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Reduced-Order Model for Dynamic Soil-Pipe Interaction Analysis


Nguyen, Kien Trung (2020) Reduced-Order Model for Dynamic Soil-Pipe Interaction Analysis. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/mekk-dc25.


Pipelines are very vulnerable infrastructure components to geohazard-induced ground deformation and failure. How soil transmits loads on pipelines and vice versa, known as soil-pipe interaction (SPI), thus is very important for the assessment and design of resilient pipeline systems.

In the first part, this work proposes a simplified macroelement designed to capture SPI in cohesionless soils subjected to arbitrary loading normal to the pipeline axis. We present the development of a uniaxial hysteresis model that can capture the smooth nonlinear reaction force-relative displacement curves (FDCs) of SPI problems. Using the unscented Kalman filter, we derived the model parameter κ that controls the smoothness of the transition zone from linear to plastic using published experimental data. We extended this uniaxial model to biaxial loading effects and showed that the macroelement can capture effects such as pinching and shear-dilation coupling. The model input parameters were calibrated using finite element (FE) analyses validated by experiments. The FDCs of the biaxial model were verified by comparison with FE and smoothed-particle hydrodynamic (SPH) simulations for different loading patterns: cyclic uniaxial, 0-shaped, 8-shaped, and transient loading. Accounting for smooth nonlinearity, hysteresis, pinching, and coupling effects, the proposed biaxial macroelement shows good agreement with FE and SPH analyses, while maintaining the computational efficiency and simplicity of beam-on-nonlinear-Winkler foundation models, as well as a small number of input parameters.

Next, this work presents analytical solutions for computing frequency-domain axial and in-plane soil impedance functions (SIFs) for an infinitely long rigid circular structure buried horizontally in homogeneous elastic half-space. Using Hankel— and Bessel—Fourier series expansion, we solved a mixed-boundary-value problem considering a harmonic displacement at the structure boundary and traction-free boundary condition at the half-space free surface. We then verified our analytical solutions using results obtained from FE simulations. The SIFs of a buried structure in a homogeneous elastic half-space calculated by these two approaches are in perfect agreement with each other. In addition, we used analytical solutions and FE simulations to comprehensively investigate factors that affect the SIFs in homogeneous and two-layered half-spaces, respectively. The parametric study shows that SIFs of buried structures in elastic half-space primarily depend on frequency of excitation, shear modulus and Poisson's ratio of the half-space, burial depth and radius of the structure. In a two-layered soil domain, SIFs depend also on material contrast and the distance from the structure location to the interface between soil layers.

Lastly, it demonstrates how the SIFs obtained previously can be incorporated into a reduced-order model to analyze SPI problems, specifically a straight pipe subjected to Rayleigh surface wave propagating through homogeneous and heterogeneous elastic half-spaces. Calculated displacement time histories at the control points are shown to agree well with those computed by direct two-dimensional FE analyses.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:reduced-order model, soil-pipe interaction, buried structures, soil impedance function, analytical solution, finite element analysis, earthquake engineering
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Civil Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Asimaki, Domniki
Thesis Committee:
  • Andrade, Jose E. (chair)
  • Daraio, Chiara
  • Hall, John F.
  • Asimaki, Domniki
Defense Date:15 May 2020
Non-Caltech Author Email:kien.nguyen.tru (AT)
Funding AgencyGrant Number
Vietnam Education FoundationUNSPECIFIED
Hellwig Graduate FellowshipUNSPECIFIED
George W. Housner Graduate FellowshipUNSPECIFIED
Record Number:CaltechTHESIS:06012020-154218098
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Ch. 2 adapted for Ch. 2
https://10.1201/9780429031274DOIArticle adapted for Ch. 2
Nguyen, Kien Trung0000-0001-5761-3156
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13762
Deposited By: Trung Kien Nguyen
Deposited On:02 Jun 2020 22:01
Last Modified:28 Oct 2021 22:30

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