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

168in Figure 4.13. It was expected that the originally-estimated pile resistances using Eq. (4.9)were higher than the measured values. In addition, the corrected pile resistances withproportioning to the cohesive soil thickness did not capture the actual pile responses. On theother hand, the pile resistances estimated using Eq. (4.9) and adjusted accordingly to the 50%effective cohesive soil layers correlated very well with the measured values. This studyconcluded the followings:1. The amount of pile setup exhibited in a mixed soil profile was smaller than thatexpected in a complete cohesive soil profile,2. The observed pile setup in the mixed soil profile followed the logarithmic trend asobserved at those test piles embedded in cohesive soil profile and as predictedusing Eq. (4.9), and3. The amount of pile setup in a mixed soil profile not only depends on theproportion of the cohesive soil layers to the embedded pile length, but alsodepends on the stratigraphic layers of cohesive and cohesionless soils thatinfluence the dissipation of the induced excess pore water pressure.It is important to note that the aforementioned study was performed based on only a field testof ISU8, additional similar field tests on piles embedded in the mixed soil profile will bebeneficial in the future to justify the conclusions, to further refine the methodology andassumptions made, and to accurately quantify the pile setup.4.6. Confidence LevelIn order to confidently implement the proposed pile setup method in practices, piledesigners prefer to know the reliability of the method in advance, so the difference betweenactual and estimated pile setup values falls within an expectable tolerance. The confidenceof the method in terms of the pile resistance ratio (R m /R t ) can be expressed at differentconfidence levels given by