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

102where,∆R= increase in pile resistance, kN or kip,i = pile segment i,n= total n number of pile segments,( ) = long term soil-pile adhesion = S u × AF, kN/m 2 or ksi,AF= adhesion factor (0.83 for stiff clay and 0.64 for soft to mediumclay),( ) = short term soil-pile adhesion ≈ S r , kN/m 2 or ksi,S rS t= remolded shear strength = S u /S t ; kN/m 2 or ksi,= soil sensitivity, andA s = segmental pile shaft surface area, m 2 or in 2 .Using pile load test data in mostly glacial sandy soil, Svinkin (1996) presented theupper and lower boundaries to estimate the pile setup of driven piles in sandy soil given byEq. (2.62). He found that the rate of pile setup with respect to the time (t) from the pile testdata was generally the same (i.e., time t has the same power 0.1), but the setup coefficientranged between 1.025 and 1.4. He also concluded that the pile setup in sandy soils wasinfluenced by the level of ground water table. Similarly, this equation is purely empiricaland no soil or pile properties were incorporated for general applications.( )( )(2.62)Titi and Wathugala (1999) presented a general numerical method for estimating thevariation of pile resistance with time for driven friction piles embedded in saturated clay.The numerical analysis formulated the completed life stages of the pile, starting from pileinstallation, subsequent consolidation of surrounding soil to loading. This analysis wasperformed using Hierarchical Single Surface (HiSS)- model, strain path method, andnonlinear analysis of porous media through a commercial finite element program ABAQUS.The (HiSS)- model was adapted, based on the nonassociative anisotropic (HiSS)- model