Retaining wall -soil - structure interaction effects due seismic excitation

Summarization: Retaining walls are very frequently used in engineering practice to support, apart from soil layers, structures founded on the retained soil layers. During a seismic event it is evident that the dynamic response of each component of this complex system (i.e., wall, soil and structure) may affect substantially the response of the rest and vice versa. This phenomenon, which could be adequately described as “dynamic wall–soil–structure interaction” (DWSSI), is a rather complicated issue that combines: (a) the dynamic interaction between the wall and the retained soil layers, and (b) the “standard” dynamic interaction of a structure with its underlying soil layers. In the present study, using two-dimensional numerical simulations, the impact of the wall flexibility and structure stiffness on the dynamic response of the overall system is investigated. Emphasis is given on the relation between the dynamic behavior of the overall system and the dynamic properties of each component (one-dimensional soil layer-structure and wall-soil-structure). Primarily, the response of a simple structure lying on a single infinite soil layer is investigated. Subsequently, a retaining wall is included in the numerical models. A parametric study is performed in order to examine at what extend the presence of the wall may affect the amplification factors of the various components, and consequently the distress imposed on the structure (with respect to its position and its fundamental eigenperiod). In addition, the eigenperiod of the soil-structure system is calculated via analytical methods. Despite the fact that there exist many open issues to be resolved, the results of the current study provide a clear indication of the direct dynamic interaction between a retaining wall and an adjacent structure. Keywords: dynamic response, soil-structure interaction, amplification factor, soil spring.Παρουσιάστηκε στο: 17th International Conference on Soil Mechanics and Geotechnical Engineerin