A discussion of a paper with the aforementioned title by Pietruszczak and Pande, published in this journal (Volume 122, Number 1, January 1996), is presented. Discusser Day acknowledges the authors' work in developing a theoretical model to predict the behavior of soil containing gas bubbles. He states that the authors' models predicts a marginal increase in the undrained shear strength with increase in the gas content. Day reports, however, that laboratory tests performed on clays from the field show the opposite effect. A decrease in the undrained shear strength is noted with an increase in gas content due to sampling. Discussion is followed by closure from the authors.

Constitutive relations for partially saturated soils containing gas inclusions. discussion and closure

A 3D analytical model for distributed low strain test and parallel seismic test of pipe piles

Studies associated with dynamic plate–medium interactions generally assumed the plate structures to be permeable for the sake of convenience. But the effect and applicability of such an assumption are still unclear, and then the pore fluid pressure on the plate and medium interfaces cannot be obtained. In this paper, the mentioned problems are discussed by studying the coupling steady-state vibration of an impermeable, rigid, circular plate resting on a finite, fluid-saturated, poroelastic soil layer underlain by rigid base and subjected to a vertical time-harmonic loading. The semi-analytical solutions for the dynamic compliance, displacements, stresses, especially the contact stress including effective stress and pore fluid pressure of the plate and the layer, are proposed. In developing these solutions, the linearly poroelastic model established by de Boer is used to describe the mechanical behaviour of the porous medium. By means of four scalar displacement potentials and the Fourier–Hankel transformation to solve the equations of motion of the poroelastic layer, and then imposing boundary and interfacial conditions, a pair of coupling Fredholm’s integral equations of the second kind formulating the plate–medium interaction are derived and evaluated with numerical methods. The proposed solutions are then verified by comparing with the existing special solutions and the FEM calculation results. Numerical examples are also performed to examine the effects of the permeability of both the plate and the poroelastic layer and the thickness of the layer on the dynamic response of the coupling system.

Vertical time-harmonic coupling vibration of an impermeable, rigid, circular plate resting on a finite, poroelastic soil layer

Vertical and torsional vibrations of a rigid circular disc on a transversely isotropic and layered half-space with imperfect interfaces

Effects of inner soil on the vertical dynamic response of a pipe pile embedded in inhomogeneous soil

Vertical vibration of a partially embedded pile group in transversely isotropic soils

Vertical vibration of a pile in transversely isotropic multilayered soils

Axisymmetric vibration of an elastic circular plate bonded on a transversely isotropic multilayered half-space

This paper focuses on the investigation of the response of a vertically loaded rigid circular disc embedded in a transversely isotropic multilayered half-space. The solutions for this dynamic interaction problem are obtained by utilizing the boundary element method, which takes the analytical layer-element solution of the transversely isotropic multilayered half-space subjected to an interior ring time-harmonic loading as the fundamental solution. The accuracy of present solutions is verified by the comparisons with existing solutions. In addition, selected numerical results are presented to illustrate the influence of embedded depth, frequency of excitation, material anisotropy and layering of the embedding medium on vertical impedance and resultant contact stresses.

Chun Lin Liu

Papers

Vertical vibration of a partially embedded pile group in transversely isotropic soils

Vertical vibration of a pile in transversely isotropic multilayered soils

Axisymmetric vibration of an elastic circular plate bonded on a transversely isotropic multilayered half-space

Dynamic analysis of a vertically loaded rigid disc in a transversely isotropic multilayered half-space

Dynamic impedance of a pipe pile in layered soils under vertical excitations