Exercise 2 Embankment 1

Geo-E2020 Nume umerica ricall Metho thods ds in Ge Geote otechnic chnics sL Wojciech Sołowski

Embankment 1

Today

Parameter Material model Type of behaviour  Soil unit weight above phreatic level Soil unit weight below phreatic level Horizontal permeability Vertical permeability Young's modulus Poisson's ratio Cohesion Friction angle Dilatancy angle

Name Model Type γunsat

Clay MC Undrained A 15

Peat MC Undrained A 8

γsat

18

11

20

kN/m3

kx ky E’ ν' c’ref  ϕ’

1⋅10-4 1⋅10-4 1000 0.33 5.0 24 0.0

2⋅10-3 1⋅10-3 350 0.35 7.0 20 0.0

1.0 1.0 3000 0.3 1.0 30 0.0

m/day m/day kN/m2 kN/m2 ° °

ψ

Sand MC Drained 16

Unit kN/m3

3

Today

4

Today

5

Today

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Today Water level at ground level.  Assumed that dense sand == rock Parameter Material model Type of behaviour  Soil unit weight above phreatic level Soil unit weight below phreatic level Horizontal permeability Vertical permeability Young's modulus Poisson's ratio Cohesion Friction angle Dilatancy angle

Name

Clay

Peat

γunsat

MC Undrained A 15

MC Undrained A 8

Sand (embankment) MC Drained 16

γsat

18

11

20

kN/m3

kx ky E’ ν' c’ref  ϕ’

1⋅10-4 1⋅10-4 1000 0.33 5.0 24 0.0

2⋅10-3 1⋅10-3 350 0.35 7.0 20 0.0

1.0 1.0 3000 0.3 1.0 30 0.0

m/day m/day kN/m2 kN/m2 ° °

Model Type

ψ

Unit kN/m3

7

To do: 1.

Consolidation analysis for the problem (pore pressures, consolidation in time, displacements, pore pressures in point A & B) - assume consolidation finished when excess pore pressures below 1kPa

2. Safety factor analysis (phi – c reduction) in each phase 3.

Extra: Influence of mesh update due to large strains, as well as adaptive meshing etc.

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Results

 A

•B

•

Figure 7. Excess pore pressure contours after consolidation to Pexcess < 1.0 kN/m2 (calculation phase 4)

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Results: safety (phi – c reduction)

Failure mode

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Grading: report part 1 1. 2. 3. 4. 5.

Replicating shown results in Plaxis for the embankment – 70% Report quality: introduction, conclusions, explanation of results - 20% Replicating large displacement analysis – 10% Mesh sensitivity study – extra 15% Replicating results in Optum – extra 45%

Total max is 160%, anything above 100% will be reduced to 100% This will be followed by Embankment 2 on next exercise – where reinforced embankment is solved. Solution of this embankment and the reinforced one should be included in a single report. The score for the report will be the average of both scores.

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Thank you