...
The details of the calculation can be found in annex A of the report. The main results are given in the table below. The global check fails but the detailed check passes.
Global check - Step 1a:
Thickness of the sensible to liquefaction layer: Hvw = 25 m
Channel depth: H = 15 m
Marge = 2 Hvw + 1.5 (H - Hvw) = 35 m
Slope of the observation profile: 1:15
Assessment level: Zbeoord = -10 m
XSsign = Xdike toe at river - marge - (Zvoorland - Zbeoord) * slope = -15 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.
D-Flow Slide results
D-Flow Slide needs extra input parameters compared to the Study Case:
...
parameters compared to the Study Case:
- Ψ5m = -0.03 (used in Global step 5 and Detailed checks)
- D50 = 180 μm and D15 = 130 μm for Calais sand
- D50 = 160 μm and D15 = 110 μm for Compacted sand
- According to the values of D50, the sand type is set to "Very fine sand"
- Cohesive layers factor = 0.2
- Migration velocity = 0.0001 mm/year
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| Unit | Benchmark | D-FLOW SLIDE | Relative error | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Marge | [m] | 353035 | 30 | 0.00% | |||||||||||
X coordinate of the observation profile (Xsign)Slope | [m-]-35 | 15 | -3515 | 0.00% | |||||||||||
Assessment levelX coordinate of the liquefaction point (XZV) | [m] | 30-1030 | -10 | 0.00% | |||||||||||
Question 1 1a : Would flow slide lead to damage on levee? |
| Yes | Yes | OK | |||||||||||
Question 21b: Criterion on slope protection met (<1:2,5)? | - | - | |||||||||||||
Question 31c: Artificially underwater installed and non-compacted sandy foreland? |
| No | No | OK | |||||||||||
Question 41d: Flow slide possible based on geometry only? |
| Yes | Yes | OK | Question 5: Is liquefaction possibleon criterion "steepest slope over 5 m"? |
| -No | Yes | Question 6: Are there any sensitive to liquefaction layers present? |
| Yes | Yes | No | OK | |
Question 71e: Is breaching possibleFlow slide possible based on average geometry only? | - | Yes | |||||||||||||
Result of the Global check |
| Failed | Failed | OK |
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| Unit | Benchmark | D-FLOW SLIDE | Relative error | ||||
---|---|---|---|---|---|---|---|---|
Fictive channel depth (Hr) | [m] | 21.571 | 21.571 | 0.00 % | ||||
Fictive slope (cotan αr) | [-] | 10.500 | 10.500 | 0.00 % | ||||
Probability of liquefaction | [-] | Not checked | ||||||
β | [-] | 3.749 | 3.749 | 0.00 % | ||||
P(L > Lallowable) | [-] | Not checked | ||||||
Probability of failure) | [-] | Not checked | 10.500 | 10.500 | 0.00 % | |||
βAllowable probability of failure | [-] | 2.50 × 1E-06 | 3.749 | 3.7492.50 × 1E-06 | 0.00 % | |||
Result of Detailed Check |
| Not checked |
1.2. Determination of the steepest possible breaching profile (step 7 of the Global check)
Description
The local critical profile given in Table A.4.2a from CUR113b is modeled in D-Flow Slide for both type of sand (not too medium fine and fairly coarse sand).
Different cases are considered:
Case | Type of sand | Number of flat berm | Description | Expected result for breaching |
---|---|---|---|---|
A | not too medium fine sand | 0 | The surface line coincides with the critical (local) profile given in Table A.4.2a from CUR113b | Fail |
B | 0 | The surface line is steeper than the critical (local) profile given in Table A.4.2a from CUR113b (local slope are 1:X-0.1m instead of 1:X) | Fail | |
C | 0 | The surface line is softer than the critical (local) profile given in Table A.4.2a from CUR113b (local slope are 1:X+0.1m instead of 1:X) | Pass | |
D | 0 | The surface line is softer than the critical (local) profile given in Table A.4.2a from CUR113b, but is steeper than the critical average profile at one point only | Fail | |
E | fairly coarse sand | 0 | The surface line coincides with the critical (local) profile given in Table A.4.2a from CUR113b | Fail |
F | 0 | The surface line is steeper than the critical (local) profile given in Table A.4.2a from CUR113b (local slope are 1:X-0.1m instead of 1:X) | Fail | |
G | 0 | The surface line is softer than the critical (local) profile given in Table A.4.2a from CUR113b (local slope are 1:X+0.35m instead of 1:X) | Pass | |
H | 0 | The surface line is softer than the critical (local) profile given in Table A.4.2a from CUR113b, but is steeper than the critical average profile | Fail | |
I | not too medium fine sand | 0 | The surface line is softer than the critical (local) profile given in Table A.4.2a from CUR113b (local slope are 1:X+0.1m instead of 1:X), but the channel is deeper than 40m. | Fail |
...
The soil has grain diameters of D50 = 200.1 μm and D15 = 100.1 μm, which corresponds to "Not too fine sand" soil Medium fine" sand type.
The local and average checks for all the points along the channel slope fail, so the Global check for Step 7 - Breaching fails.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Not too fine Medium fine sand" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
260 | 0 | ||||||
254 | -3 | 2 | 2 | 2 | 2 | Fail | Fail |
250 | -5 | 2 | 2 | 2 | 2 | Fail | Fail |
239.5 | -8.5 | 3 | 2.4118 | 3 | 2.5 | Fail | Fail |
235 | -10 | 3 | 2.5 | 3 | 2.5 | Fail | Fail |
219 | -14 | 4 | 2.9286 | 4 | 3 | Fail | Fail |
215 | -15 | 4 | 3 | 4 | 3 | Fail | Fail |
190 | -20 | 5 | 3.5 | 5 | 3.5 | Fail | Fail |
160 | -25 | 6 | 4 | 6 | 4 | Fail | Fail |
120 | -30 | 8 | 4.6667 | 8 | 4.67 | Fail | Fail |
70 | -35 | 10 | 5.4286 | 10 | 5.43 | Fail | Fail |
20 | -40 | 10 | 6 | 10 | 6 | Fail | Fail |
...
The soil has grain diameters of D50 = 200.1 μm and D15 = 100.1 μm, which corresponds to "Not too Medium fine" sand " soil type.
The local and average checks for all the points along the channel slope fail, so the Global check for Step 7 - Breaching fails.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Not too Medium fine sand" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
256 | 0 | ||||||
250.3 | -3 | 1.9 | 1.9 | 2 | 2 | Fail | Fail |
246.5 | -5 | 1.9 | 1.9 | 2 | 2 | Fail | Fail |
236.35 | -8.5 | 2.9 | 2.3118 | 3 | 2.5 | Fail | Fail |
232 | -10 | 2.9 | 2.4 | 3 | 2.5 | Fail | Fail |
216.4 | -14 | 3.9 | 2.8286 | 4 | 3 | Fail | Fail |
212.5 | -15 | 3.9 | 2.9 | 4 | 3 | Fail | Fail |
188 | -20 | 4.9 | 3.4 | 5 | 3.5 | Fail | Fail |
158.5 | -25 | 5.9 | 3.9 | 6 | 4 | Fail | Fail |
119 | -30 | 7.9 | 4.5667 | 8 | 4.67 | Fail | Fail |
69.5 | -35 | 9.9 | 5.3286 | 10 | 5.43 | Fail | Fail |
20 | -40 | 9.9 | 5.9 | 10 | 6 | Fail | Fail |
...
The soil has grain diameters of D50 = 200.1 μm and D15 = 100.1 μm, which corresponds to "Not too Medium fine" sand " soil type.
The local and average checks for all the points along the channel slope pass, so the Global check for Step 7 - Breaching passes.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Not too Medium fine sand" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
264 | 0 | ||||||
257.7 | -3 | 2.1 | 2.1 | 2 | 2 | Pass | Pass |
253.5 | -5 | 2.1 | 2.1 | 2 | 2 | Pass | Pass |
242.65 | -8.5 | 3.1 | 2.5118 | 3 | 2.5 | Pass | Pass |
238 | -10 | 3.1 | 2.6 | 3 | 2.5 | Pass | Pass |
221.6 | -14 | 4.1 | 3.0286 | 4 | 3 | Pass | Pass |
217.5 | -15 | 4.1 | 3.1 | 4 | 3 | Pass | Pass |
192 | -20 | 5.1 | 3.6 | 5 | 3.5 | Pass | Pass |
161.5 | -25 | 6.1 | 4.1 | 6 | 4 | Pass | Pass |
121 | -30 | 8.1 | 4.7667 | 8 | 4.67 | Pass | Pass |
70.5 | -35 | 10.1 | 5.5286 | 10 | 5.43 | Pass | Pass |
20 | -40 | 10.1 | 6.1 | 10 | 6 | Pass | Pass |
...
The soil has grain diameters of D50 = 200.1 μm and D15 = 100.1 μm, which corresponds to "Not too Medium fine" sand " soil type.
The local and average checks for all the points along the channel slope pass except for one point for which the average check fails, so the Global check for Step 7 - Breaching fails.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Not too fine sandMedium fine sand" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
263.83 | 0 | ||||||
257.53 | -3 | 2.1 | 2.1 | 2 | 2 | Pass | Pass |
253.33 | -5 | 2.1 | 2.1 | 2 | 2 | Pass | Pass |
242.65 | -8.5 | 3.05 | 2.4912 | 3 | 2.5 | Pass | Fail |
238 | -10 | 3.1 | 2.5825 | 3 | 2.5 | Pass | Pass |
221.6 | -14 | 4.1 | 3.0161 | 4 | 3 | Pass | Pass |
217.5 | -15 | 4.1 | 3.0883 | 4 | 3 | Pass | Pass |
192 | -20 | 5.1 | 3.5913 | 5 | 3.5 | Pass | Pass |
161.5 | -25 | 6.1 | 4.093 | 6 | 4 | Pass | Pass |
121 | -30 | 8.1 | 4.7608 | 8 | 4.67 | Pass | Pass |
70.5 | -35 | 10.1 | 5.5236 | 10 | 5.43 | Pass | Pass |
20 | -40 | 10.1 | 6.0956 | 10 | 6 | Pass | Pass |
...
The soil has grain diameters of D50 = 500.1 μm and D15 = 250.1 μm, which corresponds to "Fairly coarse sandCoarse sand/Gravel" soil type.
The local check for all the points along the channel slope fails, so the Global check for Step 7 - Breaching fails.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Fairly coarse sandCoarse sand/Gravel" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
170 | 0 | ||||||
164 | -3 | 2 | 2 | 2 | 2 | Fail | Fail |
160 | -5 | 2 | 2 | 2 | 2 | Fail | Fail |
153 | -8.5 | 2 | 2 | 2 | 2 | Fail | Fail |
150 | -10 | 2 | 2 | 2 | 2 | Fail | Fail |
138 | -14 | 3 | 2.2857 | 3 | 2.3333 | Fail | Fail |
135 | -15 | 3 | 2.3333 | 3 | 2.3333 | Fail | Pass |
120 | -20 | 3 | 2.5 | 3 | 2.5 | Fail | Fail |
100 | -25 | 4 | 2.8 | 4 | 2.8 | Fail | Fail |
80 | -30 | 4 | 3 | 4 | 3 | Fail | Fail |
50 | -35 | 6 | 3.4286 | 6 | 3.43 | Fail | Fail |
20 | -40 | 6 | 3.75 | 6 | 3.75 | Fail | Fail |
...
The soil has grain diameters of D50 = 500.1 μm and D15 = 250.1 μm, which corresponds to "Fairly coarse sandCoarse sand/Gravel" soil type.
The local and average checks for all the points along the channel slope fail, so the Global check for Step 7 - Breaching fails.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Fairly coarse sandCoarse sand/Gravel" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
166 | 0 | ||||||
160.3 | -3 | 1.9 | 1.9 | 2 | 2 | Fail | Fail |
156.5 | -5 | 1.9 | 1.9 | 2 | 2 | Fail | Fail |
149.85 | -8.5 | 1.9 | 1.9 | 2 | 2 | Fail | Fail |
147 | -10 | 1.9 | 1.9 | 2 | 2 | Fail | Fail |
135.4 | -14 | 2.9 | 2.1857 | 3 | 2.3333 | Fail | Fail |
132.5 | -15 | 2.9 | 2.2333 | 3 | 2.3333 | Fail | Fail |
118 | -20 | 2.9 | 2.4 | 3 | 2.5 | Fail | Fail |
98.5 | -25 | 3.9 | 2.7 | 4 | 2.8 | Fail | Fail |
79 | -30 | 3.9 | 2.9 | 4 | 3 | Fail | Fail |
49.5 | -35 | 5.9 | 3.3286 | 6 | 3.43 | Fail | Fail |
20 | -40 | 5.9 | 3.65 | 6 | 3.75 | Fail | Fail |
...
The soil has grain diameters of D50 = 500.1 μm and D15 = 250.1 μm, which corresponds to "Fairly coarse sandCoarse sand/Gravel" soil type.
The local and average checks for all the points along the channel slope pass, so the Global check for Step 7 - Breaching passes.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Fairly coarse sandCoarse sand*/Gravel" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
184 | 0 | ||||||
176.95 | -3 | 2.35 | 2.35 | 2 | 2 | Pass | Pass |
172.25 | -5 | 2.35 | 2.35 | 2 | 2 | Pass | Pass |
164.03 | -8.5 | 2.35 | 2.35 | 2 | 2 | Pass | Pass |
160.5 | -10 | 2.35 | 2.35 | 2 | 2 | Pass | Pass |
147.1 | -14 | 3.35 | 2.6557 | 3 | 2.3333 | Pass | Pass |
143.75 | -15 | 3.35 | 2.6833 | 3 | 2.3333 | Pass | Pass |
127 | -20 | 3.35 | 2.85 | 3 | 2.5 | Pass | Pass |
105.25 | -25 | 4.35 | 3.15 | 4 | 2.8 | Pass | Pass |
83.5 | -30 | 4.35 | 3.35 | 4 | 3 | Pass | Pass |
51.75 | -35 | 6.35 | 3.7786 | 6 | 3.43 | Pass | Pass |
20 | -40 | 6.35 | 4.1 | 6 | 3.75 | Pass | Pass |
...
The soil has grain diameters of D50 = 500.1 μm and D15 = 250.1 μm, which corresponds to "Fairly coarse sandCoarse sand/Gravel" soil type.
The local and average checks for all the points along the channel slope pass except for one point for which the average check fails, so the Global check for Step 7 - Breaching fails.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Fairly coarse sandCoarse sand/Gravel" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
171.84 | 0 | ||||||
165.69 | -3 | 2.05 | 2.05 | 2 | 2 | Pass | Pass |
161.59 | -5 | 2.05 | 2.05 | 2 | 2 | Pass | Pass |
154.42 | -8.5 | 2.05 | 2.05 | 2 | 2 | Pass | Pass |
151.34 | -10 | 2.05 | 2.05 | 2 | 2 | Pass | Pass |
139.3 | -14 | 3.01 | 2.3243 | 3 | 2.3333 | Pass | Fail |
136.25 | -15 | 3.05 | 2.3727 | 3 | 2.3333 | Pass | Pass |
121 | -20 | 3.05 | 2.542 | 3 | 2.5 | Pass | Pass |
100.75 | -25 | 4.05 | 2.8436 | 4 | 2.8 | Pass | Pass |
80.5 | -30 | 4.05 | 3.0447 | 4 | 3 | Pass | Pass |
50.25 | -35 | 6.05 | 3.474 | 6 | 3.43 | Pass | Pass |
20 | -40 | 6.05 | 3.796 | 6 | 3.75 | Pass | Pass |
...
The soil has grain diameters of D50 = 200.1 μm and D15 = 100.1 μm, which corresponds to "Not too Medium fine" sand " soil type.
The local and average checks for all the points along the channel slope pass but the channel is deeper than 40m (which is not covered by the CUR table), so the Global check for Step 7 - Breaching fails.
Inputted profile along channel slope | Critical profile from CUR table A.4.2a for "Not too Medium fine sand" | Result Global check - step 7 per point | |||||
---|---|---|---|---|---|---|---|
X [m] | Z [m +GL] | Local slope [1:xxx] | Average slope [1:xxx] | Local slope [1:xxx] | Average slope [1:xxx] | Local check | Average check |
274.1 | 0 | ||||||
267.8 | -3 | 2.1 | 2.1 | 2 | 2 | Pass | Pass |
263.6 | -5 | 2.1 | 2.1 | 2 | 2 | Pass | Pass |
252.75 | -8.5 | 3.1 | 2.5118 | 3 | 2.5 | Pass | Pass |
248.1 | -10 | 3.1 | 2.6 | 3 | 2.5 | Pass | Pass |
231.7 | -14 | 4.1 | 3.0286 | 4 | 3 | Pass | Pass |
227.6 | -15 | 4.1 | 3.1 | 4 | 3 | Pass | Pass |
202.1 | -20 | 5.1 | 3.6 | 5 | 3.5 | Pass | Pass |
171.6 | -25 | 6.1 | 4.1 | 6 | 4 | Pass | Pass |
131.1 | -30 | 8.1 | 4.7667 | 8 | 4.67 | Pass | Pass |
80.6 | -35 | 10.1 | 5.5286 | 10 | 5.43 | Pass | Pass |
20 | -41 | 10.1 | 6.1976 | 10 | 6 | Pass | Pass |
...