3-DIMENSIONAL NUMERICAL MODELING OF TUNNEL INDUCED DEFORMATION FIELD (NECATIBEY SUBWAY STATION, ANKARA, TURKEY)

In heavily settled areas, deformations induced by the tunnel excavation may cause serious damage to nearby structures. Therefore, it is necessary to study effective means of controlling tunnel induced deformations. The main parameters affecting the failure and deformation state of the soil around a circular underground opening are the physical characteristics of the soil, the diameter of the opening, and the support pressure. In this study, 3-Dimensional (3D) FDM analyses were conducted to assess tunneling induced deformations, along with movements around Necatibey Station of Kizilay-Cayyolu metro line (Ankara, Turkey). During sequential excavations, temporary and permanent shotcrete lining was also simulated. The soil behavior is assumed to be governed by an elastic-perfectly plastic constitutive relation based on the Mohr Coulomb criterion. The computed deformations around these openings have been compared with the in-situ measurements. The results of the study revealed that the 3-D elasto-plastic analyses yield comparably good correlation with the in-situ measurements