3D FEM ANALYSIS OF THE CONSTRUCTION PIT FOR A TBM-DRIVEN FLOOD DISCHARGE GALLERY

As one speciality of the Swiss hydraulic engineering tradition, several torrent diversion schemes were undertaken dating from the 18 th century, with the aim of using the natural lake as a retention basin. The recent project of flood protection of the lower Sihl valley and the City of Zurich features a gallery of 2.1km length with a 6.6m inner diameter designed for a 330m 3/s free flow, discharging into Lake Zurich in an HQ 500 event. After a short presentation of the main features of the project, the paper concentrates on the target construction pit of the TBM drive close to a major railway line at the built-up lakeside