Driven Piles in Clay (I) Installation, Modelled as the Expansion of a Cylindrical Cavity

摘要

A method is outlined for estimating the immediate changes to the total and effective stresses in a saturated clay soil around a single driven pile. Pile installation is modelled as the undrained expansion of a cylindrical cavity under conditions of plane strain. Parametric studies have been made using a work hardening soil model to investigate the effects of different consolidation histories on the subsequent behavior of the soil. The results showed that the limit pressure and the resulting stresses at the pile face are almost independent of the original value of overconsolidation ratio for the soil. During pile installation, the undrained shearing of the soil almost erases the 'memory' of the in situ condition. Simple formulae are presented so that estimates of the stress changes can be made using basic engineering properties of the soil. Predictions compare favorably with field measurements of pore pressures generated in the vicinity of driven piles.