Thunersee

Consulting and planning for the new building of a spillway adit

To counteract future severe floods a 1.200 m long spillway audit has been constructed in the inner-city area of the city of Thun (Switzerland). The audit has been driven using hydro shield tunnelling with an external diameter of 6,32 m in coarse sand soil. It connects the sewer with the water level of the Aare, lying approx. 6,45 m below.

In the context of this building operation numerous buildings as well as the track field of the Thun train station had to be tunnelled due to a cover of 13 m on average.

For the execution technical advice for the executing consortium has been provided:
_Earth pressure calculations
_Advice on choice of bentonite type
_Calculation of grouting pressure