Geotechnical Inspections and Applications in Underground Rail System Constructions: Halkalı - İstanbul Airport Metro Line Example

Abstract

In this study, geological researches carried out before the construction of underground rail systems and geotechnical application methods preferred during the construction were examined within the scope of Halkalı-İstanbul Airport metro project. The metro line consists of a total of 66.2 km long underground tunnels, 31.3×2 km main line and 1.8×2 km repertorium connection line. 1006 soil and 1230 rock samples were collected for the main line whose geological research was carried out with 198 core drillings with a total length of 9588.5 m. The results of the laboratory tests on the samples and the field tests carried out in the boreholes were obtained. In addition, a total of four two-dimensional inverse resistivity model were obtained by using the Multi-electrode Electrical Resistance Tomography measurement method in the middle of two lines (Line-1 Km. 61+440 – 61 +660 /Line-2 Km: 61 +400 - 61+620), in the Olympic Stadium station (Km: 62+215 – 62 +490) and in the TBM route (Line-2 Km: 62 +835 – 63+050). The geological sections obtained from the drillings and the geophysical sections obtained by the electrical resistivity method were compared.