Gaëlle Lefeuve-Mesgouez

Surface vibration due to a sequence of high speed moving harmonic rectangular loads

The transmission of vibrations over the surface of the ground, due to high-speed moving, vertical harmonic rectangular loads, is investigated theoretically. The problem is three-dimensional and the interior of the ground is modelled as an elastic half-space or a multilayered ground. The transformed solutions are obtained using the Fourier transform on the space variable. A new damping model in the spatial wavenumber domain, presented in Lefeuve-Mesgouez et al. [J. Sound. Vibr. 231 (2000) 1289] is used. Numerical results for the displacements on the surface are presented for loads moving with speeds up to and beyond the Rayleigh wave speed of the half-space.

Three-dimensional dynamic response of a porous multilayered ground under moving loads of various distributions

This paper presents a three-dimensional semi-analytical approach to study the displacements induced by harmonic loads moving at constant speed over the surface of a poroviscoelastic multilayered half-space. The load distribution is considered either as a rectangular load moving straight over the soil or moving on a beam resting on the ground. The displacements in the wavenumber domain are expressed in terms of incident and reflected waves in each layer. An assembly process is used to deal with the multilayered system. Numerical results for both sub- and super-Rayleigh regimes are presented in the wavenumber and spatial domains.

An improved dynamic model for the study of a flexible pavement

This paper introduces the semi-analytical and finite element models implemented to study a Falling Weight Deflectometer test conducted on a flexible pavement. These dynamic models take into account the effects of both Rayleigh damping in soil and viscous damping in bituminous materials, with respect to temperature, on structural deflection. Moreover, numerical results have been compared with in situ measurements recorded on an instrumented pavement. Results from numerical models showed the importance of taking into account the effect of damping (hysteretic or viscoelastic) of all layers of the pavement against temperature, loading and mechanical parameters. The parametric analysis introduced as a basis for future development of a dynamic backcalculation program.

Numerical modelling of poroviscoelastic grounds in the time domain using a parallel approach

In this paper, we present a parallelized finite element code developed to study wave propagation phenomena, specifically in porous soils problems which usually require millions of degrees of freedom. The parallelization technique uses an algebraic grid partitioning managed by a Single Program Multiple Data (SPMD) programming model. Message Passing Interface (MPI) library specification is the standard used to exchange data between processors. The architecture of the code is explained and numerical results show its performance.

Simulation of transient mechanical wave propagation in heterogeneous soils

A Finite Element Method using a C++ code is developed to study the mechanical wave propagation in saturated porous soils. The modelization uses the complete Biot theory including the couplings between the solid and fluid phases. A matrix-free algorithm and a selection data technique are implemented in the code. Researches are focused on homogeneous and heterogeneous semi-infinite media in the case of transient regimes. The time domain results present the displacements over and within the half-space. In particular, we will see that the fluid wave front is strongly dependent on the proportion of heterogeneities in the ground.