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

262better confidence in quantifying the k s value than the q s value. Unfortunately, the currentCAPWAP does not provide a direct input of k s value; hence, the proposed Eq. (7.8) isrecommended.( ) (7.8)( ⁄ ) (7.9)7.5.2. EOD condition for cohesive soils using CPTSimilar comparisons were performed using the CPT average unit tip resistance (q c ),average unit skin friction (f s ), and average friction ratio (FR) as summarized in Table 7.4 forISU5. The friction ratio (FR) is defined as the ratio between the unit skin friction and thetotal cone tip resistance (q t ), reported as a percentage and used as a simple index to identifysoil type. Figure 7.12(a) does not show a clear relationship between the q c value and theshaft damping (J s ) value. The q c value increased from 857 kPa near ground surface to 3310kPa near pile toe, while the J s value increased to its maximum value near the GWT anddecreased thereafter. On the other hand, Figure 7.12(b) shows an inverse relationshipbetween the q c value and the shaft quake (q s ) value. Considering that dynamic soilparameters could be influenced by the ground water table, the pore water pressure effect wasincluded by correcting the q c to a total cone tip resistance (q t ) using Eq. (7.7) as suggested byMayne (2007).( ) (7.10)where,μ= measured pore water pressure, kPa, and= net area ratio (0.80 was used for Type 2 Piezocone with a section area of 10cm 2 ).A similar observation to q t was noticed in Figure 7.13.Figure 7.14 shows no clear