A refined nonlinear analytical method for buried pipelines crossing strike‐slip faults

Abstract

This paper presents a novel nonlinear governing equation and solution procedure for analyzing a buried pipeline at an active strike‐slip fault crossing. The proposed method includes exact nonlinear axial and nonlinear transverse soil–pipe interaction terms, in addition to geometrical nonlinearity terms in the governing equation. The assumption of partitioning the pipeline into four segments with four governing equations based on the soil yield threshold is removed, and a unified governing equation is introduced. Compared with existing methods, the proposed method has a significantly extended application range with improved accuracy and provides the advantage of including the sliding of buried pipelines within soil, transverse soil spring plasticity, and improved large‐deformation effects including the sliding effect. The solution procedure is improved by removing the optimization steps and external calculations. The proposed method is verified by comparison to a verified finite element‐based model with various fault displacements and angles, and the results are in excellent quantitative and qualitative agreement with the numerical results, even for cases of large fault movement. Finally, criteria for assessing the ovalization damage of buried pipelines are proposed. The proposed method fulfills the missed part of literature, and it is valuable for (1) verification of the nonlinear FEM analysis; (2) fast, economic, and reliable stability analysis and design of buried pipelines; and (3) a strong tool for future developments of buried pipelines seismic design guidelines.

Comparison of 3D Solid and Beam–Spring FE Modeling Approaches in the Evaluation of Buried Pipeline Behavior at a Strike-Slip Fault Crossing

“…As mentioned in Section 1, Talebi and Kiyono [36,37] have extended the linear and nonlinear analytical methods for the stability analysis of buried pipelines at strike-slip faults with high accuracy results. Since, in this paper, the analytical method was just used for the parametric interpretation of the FE analyses results instead of the complex analytical approaches in the papers by [36,37], a simple linear analytical method mentioned by Talebi and Kiyono [42] was employed. A simplified differential equilibrium equation for the pipeline crossing the strikeslip is expressed in Equation (1).…”

“…In 2012, an analytical model based on the stability model of Trifonov and Cherniy [33], including the operational loads (internal pressure and temperature gradient), was developed for the stress-strain analysis of buried pipelines at a fault crossing by Trifonov and Cherniy [35]; however, their study had the same shortcomings as their previous governing differential equation [33]. In 2020 and 2021, Talebi and Kiyono [36,37] introduced a novel nonlinear governing equation that includes the longitudinal sliding behavior of a pipe within soil during large PGDs, lateral elastoplastic soil-pipe interaction springs, and longitudinal forces made by geometrical nonlinearity effects. They removed the unrealistic assumptions and remarkably increased the accuracy and application area of the analytical methods for the problem of buried pipelines at active strike-slip fault crossings.…”

Discrete Element Analysis of Soil-Pipe Interaction Subjected to Normal and Reverse Faulting

“…Suzuki [9] developed a method for calculating the deformation and crosssectional force of a buried pipe subjected to fault displacement by solving the elastic equation of the beam with the range of yielding of the ground as the unknown in a model which treats the buried pipe as an elastic beam and the ground around it as elastoplastic springs. Talebi and Kiyono [10] developed a new governing equation that includes the exact nonlinear axial and transverse soil-pile interaction terms for a strike-slip fault crossing. At present, finite element analysis, in which the pipe and the ground are modeled as a beam element and nonlinear spring, respectively, is commonly used in design practice to evaluate the cross-sectional force generated in buried pipes subjected to fault displacement.…”