This study evaluates and investigates a collapsed retaining system constituted with anchored bored files, with the aim of presenting an example for the damages caused by the errors made in a project and construction phase. For determining the reasons for the collapse occurred in retaining system, field evaluations were implemented, calculations in the project were checked through and re-analyses were made. 19 m anchored bored piles were used to implement a safe 16.1 m depth excavation. The retaining system was figured out by using finite elements and Mohr-Coulomb and Hardening Soil surface model via Plaxis software. The collapsed supporting system was re-solved with finite elements and the results were compared with by the designer of investigated project. It is obtained that the expected deformation  is about 28 cm by Mohr-Coulomb Model and is about 112 cm  by Hardening Soil Model although this value calculated by the designers was 1.53 cm. Results showed that the main reason for collapsing the anchored system is a miscalculation of expected deformation.

Key words: Anchor, bored piling, deep excavation, finite elements method, retaining.