A new non-local FE formulation for modelling piles and barrettes
A new non-local FE formulation designed for modelling piles and barrettes enhances ZSoil in the domain of deep foundation design.
Contrary to the previous local formulation, the new formulation offers a significantly reduced mesh dependency as well as good convergence features for fine meshes. The new formulation is designed for two standard cross sections i.e., circular and quadrilateral one. The latter makes it possible to model a barrette.
The pile/barrette elements can be linked with the shell elements eliminating another spurious effect of strong mesh dependency of the bending moment and shear forces in piles/barrettes in the connection zone.
The plot below illustrates a comparison of force-displacement diagrams obtained with a reference true 3D geometry model of an axially loaded pile and two models based on the embedded beam approach with the local and the non-local formulation. The results are obtained for different mesh sizes for 800mm circular pile show how the new formulation eliminates the strong mesh dependency.
Predictions of force-displacement curves for local and non-local technique
A very good match between the true 3D model and the simplified non-local one is proven for a horizontally loaded circular pile.
Predictions of bending moment and deflection for a horizontally loaded pile using local and non-local technique
The image below shows a distribution of settlements for a an axially loaded barrette (cross section 1.6m x 0.8m). It can be noticed that the non-local embedding technique is able to reproduce the deformation pattern of a real geometry of barrette in a very realistic manner.
Distribution of settlements around a barrette accounting for its real geometry geometry
The new formulation proves to give reasonable predictions for horizontally loaded barrettes in terms of bending moment and deflection profiles.
Bending moment and deflection in a horizontally loaded barrette using local and non-local technique
Reduction of computational time
A significant improvement in the calculation module makes it possible to reduce the overall computation time of a simulation by 10 to 30%, depending on the analyzed problem and the number of models which are run in parallel.
ZSoil 2023 brings a few new features which aim at improving model creation such as :
- coloring line objects
- improved selection dialog box for elements
- customized verification of model data and geometrical consistency
The new ZSoil 2023 brings a simplified template for ZSoil 2D with a special reference to fast modelling of slopes for stability analysis.
The application offers:
- stability checks based on incremental tan(ϕ)-c reduction algorithm
- rapid pre-processing of different-shaped slopes based on automated finite element mesh generation including locking-free finite elements
- importing geometry from DXF files
- creating simple slopes using pre-defined geometries
- definition surface loads, pseudo-static body load, rain flux
- enforcement of user-defined slip surfaces
- control of actions by means of time-dependent functions (loads, fluxes and ground water table changes)
- modelling of soil behavior by means of advanced elasto-plastic constitutive model for soils (HSS)
- time-dependent (consolidation) or steady-state analysis including partially-saturated effects in soil
- analysis of infinite slopes
- automatic PDF reporting for the computed results
A number of improvements enhance Virtual Lab in ZSoil 2023.
Material database manager
Users who used the previous versions of Virtual Lab can connect to previously created databases. The user can also create material databases in a user-defined location.
From now, generation of a full user-configured or a simple PDF report with a list of model parameters only is possible from the database manager level. The latter allows the user to print list of parameters for the material models which are exported to the database manager from the ZSoil’s material definition list.
The improvements in the parameter identification module have been focused on eliminating singularities which in the previous versions, used to halt the parameter identification process in the case of poorly or un-processed laboratory data. An automatic detection of docking phase for triaxial test measurements and a new dedicated toolbox for trimming the non-processed data has been integrated on this occasion.
Docking data trimmer tool
Lab test simulator
A few modifications have been introduced in the lab test simulator with respect to the oedometer test for the Hardening Soil model.
Automatic/Interactive parameter selection
A minor update of the correlations database has been focused on upgrading a few correlations for the friction angle in granular soils. The revisions are listed in the Correlation Database Log.