ABSTRACT

The new “Induno” railway tunnel is located in the municipality of Induno-Olona (Varese, North Italy) approximately on the axis of the historical line; it develops under the single track of the historical railway line built at the end of the 19th century.

Geologically, the excavation of the natural tunnel involved fluvioglacial and glacial deposits mainly characterised by silt-sand-gravel lithology. Pebbles are generally heterogeneous, highly rounded and poorly sorted (from fine gravels to boulders), sometimes well cemented.

To improve ground characteristics, the project is based on the consolidation of loose soil through injection treatment extended also to the area of contact between the ground and the underlying rock formation.

The new railway tunnel has an excavation length of 478 m approximately; the excavation section is about 115 m2 and the maximum coverage is approximately 45 m.