DYNAMIC RESPONSE OF SHALLOW FOUNDATIONS ON REINFORCED SOIL WITH RIGID INCLUSIONS

The soil-improvement technique by rigid inclusions represents today a practical, economical and time-saving solution that allows the use of shallow foundations on compressible soils. Several studies have recently focused on the static behavior of this reinforcement system (i.e. ASIRI French national project), however, its seismic performance has not yet received the same amount of attention. This paper presents a state of the art in the dynamic soil-structure interaction (SSI) analysis of structures supported on shallow foundations on reinforced soil with rigid inclusions. Special attention is given to the calculation methods that are currently being used in design offices. A parametric study is conducted by means of 3D numerical models and the hybrid BEM-FEM method in order to highlight the possibilities and limitations of these methods, especially for the study of inertial and kinematic interaction effects. Different configurations of rigid inclusions are studied, including several lengths, spacing and foundation layout. The results of this parametric study are compared to those obtained for equivalent shallow and deep foundations in terms of impedance functions and kinematic interaction factors. Finally, a discussion on different aspects that may control the dynamic linear and non-linear response of these foundation systems is undertaken.