Response of buried pipelines subjected to ground subsidence using a nonlinear Pasternak approach

Abstract

Pipelines, vital for transporting resources, face significant structural challenges due to ground movement. Many studies have been conducted to examine the impact of ground subsidence on pipelines, each aiming to improve our understanding of soil-pipe interaction using various techniques. Commonly, Winkler or Pasternak models are adopted to account for the interaction between the pipeline and its supporting soil. However, these models fall short in addressing the inherent nonlinearity of the supporting soil, which may lead to considerable inaccuracies. To address these limitations, a nonlinear Pasternak model is developed in this research that is capable of capturing the nonlinearity of the soil supporting the pipelines. Besides, the settlement trough is appropriately modeled to consider the surface subsidence profile. The nonlinear soil behavior is modeled using a hyperbolic load-settlement relationship while the pipeline is represented by an Euler-Bernoulli beam. Validation of the model is carried out against centrifuge test data that confirm the model’s capability to accurately simulate displacements and bending moments along the pipe. A parametric study highlights that higher soil bearing capacity and initial subgrade reaction modulus lead to reduced deflection and internal forces in the pipeline. Additionally, the results indicate a threshold for the soil’s bearing capacity beyond which variation in the vertical displacements and bending moments is minimal. Also, an increase in the distance between the inflection point and maximum settlement of the subsidence profile results in higher pipeline deflection, bending moments, and shear forces. Furthermore, using Genetic Programming, empirical equations are derived that offer reliable estimates for the maximum vertical displacement, bending moment, and shear force, providing practical tools for pipeline design in subsidence-prone areas.