Research Papers - Department of Civil Engineering

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Subject: search.filters.subject.Anisotropy

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Now showing 1 - 3 of 3
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    Vertical vibrations of an elastic foundation with arbitrary embedment within a transversely isotropic, layered soil
    (Elsevier, 2014) Labaki, J; Mesquita, E; Rajapakse, R. K. N. D
    Analytical methods based on linear elasticity have been used to model the dynamic response of foundations. These solutions commonly assume that soils are isotropic and elastic. Incorporation of anisotropy and the twophased nature of soils (solid skeleton with pores filled with water) is important in the study of dynamic response of foundations. This paper presents the explicit analytical solutions for a transversely isotropic poroelastic soil half-space under a buried time-harmonic vertical load and a time-harmonic pore pressure discontinuity. These versatile fundamental solutions are derived by using Hankel integral transforms. They can be used to analyze a variety of dynamic problems in geomechanics. The fundamental solutions are then applied to solve the timeharmonic vertical vibration of a flexible circular foundation by using variational methods. Selected numerical results are presented to demonstrate the influence of soil anisotropy, poroelasticity, foundation flexibility, depth of embedment and frequency of excitation on the vertical dynamic response of foundation and the force transmitted to soil.
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    Vertical vibration of a circular foundation in a transversely isotropic poroelastic soil
    (Elsevier, 2020-05-01) Senjuntichai, T; Keawsawasvong, S; Rajapakse, R. K. N. D
    Analytical methods based on linear elasticity have been used to model the dynamic response of foundations. These solutions commonly assume that soils are isotropic and elastic. Incorporation of anisotropy and the two-phased nature of soils (solid skeleton with pores filled with water) is important in the study of dynamic response of foundations. This paper presents the explicit analytical solutions for a transversely isotropic poroelastic soil half-space under a buried time-harmonic vertical load and a time-harmonic pore pressure discontinuity. These versatile fundamental solutions are derived by using Hankel integral transforms. They can be used to analyze a variety of dynamic problems in geomechanics. The fundamental solutions are then applied to solve the time-harmonic vertical vibration of a flexible circular foundation by using variational methods. Selected numerical results are presented to demonstrate the influence of soil anisotropy, poroelasticity, foundation flexibility, depth of embedment and frequency of excitation on the vertical dynamic response of foundation and the force transmitted to soil.
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    On a plane crack in piezoelectric solids
    (Pergamon, 2001-10-01) Rajapakse, R. K. N. D; Xu, X-L
    A new analytical solution for a piezoelectric plane with an elliptical void is derived by removing the commonly held assumptions that the void boundary is impermeable and a void axis is perpendicular to the poling direction. The approach of Lekhnitskii's complex potential functions is used in the derivation. Applicability of the common practice of reducing a void solution to a crack solution is examined. It is shown that a recently reported solution for exact electric boundary conditions is actually the well known solution for a permeable crack. A unified formulation for plane cracks containing air or vacuum is then developed to account for different electric boundary conditions. Crack closure is taken into consideration in the analysis. The influence of electric boundary conditions and crack orientation on fracture parameters is discussed.