Pile Design and Construction Practice, Fifth edition

250 Pile groups under compressive loading

5.2.2 Settlement

The first step in the settlement analysis is to determine the vertical stress distribution
below the base of the equivalent block foundation (Figure 5.3) using the curves shown in
Figure 5.13, where the stress at any depth zbelow this level is related to its length/breath
ratio. The curves assume that the foundation is rigid, but it is sufficiently accurate to assume
that the superstructure, pile cap, piles and soil surrounding them have the required degree
of rigidity.

≥ 2 dF

Top of bearing

stratum

(a) (b)

≥ 3 d

dF

d

d

Figure 5.12German practice for spacing of bored and cast in-situ piles in groups (a) Straight-sided
piles (b) Piles with enlarged bases.

e ee

d d dF 2

≥ 2 dF 1

e≥ 3 d≥ 1 m+d

≥1.00

dF 1

dF 2

dF 2

dF 1

dF 1

ee

(a) (b) (c) (d)

Figure 5.11German practice for spacing of driven piles in groups (a) Vertical piles (b) Raking piles
(c) and (d) Raking winged piles.