Finite element modelling of extent of failure zone in c-φ soil at the cutting edge of open caisson

Open caissons are sunk into the ground by removal of soil within the caisson shaft. During sinking of caisson, the stresses in the soil at the cutting edge increase and result in the bearing failure of soil. The extent of soil failure in the excavation side of the open caisson is termed as influence zone. In this paper, the finite element analysis is carried out to study the effect of geometric configuration (radius ratio and tapered angle of the cutting edge), strength parameters (c’ and φ'), unit weight of soil and surcharge on the extent of the influence zone. The caisson considered in the study is having a radius ratio of 0.8, steinning thickness of 1 m and cutting edge with a tapered angle of 45°. The reaction offered by the soil at the cutting edge is also evaluated. The identification of the extent of failure zone at the cutting edge of the caisson helps in devising proper excavation strategy in the field for the controlled sinking of the caisson.