FELA evaluation of undrained bearing capacity of cutting edge of circular open caisson

Abstract

ABSTRACT Circular open caissons are deep foundations sunk into the ground utilising the self-weight of cutting edge and steining as driving force along with the subsequent failure of soil in bearing. During the sinking of the caisson, the clay in contact with the cutting edge is subjected to undrained loading and the controlled sinking of the caisson can be achieved by evaluating the undrained bearing capacity of the cutting edge. In the study, the undrained bearing capacity factor (N) of the cutting edge for varying cutting angle (b), radius ratio of the caisson (r i /r o ), full embedment of the caisson (d), removal of soil within the caisson (d'), and different roughness (α) conditions of the steining are evaluated using finite element limit analysis (FELA). The factors affecting the undrained stability of caisson considering all practical scenarios are addressed and presented as charts to be used in practice.