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H
CaseStep 1aStep 1cStep 1dStep 1e
Average slope

Step 1e

Breach flow

Step 1eGlobal checkDetailed checkOverall result Warning message(s)Information message 
ANo     PassPass-WarningD50 < 200 μm in the Detailed check, Advanced check needed (a) 
BYesYes    FailFail-Fail Artificial foreland , Advanced check needed (b)
CYesNoYes   FailFailFail- Criteria on "steepest Steepest slope over 5 m " met, Advanced check needed (c)
DYesNoNoYesNoYesFailPass-Pass  
EYesNoNoYesYesYes FailPassWarning-

D50 < 200 μm

in the Detailed check, Advanced check needed

(a)

Very fine sand (d)

 
FYesNoNoNoYesYesFailFail-Fail 

D50 < 200 μm

in the Detailed check, Advanced check needed

(a)

Very fine sand (d)

 
GYesNoNoNoNoNoPass-  
HYesNoNoNoNoNoPassPass-  
IYesNoNoNoNoNoPassNot available  
JYesNoNoYesNoYesFailWarningNot available Global passes but Detailed fails, check input 

 

a  D50 < 200 μm in the Detailed check, Advanced check needed.

b  The criteria on "steepest slope over 5 m" is met, Advanced check needed.

c  Artificial foreland, Advanced check needed.

d  The selected sand type is "Very fine" so the breach flow check in step 1e could not be performed, Advanced check needed.

 

 

For case A, For case A, the same input as benchmark 1-1 (see group 1)  is used except:

...

  • for the distribution of the stochastic parameters of the Detailed check (LogNormal instead of Deterministic/Normal)
  • for the channel slope which is 1: 5 5 instead of 1:6

 

For case F, the same input as benchmark 1-1 (see group 1) is used except:

  • for the distribution of the stochastic parameters of the Detailed check (LogNormal instead of Deterministic/Normal)
  • for the channel slope which is 1: 77.1 instead of 1:6.

 

For case G, the same input as benchmark 1-1 (see group 1) is used except:

  • for the distribution of the stochastic parameters of the Detailed check (LogNormal instead of Deterministic/Normal)
  • for the channel slope which is 1: 76.1 6 instead of 1:6.
  • for the grain diameters:
    • for Calais sand : D50 = 230 μm  (instead of 180) and D15 = 130 μm (unchanged)
    • for Compacted sand : D50 = 210 μm (instead of 160) and D15 = 110 μm (unchanged)

...

    • for the distribution of the stochastic parameters of the Detailed check (LogNormal instead of Deterministic/Normal)
    • for the channel slope which is 1:6.6 instead of 1:6.
    • for the state parameter which is equal to -0.06 instead of -0.03
    • for the grain diameters:
      • for Calais sand : D50 = 230 μm  (instead of 180) and D15 = 130 μm (unchanged)
      • for Compacted sand : D50 = 210 μm (instead of 160) and D15 = 110 μm (unchanged)
    • for the Detailed check, the required probability of failure is 1 per 40000 years instead of 1 per 4000 years and the migration velocity is 0.5m/year instead of 10 mm /year.

 

For case I, the same input as case H is used except that the Detailed check is not performed.

 

For case J, the same input as case D is used except that the Detailed check is not performed.

 

Benchmarks results

For each cases, the Global and Detailed checks are worked out in an Excel spreadsheet.

...

XSsign > XSzv => Flow slide would not lead to damage on levee => Global check passes.

Detailed check: ( see table below for intermediary results) Probability of flood damage by liquefaction  (= 0.00) < Allowable probability of failure (2.50 × 10-6) => Detailed check passes.D-Flow Slide results

Overall check: The Overall Overall check: as Global and Detailed check pass, the Overall check gives a Warning message because D50 < 200 μm , an Advanced check is therefore needed. 

...

Global check - Step 1c: 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.D-Flow Slide results

Overall check: as step 1c of Global check fails, the Overall check fails whatever the Detailed check result. The Overall check gives a Information message because the Global check fails.

Case C:

Global check - Step 1a:

...

Global check - Step 1d: The average slope over a height of at least 5 m is 1:3.901 so steeper than 1:4 => Flow slide is possible based on criterium "steepest slope over 5 m" => Global check fails.

Detailed check: ( see table below for intermediary results) Probability of flood damage by liquefaction  < Allowable probability of failure  => Detailed check passes.D-Flow Slide results

Overall check: the Overall result fails (even if the Detailed check passes) gives a Warning because the criteria on "steepest slope over 5 m" is met, an Advanced check is therefore needed.

...

But the total slope is 1:6 so steeper than 1:7 => Flow slide is possible based on average slope => Global check fails.

Detailed check: ( see table below for intermediary results) Probability of flood damage by liquefaction  < Allowable probability of failure  => Detailed check passes.D-Flow Slide results

Overall check: the Overall result passesNo message.

Case E:

Global check - Step 1a:

...

And the total slope is 1:5 so steeper than 1:7 => Flow slide is possible based on average slope => Global check fails.

Detailed check: ( see table below for intermediary results) Probability of flood damage by liquefaction  < Allowable probability of failure  => Detailed check passes.D-Flow Slide results

Overall check: the Overall check gives two Warning messages Overall check: the Overall check gives a Warning message because D50 < 200 μm and because the selected sand type is "Very fine", an Advanced check is therefore needed.

...

=> Flow slide is possible based on average slope => Global check fails.

Detailed check: ( see table below for intermediary results) Probability of flood damage by liquefaction  < Allowable probability of failure  => Detailed check passes.D-Flow Slide results

Overall check: as Detailed check passes, the The Overall check gives a two Warning message messages because D50 < 200 μm and because the selected sand type is "Very fine", an Advanced check is therefore needed. 

...

Global check - Step 1e:

The slope channel is 1:76.1600, so the slope is softer than the critical (local) slope from the CUR table (not too fine sand with  D50 = 230 μm and D15 = 130 μm) => Breaching is not possible.

And the total slope is 1:76.1 600 so softer than 1:7651 as (HR/24)1/3 = 1.651 with HR = 19.308 m.

=> Flow slide is not possible based on average slope => Global check passes.

Detailed check: ( see table below for intermediary results) Probability of flood damage by liquefaction  < Allowable probability of failure  => Detailed check passes.D-Flow Slide results

Overall check: as Global and Detailed check pass, the Overall passes. 

 

Overall check: Global passes and Detailed checks fails, that's not logical, so a warning message is displayed in the Overall check. 

D-Flow Slide results

D-FLOW SLIDE results are in accordance with the results by hand as show in the tables below.

No message.

 

Case H:

Global check - Step 1a: Flow slide would lead to damage on levee => Go to step 1c.

Global check - Step 1c: The foreland is natural => Go to step 1d.

Global check - Step 1d: The average slope over a height of at least 5 m is 1:7.1 so softer than 1:4 => Flow slide is not possible based on criterium "steepest slope over 5 m" => Go to step 1e.

Global check - Step 1e:

The slope channel is 1:7.1, so the slope is softer than the critical (local) slope from the CUR table (not too fine sand with  D50 = 230 μm and D15 = 130 μm) => Breaching is not possible.

And the total slope is 1:7.1 so softer than 1:7

=> Flow slide is not possible based on average slope => Global check passes.

Detailed check: see table below for D-Flow Slide results

Overall check: No message.

 

Case I:

Global check : idem case H => Global check passes.

Detailed check: Results not available.

Overall check: No message.

 

Case J:

Global check : idem case B => Global check fails.

Detailed check: Results not available.

Overall check: No message.

 

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

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

No

30.000

15.000

-10.000

 

No

30.000

15.000

-10.000

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No

6

 

No

6

 

OK

0.00 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes

6

Yes

 

Yes

6

Yes

 

OK

0.00 %

OK

Result of the Global check

Pass

Pass

OK

Fictive channel depth Hr [m]19.08719.087 0.00 %
Fictive slope cotan αr  [-]23.00023.000 0.00 % 
Max. allowable retrogression length Lallowable [m]150.000150.0000.00%
Probability of occurence P(ZV) [/year] 3.66 × 10-73.66 × 10-70.00 %
Reliability index critical length β-39.999 -
Probability P(L > Lallowable) [/year] 0.000.000.00 %
Probability of flood damage by liquefaction P(falen|ZV) [/year]0.000.000.00 %
 
Results of benchmark 3-1 for case

...

B: 

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

NoYes

30.000

15.000

-10.000

 

NoYes

30.000

15.000

-10.000

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoYesNoYesOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No

6

 

No

6

 

OK

0.00 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes

6

Yes

 

Yes

6

Yes

 

OK

0.00 %

OK

Result of the Global check

PassFailPass

Fail

OK

Fictive channel depth Hr [m]1921.0875711921.087 5710.00 %
Fictive slope cotan αr  [-]2310.00052310.000 50.00 % 
Max. allowable retrogression length Lallowable [m]150.0006060150.0000.00%00 %
Probability of occurence preventing a liquefaction P(ZV) [/km/year] 24.92 × 94 × 10-724.92 × 94 × 10-70.00 %
Reliability index critical length ββ-391.999 712-
Probability P(L > Lallowable) [/year] 0.004.34 × 10-24.34 × 10-20.000.00 %
Probability of flood damage by liquefaction P(falen|ZV) [/year]0.000.000.00 %Allowable probability of failure ZV) [/year]2.50 × 15× 10-68 22.50 15 × 10-680.00 %

Result of the Detailed check 

PassPassOK 
Overall resultWarningWarningOK 
 
Results of benchmark 3-1 for case

...

C:

...

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

3028.000016

15.000

-10.000331

 

Yes

3028.000016

15.000

-10.000331

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?YesNoYesNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

NoYes6

3.901

 

NoYes6

3.901

 

OK

0.00 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes6

7.395

Yes

 

Yes6

7.395

Yes

 

OK

0.00 %

OK

Result of the Global check

Fail

Fail

OK

Fictive channel depth Hr [m]2123.5717912123.5717910.00 %
Fictive slope cotan αr108.5413108.54130.00 % 
Max. allowable retrogression length Lallowable [m]60600.00 %
Probability of preventing a liquefaction P(ZV) [/km/year] 3.95 × 10-73.95 × 10-70.00 %
Reliability index β-1.712-
P(L > Lallowable)4.34 × 10-24.34 × 10-20.23 %
60600.00 %
Probability of preventing a liquefaction P(Probability of flood damage by liquefaction P(falen|ZV) [/year] 17.72× 04 × 10-817.72 04 × 10-80.00 %
Allowable probability of failure [/year]2.50 × 10-6 2.50 × 10-60.00 %

Result of the Detailed check 

PassPassOK 
Reliability index β-39.999 -
P(L > Lallowable) [/year] 000.00 % 
Probability of flood damage by liquefaction P(falen|ZV) [/year]000.00 %Overall resultFailFailOK
 
Results of benchmark 3-1 for case

...

D: 

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

2830.016000

15.000

-10.331000

 

Yes

2830.016000

15.000

-10.331000

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

YesNo

3.9016

 

YesNo

3.9016

 

OK

0.00 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes

7.3956

YesNo

 

Yes

7.3956

YesNo

 

OK

0.00 %

OK

Result of the Global check

Fail

Fail

OK

Fictive channel depth Hr [m]2321.7915712321.7915710.00 %
Fictive slope cotan αr810.413500810.4135000.00 % 
Max. allowable retrogression length Lallowable [m]60600.00 %
Probability of preventing a liquefaction P(ZV) [/km/year] 54.63 90 × 10-8754.63 × 90 × 10-870.00 %
Reliability index β--1.334712 -
P(L > Lallowable) [/year] 94.09 34 × 10-1294.09 34 × 10-120.00 % 
Probability of flood damage by liquefaction P(falen|ZV) [/year]52.12 × 13 × 10-852.12 13 × 10-80.00 %Allowable probability of failure [/year]2.50 × 10-6 2.50 × 10-60.00 %Result of the Detailed check PassPassOK
Overall resultFailFailOK
 
Results of benchmark 3-1 for case

...

E:

...

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

3036.000

15.000

-109.000

 

Yes

3036.000

15.000

-109.000

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No6

5.000

 

No6

5.000

 

OK

0.00 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes6

5.000

NoYes

 

Yes6

5.000

NoYes

 

OK

0.00 %

OK

Result of the Global check

Fail

Fail

OK

Fictive channel depth Hr [m]2125.57114325.5711430.00 %
Fictive slope cotan αr10.500141410.5000.00 % 
Max. allowable retrogression length Lallowable [m]60600.00 %
Probability of preventing a liquefaction P(ZV) [/km/year] 31.92 80 × 10-7631.92 × 80 × 10-760.00 %
Reliability index β-1.712234 -
P(L > Lallowable) [/year] 41.34 08 × 10-2141.34 08 × 10-210.00 %
Probability of flood damage by liquefaction P(falen|ZV) [/year]1.70 × 10-81.70 95 × 10-870.00 %
Allowable probability of failure [/year]2.50 × 10-6 2.50 × 10-60.00 %

Result of the Detailed check 

PassPassOK
Overall resultPassPassOK
 
 1.95 × 10-70.00 %

 

Results of benchmark 3-1 for case

...

F:

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

3025.000360

15.000

-10.000775

 

Yes

3025.000360

15.000

-10.000775

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No

57.000094

 

No

57.000096

 

OK

0.00 03 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes

57.000100

Yes

 

Yes

57.000100

Yes

 

OK

0.00 %

OK

Result of the Global check

Fail

Fail

OK

Fictive channel depth Hr [m]25.14386425.1438640.00 %
Fictive slope cotan αr146.6466.646140.00 % 
Max. allowable retrogression length Lallowable [m]60600.00 %
Probability of preventing a liquefaction P(ZV) [/km/year] 13.44 33 × 10-6713.44 33 × 10-670.00 %
Reliability index β-039.999-
P(L > Lallowable) 5.00 × 10-1 [/year] 005.00 × 10-10.23 00 %
Probability of flood damage by liquefaction P(falen|ZV) [/year]7.18 × 10-7 7.18 × 10-70.18 %Allowable probability of failure [/year]2.50 × 10-6 2.50 × 10-6000.00 %

Result of the Detailed check 

Pass

Pass

OK 
Overall resultWarning

Warning

OK 

 

Results of benchmark 3-1 for case

...

G:
60OK 

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

2527.352280

15.000

-10.775453

 

Yes

2527.352280

15.000

-10.775453

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No

76.099595

 

No

76.100596

 

OK

0.01 02 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes

7.100

Yes

 

Yes

7.100

Yes

 

OK

0.00 %

OK

Result of the Global check

Fail

Fail

OK

Fictive channel depth Hr [m]25.87425.8740.00 %
Fictive slope cotan αr6.6416.6410.00 % 

No

6.600

No

 

No

6.600

No

 

OK

Max. allowable retrogression length Lallowable [m]60

0.00 %

OK

Result of the Global check

Pass

Pass

OK

Fictive channel depth Hr [m]19.30819.308Probability of preventing a liquefaction P(ZV) [/km/year] 2.67 × 10-72.67 × 10-70.00 %
Reliability index β-0.974-
P(L > Lallowable)1.65 × 10-11.65 × 10-10.10 %
Fictive slope cotan αr10.50010.5000.00 % 
Max. allowable retrogression length Lallowable [m]6060Probability of flood damage by liquefaction P(falen|ZV) [/year]4.40 × 10-8 4.40 × 10-80.00 %
Allowable probability of failure Probability of preventing a liquefaction P(ZV) [/year] 2.50 30 × 10-67 22.50 31 × 10-670.00 %

Result of the Detailed check 

PassPassOK 
Overall resultWarningWarning
43 %
Reliability index β-39.999-
P(L > Lallowable) [/year] 000.00 %
Probability of flood damage by liquefaction P(falen|ZV) [/year]000.00 %

 

 

Results of benchmark 3-1 for case

...

H:

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

2527.352280

15.000

-10.775453

 

Yes

2527.352280

15.000

-10.775453

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No

76.099596

 

No

76.100596

 

OK

0.01 02 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

No

76.100600

No

 

No

76.100600

No

 

OK

0.00 %

OK

Result of the Global check

Pass

Pass

OK

Fictive channel depth Hr [m]2519.8740382519.8740380.00 %
Fictive slope cotan αr610.641500610.6415000.00 % 
Max. allowable retrogression length Lallowable [m]60600.00 %
Probability of preventing a liquefaction P(ZV) [/km/year] 25.65 80 × 10-7425.65 80 × 10-740.00 %
Reliability index β-039.974999-
P(L > Lallowable)1.65 × 10-1 [/year] 001.65 × 10-10.00 %
Probability of flood damage by liquefaction P(falen|ZV) [/year]4.38 × 10-84.38 × 10-80.00 %
Allowable probability of failure [/year]2.50 × 10-6 2.50 × 10-60.00 %

Result of the Detailed check 

Pass

Pass

OK 
Overall result

Pass

Pass

OK 

...

000.00 %

 

Results of benchmark 3-1 for case

...

I:

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

2527.352280

15.000

-10.775453

 

Yes

2527.352280

15.000

-10.775453

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?NoNoOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No

76.099595

 

No

76.100596

 

OK

0.01 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

No

76.100600

No

 

No

76.100600

No

 

OK

0.00 %

OK

Result of the Global check

Pass

Pass

OK

Fictive channel depth Hr [m]25.87425.8740.00 %
Fictive slope cotan αr6.6416.6410.00 % 
Max. allowable retrogression length Lallowable [m]60600.00 %
Probability of preventing a liquefaction P(ZV) [/km/year] 6.66 × 10-46.66 × 10-40.00 %
Reliability index β-0.974-
P(L > Lallowable)1.65 × 10-11.65 × 10-10.00 %
Probability of flood damage by liquefaction P(falen|ZV) [/year]1.10 × 10-41.10 × 10-40.00 %
Allowable probability of failure [/year]2.50 × 10-7 2.50 × 10-70.00 %

Result of the Detailed check 

FailFailOK 

Pass

Pass

OK

Result of the Detailed check 

Not availableNot availableOK 

 

 

Results of benchmark 3-1 for case J: 

 

Benchmark

D-FLOW SLIDE

Relative error

Step 1a:

Would flow slide lead to damage on levee?

Marge [m]

Slope [1:xxx]

Assessment level [m + NAP]

 

Yes

30.000

15.000

-10.000

 

Yes

30.000

15.000

-10.000

 

OK

0.00 %

0.00 %

0.00 %

Step 1c: Artificially underwater installed and non-compacted sandy foreshore?YesYesOK

Step 1d:

Flow slide possible based on criteria "steepest slope aver 5m" ?

Average slope over a height of at least 5 m [1:xxx]

 

No

6

 

No

6

 

OK

0.00 %

Step 1e:

Flow slide possible based on average geometry only?

Total inclination of the channel slope [1:xxx]

Is breaching possible?

 

Yes

6

Yes

 

Yes

6

Yes

 

OK

0.00 %

OK

Result of the Global check

Fail

Fail

OK

Result of the Detailed check 

Not availableNot availableOverall result

Warning

WarningOK