Friction Piles in Clay. The upper left figure shows the pressure distribution for a pile group
embedded in clay. The load P that the pile cap supports is first turned into an applied stress q by using
Eq. 4.32.
In essence, the 2:1 approximation starts at a depth of 23 L below ground surface. In Fig. 8.17, it
is assumed that there is a hard layer located below the clay. In this case, the primary consolidation
and secondary compression would be calculated for the zone of clay defined as H in the upper left
diagram of Fig. 8.17. The clay of thickness H may have to be divided into several layers in order to
calculate the primary consolidation and secondary compression