ABSTRACT
This tunnel was constructed under the archeological area of Iridanos River, Monastiraki Station, Attiko Metro. The presence of antiquities implies the requirement of minimizing surface settlements. For that reason a presupporting system of microtunnels is provided consisting of longitudinal horizontal steel tubes arranged outside the arch of the temporary lining. The most important scope of the design was to restrict surface settlements at the archeological area. The associated settlements have been carefully investigated using a nonlinear analysis method on a highly sophisticated 3-dimensional FE model, applied for the complete sequence of the steps of excavation and lining construction, insuring the better approximation to the actual performance of the structure. In the model are also introduced soil parameters resulting from the relevant soil borings and the previously executed excavations. A nonlinear elastoplastic analysis applied for the 3-D model of the system by the introduction of the Mοhr–Coulomb failure criterion, for the soil 3D finite elements. Rockmass environment consists of: “black Athenian schist” with very low shear strength and deformability parameters. Application was successful and the limitation of settlements at the Iridanos River archaeological area, during the construction to acceptable serviceability, was achieved. The provisions of the study were verified to a large extent, with a deviation not exceeding 8%.
