ABSTRACT
The paper describes a case history and numerical modeling of an anchored diaphragm wall designed to secure an 18 m deep excavation pit for the construction of an underground garage and mall in downtown Zagreb. The numerical analysis performed by FLAC included detailed modeling of staged excavation and prestressing of ground anchors. The soil behavior, ranging from large stiffness at very small strains to low stiffness at large strains, was accounted for by a new elasto-plastic model, which was incorporated into FLAC by the FISH programming language. The new model allows for adjustments to arbitrary shear stiffness reductions, depending on shear strains during loading. The required soil parameters were determined from field and laboratory tests, including triaxial tests with measurements of small strains and field geophysical tests. The wall deflections, observed during different construction stages, compared very well with the predicted behavior.
