Reinforced soil cement retaining walls for foundation pit excavation in Odessa (UA)

The deep excavation required for the planned construction of a residential building in Odessa, standing the site specific geotechnical and hydrogeological environment, presents delicate stability problems with potential critical effects on the existing confining structures. Soil cement retaining walls were selected as possible solutions to minimize the induced settlements and provide at the same time a hydraulic cut off to guarantee dry conditions for the following working phases. The geotechnical characterization of soils, show a complex subsoil profile due to the presence of loose collapsible water bearing silty sandy loess layer and of interbedded soft to firm silty clay layer, which lies down to about GL-20 m under the excavation plane. Standing the unfeasibility of adopting bracing methods due to the very large area and construction costs, the conceptual design of cantilever retaining structures followed the “displacement-based design” method, similarly to what is usually done in earthquake engineering. For this purpose, reinforced soil cement retaining walls system were proposed and the relative design analysis have been carried out with the aid of 3D finite element software. Unfortunately, the project after a brief start is currently on hold due to the ongoing conflict.