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M = Max [ Mbestorting ; 2 Hvw + 1.5 (H - Hvw) ] in case a revetment is present
where:
H is the channel depth in case no revetment is present and H = Honbest in case a revetment is present
Hvw is the thickness of the sensitive layer(s). The sensitivity is determined using the following criterion:
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sand (or gravel) layers with Ψ5m > -0.05 (when considering all the layers until 1.5*H below the toe of the submerged slope),
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are considered as sensitive.
Honbest is the depth of the channel below the revetment.
Mbestorting is the horizontal projection of the length of the revetment.
In case no slope protection is present, if over the entire channel depth softening sensitive sand is present, this margin is thus equal twice the fictive channel depth (M = 2 H).
The inclined part of the observation profile in line with the horizontal portion. The inclinaison of the slope depends on the channel depth:
- 1:15 if the fictive channel depth is less than 40 m (H < 40 m)
- 1:20 if the fictive channel depth is more than 40 m (H ≥ 40 m)
2) Determination of the assessment level
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