Environment and geology
The construction of the second tube will inevitably have an impact on the environment. Various measures are designed to mitigate this. Here you can find out more about the local geology, and how a large proportion of the excavated material is reused as building material or for landscape development.
Geology
From the north, the tunnel cuts through the Aar Massif, which consists mainly of granite and paragneiss. The tunnelling machine then will then bore through the Urseren zone, which is made up of Mesozoic and Permo-Carboniferous rocks. The third formation is the Gotthard Massif, which is mainly composed of gneiss and granite. At the Airolo portal, the tunnel reaches the metasedimentary Nufenen zone. In the portal areas, i.e. at the entrance to the tunnel, there are sections of loose rock of varying length.
Here is a short explanation of the rock types mentioned:
- Granite: Massive and relatively coarse crystalline deep rock
- Gneiss: Metamorphic rock formed deep in the earth's crust
- Paragneiss: Gneisses are categorised according to type of rock from which they are formed. Paragneiss is formed by the metamorphism of a sedimentary rock.
- Mesozoic: Geological era, from the Greek "middle life"
- Permo-Carboniferous: Red sedimentary rocks formed from the Carboniferous and Permian systems
- Metasedimentary: Sedimentary rock that has undergone metamorphosis.
Gotthard massif cross section
Use of excavated material
The construction of the second tube will generate around 7.4 million tonnes of excavated material. As much of the excavated material as possible will be reused so that the environmental impact can be minimised. As the geology of the first tunnel tube is already known, a reasonable prediction can be made about how much material can actually be reused.
Of the excavated material, 1.8 million tonnes will be used directly as new building material. FEDRO is using around 1.9 million tonnes for land contouring and tunnel covering in Airolo. A further 3.5 million tonnes of material is being used to rewild the shallow water zones in Lake Uri.
Contaminated excavated material and construction waste, such as contaminated demolition and dismantling waste, metal parts, bulky items and other waste (wood, glass, plastic, pipe sections, etc.) are sorted, assessed and correctly disposed of.
Environmental report summaries
The impact of the construction site on its environment is regularly checked in terms of air, noise, vibrations and water. You will find the quarterly reports of the environmental measurements below.