A case study for the utilization of various retaining systems for different subsoil and groundwater conditions encountered within a given site is presented in this paper. The project is known as “BJK Fulya Complex”, covering approximately 160,000 m2 floor area. It is located at a very prestigious district of the city, therefore maximum underground space gain were desired. As a result nearly 20 m of excavation is planned to be performed partly under groundwater. Due to unique topography and geology of the site, subsoil and groundwater conditions at various faces of the excavation differ considerably. Because of the complicated geology, budget constraints of the project and the high seismicity, it was compulsory to employ various retaining structures such as flexible and rigid retaining systems at various locations within the site including permanent and temporary soil nailing, permanent tie-back cast in-situ reinforced concrete wall and temporary tied-back diaphragm wall consist of soldier cast in-situ piles with jet grout columns in between. Performances of various systems are monitored closely by means of inclinometers. Displacement data and experience obtained from this case study serves an excellent source of data and example for future applications in similar conditions within the city
