Stability problems in a deep excavation in clay: Aas, G Proc International Conference on Case Histories in Geotechnical Engineering, Rolla, Missouri, 6–11 May 1984V1, P315–323. Publ St Louis: Geotechnical Engineering, 1984

Abstract

This paper describes the excavation procedure and some stability problems encountered in connection with a 10-m deep braced excavation in medium soft clay. Very large deformations in the first excavated sections made it clear that the factor of safety with respect to bottom heave failure was very close to unity, and hence, much lower than the value of 1.5 calculated from a conventional total stress analysis based on vane strength. Thus, the experiences from this excavation yield an excellent opportunity to test new and better methods of stability analysis which have been developed during the last 10 years. Furthermore, recorded values of horizontal displacements and strut loads contribute to improve our knowledge about earth pressure against flexible structures and behaviour of braced deep excavations in clay.