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The global check as implemented in D-Flow Slide comprises the following steps, which can also be found in Toetsmethode zettingsvloeiing (draft version 2, 22 febr. 2016).
Step 1a : Would flow slide lead to damage on levee (i.e. is the "schadelijksheidscriterium" met)?
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The required margin (the horizontal part from the "invloedslijn" of the dike) depends on the presence of a revetment and is determined by the relation:M
- in case no revetment is present: M = 2 Hgeul
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- with Hgeul is the channel depth
- in case
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- a revetment is present
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- : M = Max [ Mbestorting ; 2 Honbest) ]
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where:
Hgeul is the channel depth in case no revetment is present and Hgeul = Honbest in case a revetment is present
Honbest is the depth of the channel below the revetment.
Mbestorting is the horizontal projection of the length of the revetment
NOTE: in WBI2017 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) ]
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NOTE: In case the user-defined sand type is "very fine sand", the breach flow criteria cannot be checked and the program gives always that breach flow is possible and a warning message will be given in the Overall Results window.
NOTE: Only the case "without horizontal steps" is implemented in D-Flow Slide.
Table A.4.2a from CUR113b, profile without horizontal steps:with th average and local slope
from depth | to depth z [m +GL(a)] | Average slope | |||
|---|---|---|---|---|---|
Medium fine sand D50 > 200 μm and D15 > 100 μm | Coarse sand/Gravel D50 > 500 μm and D15 > 250 μm | ||||
| Local slope | Average slope 0 - z | Local slope | Average slope 0 - z | ||
0 | -5 | 1:2 | 1:2 | 1:2 | 1:2 |
-5 | -10 | 1:3 | 1:2.5 | ||
-10 | -15 | 1:4 | 1:3 | 1:3 | 1:2.5 |
-15 | -20 | 1:5 | 1:3.5 | ||
| -20 | -25 | 1:6 | 1:4 | 1:4 | 1:3 |
| -25 | -30 | 1:8 | 1:4.67 | ||
| -30 | -35 | 1:10 | 1:5.43 | 1:6 | 1:3.75 |
| -35 | -40 | 1:10 | 1:6 | ||
(a) In D-Flow Slide, the ground surface level (GL) (maaiveld in Dutch) is the lowest level between the water level and the top of the channel slope (called "Insert river channel").
NOTE:
The above table is based on Table A.4.2a from CUR113b, In D-Flowslide only "without horizontal steps" are implemented