The check on safety against liquefaction consist consists of passing through three phases, where the depth increases every time:

• Simple or Gloabel Global check:
  • Global check according to VTV (i.e. step 1 till 5 of VTV-2006)
  • Simple check according to CUR-113
• Detailed check (step 6 as described in the VTVreport "Technische Rapport ...")
• Advanced check (using the existing program SLIQ2D)

1. Global check (steps 1 t/m 5 described in VTV-2006)

Figure 1: Toetsschema zettingsvloeiingenchecking scema for liquefaction

1.1 Step 1 - Geometrical check: damaging criterium liquefaction

The damaging criterion is met if at the so-called assessment level is situated within the slope (i.e. on landward side of) the so-called observation profile, in accordance with Annex 9.4 of the VTV-2006.

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• a. The required margin (the horizontal part from the outside toe of the dike). The margin is now determined by the relation:
  xxx M = 2 Hvw + 1.5 (H - Hvw)
  where H is the channel depth and HVW is the thickness of the softening- sensitive layer. If over the entire channel depth softening sensitive sand is present, this margin is thus equal twice the fiectieve trench fictive channel depth (M = 2 H).b.
  A. The required margin CAPAC M = 2 + 1.5 (H CAPAC)
  b. The inclined part of the observation profile in line with the horizontal portion. The taludhellig is afhankeijjk inclinaison of the trench slope depends on the channel depth:

1. Determination of the assessment level
2. Comparison of the observation profile with the existent existing profile
   X Ssign = X co-ordinaat of the observation profile from the forelandforeshore
   X SZV = X co-ordinaat of the liquefaction point from the forelandforeshore

Step 2: Artificially underwater installed and non-compacted sandy foreshore?

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