Group 3: Benchmarks from spreadsheets
This section uses tests performed by hand or by means of an Excel spreadsheet.
3.1 Test of all possible trajectories of the Global check and the Overall result
Description
This benchmark tests all possible trajectories according to the Global check. Those trajectories are:
| Case | Step 1 | Step 3 | Step 4 | Step 5 | Step 6 | Step 7 | Global check | Detailed check | Overall result |
|---|---|---|---|---|---|---|---|---|---|
| A | No | Pass | Pass | Pass | |||||
| B | Yes | Yes | Fail | Pass | Fail | ||||
| C | Yes | No | No | Pass | |||||
| D | Yes | No | Yes | Yes | Fail | Pass | Pass | ||
| E | Yes | No | Yes | No | Yes | Fail | |||
| F | Yes | No | Yes | No | No | Yes | Fail | ||
| G | Yes | No | Yes | No | No | No | Pass | Fail | Warning message |
For case A, the same input as benchmark 1-1 (see group 1) is used except for the surface line: the length of the foreland is increased to 160 m (instead of 60 m).
For case B, the same input as benchmark 1-1 (see group 1) is used except for the foreland: an artificial instead of a natural foreland is assumed.
For case C, the same input as benchmark 1-1 (see group 1) is used except for the position of the characteristic point "Insert river channel" which is lowered to get a slope channel of 1 : 7,1.
For case D, the same input as benchmark 1-1 (see group 1) is used.
For case E, the same input as benchmark 1-1 (see group 1) is used except for the state parameter which is equal to -0.06 instead of -0.03.
Benchmarks results
Hereafter are given the analytical results per case.
Case A:
Global check - Step 1:
Channel depth: H = 15 m
Thickness of the sensitive layer: Hvw = 25 m
Marge = 2 Hvw + 1.5 (H - Hvw) = 35 m
Slope of the observation profile: 1:15
Assessment level: Z = -10 m
XSsign = 85 m
XSzv = 30 m
XSsign > XSzv => Flow slide would not lead to damage on levee => Global check passes.
Detailed check: see table below: Probability of flood damage by liquefaction (= 8.10 × 10-11) < Allowable probability of failure (2.50 × 10-6) => Detailed check passes.
Overall check: as Global and Detailed check pass, the Overall check passes.
Case B:
Global check - Step 1: Same results as benchmark 1-1 (flow slide would lead to damage on levee) => Go to step 3.
Global check - Step 3: The foreland is artificial => Global and Detailed check fail, an Advanced check is needed.
Detailed check: see table below for intermediary results: Probability of flood damage by liquefaction < Allowable probability of failure => Detailed check passes.
Overall check: as step 3 of Global check fails, the Overall check fails whatever the Detailed check result.
Case C:
Global check - Step 1: Same results as benchmark 1-1 (flow slide would lead to damage on levee) => Go to step 3.
Global check - Step 3: The foreland is natural => Go to step 4.
Global check - Step 4: The slope channel is 1:7,1 so steeper than 1:7 => Flow slide is not possible based on geometry => Global check passes.
Detailed check: The determination of the reliability index for the Detailed check is not possible using the spreadsheet because the formula implemented in the spreadsheet applies only for horizontal foreland, which is not the case here.
Overall check: As the Detailed check result is not known, the Overall result can't be deduced.
Case D:
Results are identical to benchmark 1-1 and can be found in Group 1.
Case E:
Global check - Step 1: Same results as benchmark 1-1 (flow slide would lead to damage on levee) => Go to step 3.
Global check - Step 3: The foreland is natural => Go to step 4.
Global check - Step 4: The slope channel is 1:6 so softer than 1:7 => Flow slide is possible based on geometry => Go to step 5.
Global check - Step 5: The state parameter is -0.06 so less than -0.05 => Liquefaction is not possible based on the state parameter => Go to step 6.
Global check - Step 6: The
Global check passes.
Detailed check: see table below for intermediary results: Probability of flood damage by liquefaction < Allowable probability of failure => Detailed check passes.
Overall check: as step 3 of Global check fails, the Overall check fails whatever the Detailed check result.
D-Flow Slide results
D-FLOW SLIDE results are in accordance with the results by hand as show in the tables below.
Results of benchmark 3-1 for case A
| Benchmark | D-FLOW SLIDE | Relative error |
|---|---|---|---|
Marge | 35 | 35 | 0.00 % |
| Slope [1:xxx] | 15 | 15 | 0.00 % |
Assessment level | -10 | -10 | 0.00 % |
Step 1: Would flow slide lead to damage on levee? | No | No | OK |
Result of the Global check | Pass | Pass | OK |
| Fictive channel depth Hr [m] | 19.087 | 19.087 | 0.00 % |
| Fictive slope cotan αr | 23.000 | 23.000 | 0.00 % |
| Probability of preventing a liquefaction P(ZV) [/km/year] | 9.14 × 10-7 | 9.14 × 10-7 | 0.00 % |
| Reliability index β | 3.749 | 3.748 | 0.03 % |
| P(L > Lallowable) | 8.86 × 10-5 | 8.90 × 10-5 | 0.45 % |
| Probability of flood damage by liquefaction P(falen|ZV) [/year] | 8.10 × 10-11 | 8.13 × 10-11 | 0.37 % |
| Allowable probability of failure [/year] | 2.50 × 10-6 | 2.50 × 10-6 | 0.00 % |
Result of the Detailed check | Pass | Pass | OK |
| Overall result | Pass | Pass | OK |
Results of benchmark 3-1 for case B
The overall result is not correctly determined in D-Flow Slide if the foreshore is artificial: D-Flow Slide uses the Detailed check result but it should directly conclude that the Overall check fails.
| Benchmark | D-FLOW SLIDE | Relative error |
|---|---|---|---|
Marge | 35 | 35 | 0.00 % |
| Slope [1:xxx] | 15 | 15 | 0.00 % |
Assessment level | -10 | -10 | 0.00 % |
Step 1: Is liquefaction damaging on basis of geometry? | Yes | Yes | OK |
Step 3: Artificially underwater installed and non-compacted sandy foreshore? | Yes | Yes | OK |
Result of the Global check | Fail | Fail | OK |
| Fictive channel depth Hr [m] | 21.571 | 21.571 | 0.00 % |
| Fictive slope cotan αr | 10.5 | 10.5 | 0.00 % |
| Probability of preventing a liquefaction P(ZV) [/km/year] | 1.24 × 10-6 | 1.24 × 10-6 | 0.00 % |
| Reliability index β | 3.749 | 3.749 | 0.00 % |
| P(L > Lallowable) | 8.86 × 10-5 | 8.88 × 10-5 | 0.23 % |
| Probability of flood damage by liquefaction P(falen|ZV) [/year] | 1.10 × 10-10 | 1.10 × 10-10 | 0.00 % |
| Allowable probability of failure [/year] | 2.50 × 10-6 | 2.50 × 10-6 | 0.00 % |
Result of the Detailed check | Pass | Pass | OK |
| Overall result | Pass | Fail | not OK |
Results of benchmark 3-1 for case C
| Benchmark | D-FLOW SLIDE | Relative error |
|---|---|---|---|
Marge | 31.514 | 31.514 | 0.00 % |
| Slope [1:xxx] | 15 | 15 | 0.00 % |
Assessment level | -10.775 | -10.775 | 0.00 % |
Step 1: Is liquefaction damaging on basis of geometry? | Yes | Yes | OK |
Step 3: Artificially underwater installed and non-compacted sandy foreshore? | No | No | OK |
Result of the Global check | Fail | Fail | OK |
| Fictive channel depth Hr [m] | 17.762 | 17.762 | 0.00 % |
| Fictive slope cotan αr | 10.5 | 10.5 | 0.00 % |
| Probability of preventing a liquefaction P(ZV) [/km/year] | 3.29 × 10-7 | 3.29 × 10-7 | 0.00 % |
| Reliability index β | Not available | 3.749 | |
| P(L > Lallowable) | Not available | 8.88 × 10-5 | |
| Probability of flood damage by liquefaction P(falen|ZV) [/year] | Not available | 1.10 × 10-10 | |
| Allowable probability of failure [/year] | 2.50 × 10-6 | 2.50 × 10-6 | 0.00 % |
Result of the Detailed check | Not available | Pass | - |
| Overall result | Not available | Pass | - |
Results of benchmark 3-1 for case D
Results of benchmark 3-1 for case E
