| \(A_b\) |
area of pile base |
| \(A_s\) |
area of shaft surface |
| \(c_u\) |
undrained cohesion at the pile toe |
| \(c_{u\text{, avg}}\) |
average undrained cohesion of soil layer |
| \({FS}_b\) |
factor of safety for tip resistance |
| \({FS}_s\) |
factor of safety for skin friction |
| \(h_\text{penet.}\) |
depth of penetration into the layer |
| \(K\) |
coefficient of lateral earth pressure |
| \(N_c\) |
bearing capacity factor |
| \(N_q\) |
bearing capacity factor (function of shear resistance angle, see Table 1) |
| \(N_\text{SPT}\) |
standard penetration test blow count |
| \(p_a\) |
atmospheric pressure (101 kPa or 14.7 psi) |
| \(Q_a\) |
allowable bearing capacity |
| \(Q_b\) |
ultimate tip resistance |
| \(q_b\) |
ultimate unit tip resistance |
| \(Q_s\) |
ultimate skin friction |
| \(q_s\) |
ultimate unit skin friction |
| \(Q_u\) |
ultimate bearing capacity |
| \(W\) |
submerged pile weight |
| \(\alpha\) |
factor of adhesion (see Figure 1 for weak rock and IGMs) |
| \(\phi’\) |
effective angle of internal friction for the soil layer |
| \(\phi_\text{red} \) |
coefficient of diameter reduction for weak rock and IGMs |
| \(\sigma_c\) |
unconfined compressive strength of the weak rock or IGM |
| \(\sigma_v’\) |
vertical effective stress at the pile toe |
| \(\sigma_{v \text{, avg}}’\) |
average vertical effective stress along the layer |