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Honbest is the depth of the channel below the top revetment.
Mbestorting is the horizontal projection of the length of the top revetment
De "invloedslijn" is defined as "de uiterste lijn op het maaiveld waarvoor geldt dat als aan dijkzijde van die lijn het maaiveld wordt verstoord de veiligheid van de waterkering zakt onder de (volgens de toetsing) vereiste veiligheid, gelet op alle directe faalmechanismen" NOTE: in WBI-2017 in case of a revetment the margin is defined in a slightly different way. Instead of Honbest, Hgeul is used: M = Max [ Mbestorting ; 2 Hgeul) ]
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 inclination of the slope depends on the channel depth:
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