Browsing by Author "Keawsawasvong, S"

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Consolidation settlement of vertically loaded pile groups in multilayered poroelastic soils
(Elsevier Ltd, 2023-01) Senjuntichai, T; Sornpakdee, N; Keawsawasvong, S; Phulsawat, B; Rajapakse, R.K.N.D.
Pile groups are commonly used as the foundations of many structures including those used in transportation infrastructures. Consolidation settlement of a pile foundation is an important design parameter. A theoretical model is developed in this study to estimate the consolidation settlement and axial load transfer of vertically loaded pile groups in multilayered poroelastic soils. The multilayered saturated soil is modeled according to Biot's poroelasticity theory. In order to determine quasi-static response of pile groups, the interaction problem is first formulated in the Laplace transform domain. Vertical displacement compatibility is enforced at the pile-soil interface to simulate the pile group-soil interaction. Axial deformation of each pile is represented by an exponential series with undetermined coefficients, which are obtained from a variational approach. Vertical displacement influence functions due to a buried uniform vertical load applied to the layered soil are required in the formulation. The application of an exact stiffness matrix method yields the required influence functions. Time-domain solutions are obtained by employing a numerical Laplace inversion method. Numerical results for time-dependent vertical stiffness and consolidation settlement are presented for different pile group configurations, layer profiles, pile elastic moduli and pile lengths.
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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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Vertical Vibration of Multiple Flexible Strip Foundations on Multilayered Transversely Isotropic Poroelastic Soils
(American Society of Civil Engineers, 2021-11-01) Senjuntichai, T; Keawsawasvong, S; Rajapakse, R. K. N. D
In this paper, vertical vibrations of a group of flexible strip foundations on multilayered transversely isotropic poroelastic soils are presented. The dynamic interaction problem is studied by employing a variational approach based on the discretization of the strip-soil contact region. Exact stiffness matrices for each layer and the half-plane are explicitly derived in the Fourier transform space for the first time to determine the influence functions required in the variational scheme. A set of numerical results for the vertical displacement and the bending moment of the foundations are presented to illustrate the influence of governing parameters such as anisotropic properties, foundation rigidity, and distance between strips on the dynamic interaction between foundations.