1) Earthquakes can damage levees through liquefaction of sand layers in or under the levee, which causes crest settlement and instability. 2) Recent studies on earthquake-resistant design of levees in Groningen, Netherlands have applied software models to analyze mechanisms of sliding, squeezing, compaction, and sheet pile bending during earthquakes. 3) The software models incorporate liquefaction analysis, nonlinear soil response, and finite element simulations to derive fragility curves and inform design.

1. Earthquake resistant design of
levees and adjacent sheet piling
Marcel Visschedijk

2. Proven earthquakes damage to levees
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Especially if sand in or under the levee liquefies
All pictures from: Y. Sasaki et al. / Soils and Foundations 52 (2012) 1016–1032

3. Damage caused by liquefaction
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4. Damage caused by liquefaction
Kobe, picture from http://geot.civil.metro-u.ac.jp/archives/eq/95kobe/index.html
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5. 24-Jun-15 5
Proven earthquakes damage to levees
Slide from: Presentation of Ikuo Towhata, at the Second International Conference on Performance‐Based design in Earthquake
Geotechnical Engineering, Taormina, Italy on May 29, 2012

6. Proven earthquake damage in the Netherlands
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Roermond, 1992 (magnitude 5.8)
All pictures from: beeldbank.rws.nl

7. Groningen levees
Questions for the 2013 study*:
• Show the current state of the primary and
regional defences
• Give an indication of the required
improvement, differentiating between the
situation without and with earthquakes
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Continued studies in 2014/2015 on most critical stretches:
• Eemskanaal: levees and sheet-piling
• Eemshaven-Delfzijl
*http://www.rijksoverheid.nl/onderwerpen/aardbevingen-in-groningen/documenten-en-publicaties/rapporten/2014/01/17/deltaers-effecten-van-aardbevingen-op-kritische-infrastructuur.html

8. Important questions for EQ resistant design
• Which mechanisms to consider and which (software) models to use
• Which loading to apply
• (How to reduce liquefaction, or minimize its effect)
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PGA
T
(Picture from: Y. Sasaki et al.)
(Picture from: Y. Sasaki et al.)
(Picture from: I. Towhata)

9. Further content of the presentation
• Which mechanisms to consider
• Recently applied software models for the Groningen levees
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10. Mechanims caused by earthquakes
• Instability or damage by earthquake force
• Crest settlement or damage by liquefaction of sand
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11. Content of the presentation
• Which mechanisms to consider
• Recently applied software models for the Groningen levees
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12. AAD: dedicated software for embankments
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AardbevingsAnalyse Dijken
Input: D-Geostability schematizations + cone resistances
Output: Fragility curves

13. AAD v1: Applied Peak Ground Acceleration
Along Eemskanaal
00
01
02
03
04
05
06
07
1 10 100 1000 10000
km31.5
Along Eemshaven-Delfzijl
PGA [m/s^2]
Return period [year]
• Probability distribution According to KNMI
• Semi-probabilistic determination of design value
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PGA [m/s^2]
Return period [year]

14. AAD v2: Nonlinear Soil Response
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15. AAD: Applied Liquefaction model
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EERI MNO-12*:
Determines the excess pore pressure ratio 𝑟𝑢=
Δ𝑢
𝜎 𝑣.0
′ in clean sand as a function of
field stresses, CPT resistance (𝑞 𝑐) en Peak Ground Acceleration (PGA)
Example: Sand layer of 10m, without
cover layer: 𝑟𝑢 5m below surface
*Idriss, I.M. and Boulanger, R.W., 2008, Soil liquefaction during earthquakes, EERI MNO-12
𝑞c = 12 Mpa
𝑃𝑃𝑃 = 0.1𝑔
Empirical
cyclic shear stress ratio resistance
15

16. AAD: models for the embankment
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Displacement by sliding
Settlement by squeezing
Settlement by compaction
F

17. Displacement by sliding
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Force = Mass * Acceleration Displacement above yield
value by double integration
“Newmark Sliding Block” – also mentioned in EC8
Criterion: maximum sliding displacement = 0.15m (Jibson*)
For design: inverse application to determine the critical acceleration value where
static stability with D-Geostability has to be preserved to keep displacement
below criterion.
*Jibson, R.W., 2011, Methods for assessing the stability of slopes during earthquakes—A retrospective: Engineering Geology, v. 122, p. 43-50.

18. Displacement by sliding in case of liquefaction
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Reduced tangent of the angle of friction tan(𝜙) by (partial) liquefaction
• 50 % reduction during earthquake:
tan 𝜙reduced = 1 − 0.5ru ⋅ tan 𝜙initial
• 100 % reduction after earthquake:
tan 𝜙reduced = max (0.06, 1 − ru ⋅ tan 𝜙initial)
(analogous to draft Dutch National Application Document – NPR 9989)

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Scaling of measured accelerogram
Derivation of (horizontal) design accelerograms
1. EC8: use at least 3 representative ground signals (4 used)
2. Scale measured signals for acceleration and time* with the Peak
Ground Acceleration ratio: 𝑃𝑃𝐴design/𝑃𝑃𝐴measured
PGA

20. Crest settlement by squeezing
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h_levee
d_top
d_liquefied
Finite Element results were used to fit an approximate (!) function between
crest settlement and ℎlevee ⋅
𝑑liquefied
𝑑top
2 (inspired by Finn*)
* Finn, W. (2000). State-of-the-art of geotechnical earthquake engineering practice. Soil Dynamics and Earthquake Engineering, 20, pp 1-15.

21. Crest settlement by compaction
Accepted empirical function of cyclic Factor of Safety against
liquefaction and Relative Density 𝐷𝑟 (based on Ishihara & Yoshimine*)
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* Ishihara, K., & Yoshimine, M. (1992). Evaluation of settlements in sand deposits following liquefaction during earthquakes. Soils and Foundations, Vol. 32, No.1, March 1992, pp 173-188.
Factor of safety is cyclic shear ratio (CSR)
divided by cyclic resistance ratio (CRR)

22. Example of resulting Fragility Curves
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FoS Slope Stability versus PGA
Crest Settlement versus PGA

23. Models for Sheet-Piling: before and after EQ
Before earthquake: D-Sheetpiling
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After earthquake: D-Sheetpiling with
100 % reduced strength by (partial)
liquefaction

24. Models for Sheet-Piling: during EQ
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Comparison of bending moments between generalized Mononobe-Okabe
method (also suited for cohesive soil) and Finite Element Method (FEM)
FEM is preferred: Mononobe-Okabe method is too conservative,
and not able to find solutions for larger PGA values
M-O
M-O
M-O
FEM

25. • Used to derive an approximate factor between static and dynamic
moments and anchor forces (load and site specific)
• Liquefaction modeling by manual strength reduction (using 50 % of
the final 𝑟𝑢) in combination with (damping) Hardening Soil Small
Strain model
• In progress: comparison with implicit pore pressure generation by
constitutive models such as UBC-Sand or Hypoplasticity.
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Current usage for Groningen levees:
Dynamic FEM for sheetpiling during EQ

26. 24-Jun-15 26
Dynamic FEM for sheetpiling during EQ
Derivation of (horizontal) base acceleration
1. EC8: use at least 3 representative ground signals (4 used)
2. Translate measured surface signals to the base at the location of the
measurement, using the local soil profile and for example the EERA*
software
3. Scale the base signals for acceleration and time with the ratio
𝑃𝑃𝐴design/𝑃𝑃𝐴measured (see Newmark Sliding Block)
*A Computer Program for Equivalent linear Earthquake site Response Analyses of Layered Soil Deposits. Bardett et all, 2000
surface
base

27. Finite Element simulation of liquefaction
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• Hypoplasticity model is more generic than UBC-Sand model (initial state,
different CSR values), but parameter determination is more difficult
• Models are sensitive to variations of dominant parameters (HP: blow count,
UBC-Sand: initial void ratio)
• Current models can determine the undrained onset of liquefaction, but don’t
supply reliable post-liquefaction deformations

28. Cyclic DSS test simulation on Loose sand
0.08
0.1
0.12
Green: UBCSAND Green: Hypoplastic
Excess Pore Pressure Ratio
28
Shear
Stress
Ratio
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29. Expected further application of Finite Elements
• Liquefiability of Groningen sand with “single pulse” signals,
compared to tectonic signals
• Nonlinear response of subsoil plus levee, incl. pore pressure
generation
• Effectivity of mitigating measures
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