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

259which were identified as ISU2, ISU3, ISU4, ISU5, and ISU6, were selected primarily forquantifying the cohesive dynamic soil parameters. To quantify dynamic soil parameters forcohesionless soils, only test pile ISU9 was chosen, but test pile ISU10 was not included dueto incomplete CPT results. For accurate correlation studies, piles ISU1, ISU7, and ISU8embedded in mixed soil profiles were not considered. However, test pile ISU8, which hasboth SPT and CPT data, was selected for the validation of the estimated parameters. Thefield tests of these test piles were explicitly described in Chapter 3 and Ng et al. (2011).Table 7.4 summarizes the average unit tip resistance (q c ) and unit skin friction (f s )measured using CPT and the average SPT N-value at the depth of each soil model along thetest pile. Referring to Figure 7.1, each soil model represented by a linear elastic-plasticspring and a linear viscous damper was used in CAPWAP to characterize the surroundingsoil at the designated soil layer. The soil resistance (R s ) at each soil layer estimated usingSchmertmann’s (1978) method was adjusted proportionally as listed in Table 7.4, so that thetotal estimated soil resistance matched the total pile resistance estimated based on the defaultCAPWAP matching procedure. Following the proposed CAPWAP matching proceduredescribed in Section 7.4, the shaft damping factor (J s ) and the shaft quake value (q s ) werequantified for each soil model. These dynamic soil parameters represent the soilcharacteristics at the EOD condition, in which the PDA recorded pile responses wereengaged during the CAPWAP matching process.To investigate the effect of pile setup on cohesive dynamic soil parameters, two PDApile responses recorded from the beginning of the last restrike, BOR6 of test pile ISU5 andBOR8 of test pile ISU6, were selected. The BOR6 of ISU5 performed at 8 days after EODhad a close duration with the BOR8 of ISU6, performed at 10 days after EOD. Aligned withthe similar procedure described for the EOD condition, the dynamic soil parameters at thetime of last restrikes were determined. Table 7.5 summarizes the location of the soil models,the measured soil properties, and the computed dynamic soil parameters.