Abstract
Caissons are often used as the foundations of quay walls that protect the reclaimed soil on soft clay layers. Caissons are quite popular because they can transfer vertical loads from the walls to the bearing strata and they are also effective in resisting the lateral plastic flow of soft clay due to surcharge. This paper examines the possibility of improving existing caisson design by including drains at the back face. Theoretical solutions for two-dimensional consolidation with a lateral drainage boundary are provided. A simple numerical example involving isotropic clay shows that the lateral influence distance of the caisson drains is roughly equal to the height of the caissons. This procedure should allow the marine clay in close proximity to the caissons to gain strength at a faster rate, hence reducing earth pressures. In addition, it may not be necessary to install vertical drains close to the quay wall and caissons.