S - Kam Ng PhD Dissertation Final.pdf - Digital Repository of CCEE ...

104and Sutabutr (1999) proposed a numerical procedure to predict pile setup specifically forlarge diameter, open-ended steel piles used to anchor offshore platform. They used the strainpath model presented by Baligh (1985) to characterize pile installation disturbance for agiven pile geometry. MIT-E3 soil model formulated by Whittle and Kavvadas (1994) wasused to predict effective stress-strain strength properties throughout pile installation andsetup based on specified initial stress state, stress history, and material input parametersdetermined from one-dimensional consolidation tests and undrained triaxial shear tests.Subsequently, one-dimensional finite element model was used to simulate nonlinear coupledconsolidation that occurs radially around the pile shaft. The proposed procedure for pilesetup estimation was validated using (1) Piezo lateral stress (PLS) cell data on a closed-endedmodel pile in a clay deposit performed at the Saugus site reported by Azzouz and Morrison(1988); and (2) an instrumented model pile with 104 mm outside diameter and 6 m longembedded in a soft marine clay at Bothkennar site developed at Imperial College, London, byLehane and Jardine (1994). Again, the numerical procedure is highly technical and complexwhich may not conveniently implemented by pile designers for practical pile setupestimations.Maintaining the opportunity of using the logarithmic time scale by setting thereference time (t o ) given in Eq. (2.60) to 0.1 day, Svinkin and Skov (2000) presented analternative setup Eq. (2.63) that accounts for the actual time elapses immediately after EODand independent of t o . Although this method has taken into an account the actual time afterEOD (t EOD ) by allowing the reference pile resistance to be estimated at the EOD condition,the alternative soil dependent setup factor (B) value was not quantified in terms of any soilproperties and relied on pile restrikes for pile setup estimation., ( ) - (2.63)Using an extensive database of pile load tests and restrikes with CAPWAP analysison closed-ended piles, Paikowsky et al. (2004) concluded that the actual increase in pileresistances measured using static load tests was much slower than that exhibited by the