Pile Design and Construction Practice, Fifth edition

100

Upper limit

Lower limit

B is in metres

af

af

B0.7

102

mm/kN/m^2

q^1

D

D

ri

Ic 

Ic

10

1

0.1 110100

Standard penetration test, N-value

(Blows/0.3 m)

Compressibility grades

VII VI IV III II IV

Figure 5.26Relationship between compressibility index and averageN-value over depth of
influence (after Burland and Burbidge(5.19)).

100

10

(^1110100)
B, metres
z^1
, metres
Figure 5.27Relationship between breadth of loaded area and depth of influence zI(after Burland
and Burbridge(5.19)).