Experiences from the construction of the Athens Metro project Experiences obtenues par la construction du Metro d' Athenes

摘要

The on-going construction of the Athens Metro has provided extensive experience on soft ground tunneling in urban environment. The paper reviews the local geological and geotechnical conditions (Athens schist formation), the applied construction practices (TBM excavated running tunnels and stage excavation of station caverns), the technical complications (mainly due to TBM over-excavations) and the methods used to resolve the construction problems (ground pre-treatment). It is concluded that the technical difficulties are due to the combined effects of the extremely heterogeneous ground conditions and the existence of deep ancient man-made structures (wells, water conduits, etc).