This section uses the results of a by-hand calculation performed for three profiles of the Spui dike project (see figure below):
- km 63.9 (Nieuw Beijerland)
- km 65.0 (between Oud Beijerland and Nieuw Beijerland)
- km 67.8 (Oud Beijerland)
As the details of the calculation performed by hand are not available, those benchmarks are set in group 2.
2.1. Spui dike at km 63.9 (Nieuw Beijerland)
Description
The dike profile at hmp 63.9 is given in the figure below.
The soil profile and the material properties are given in the following table:
Top level | Material | Formation | Sensitive | Dr | n | nmin | nmax | γunsat | γsat | γgrains | D50 | D15 | φ | c |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Grond level | Clay | Dunkirk / anthropogenic | No |
|
|
|
| 18 | 18 | 26.5 |
|
| 25 | 0 |
-0.5 | Clay/Sand | Dunkirk | No |
|
|
|
| 18 | 18 | 26.5 |
|
| 25 | 0 |
-6.5 | Peat | Holland | No |
|
|
|
| 10 | 10 | 26.5 |
|
| 25 | 0 |
-7.5 | Clay | Calais | No |
|
|
|
| 18 | 18 | 26.5 |
|
| 25 | 0 |
-8.5 | Sand clayey/Sand | Calais | Yes | 34.6 | 45 | 36.5 | 49.5 | 19 | 19 | 26.5 | 0.160 | 0.080 | 25 | 0 |
-9.5 | Sand | Calais | Yes | 30.0 | 45.6 | 36.5 | 49.5 | 20 | 20 | 26.5 | 0.160 | 0.080 | 30 | 0 |
-12.5 | Sand | Calais | Yes | 24.6 | 46.3 | 36.5 | 49.5 | 20 | 20 | 26.5 | 0.160 | 0.080 | 30 | 0 |
-18 | Sand | Pleistocene | Yes | 60.0 | 41.7 | 36.5 | 49.5 | 20 | 20 | 26.5 | 0.160 | 0.080 | 35 | 0 |
The other calculation parameters used are:
- Water level: 0.9 m
- Required probability of failure of the dike: 1:4000
- Percentage probability of failure byliquefaction: 1 %
- Model factor: 1
- Area ratio (c = A2/A1): 1.4
- Standard deviation cot(gamma): 4.6
- Considered dike length: 100 m
Benchmark results
According to the by hand calculation, both Global and Advanced checks fail.
D-FLOW SLIDE results
By lack of information, the following values are chosen:
- A state parameter (for Global step 5 and Detailed checks) of -0.05
- A critical retrogression length of 34.353 m (which corresponds to the foreland length = 79.035 m - 44.682 m)
- A migration velocity foreshore of 100 mm/year
- For the state parameter per layer, a value of -0.04 is used for sand layers and -0.06 for the other layers.
D-FLOW SLIDE results are in accordance with the results by hand as show in the table below.
Method | Benchmark | D-FLOW SLIDE | Relative error |
---|---|---|---|
Global check | Failed | Failed | OK |
Detailed check | Failed | Failed | OK |
2.2. Spui dike at km 65.0 (between Oud Beijerland and Nieuw Beijerland)
Description
The dike profile at km 65.0 is given in the figure below.
The soil profile and the material properties are the same as for the profile at km 63.9 (see paragraph 2.1).
Benchmark results
According to the by hand calculation, both Global and Advanced checks pass.
D-FLOW SLIDE results
By lack of information, the following values are chosen:
- A state parameter (for Global step 5 and Detailed checks) of -0.05
- A critical retrogression length of 10.930 m (which corresponds to the foreland length = 36.817 m - 25.887 m)
- A migration velocity foreshore of 100 mm/year
- For the state parameter per layer, a value of -0.04 is used for sand layers and -0.06 for the other layers.
D-FLOW SLIDE results are not in accordance with the results by hand as show in the table below.
However, by lack of information about the hand calculation, it can't be concluded that the program gives incorrect results.
Method | Benchmark | D-FLOW SLIDE | Relative error |
---|---|---|---|
Global check | Passed | Failed | not OK |
Detailed check | Passed | Failed | not OK |
2.3. Spui dike at km 67.8 (oud Beijerland)
Description
The dike profile at km 67.8 is given in the figure below.
The soil profile and the material properties are given in the following table:
Top level | Material | Formation | Sensitive | Dr | n | nmin | nmax | γunsat | γsat | γgrains | D50 | D15 | φ | c |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Grond level | Clay | Dunkirk / anthropogenic | No |
|
|
|
| 18 | 18 | 26.5 |
|
| 25 | 0 |
-0.5 | Clay/Sand | Dunkirk | No |
|
|
|
| 18 | 18 | 26.5 |
|
| 25 | 0 |
-4 | Peat | Holland | No |
|
|
|
| 10 | 10 | 26.5 |
|
| 25 | 0 |
-5 | Clay | Calais | No |
|
|
|
| 18 | 18 | 26.5 |
|
| 25 | 0 |
-6 | Sand | Calais | Yes | 20 | 46.9 | 36.5 | 49.5 | 20 | 20 | 26.5 | 0.160 | 0.080 | 30 | 0 |
-20 | Sand | Pleistocene | Yes | 60 | 41.7 | 36.5 | 49.5 | 20 | 20 | 26.5 | 0.160 | 0.080 | 35 | 0 |
Benchmark results
According to the by hand calculation, the Global check fails and the Advanced check passes.
D-FLOW SLIDE results
By lack of information, the following values are chosen:
- A state parameter (for Global step 5 and Detailed checks) of -0.05
- A critical retrogression length of 42.098 m (which corresponds to the foreland length = 97.460 m - 55.362 m)
- a migration velocity foreshore of 100 mm/year
- For the state parameter per layer, a value of -0.04 is used for sand layers and -0.06 for the other layers.
D-FLOW SLIDE results differ from the results by hand for the Detailed check, as show in the table below.
Method | Benchmark | D-FLOW SLIDE | Relative error |
---|---|---|---|
Global check | Failed | Failed | OK |
Detailed check | Passed | Passed | OK |