Environmental Engineering Reference
In-Depth Information
Figure 6.22.
Empirical cone correlation factor N
K
- based on uncorrected vane shear strengths - Lunne
and Kleven (1981), reproduced with permission of ASCE.
Figure 6.23.
Empirical cone correction factor N
K
based on corrected vane shear strengths - Aas et al.
(1986), reproduced with permission of ASCE.
Aas et al. (1986) point out that the N
K
values proposed by Lunne and Kleven (1981)
and others, are not corrected for the effect of pore pressure, and since they use different
cones with varying geometry, and the pore pressure generated depends on clay type, much
of the scatter in N
K
values can be explained by these effects. They recommend that future
correlations should be based on piezocones, where pore pressure is measured, and cor-
rected cone resistance q
T
can be estimated, i.e. S
u
should be estimated from:
Aas et al. (1986) present cone factors N
KT
for several sites in Norway. These are repro-
duced in
Figure 6.25
.
