O.J. Gastebled & S. Baghery
Coyne & Bellier Consulting Engineers,Tractebel Engineering, Gennevilliers, France
In densely built area with high land value, the trend is towards building higher and deeper, often adjacent to existing structures. Such projects involve the adoption of tight ground movement criteria which are nowadays commonly checked using 2D finite element analysis. For the excavation discussed here, however, the constraints in terms of site configuration and projects requirements lead to adopting a retaining system which takes advantage of its 3D arching effects. 3D finite element analysis was thus adopted at the design stage. The project concerns a high-rise 49 floors tower to be constructed in Monaco, on a sloping site. The tower basement and foundations involve a deep excavation, mainly in marlstone, with depths of 70m on the uphill side and 30m on the downhill side. The results obtained using 3D modelling are discussed in term of induced ground movements and plasticity in so far that it provides better insight into the way the retaining system fulfills its role."