This website is an introduction to the basics of using the PLAXIS finite element software package.
Followers can also comment on and discuss posts related to PLAXIS (2D and 3D), numerical modelling and various geotechnical engineering topics.
Use an axisymmetric model. In the creation of your model, create a rectangle at the symmetry boundary.....with an axissymmetric model this will create a cylinder. In calculation mode, use staged construction as follows: 1) K0 procedure for initial stresses 2) Stone column installation by changing the properties of the soil within the cylinder you created to the properties of stone 3) Whatever loads you inted to apply
Very valuable information it got from this blog. One Que. How can i model Geo foam(EPS) as replacement to soil. 1. By giving Geofoam properties to localized soil. or 2.by modeling beam element and giving geofoam properties
also interface is required in which case (plaxis 2D 8.2)
Aplogies for late reply. I recommend using soil replacement. You can use with interface elements on or off but is good to use both to consider the effect of nodal slip
sir thank u Sir, I use undrain for clay and water level 0.5m below GL. If my foam thickness is 1.0m. then for foam what shall is consider 1. Undrain 2. Drain 3. non porous (it will float, as EPS foam is non porous)
Q.2 How much factor shall i consider for Rinter = 0.6 to 1 ( pls. suggest value)
You use undrained if you wish to consider the build-up and dissipation of excess pore pressures. If the GeoFoam you use is impermeable - then use non-porous. If it is permeable - use drained.
The correct value of Rinter to use is a tough one and depends on the foam-soil interface and depends on the soil type, installation method etc. I recommend researching interface friction values in the literature for foam-soil interfaces. Your Rinter will then be tan(interface friction angle)/tan(friction angle soil).
If you cannot find articles on this, I recommend keeping it simple and using a value of Rinter=1. Then carry out a parametric study where you vary Rinter from 1 to 0.5 to see what effect this has on your results
sir, as GWT is below 1.0m and geofoam thickness is 450mm, undrain soil condition, soft clay, MC model during calculation after some Mstage there is massage in log info 1. Prescribed ultimate state not reached! 2. load advancement procedure fails, try manual control,
in iterative proce, manual setting what are reference values can i take for soft marine clay so that ultimate state occure
Sir, My name is Prashanth Talkad and I have been working on modeling Leg penetration analysis of Spud Can in PLAXIS 2D, I have difficulties in running the Analysis because of soil body collapse message. This is a layered soil profile with a very low shear strength in the top layer. I have assigned prescribed displacement (12m) at the widest section of the spudcan. Can you please suggest me modeling technique. I would really appreciate your help.
Your research sounds interesting. A couple of things: when the analysis stage 'fails' check plastic points to see exacty where the soil is failing...this might give some insight into the problem. Also...have you 'arc length control' off? The soil model you are using is also important and whether you have specified total stress parameters or effective stress parameters. Drained or undrained analyses?
Thanks for the information Sir, I have specified Drained conditions for sand layers and Undrained conditions for clay layers. Now that you have specified about Arc Length control, will try to run the analysis by having this option tuned off. Will keep you posted on my model analysis. Thank you very much for your timely feedabck
hi i want to model tunneling advancement in plaxis 3d 2013, and when i model the tunnel full space not take axis of symmetry, yhe model of tunneling is open face tunneling which mean every phase of calculation i remove soil slice and add shotcrete ling and the water level at the surface of soil the soil collapse when i perform analysis but if i put water table at the bottom the soil not collapse. same model but i take half space about the axis of symmetry and the water level at surface the soil not collapse? why is that?please
Hello Sir, My name is Preethi suvarna and I have been working on modeling touch pile analysis in PLAXIS 2D, I have difficulties in running the Analysis because of error showing "load advancement procedure fails". This is a layered soil profile with loose to dense SAND property. I have assigned Mohrs columb model with drained condition. Can you please suggest me modeling technique.
Dear, i am Afewerki I am curently working on numerical analysis of soil column into the effect of settlement of raft foundation. So during analysis i have facing alot of challenges for instance 1. The soil body seems to collapsa 2. Load advancement procedure failes 3. Meshing output is not found 4.unknown errors ets So how can i solve these errors and how can i generate load displacement curve in 3d 2013
i recieved this message from plaxis 2d when i try to analyze the slope under high ground water table. Here is the message" prescribed ultimate state not reached. soil body collapses. and inspect output and load displacement curve" the software is showing me this message again and again what shall i do? please help me.
i recieved this message from plaxis 2d when i try to analyze the slope under high ground water table. Here is the message" prescribed ultimate state not reached. soil body collapses. and inspect output and load displacement curve" the software is showing me this message again and again what shall i do? please help me.
27 comments:
Hi. Sir i need step by step command for modeling of stone column using plaxis 2D. Pls reply me sir.
Hi. Sir i need step by step command for modeling of stone column using plaxis 2D. Pls reply me sir.
Use an axisymmetric model. In the creation of your model, create a rectangle at the symmetry boundary.....with an axissymmetric model this will create a cylinder.
In calculation mode, use staged construction as follows:
1) K0 procedure for initial stresses
2) Stone column installation by changing the properties of the soil within the cylinder you created to the properties of stone
3) Whatever loads you inted to apply
Very valuable information it got from this blog. One Que. How can i model Geo foam(EPS) as replacement to soil.
1. By giving Geofoam properties to localized soil. or
2.by modeling beam element and giving geofoam properties
also interface is required in which case (plaxis 2D 8.2)
waiting for valuable reply
Aplogies for late reply. I recommend using soil replacement. You can use with interface elements on or off but is good to use both to consider the effect of nodal slip
sir thank u
Sir, I use undrain for clay and water level 0.5m below GL.
If my foam thickness is 1.0m. then for foam what shall is consider
1. Undrain
2. Drain
3. non porous (it will float, as EPS foam is non porous)
Q.2 How much factor shall i consider for Rinter = 0.6 to 1 ( pls. suggest value)
There is no easy answer for this.
You use undrained if you wish to consider the build-up and dissipation of excess pore pressures.
If the GeoFoam you use is impermeable - then use non-porous. If it is permeable - use drained.
The correct value of Rinter to use is a tough one and depends on the foam-soil interface and depends on the soil type, installation method etc. I recommend researching interface friction values in the literature for foam-soil interfaces. Your Rinter will then be tan(interface friction angle)/tan(friction angle soil).
If you cannot find articles on this, I recommend keeping it simple and using a value of Rinter=1. Then carry out a parametric study where you vary Rinter from 1 to 0.5 to see what effect this has on your results
Thank you for help, I used interface result is excellent.
sir,
as GWT is below 1.0m and geofoam thickness is 450mm, undrain soil condition, soft clay, MC model during calculation after some Mstage there is massage in log info
1. Prescribed ultimate state not reached!
2. load advancement procedure fails, try manual control,
in iterative proce, manual setting what are reference values can i take for soft marine clay so that ultimate state occure
There is not a simple solution to this.
Check plastic points in the output program to see where the soil is failing....this might give some insight to the problem.
Also, try increasing the number of steps in the phase and the max number of iterations.
You can also try un-checking 'arc-length control'
sir thank
when i uncheck arc-length control it will run up to max steps.
how to check stress, strain in geofoam?
Sir,
My name is Prashanth Talkad and I have been working on modeling Leg penetration analysis of Spud Can in PLAXIS 2D, I have difficulties in running the Analysis because of soil body collapse message. This is a layered soil profile with a very low shear strength in the top layer. I have assigned prescribed displacement (12m) at the widest section of the spudcan. Can you please suggest me modeling technique. I would really appreciate your help.
Hi Prashanth,
Your research sounds interesting. A couple of things: when the analysis stage 'fails' check plastic points to see exacty where the soil is failing...this might give some insight into the problem.
Also...have you 'arc length control' off?
The soil model you are using is also important and whether you have specified total stress parameters or effective stress parameters.
Drained or undrained analyses?
Also, I suggest you join the "PLAXIS Users" facebook group and post your probem there
Thanks for the information Sir, I have specified Drained conditions for sand layers and Undrained conditions for clay layers. Now that you have specified about Arc Length control, will try to run the analysis by having this option tuned off. Will keep you posted on my model analysis. Thank you very much for your timely feedabck
hi
i want to model tunneling advancement in plaxis 3d 2013, and when i model the tunnel full space not take axis of symmetry, yhe model of tunneling is open face tunneling which mean every phase of calculation i remove soil slice and add shotcrete ling and the water level at the surface of soil the soil collapse when i perform analysis but if i put water table at the bottom the soil not collapse.
same model but i take half space about the axis of symmetry and the water level at surface the soil not collapse? why is that?please
Hi. Sir i need step by step command for pore pressure generation in sand and compare with Cyclic Triaixal test using PLAXIS. Pls reply me sir.
I recommend you join the "plaxis users" facebook group and post the question there
Hello Sir,
My name is Preethi suvarna and I have been working on modeling touch pile analysis in PLAXIS 2D, I have difficulties in running the Analysis because of error showing "load advancement procedure fails". This is a layered soil profile with loose to dense SAND property. I have assigned Mohrs columb model with drained condition. Can you please suggest me modeling technique.
Sir, can u help with the step wise procedure of stone column modelling in plaxis 3D
Greeting Sir,
Iam need some notes about modelling of stone columns in PLAXIS 3D 2013.
How can i generate load displacement gragh from plaxis 3D 2013
Dear, i am Afewerki
I am curently working on numerical analysis of soil column into the effect of settlement of raft foundation. So during analysis i have facing alot of challenges for instance 1. The soil body seems to collapsa
2. Load advancement procedure failes
3. Meshing output is not found
4.unknown errors ets
So how can i solve these errors and how can i generate load displacement curve in 3d 2013
i recieved this message from plaxis 2d when i try to analyze the slope under high ground water table. Here is the message" prescribed ultimate state not reached.
soil body collapses. and
inspect output and load displacement curve" the software is showing me this message again and again what shall i do? please help me.
i recieved this message from plaxis 2d when i try to analyze the slope under high ground water table. Here is the message" prescribed ultimate state not reached.
soil body collapses. and
inspect output and load displacement curve" the software is showing me this message again and again what shall i do? please help me.
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