Users Forum
ADONIS Category => ADONIS Users => Topic started by: GabrielOprea on June 21, 2018, 12:43:03 am
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Hello,
I am new in geotechnical and i encountered some problems in adonis.
First i made my retaining wall back-to-back, apply mesh but i do not understand how assigned material works.
What soil parameters i must introduce?
I do not find an explanation on this program or example for this.
i must do some structural analysis like deformation based on surcharge.
Thank you.
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In order to assign property you need to create new material choose the right constitutive model add it to the list specify properties and then click on created material then use your mouse to pick the region you want to apply the selected material at then press apply or enter. In the help attached to the program you will be able to find simple explaination.
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Hello,
I tried as i see on example but did not go well, my Teacher wants me to make a modeling but he is a fan for Abaqus or Plaxis and i do not have those programs.
I am very new on fine element programs and first i created a model with 2 layers of material ( first layer clay with the folowing properties γ= 19 (kN/m3) E= 10.000 (kPA) c= 28 ( kPa) and friction angle 16, on layer to i got sand+ gavrel
γ= 20 (kN/m3) E= 20.000 (kPA) c= 0 ( kPa) and friction angle 35.
From what i undestand i must use at material Mohr-Coulomb and i do not now if i add this paramters corectly? ( can you help me?
Also i did o small scale a something like sandbox and i applied boundary on botom,left and right to see how the material behaves under gravity and depends on the material.
I need to understand this part, untill i can add my retaining wall ( back-to-back wall) too see after how will affect the soil under this load.
Thank you.
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please generate the script using "save script" from the file menu and attach it in here for review. thanks
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I started to make faster, i attached the script, i may miss some parameters.
from what i saw on density i got MN/m3 and i thought i need to convert it from kN/m3.
The teacher wants to see a smooth displacements not chaotic like mine.
I know i skipped some classes and sleep on presentations, T_T.
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you had couple of mistakes. major one was when you used zero bulk modulus. you need to make sure that shear and bulk modulus are non zero otherwise model is going to collapse.
also always make sure you use newmodel() at the first line of your script to avoid error every time you load this script.
in boundary condition sides are fixed only in x-direction and base in y-direction. fixing sides in y-dir might cause some problem specially for the cases that boundary is close to the structure so it's better to realistically use x-fix only.
I modified your model and attached in here. please go through the changes line by line and make sure you follow the concept.
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Thank you,
May i ask why i got on Sand+Gravel bulk 40.000 kPa?
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rndom number simply doubled the shear modulus that's all. you should put your actual value in there.
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I do not have a detailed geotehnical study, i only got those parameters, now i will make the retaining wall in wich will have a 1.35 m depth in the first layer, i will make an analysis withouth geogrids then i will add the greogids, may i ask how should i apply the load on top on MSE? ( i got a surchage q= 26 kN/m2)
I will post here each step.
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Hello, i did de model with the coordinates from Autocad.
I added third material ballast and not sure if displacements are corect.
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Hello,
I added surchage -26 kPa ( stress), still figuring the geometry of the geogrids.
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I recommend you to keep a clean script file in a separate folder and after every couple lines of commands update this file by including commands and removing unnecessary lines to make it easier for reviewers or other users to follow. unfortunately current script file keeps almost all the changes you made during your simulation and it's a mess. it's very difficult to follow.
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I will make new simulations much cleaner, since i did not found undo command everytime when i do a mistake i start over again and sometimes the program crashes.
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Whenever you run script and it crashes please send me the script so I will be able to find and solve the problem. Thanks.
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The crash usualy starts:
For example when i did multiple lines in a wrong way and i try to delete them all at the same time the program crash. ( this is the most frequently)
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is it possible for you to repeat the same mistakes as you said and save the script right before deleting the lines and send it to me? unfortunately I can not recreate the same bug. no crash here for me after deleting lines.
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Hello,
Before i try to make 5 example
Note: this is only for my dissertation project
1: Terrain in natural conditions as you showed to me in an example
2: Retaining wall with no surcharge or geogrids
3: Retaining wall with surcharger applied but without geogrids
4 Retaining wall with geogrids but no surcharge
5 Retaining wall with surcharge and geogrids
I will do again Nr.1 but i got few questions
Physical unit set: m-kPa-kN/m3
Equilibruim ratio: in the example you corected for me you set this parameter 9,91e-4 ( based on what? - need to know why is this suitable for my retaining wall)
Water table: i stated in my project that i have water located at -10 m - the manual says to add water density wich means 1e-9 mg/m3 i think but when i did some solve i do not see some changes at pore pressure
On Mesh Type: wich is more suitable in retaining wall 3-node triangle or 6- node triangle
If i chose solve fos without change some setting there i receive the folowing msg: factor of safety is greater than upper bound limit 32 , :'(
On Force/Stress section i got from surcharge 26 kPA how can i apply it corectly?
I do not find enough documentation to solve alone :(
My Teacher says this program is rubish and wants to force me to make my model in Abaqus or Plaxis, but these are not free or easy to install and i set up already that i want to finish my project with Adonis, so i can show to other students that there are other ways.
Let me know how to overcome this problems.
Thank you.
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by default equilibrium ratio is set to 1e-3 based on experience this value is good enough for most practical cases but if you need smaller value you will easily be able to modify this in the setting.
if you choose m-kPa-kN/m3 as unit the density of water would be 1000 Kg/m3
uniform distributed stress can be applied easily from Initial Condition" section. please read this part of manual carefully.
http://geowizard.org/doc_manual.html
traditionally simulators start with coarse mesh and lower accuracy (3-node mesh) to get the initial result quicker and then they increase the accuracy with reducing the mesh size and also using higher degree elements (6-node). but again from experience for most geotechnical practices the fine 3-node element is good enough.
fos>32 means your model is "very stable" for given information if needed you can change the max value in the fos dialog box. please double check the shear strength of your model and note that fos only works for Mohr-Coulomb and Hoek-Brown constitutive models.
from my understanding you have a little knowledge on basics of finite element methods and from my point of view you are making a big mistake of jumping into simulation without even understanding the basics. also your teacher is making a big mistake that forces you to this without teaching you the methods itself. this could be very discouraging for you regardless of the name of the software your going to use.
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Hello,
Since the summer has ended i finally finished my retaining wall and hope i got less mistakes that i used to have from start. :o
See attached script in mail.
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Hello,
While i finished my first retaining wall with Adonis i encountered some problems in setting corectly the right parameters in some points and i get confused and the online manual does not help to much.
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which ones? I might be able to clarify a bit more later on.
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Hope i can explain corectly my little problem.
After i did the calculations on my retaining wall i found that i have 30 km displacements ( wich is bad)
I selected Units: m-kPa- kN/m3 ( wich is good for me) but i think i might put the wrong parameters on material.
First part:
I chose Mohr-Coulomb method
Material ID: 1
Density [Mg/m3]: this unit measure is a bit confusing why not kg/m3? i have for example 21 kN/m3 from earlier posts i asume it would be 2.1?
Shear: good got E=10.000 kPa
Bulk: kinda confused why i should put 20.000 kPA twice shear
Coh: good
Frig: good
dil: ?
tens: ?
And for strips i found another problem with the units:
I use geogrids ( uniaxial geogrids made from HDPE) in my model but not sure if i put corectly the parameters.
Geometry: Calc. Width (m) ?
Num Strip/ Calc. Width ?
Width: twice width?
Thickness: just for the geogrid?
Elastic Parameter: for the geogrild material wich is HDPE?
Density: of HDPE ( should be good)
Yeld Strength:
Com. Yeld Strength: ? kPA
Ten. Yeld Strength:?
Interface
Bond Stiffness: Kpa?
Bond Strength:?
Bond Fric. Angle: ?
And on a retaining wall i got many layers of geogrid, should i use just 1 strip ( ID S1?) or new ID for every new layer i add?
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to save some time please go to link below and download the pdf file. it's a manual for structural element for commercial software called FLAC. the concept of geogrid element in the ADONIS is almost identical to the strip element explained in there. the detail explanation for each parameters are given. please take a look at page 1-153.
http://web.mst.edu/~norbert/ge5471/Assignments/Assign%201%20-%20FLAC%20I/FLAC%20manual/FLAC%20manual/f2d416.pdf