343x
000218
2023-02-20

VE 218 | Settlement of Foundation in Clay

Description

The settlements of a rigid square foundation on a lacustrine clay [1] are calculated with RFEM. One quarter of the foundation is modelled. The foundation has a width of 75.000 m in both sides. Construction stages are used to generate the results.

Material Lacustrine Clay Modulus of Elasticity E 10.000 MN/m2
Shear Modulus G 3.846 MN/m2
Poisson's Ratio ν 0.300 -
Specific Weight γ 17.000 kN/m3
Specific Weight γsat 18.000 kN/m3
Foundation Modulus of Elasticity E 30000.000 MN/m2
Poisson's Ratio ν 0.150 -
Specific Weight γsat 50.000 kN/m3
Geometry Foundation Length l 18.000 m
Foundation Width b 18.000 m
Foundation Thickness h 2.000 m
Load Cases Foundation Self-weight LC1 - -
Soil Self-weight LC2 - -

RFEM Settings

  • The borehole used for the generation of the soil massif has the lacustrine clay as an only soil layer and is 40.000 m long.
  • The foundation is embedded in the soil massif by means of solid intersections.
  • The length of the finite elements lFE for the soil is set to 4.000 m. A refinement of the mesh is considered around the foundation and lFE is set to 0.500 m.
  • For the calculation phases, two static analysis settings are used:
Static analysis settings Analysis type Options
SA1 Geometrically linear Non-symmetric direct solver if demanded by nonlinear model
SA2 Geometrically linear Non-symmetric direct solver if demanded by nonlinear model
Equilibrium for undeformed structure
  • The calculation phases are then defined using construction stages:
Construction stage Static analysis settings Assigned load cases
CS1 SA1 LC2
CS2 SA2 LC2
CS3 SA1 LC2 and LC1

Results

The obtained displacements in x, y and z directions are compared to the results calculated with the software PLAXIS 3D:

RFEM 6 PLAXIS 3D Ratio
max ux [mm] 14.4 14.5 0.99
RFEM 6 PLAXIS 3D Ratio
max uy [mm] 13.0 13.7 0.95
RFEM 6 PLAXIS 3D Ratio
max uz [mm] 110.4 111.0 0.99

References
  1. Bentley Systems. (2022). PLAXIS 3D CE V22.02: 1 – Tutorial Manual.


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