Mechanical Behavior of Buried Pipelines Subjected to Faults

Xiaolong Wei,Xi Zeng,Wenshuai Jiao,Danfu Zhang,Guofeng Du,Valeria Vignali

doi:10.1155/2021/9984519

Abstract

The length of buried pipelines usually extends thousands of meters or more in engineering, and it is difficult to carry out full-scale tests in the laboratory. Therefore, considering the seriousness of pipeline damage and the difficulty of operating tests and other test limitations, it is necessary to develop a reasonable method to simplify the length of the model for a practical lab test. In this research, an equivalent spring model was established to simulate the small deformation section of the pipeline far away from the fault and the effect of fault displacements, pipeline diameters, wall thicknesses, buried depths, soil materials, and spring constraints on the mechanical properties of pipelines was analyzed. Based on the finite element model using ABAQUS software, the results of the shell model with fixed boundary at both ends were compared; in addition, the dynamic effect of pipelines was investigated. The results show that the two-end spring device can better control the size of the test model and enhance the reliability of the test results. The vibration response of the pipeline mainly depends on the inconsistent movement of soil at both ends of the fault. The analysis results show that choosing a larger pipeline diameter, smaller buried depth, noncohesive backfill soil, and spring with a smaller elastic coefficient is beneficial to reduce pipeline strain and resist pipeline deformation. A simplified formula of the axial compressive strain of buried pipelines across oblique-slip fault is obtained.

Highlights

Introduction e San Fernando earthquake in1971 gave birth to the lifeline earthquake project [1, 2], and much research has been conducted to understand further the action mechanism of the pipeline under fault movement
Based on the finite element model using ABAQUS software, the results of the shell model with fixed boundary at both ends were compared; in addition, the dynamic effect of pipelines was investigated. e results show that the two-end spring device can better control the size of the test model and enhance the reliability of the test results. e vibration response of the pipeline mainly depends on the inconsistent movement of soil at both ends of the fault. e analysis results show that choosing a larger pipeline diameter, smaller buried depth, noncohesive backfill soil, and spring with a smaller elastic coefficient is beneficial to reduce pipeline strain and resist pipeline deformation
Erami et al [3] carried out a full-scale test to study the pipe-soil interaction equation. e experimental results were compared with the results of the computeraided analysis. e results show that the nature of the soil and the connection nodes have a great influence on the pipesoil interaction

Summary

Introduction

Introduction e San Fernando earthquake in1971 gave birth to the lifeline earthquake project [1, 2], and much research has been conducted to understand further the action mechanism of the pipeline under fault movement. Some experimental studies were carried out, mainly including the small-scale test based on shaking tables or the centrifuge device and the full-scale test. Feng et al [4] conducted static and dynamic seismic tests on buried pipelines across faults. Conducted a series of experiments to analyze the behavior of continuous buried pipelines subjected to reverse fault motion and developed a novel experimental device for studying pipelines crossing reverse faults. Zhang et al [6] carried out a full-scale test to study the effect of soil settlement on the pipeline. Zhang et al [7, 8] conducted the shaking table test of buried pipelines under the strike-slip fault and found that the dynamic effect of the pipeline-soil system itself has little effect on the mechanical properties of pipelines. Oskouei et al [12] conducted multiple sets of tests to evaluate the impact of buried depth on the buried steel pipelines crossing the strike-slip faults

Results

Discussion

Conclusion