Design and Construction of Kallidromo Twin Railway Tunnel

摘要

The Kallidromo twin railway tunnel has an overall length of 18 km and is part of the new 500 km, high speed, double track railway line from Athens to Thessaloniki. At the time of writing, 15 percent of the total length had already been constructed. The project involves two, one-way, parallel bores at 30 m axial distance, with cross passages every 500 m. Excavation of each bore is up to 85m~2 under 540 m maximum overburden (Kallidromo mountain, central Greece). The initial part of the project is driven through recent pho-pleistocene sediments with poor mechanical properties, composed of slickensided clay and loose sand. Tunnelling encountered sections with high convergence (settlements reached 47 cm), significant groundwater inflow (up to 120 m~3/hour) and instability of the working face (36 incidents of falls or slides).