UM E-Theses Collection (澳門大學電子學位論文庫)
Title
Application of Bayesian model class selection on differential problems in geotechnical engineering
English Abstract
Researches on nonlinear behavior of soil are significant since many studies in civil engineering rest on it. Derivative calculation on nonlinear behavior is frequently encountered in soil mechanics such as the evaluation of dilatancy and shear modulus from the strain-stress behavior of geomaterials. Experimental data are acquired in discrete form and contaminated by noise so direct finite difference calculation is well known to be unreliable. In this thesis, a Bayesian nonparametric methodology is proposed for derivative computation. The raw data will first be transformed to satisfy some periodicity conditions in order to avoid the error induced by the Gibbs phenomenon. Model class candidates are then constructed based on partial Fourier series. Bayesian inference provides the quantitative criterion to choose the most suitable model for curving fitting. The derivative can be computed directly by differentiating the chosen model. Especially to poor quality measurements with large noises and non-uniform intervals, the proposed approach can provide satisfying data-fitting results and derivative computation. The proposed method is applied on three examples in this thesis. Two illustrative examples are discussed to verify the efficiency and robustness of the methodology. One set of data coming from pressuremeter tests are processed in order to obtain the shear stress-strain relationship and secant shear modulus reduction curves which are the main aims herein. Only the first order derivatives are involved in this thesis. Key words: Bayesian inference; Fourier series; model class selection; numerical differentiation; shear stress-cavity strain relationship; normalized modulus reduction curves
Issue Date
2012
Author
Zhang, Li Zhi
Faculty
Faculty of Science and Technology
Department:
Department of Civil and Environmental Engineering
Degree
M.Sc.
Subject
Civil Engineering -- Department of Civil and Environmental Engineering
Soil stabilization
Soil consolidation
Engineering geology

Supervisor
Yuen Ka Veng
Library URL
b2590616
Files In This Item:
TOC & Abstract
Full-text
Location
1/F Zone C
Supervisor
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