Assessing Unit Skin Friction of Pneumatic Caissons

Abstract

A study was carried out to establish an empirical method to estimate unit skin friction of rigid large-size pneumatic caissons. Field instrumentation during construction and installation of the rigid pneumatic caissons was in place, where the water load, air pressure, and reaction force (contact pressure) were measured accordingly. Using these data and the weight of caisson, the unit skin friction was estimated. The unit skin friction distribution with depth decreased in a parabolic shape. The unit skin frictions predicted by the K _n and λ methods used for deep foundations were compared with the measured data. The comparison showed that the K _n method is more suitable for estimating the skin friction of the large-size rigid pneumatic caisson than the λ method in this particular construction project.

Keywords:

• Deep foundation
• K _n and λ methods
• pneumatic caisson
• unit skin friction