EFFECTS OF NON-LINEAR SOIL BEHAVIOUR ON THE SEISMIC RESPONSE OF MULTI-STOREY SHALLOW UNDERGROUND STRUCTURES

The assessment of the seismic behaviour of underground structures is one of the most current research topics in seismic geotechnical and structural engineering due to the complex soil-structure interaction phenomena that are involved. In the last decades, several numerical approaches, more or less simplified, have been developed to evaluate the seismic behaviour of these structures, especially following the significant damage observed after recent strong earthquakes. In parallel, the International Codes have begun to address to the concepts of seismic design. Despite the significant progress made, several uncertainties remain regarding the correct representation of the seismic behaviour of underground structures. The paper presents the main results of nonlinear analyses performed to evaluate the seismic behaviour of a multi-storey, shallow underground structure embedded in coarse grained soils varying seismic intensity. The results are compared with those obtained for the same models using linear model both for soil and structure behaviour, in order to assess the influence of the non-linearity of the seismic response on the magnitude of the stresses acting on the concrete retaining walls