There are two options to model a massive tapered pile easily:

1. Using the cone

This shape of a tapered pile can be achieved by making use of the "cone" command.

To create a cone for a tapered pile

1. use the command for PLAXIS 3D AE:
    cone <radius r> <coneheight h> <point> <direction vector>
   or for earlier versions (3D 2013 or earlier), use this command with the now obsolete accuracy parameter:  cone <radius r> <coneheight h> <accuracy> <point> <direction vector>
   with
   • radiusr = Dtop /2 (Dtop is diameter at the top of the pile)
   • coneheight h is determined by h = L_pile / ( 1 - ( D_foot /  D_top) )
   • accuracy gives the number of segments along the circumference of the cone. Note this is now obsolete since PLAXIS 3D AE.
   • point is the center point for the cone’s base
   • direction vector tells in which direction the cone should be pointing. For a vertical tapered pile this should be (0 0 -1)
   • Note: the cone command only creates a shell, not the volume.
   • For more details on the cone command, please refer to the Commands reference (in the Help menu)
2. at the foot level, insert a horizontal surface larger than the cross sectional area of the tapered pile at this level
3. now intersect the cone and surface: multiselect the cone and the surface, right click the selection and choose intersect
4. now remove the redundant parts: the extended surface and the cone part below the pile foot level
5. make sure to add a surface to cap the cone to create a closed body within the surfaces.
6. when one wants to model soil-structure interaction, interfaces should be introduced. Select the cone (and the bottom), and apply outside interfaces to all these surfaces

This concludes the geometry creation. To activate the pile for the calculation, make sure to change the soil material inside the pile volume into the pile’s material in the appropriate phase including activation of the interfaces.

2. Import from CAD

Of course it is always possible to model the geometry in a third party CAD program and then import this geometry in PLAXIS 3D. See How do I import a geometry in PLAXIS 3D? for more tips on importing

After importing, make sure to add interfaces to properly model soil-structure interaction.

Sometimes you want to reuse a part of the geometry of an already existing PLAXIS 3D model in a different model. With PLAXIS 3D it is possible to export geometrical objects from Input using the command __saveobjects. The volumes and surfaces from these objects can be easily imported into the newly created PLAXIS 3D project using the Import soil... and Import structures... options in Input.

The available formats of the exported files are the following:

• Plaxis 3D Object files (*.px3o)
• Stereolithography files (*.stl)
• Plaxis Mesh files (*.plxmesh)

The command has the following structure:
__saveobjects "px3o""C:\PLAXIS3D\Objects"

Parameters:

The files exported in the specified directory include objects present in both Blue and Green coloured tabs in PLAXIS Input program.

Geometry in blue tabs

The exported files of objects created in Blue tabs (Soil / Structures) are:

• Surfaces and Polygons
• Volumes
• Soil volumes from boreholes

Example
In the case of an object called Polygon_1 in Structures mode, it can be exported to a *.px3o file. This file would be named:
StrucSurf-Polygon_1.px3o
Note that the first part of the name indicates that this object was created in Structures mode and it is a surface.

Geometry in green tabs

The exported files of objects present in Green tabs (e.g. Staged construction mode), which contain all intersected objects are the following:

• Surfaces and Polygons
• Volumes
• Soil volumes from boreholes
• Points (note: cannot be imported)
• Lines (note: cannot be imported)

Example PLAXIS 3D AE
In the case of an object called Polygon_1_1 in Staged construction mode, it can be exported to a *.px3o file, and this file would be named:
Polygon_1_1-000.px3o
Note that relevant files are created for every object after the intersection process that are present in Water levels/Stage construction mode.

Example 3D 2013
In the case of an object called Polygon_1, in Staged construction mode, it is called e.g. CS_Polygon_1, it can be exported to a *.px3o file, and this file would be named:
CS_Polygon_1-000.px3o
Note that the first part of the name indicates that this object is created after the intersection process, C(ross) S(ection), and it is present in Water levels/Stage construction mode.

Note that when choosing the *.stl or *.px3o formats each object is saved in its separate file. However, in the case of the *.plxmesh format all objects of the geometry are exported in a single file.

For more details on the __saveobjects-command or any other command, please refer to the Plaxis 3D Command Reference, available via the Help menu.

Earthquakes propagate from the bedrock to the surface through the overlying soil deposit,which acts as a filter and modify the ground motion characteristics. The variation of the seismic waves in terms of amplitude, duration and frequency content at any depth can be evaluated through a ground response analysis. The local soil stratigraphy, the material properties, the site topography, the ground water table depth and the characteristics of the earthquake (for example, duration, peak acceleration, frequency content) have a high influence on the ground response and on the modelling strategy. The ground response analysis of a soil deposit can be considered as a necessary preliminary study for the dynamic analysis of a structure, since its seismic response is influenced by the geological and geotechnical properties of the supporting soil. Due to its filter effect, the soil deposit modifies the seismic waves by amplifying the signal at some specific frequencies and damping it at some others. If the frequency at which the maximum amplification of the ground motion occurs is close to the natural frequency of the overlying structure, the building and the ground motion are in resonance with one another. This means that the system oscillates with very high amplitudes that can cause great damages in the building.

This example (with elaborated background information) concerns the one-dimensional wave propagation analysis through a clay deposit 40 m thick above the bedrock. One-dimensional analysis can be performed when the soil layers and the bedrock surface are horizontal and they extend to infinity, and the seismic waves coincide with shear waves propagating vertically from the underlying bedrock. This last assumption can be justified considering that the seismic waves, propagating from the earthquake source through the soil, are bent by successive refractions into a nearly vertical path (according to Snell's law of refraction). The problem can be modelled through a soil column with specific features, as described in the attached document.

This example presents the results of a one dimensional site response analysis performed with PLAXIS 2D, aimed at modelling the non-linear dissipative behaviour of soils subjected to an earthquake loading. In this respect, an important role is played by the choice of the constitutive model for the soil. The results of the fully dynamic analysis performed with PLAXIS 2D are compared to an equivalent-linear site response analysis performed with EERA, where the secant shear modulus and the damping ratio are updated in subsequent iterations to be consistent with the level of strain induced in each layer. In PLAXIS , the Hardening Soil model with small strain stiffness has been chosen showing that, for earthquakes characterized by moderate peak accelerations, it is capable to capture the soil behaviour during earthquake shaking. The results from both approaches are compared showing a good agreement.

Relative displacement response spectrum at 3.6 m from the surface level.
Comparison PLAXIS - EERA

When using certain command templates multiple times, it would be helpful if you can re-play these commands with just a single click. With a Macro you can do this: you can easily play a set of predefined commands.

Creating a macro

To create a macro:

• Go to the Macro library menu item (available under the Expert menu)
• Here choose to manage the library
• And add a new Macro
• Give it a descriptive title
• And add the commands you would like to perform when executing this macro

Figure 1. The Macros library window

Using a macro

In order to make use of a macro, open the menu item Expert > Macro library > and here you will see the available macros. Now click on a macro to execute it.

Figure 2. Macros in the Expert menu

Keyboard shortcuts

Next to using the menu item to run a macro, PLAXIS also offers to execute a command via a keyboard shortcut. The first macro will be accessible via the key combination Shift + Ctrl + Alt + 1. This keyboard shortcut is also shown in the menu Expert > Macro library, see in the image above.

Examples

Tip: to make any command more flexible and useful in any Plaxis model, use the Group Filtered and Apply commands [link] in combination with the possibility to refer to any object using their index [link]. See also the examples below.

Calculation settings

Let’s say you have a large project with many phases and want to switch all of them except the initial one to use

• a max. of 2 CPUs (cores)
• and you want to store 10 steps for each phase.

You can write this macro for it:

groupfiltered Phases "PreviousPhase!="# all except the initial phaseapply Groups[-1]"setproperties""MaxCores"2apply Groups[-1]"setproperties""MaxStepsStored"10ungroup Groups[-1]# get rid of temporary group to leave model clean

This will work regardless of how many phases and/or groups you already have. It will only fail if you just have the initial phase, as that would try to create an empty group at the beginning.

Or, if you want to only change this for all the phases that are set to be calculated, we can add a new filter (groupfiltered command) to only use phases that are set to be calculated (ShouldCalculate == True), and then directly calculate it:

gotostagesgroupfiltered Phases"ShouldCalculate=True"groupfilteredGroups[-1]"PreviousPhase<>"applyGroups[-1]"sps""MaxCores"2#insert here the number of CPUsapplyGroups[-1]"sps""MaxStepsStored"10#max steps to save per phaseungroupGroups[-1]ungroupGroups[-1]calculate

Switch to Updated Mesh

To change all phases to use Updated Mesh, you can use this macro:

gotostagesgroupfiltered Phases"ShouldCalculate=True"groupfilteredGroups[-1]"PreviousPhase<>"applyGroups[-1]"sps""Deform.UseUpdatedMesh"TrueapplyGroups[-1]"sps""Deform.UseUpdatedWaterPressures"True#2D ONLYungroupGroups[-1]ungroupGroups[-1]

Note that UpdatedWaterPressures is currently (2015) only available in PLAXIS 2D.

Geometry checks for meshing in PLAXIS 3D

The tabulate command can also be used to detect if small surfaces or volumes are present in the intersected 3D geometry in the mesh mode. This could indicate problem areas for the 3D mesh generation.
To check for small volumes ( < 1 m³), small surfaces (e.g. a surface area < 0.1 m²) and small lines, you can use this macro:

tabulate SoilVolumes"Volume""Volume<1"tabulate Volumes"Volume""Volume<1"tabulate Surfaces"Area""Area<0.1"tabulate Lines"Length""Length<0.1"

Show a table of safety factors

To show a table of the SumMsf values, you can use this single command as a macro to quickly get this table in the Input program:

tabulatephases"PreviousPhaseReached.ReachedMsf""DeformCalcType=Safety"

This page list the changes in the commands and its parameters per version

PLAXIS 3D AE.00

GeneratedSoilVolume changes to BoreholeVolume

The soil volumes/polygon generated from boreholes are now renamed to use Borehole as prefix rather than GeneratedSoil. This is more clear where the soil volume originates from (from the Borehole definition), and also more consistent with the naming of the waterlevels generated in the boreholes (BoreholeWaterLevels).

Embedded pile changes to embedded beam

The embedded pile has been renamed to embedded beam to make clear this embedded beam can be used for more than just piles, e.g. grout anchors.

To create a new embedded beam:

embeddedbeam(x1y1z1)(x2y2z2)

To create a new embedded beam row material dataset:

embeddedbeammat

Note: in this version the old commands for the embedded pile rows will be supported, but may become deprecated in later versions.

Cutobjects (staged construction and mesh mode) and manual intersection

Due to an issue in the sorting routine of the cut objects (i.e. the intersected result of soils, volumes, polygons, lines), and the fact that the source of a cut objects was not clear in its naming, the automatic naming of items in the intersected geometry (mesh mode, flow conditions mode, staged construction, or just manual intersection in e.g. Structure mode by using the intersect command) has been changed. This also involves removing the prefix CS_ for these items, see this example:

• PLAXIS 3D 2013: CS_Line_1
• PLAXIS 3D AE: Line_1_1

Also, reference points per volume, surface and line may vary. This is important for when setting reference and incremental values.

Decomposed geometry

When decomposing e.g. a volume into surfaces, PLAXIS 3D 2013 would give this response:

0005> _decomposesrfVolume_1Added Polygon_Volume_1_1 Added Face_Volume_1_1 Added Polygon_Volume_1_2 Added DecomposedGeometry_1 

With PLAXIS 3D AE, this naming of the resulting surfaces is now more uniform:

0005> _decomposesrfVolume_1Added Surface_Volume_1_1 Added Surface_Volume_1_2 Added Surface_Volume_1_3 Added DecomposedGeometry_1 

This means that the names of the new surfaces is different than in PLAXIS 3D 2013. Also, reference points per surface may vary. This is important for when setting reference and incremental values.

Local mesh refinements

The local mesh refinement value parameter is now renamed from FinenessFactor to CoarsenessFactor. For now, existing projects and command lines will remain compatible for using this property name. In this version the old naming of the local mesh coarseness will be supported, but may become deprecated in later versions.
Please also note the change in naming of cutobjects for full compatibility.

Default boundary conditions

The deformation boundary conditions have been changed to make it easier to change only one side of the model, instead of all sides as in 3D 2013. Now you can set either side to be Free, Normally fixed, Horizontally fixed, Vertically fixed, and Fully fixed.
Next to that, these boundary conditions now only work on model sides that are parallel to one of the axis and coincide with the minimum or maximum coordinate for each axis.

The command to set UseDefaultFixities is now obsolete and will not work. For example:

setDeformations.UseDefaultFixitiesPhase_1False

In 3D AE, you can change this to:

deactivateDeformationsPhase_1

For more details, please see Modifying boundary condition.

Multiplier on vector based features

The name for the multiplier userfeature has been changed. For point loads and point prescribed displacements, this userfeature name has been changed from .Multiplier_x/_y/_z to .MultiplierFx/Fy/Fz. To set a LoadMultiplier for a dynamic point load using the command line:

• 3D 2013: setDynLineLoad_1_1.Multiplier_xPhase_1LoadMultiplier_1
• 3D AE: setDynPointLoad_1_1.MultiplierFxPhase_1LoadMultiplier_1

For line loads, this userfeature name has been changed from .Multiplier_x/_y_z to .Multiplierx/y/z, and this would be the command line:

• 3D 2013: setDynLineLoad_1_1.Multiplier_xPhase_1LoadMultiplier_1
• 3D AE: setDynLineLoad_1_1.MultiplierxPhase_1LoadMultiplier_1

For surface loads, this userfeature name has been changed from .Multiplier_x/_y_z to .Multiplierx/y/z, and this would be the command line:

• 3D 2013: setDynSurfaceLoad_1_1.Multiplier_xPhase_1LoadMultiplier_1
• 3D AE: setDynSurfaceLoad_1_1.MultiplierxPhase_1LoadMultiplier_1

Parametric geometry: cylinder, cone and arcs

Since PLAXIS 3D AE, parametric geometry is supported. This means that any curved shape made inside PLAXIS 3D does not need a discretization in sections to approximate the 3D curved shape. This has influence on the used commands that needed this discretization angle.

• the cylinder command does not need the number of segments any more:
  • 3D 3013: cylinder<radiusr><heighth><accuracy><point><directionvector>
  • 3D AE: cylinder<radiusr><heighth><point><directionvector>
  • Note, in 3D AE, next to the volume creation for the cylinder, it will automatically assign a Soil feature to the volume. This was not done automatically in 3D 2013.
• the sphere command does not need the number of segments (accuracy) any more:
  • 3D 2013: sphere<radiusr><accuracy><point>
  • 3D AE: sphere<radiusr><point>
  • Note, in 3D AE, next to the volume creation for the sphere, it will automatically assign a Soil feature to this new volume. This was not done automatically in 3D 2013.
• the cone command also does not need the number of segments (accuracy) any more:
  • 3D 2013: cone<radiusr><coneheighth><accuracy><point><directionvector>
  • 3D AE: cone<radiusr><coneheighth><point><directionvector>
  • see also http://kb.plaxis.com/tips-and-tricks/modelling-tapered-pile
• the shape designer does not need an angle discretization for arcs anymore. The command will not fail, but the setting is obsolete.

Gravity value

The gravity value is now a fixed value of 9.81 m/s² and will be converted correctly to the used units in the PLAXIS 3D AE project. This property should be removed from any command to set the general project properties.

Material sets

The reference to LoadCase items (LoadCaseRef0, LoadCaseRef1, LoadCaseRef2, etc) should now be removed from the command when setting up material datasets or when changing properties.

Re-applying same materials set

In PLAXIS 3D 2013, re-applying the same material set to a soil or structural element fails, see also this related known issue. This is now fixed in PLAXIS 3D AE.00

Calculation type for initial phase: flow only

When performing a groundwater flow calculation only (so when you are not interested in deformations), the calculation type of the Initial Phase now needs to be set to "Flow only" (it was "Groundwater flow only" in previous versions):

setInitialPhase.DeformCalcType"Flow only"

Groups in staged construction

When grouping items in Staged construction mode (or any of the green modes), groups are now called S_Group_#, instead of CS_Group_# with # the number of group.

Cannot manually intersect mixed objects

When having mixed objects (parametric and non-parametric), it is not possible to manually intersect these using the intersect command.

To check if a geometric item is parametric or not, we can use this command for e.g. Volume_1:

echoVolume_1.ParametricBehaviour

Also, to remove the parametric setting and fall back to the non-parametric (internally triangulated) geometry, use this command:

removeparametricVolume_1

Nonplanar polygon is now invalid

When using the surface command, if one or more points are not defined in the original plane of the surface (defined by the first three points), the surface will not be valid. To fix this, you can use the option to project the points onto the plane, via right click on the invalid polygon, or use this command:

projectpointsPolygon_1

You can recognize such invalid polygons by blue corner points and dashed lines:

Cannot import step files with anisotropic scale factors

When importing parametric geometry (e.g. STEP file), it is not possible to use different scale factors for the x, y and z direction.

PLAXIS 3D 2013.00

Water levels from boreholes: BoreholeWaterlevel

In 3D2012 and earlier, water levels created by the water definition in boreholes were called GeneratedWaterLevel_1, GeneratedWaterLevel_2, etc. However, this was somewhat confusing where this data originated from. Since PLAXIS 3D 2013 this is now clearer: such waterlevels are now called BoreholeWaterlevel_1, BoreholeWaterlevel_2, etc.

Surface Contractions

The collection of surface contractions used to be called Contractions, which was inconsistent with the name of individual surface contractions (e.g. SurfaceContraction_1). This collection name is now changed into SurfaceContractions.

Groundwaterflow boundary conditions

The general boundary conditions for flow and consolidation to tell which side (x_min, x_max, y_min, y_max, z_min, z_max) was open or closed are no longer part of the phase settings, but are now part of the global boundary conditions, or under Model Conditions in the Phase Model Explorer.

Example: The command to open the x_min boundary is now changed to:

set GroundwaterFlow.BoundaryXMin Phase_1 "Open"

Impermeable interfaces

Interfaces now have an independent setting to define an interface as permeable or impermeable, whereas this was an implicit setting in PLAXIS 3D2012 and earlier.

Example to set an interface to impermeable, use:

set PositiveInterface_1_1.Permeable Phase_1 False

Note that when activating an interface, it will automatically change its permeability setting to False (so making it impermeable), but not the other way around:  when deactivating an interface, the permeability setting will remain as it was.

PLAXIS 3D 2012.00

Phase object

In PLAXIS 3D 2012, the Phase object has been completely revised in order to allow for more control on calculation parameters and iterative settings. Also the whole graphical user interface for phases has been updated, taking advantage of this new structure. This also means that a great deal of all phase-object properties are changed. For details, please see the object reference via the program's Help menu. Some examples:

• the enumeration for the calculation type has been changed
• the calculation types Plastic and Plastic Drained are now merged into Plastic. You can still switch the option ignore undrained behaviour on or off again to get the same options available

PLAXIS 3D 2011.00

Geotextile materials

When trying to play back PLAXIS 3D 2010 commands that create/modify geotextile materials, an error may be given because of the new anisotropic functionality. The EA property has been split into EA1 and EA2 (which are identical if the new IsIsotropic property is set to True), and the Np property has been split into Np1 and Np2 (which are identical if the new IsIsotropic property is set to True). When (re)using these geotextile material commands, please adjust these according to the new specifications. For more details, please see the command “geogridmat” in the commands reference.

The Groninger Forum will be constructed in the center of Groningen city. The building is commissioned by the groningen municipality. This 45-m-height and eccentric-styled cultural center will include a library , museums, cinemas, restaurants and bars. Two basements complete the structure: a five-storey car park (suitable for 390 cars) and a one-storey bicycle parking (suitable for 1,500 bicycles). The car park is located exactly underneath the main structure, whereas the bicycle parking keeps a horizontal distance from it. 

As part of the InfraQuest research into the sustainability of immersed tunnels in the Netherlands, a study was carried out at Delft University of Technology to analyze the up and down movements of the Vlaketunnel. InfraQuest is a joint research program of the Ministry of Infrastructure, Delft University of Technology and Delft TNO. The research was done by N. Benhaddou as a final MSc. project.