Evaluation of the seismic behavior of multi-propped shallow underground structures embedded in granular soils: A comparison between coupled and decoupled approaches

The evaluation of the seismic behavior of underground structures represents one of the most actual seismic geotechnical and structural engineering research topics about the study of the complex phenomena of soil-structure interaction. In the last decades, different types of simplified and numerical approaches have been developed for the evaluation of the seismic behavior of these structures, especially after the recent strong earthquakes where they have been subjected to significant damages. In the same way, in the last few years, the International Codes are beginning to pay attention to the concepts of their seismic design. Despite the significant development of knowledge still remain open several uncertainties of the correct reproduction of the underground structures behavior under seismic load. The paper presents the main results of the comparison between coupled and decoupled approach used for the evaluation of the seismic behavior of multi-propped shallow underground structure embedded in granular soils, considering four homogeneous soil profiles characterized by a different value of shear wave velocity and five natural accelerograms included within the European Strong Motion Database. The results of the analysis show the influence of the soil characteristics related to the seismic signal parameters on the seismic response of the structure in terms of maximum bending moment acting on the concrete retaining walls.