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Allowable probability of failure

Toelaatbare faalkans

Required probability of failure

1:n year

0

(1-1000000)

Percentage p.o.f. flow slide

Faalkans zettingsvloeiing

Percentage of probability of failure by flow slide

–

100.00

(0-1)

Area ratio

Gebiedsratio

c = Area2 / Area1

c

–

1.40

(1-5)

Max. allowable retrogression length

Max. toelaatbare inscharingslengte

The maximum allowable length for retrogression

L_allowable

m

0.000

(0.001-1000)

Considered dike length

Beschouwde dijk lengte

Length of the dike section

L_{trajectlengte}

m

0.00

(1-10000)

0.00000

(0.0001-100)

Factor which evaluates the presence of cohesive layers or peat layers within the sand body.

Cohesive and peat layers start to play a role if their (individual) thickness is larger than 0,5 m (CUR113, 2008).

If their thickness exceeds 5 m it can be assumed in most situations the breach will be stopped.

The following values are proposed:

• Virtually no cohesive and/or peat layers (thickness cohesive layers < 0.5 m), then F_{cohesive layers} =  1/3
• Small number of cohesive and/or peat layers (0.5 m < thickness cohesive layers < 5 m), then F_{cohesive layers}=  1
•  Large number of cohesive and/or peat layers(thickness cohesive layers > 5 m), then F_{cohesive layers}=  3  

–

0.00

(0-100)