The results of an analysis of the bottom heave failure mechanisms of braced excavations supported by diaphragm walls is reported in the paper. The influence on these mechanisms of factors such as the initial stress condition, the ratio between the width and the height of the excavation, the depth of embedment of the diaphragm walls in the soil below the bottom, the dissipation of excess pore water pressures has been studied. It is shown that the usual stability analyses in terms of total stresses and undrained strength su may result in unsafe evaluation of the stability conditions, and that the at rest earth pressure coefficient K0 as well as the depth of embedment and the ratio width/height can play an important role on the failure mechanism and on the safety factor. It is also shown that the safety factor decreases considerably as the dissipation of negative excess pore water pressures progresses; the latter process may cause sometimes delayed failure.
|Numero di pagine||0|
|Rivista||MECCANICA DEI MATERIALI E DELLE STRUTTURE|
|Stato di pubblicazione||Published - 2012|