Dear
I modeled a real point cloud data in to the Plaxis 3D FEM and the data comes from the real survey of an investigation. In this regard, it is obvious that we have a complex surface from the real data. In this analyze, we want to investigate the land sliding hazard in different areas and controlling the safety factor in different areas. The phases are determined as the following:
Initial phase:
Calculation type: Gravity loading
Loading type: staged construction
…
2nd phase:
Calculation type: Safety
Loading type: Incremental multipliers
Msf: 0.1
Question 1: Does the Plaxis 3D FEM has this ability to define some specific area or draw some lines to determine the safety factors in these areas and lines and show the worst lines and points with fewer safety factor on the model? I want to evaluate which area and lines have the lowest safety factor on them.
Question 2: If I go to the “view calculation results” and draw a curve with the x-axis defined with the “step” instead of defining the specified nodes and in the y-axis defining the multiplier “Sigma Msf”, the Plaxis shows me for each step, the worst node has the maximum reduction in the shearing parameters and finally shows me the failure in a specified node with the maximum reduction in the shearing failure which reveal the safety factor. In this regard, if I want to know the other nodes that reached the failure then after that, what should I do? How could I understand the other failed nodes in the model in the following because I want to know the failed points and values of the safety factor in different area of the model to define specific design for them?
I would be thankful if you may please guide me in this process
Thanks for your response
I look forward to hearing from you
Sincerely
Dear Amir,
I will answer both of your questions below:
1. PLAXIS computes a global safety factor. That means that the calculation will find the most critical failure mechanism in the model you have and determine a safety factor based on that. Therefore, the value you get would be the lowest safety factor based on what PLAXIS has determined to be the most critical failure zone.
Note that sometimes PLAXIS calculation focuses on a local failure that from an engineering point of view is not relevant or is to be disregarded. PLAXIS offers an option to exclude part of the model using the Apply strength reduction option for volumes. Therefore, you can partition your geometry in the area of the irrelevant local failure and uncheck the option:
For more information, please check our Reference manual.
2. The curve plot you create (as you mention) is "step vs. ΣMsf". That again refers to the most critical failure mechanism found by the calculation. If you want data from other areas of the model, you can select as many curve points as you want and plot the relevant data.
I would advise you to follow our webinar on Using PLAXIS to Determine Factors of Safety:event.on24.com/.../6BA8A61A920F589C3E5C23DA3B23FDD6
Thanks for your information. I have a question, could there be the possibility that we adjust the output result of the Plaxis to show us, not only the most critical failed point, but also to show us the first, for example 20 first points that have the maximum failing in the model?
I ask this question, because in the model maybe also there are some other parts of the model that failed, and we do not know and we are just seeing and checking the maximum failed point in the model.
Thanks for your response Sincerely