk to their structural and mechanical integrity. The performance of these buried pipelines is a crucial engineering consideration in the oil and gas industry because its failure can cause severe risks to public safety and properties. Although pertinent efforts have been made to curb these pipeline incidents caused by abrupt ground movements, the existing solutions are deemed costly or inefficient.
  This study focused on the development of an efficient mitigation method expected to address high construction or upgrade costs for buried pipelines undergoing ground deformation. This study proposed a novel mitigation technique that involves altering the boundary condition of buried pipelines with adjacently installed special geomaterial blocks (SGB). The proposed geomaterial involves a set of EPS geofoams and lightweight polypropylene squared plastic boxes designed to act as voids between the EPS geofoam blocks. The SGB was oriented such that the orthotropic mechanical property of these SGB allows the pipe to move laterally, accommodating a significant amount of ground deformation without developing significant reactions while reducing the ground-induced forces on the pipe. Firstly, the mitigation technique is first presented, followed by the experimental test program developed to evaluate the beneficial effects of the SGB on the local pipe response when subjected to lateral and oblique displacements. In addition, a simplified spring-based analytical modelling approach was proposed for predicting the force-displacement response of the pipe-SGB-soil assembly with emphasis on the interaction between the pipe and soil under the new boundary condition. The analytical model is validated using the experimental test data.
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  Secondly, six full-scale experimental test programs were developed to evaluate the beneficial effects of the SGB on the pipe response when subjected to lateral and oblique displacements; following these tests, a simple yet efficient finite element model was proposed to numerically simulate the pipe -SGB -soil interaction under lateral soil displacement. The result of the numerical model was validated using the data obtained from the experimental tests. The results of laboratory testing and numerical simulations confirm the efficiency of the proposed remediation technique in improving the structural integrity of buried pipelines.

• Subjects / Keywords

  • Buried pipelines
  • Ground deformation
  • Experimental testing
  • SGB
  • Geohazards
  • Geomaterial

• Graduation date

  Fall 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-8ydr-yt58

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.