New Plaxis 3D tutorial

Easy and good tutorial for the analysis of a concrete slab in Plaxis 3D.
This tutorial goes through some nice tricks as well as some commands to speed up the modelling process.
The video can be found at here - Link

Automate the packing process in Plaxis - Plaxis 2D / Plaxis 3D

Automate the packing process in Plaxis


YouTube-tutorial that explain the creation of .bat files for automating the packing of Plaxis-projects. The option of automatically pack your Plaxis 2D or Plaxis 3D files provides both energy and time saving for the user.


The video explains the lines needed in a .bat files and can be applied to all Plaxis files. However different versions of Plaxis as well as the 2D/3D programs needs different file-endings to work. These can be easily checked by looking at the files you want to pack.


Link to video: Packing Plaxis 2D and Plaxis 3D projects

Common mistakes made in Plaxis

There are a lot of mistakes to be made when modelling in Plaxis. A term often adopted is shit in shit out or something similar and it is completely right!

The lack of understanding can result in serious consequences and software like Plaxis is not to blame. Except in rare occasions where the software is actually wrong the answers given will be a direct result of the input/instruction given by the user. This problem is not helped by the simplicity of Plaxis where someone without understanding quite easily could; create, run and obtain results from a model and therefore believe that everything is OK and correct.

It is vary important to check input, assumptions, model and output and more importantly have someone else check. The problematic thing is that even thou everything is checked multiple times by different people, things can get overlooked.

Here are a few things where people tend to make mistakes in Plaxis:

Generating initial conditions with k0-procedure
Engineers often run the k0 without thinking of what the k0 procedure does to generate the initial effective stresses. The k0-procedure is only correct when all the geometry of the ground surface, the ground layers, and the ground water table are horizontal. If this is not the case the k0-procedure will lead to the existence of unbalance forces or non-equilibrium of initial forces.
 

Changing (SUM)M_stage in a faulty manner
In some cases the user can choose to change the Sum M_Stage to a value smaller than 1.0. If the user does this it is important that the user knows what happens. Say that the goal is to run 50% then 25% and then the final 25% the way to do this is to have the M_Stage set to 0.5, 0.5 and 1. 50% in the first stage, 50% of the remaining 50% in the second stage (i.e. 25%) and 1, 100% of the remaining 25%. (This is explained in more detail in the Plaxis Tunnel Webinar. LINK)
 

Switching back and fourth between Mohr-Coulomb and Linear Elastic material
If the switch is made for a material from Mohr-Coulomb material model to Linear Elastic the user needs to pay attention to the input-parameters. These can change between every flip that is made and should be checked so that they correspond to the values that the user wants to use.

Putting Interface Elements where they don't belong
The user should check if the interfaces used actually obtain the results that is sought. For example interfaces on node-to-node anchors and embedded beam rows are sometimes inserted.

Not Checking the undrained shear strength when using Undrained (A)
The shear stress values have to be checked so that they do not violate the undrained shear strength from soil or laboratory tests.

Dilatency angle when modelling with Undrained (A)
Dilatency angle for Undrained (A) should be used with care. Plaxis recommends that the dilatency angle is set to 0 in their manuals. Positive angles may lead to unrealistic values in tensile pore stresses i.e. unrealistic values of  shear strength. Negative angles may lead to unrealistic values in pore pressures and therefore behaviour.

NEW Plaxis Webinar - Embankment on Rigid Inclusions

Interesting webinar focusing on the modelling of rigid inclusions as Embedded beam elements under embankment. The reason for the rigid inclusions are layers of softer materials that have to be reinforced to enable the embankment to be built on top.

This webinar is a good introduction to these kinds of problems with a live demonstration where the full model with embankment and two types of embedded piles are created and run.

The introduction part of the webinar was sufficient to understand the creation of the model and the trick used for the embedded beam row where a small part of the beam is created in the material above the connection-point to overcome the problem with the fixed connection. Instead of the fixed connection, an axisymmetric model is created with the same material for one beam only. The correct skin friction for each beam is extracted and used for the connection-part of the beam in the layer above.

Overall, the Webinar was good and well built with a good combination of introduction/theory and axial modelling. The amount of information however does not enable a non-experienced user to create their own models.

With the amount of Tutorials etc. for Plaxis being so low, it is very good that Plaxis has these webinars.

As soon as the webinar is uploaded, a link will be posted.

Also a teaser for Plaxis 2D 2016 has been uploaded on the official Plaxis channel. Link in the News section

New problem in Plaxis 2D

New problem posted by Plaxis for Plaxis 2D
No Solution or workaround yet.
Link in News page

List of new Plaxis - Webinar videos; 2015/2016

List of new Plaxis - Webinar videos; 2015/2016


This List will be updated as new Plaxis webinars have been held and announced!
Here are some dates for upcoming webinars which have been announced by Plaxis:

• Free Webinar: Embankment on Rigid Inclusions, 3rd of Feburary 2016

Previous Webinars:
1. Free Webinar: Tunneling in Rock
This webinar gives an introduction and overview of the tunnel and rock modelling capabilities in Plaxis. This webinar includes both Plaxis 2D and Plaxis 3D.  A short demonstration of a multi-stage tunnel-excavation in Plaxis 2D is included.The demonstration also demonstrate the modelling of rock bolts.

Control Plaxis-modules that should load in Plaxis

Control Plaxis-modules that should load in Plaxis (Flexible/Network licenses).

To not load and therefore not allocate the Flow- or Dynamics-module easy toggles can be created.

These toggles switched on/off easily and enables for persons who needs the specific module to have access to these. If no toggles exists the first person loading Plaxis will load the extra modules witch can be problematic if you have multiple Plaxis standard licenses and only one or a few modules.

Files without file-extensions are created (one for each module) with the specific names as below: 

PRETEND_NO_TRANSIENT_FLOW

PRETEND_NO_DYNAMICS

These are created in the folder “toggles” (“\PLAXIS 2D\toggles”) if this folder does not exist; create it. The toggles can be switched off by deleting them or changing the name ex. (NO_PRETEND...).

A toggle for the Thermal-module will be precented here if one is found. 

 

The Author accepts no liability for assumptions taken from this post, or for the consequences of any actions taken on the basis of the information provided, this information is intended as educational and should be treated as such. 

 

Slide 7.0 release

The new version of Slide by Rocscience is released!

The new release offers the user a lot of new features amongst these features is the new Multi-scenario modelling which allows the user to create, edit and analyse multiple Slide models within a single document file.

Some of the other new features in the new release of Slide:

• Soil Profile
• Sarma Block Analysis
• Seismic Analysis Options
• Newmark Seismic Analysis
• Material models
• Pile support

There are a lot of new features in the new release of Slide and the full list of changes and updates from previous versions can be found on the Rocscience webpage.


Check out their webpage for more information

Link can be found HERE under Rocscience

New problem in Plaxis 2D 2015

New problem posted by Plaxis for Plaxis 2D 2015


No Solution or workaround yet.
Link in News page

New Midas GTS NX - Webinar videos

List of new Midas GTS NX - Webinar videos; 2015/2016


This List will be updated as new Midas GTS NX webinars have been held and announced!
Here are some dates for upcoming webinars which have been announced by Midas:

•  Expert Webinar - Evaluating the stability of landslide and geostructures with numerical analyses - 1 April 2016

Previous Webinars:
1. Limit Equilibrium vs 2D FEM vs 3D FEM of Embedded Retaining Wall in Birmingham New St

This webinar is interesting and provides a summary of research project with a contiguous piled retaining wall analysed in Midas GTS NX in both 2D and 3D. The selected geometry, construction staging and site conditions are from a project where excavation where made for a rainwater tank in Birmingham.

2. Evaluating the stability of landslide and geostructures with numerical analyses
This webinar goes through the methods and paths for assessing the stability of landslide and geo-structure. Both simple and complex cases are shown with step-by-step description in both 2D and 3D.

Interesting lectures by Dr. Evert Hoek

The Art of Tunnelling in Rock

Tunnelling in rock presents a large number and special challenges to the geotechnical engineer. In this lecture, Dr. Evert Hoek briefly presents a few interesting cases and examples of tunnelling around the world.

Click here to watch the video
Click here to watch the video with Spanish subtitle.

Development of Rock Engineering

Very interesting lecture surrounding the art of tunnelling in rock with Dr. Evert Hoek.

This lecture provides a brief history in the field of rock engineering. There is also a look into a number of interesting examples and real-life cases.

Click here to watch the video
Click here to watch the video with Spanish subtitle.