Geoscience Reference
In-Depth Information
0.4
Group 1 -- Case histories
with an adequate amount
of in-situ measurements
and reasonably complete
geometric details
Recommended Curve
for conditio
n
s where void
redistributi
on
effects are
expected to be negligible
0.3
Group 2 & Group 3
(see text for more details)
Recommended Curve
for conditio
n
s where void
redistribution effects
could
b
e significant
0.2
0.1
Seed (1987)
Seed & Harder (1990)
Olson & Stark (2002)
0.0
0
30
60
90
120
150
180
Equivalent Clean Sand CPT Normalized Corrected Tip Resistance, q
c1Ncs-Sr
Fig. 1.12. S
r
/
σ
vo
versus q
c1Ncs
-
Sr
for casehistories listedinTable 1.5
and curves proposed for relatingresidual shear strengthratio, S
r
/
σ
vo
,
of liquefied soil to median values of equivalent clean-sand CPT normalized
corrected tipresistance for
σ
vo
lessthan 400kPa
physical and analytical modeling studies of void redistribution mechanisms. A lower
design relationship was provided for conditions where the effects of void redistribu-
tion could be significant, while an upper design relationship was provided for conditions
where the effects of void redistribution can be confidently judged to be negligible. Mak-
ingthedistinctionbetweenthesetwocasesforanearthembankmentorslopewillrequire
appropriately detailed field and analytical studies.
It is hoped that the relationships included in this paper provide reasonable means for
engineers to estimate the residual strength of liquefied soils in the field. It is also hoped
that research in this area will continue using physical and analytical models to allow for
greater understanding of the void redistribution phenomenon and its effects on residual
strength.
Acknowledgments
The writers are grateful for the valuable review comments and thoughtful suggestions
providedbyDrs.YoshiMoriwaki,SteveL.Kramer,GonzaloCastro,andRobertPykeon
an earlier version of this manuscript that addressed SPT-based relationships.
