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Numerical simulations of two-dimensional saturated granular media

Citation

Tan, Phalkun (1990) Numerical simulations of two-dimensional saturated granular media. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-06232005-154613

Abstract

The liquefaction phenomenon in soil has been studied in great detail during the past 20 years. The need to understand this phenomenon has been emphasized by the extent of the damages resulting from soil liquefaction during earthquakes. Although an overall explanation exists for this phenomenon through the concept of effective stress, the basic mechanism of loss of strength of the soil skeleton has not been thoroughly examined and remains unclear.

The present study proposes a numerical model for simulations of the behavior of saturated granular media. The model was developed with two main objectives:

1. To represent the mechanical response of an assemblage of discrete particles having the shape of discs.

2. To model and represent the interaction of interstitial pore fluid present with the idealized granular media.

The representation of the solid skeleton is based on Cundall and Strack's distinct element model, in which discrete particles are modelled as discs in two dimensions, each obeying Newton's laws. Interparticle contacts consisting of springs and frictional element dashpots are included. Assuming a Newtonian incompressible fluid with constant viscosity and density, and quasi-steady flow, the fluid phase is described by Stokes' equations. The solution to Stokes' equations is obtained through the boundary integral element formulation. Several validation test cases are presented along with four simple shear tests on dry and saturated granular assemblages. For these last four tests, the numerical results indicate that the model is able to represent qualitatively the behavior of real soil, while at the same time clarifying the processes occurring at the microscale that influence soil response.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Civil Engineering
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Scott, Ronald F.
Thesis Committee:
  • Unknown, Unknown
Defense Date:31 October 1989
Record Number:CaltechETD:etd-06232005-154613
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-06232005-154613
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2704
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:24 Jun 2005
Last Modified:26 Dec 2012 02:53

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