PLAXIS 2D – Unable to reproduce bowl-shaped settlement and geogrid axial force distribution
Hello everyone,
I am trying to calibrate a PLAXIS 2D model of a rubble mound breakwater constructed on soft marine clay.
The overall settlement magnitude is reasonably close to the reference, but I still cannot reproduce the deformation pattern.
Model information
- Breakwater materials: Mohr-Coulomb
- Soft clay: Soft Soil Creep (SSC)
- Sandy layers: Hardening Soil (HS)
- Geogrid element with interfaces on both sides (Rinter = 0.9)
- Staged construction using Consolidation phases
- Final consolidation period: 800 days
- Updated mesh enabled during large deformation stages
Soil profile
- Soft clay layer over sandy layers.
- Sandy layers are classified as silty sand (SM-ML and SM-CH).
- SPT values range approximately from 40 to more than 50.
What I have already checked
- SSC parameters (λ*, κ*, μ*)
- OCR
- Unit weights
- HS stiffness parameters (E50ref, Eoedref, Eurref)
- Sandy layer permeability
- Drained and Undrained A behaviour
- Geogrid axial stiffness
- Interface properties
- Mesh refinement
- Construction sequence
- Consolidation time
Current problem
The maximum geogrid axial force in my model is about 137 kN/m, while the reference model reaches about 170 kN/m.
More importantly, my geogrid axial force distribution has a dip at the center, whereas the reference model has a clear peak beneath the center of the breakwater.
Also, my settlement profile is much flatter and does not develop the expected bowl-shaped settlement.
At this stage I feel that the issue is probably not only related to soil parameters.
Has anyone experienced a similar problem in PLAXIS?
Which aspects would you investigate next?
Could it be related to:
- Initial stress generation (K0)?
- Interface implementation?
- Geogrid activation?
- Consolidation settings?
- Something else?
