PSI - Issue 5

K Bouzelha et al. / Procedia Structural Integrity 5 (2017) 77–84 K Bouzelha et al./ Structural Integrity Procedia 00 (2017) 000 – 000

83 7

0,0035

0,0030

0,0030

0,0025

0,0019

0,0020

0,0015

0,0012

0,0010

0,0005

0,0005 failure probability Pf

Seismic zone

0,0000

low (I)

Medium (IIa)

Medium (IIb)

high(III)

Fig. 5. Evolution of failure probability as a function of seismic zone without considering the saturation line.

Failure probability evolution obtained for the different seismic zones, taking into account saturation line is illustrated in fig. 6. We notice that all the failure probability values exceed the admissible value for civil engineering structures.

0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00

0,88

0,85

0,70

0,25

failure probability Pf

Seismic zone

low (I)

Medium (IIa)

Medium (IIb)

high(III)

Fig. 6. Evolution of failure probability as a function of seismic zone taking into account of the saturation line.

The reliability analysis of embankment stability is conducted with upstream slope angle ( β = 18.43 ° ) (Fig. 2) led to failure probabilities exceeding admissible value P f =10 -3 . An optimization study of this angle, for a target value (P f =10 -3 ) was conducted for different seismic zones and considering the saturation line embankment. Obtained results are presented in Fig. 7. We conclude that the values of ( β ) ensuring embankment stability are lower than the adopted value of a deterministic design. Once again, we confirm with the reliability analysis the necessity to consider seismic effect and the embankment’s saturation line in the design phase by the engineers.

10 12 14 16 18 20

17,23

17,23

14,57

12,05

β °

0 2 4 6 8

Seismic zone

low (I)

Medium (IIa)

Medium (IIb)

high(III)

Fig. 7. Evolution of upstream slope angle ( β ) as function of seismic zone for P f =10 -3 .