Geoscience Reference
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Fig. 11.16. Effect of liquefaction induced settlements
ρ
dyn
/
B
onexcess pore pressure
parameter
a
(Eq.11.11)
σ
v
o
σ
v
o
+ ∆
σ
v
U
foot
,
C
=
α
(11.10)
where
is the additional vertical stress caused by the foundation load at the charac-
teristic point. Consistently with the view expressed earlier with regard to the settlement
induced dilation of the liquefiable subsoil, and its effect on the excess pore pressures
below the foundation, it was found (Figure 11.16) that the pore pressure parameter
a
in
Eq.11.10 can be reasonably well correlated to normalized seismic settlements,as
∆
σ
v
250
ρ
dyn
B
2
a
=
1
−
(11.11)
5. Evaluation of liquefaction settlements
Computationofliquefaction-inducedsettlementsisthesecondstepforthecompletionof
the performance-based design process, as these settlements may become excessive even
forvaluesofthedegradedfactorofsafetylargerthan1.0.Unliketheproblemofdegraded
bearingcapacity,thatofsettlementaccumulationhasnotbeenyetmodeledanalyticallyin
a simple and robust way. Thus, for a first approximate solution of this problem we relied
on a step-by-step statistical analysis of results obtained from the parametric numerical
analyses which weredescribed in previous sections.
