Geological – geotechnical investigations and evaluation of the new extension line 4 of the Athens Metro (Contract No TSA-334/07). Sections: Panepistimio – Filothei and depot Alsos Veikou

The geological study covered the section of the new Athens Metro Line 4 between Panepistimio Station (CH. 5+800) and Faros Station (CH. 13+675), together with the adjacent sections of the Exarchia–Panepistimio alignment (CH. 5+600–5+800) and Faros–Filothei alignment (CH. 13+675–14+400), covering a total length of approximately 9 km.

The study included the collection and assessment of bibliographic and geological data, the review of aerial photographs and contemporary satellite imagery, and the compilation, documentation and engineering geological assessment of available subsurface investigations from previous projects in the area. A total of 245 investigation boreholes were recorded within a 350 m corridor on either side of the alignment, including 29 boreholes carried out as part of Phase A of the geotechnical investigation for the project.

Field investigations included geological and hydrogeological reconnaissance of the wider study area, with geological observations carried out at exposed artificial slopes and foundation excavations. Water occurrence points were also recorded, and groundwater level measurements were undertaken in piezometric investigation boreholes. The work further included the preparation of an engineering geomorphological map, geological longitudinal profiles and cross-sections, and the assessment of the engineering geological and hydrogeological conditions along the alignment.

The study also included an extensive inventory of water occurrence points and subsurface investigation works, water sampling and chemical and microbiological analyses, with the aim of identifying and assessing potential engineering geological and hydrogeological problems that could affect the construction of the project.