Dear all,
I am doing my thesis about dilatancy and I am simulating the impact that the angle of dilatancy has in an oil well.
I am using Drucker Prager Hardening which includes dilation angle. The thing is, that does not matter if I put 80 degrees or if I put 3 degrees in dilation angle, the answer of the simulation is always the same. I expected that stresses or strains were affected by changing the dilation angle, but nothing different happens.
I made two steps. The first one is geostatic and the second is static general. In geostatic I applied a pressure inside the well of 14815096.32 Pa and in static general the pressure decreases to 9000000 Pa .
I introduced the main stresses S11 and S22 = 19587382 Pa and S33= 23606663.71 Pa.
Any ideas? Please help me. Thank you in advance.
Hey Cesar
The problem is the constitutive soil model that you are using right now. Even though Drucker Prager model includes the dilatancy angle as an input parameter, it has few limitation. I recommend you to use the Hardening Soil Model (HSM), i tested it and the results are very interesting. By the way, i use PLAXIS instead Abaqus.
Regards, Jaime.
@Jaime A. Mercado
Thank you for your recommendation, I will try to get a license for PLAXIS, meanwhile I will keep trying with Abaqus CAE.
Does HSM show a change in stresses and strains if you change the dilation angle? .
Regards
Cesar
Yes, it does. Check out this link: http://kb.plaxis.nl/sites/kb.plaxis.nl/files/kb-publications/The%20Hardening%20Soil%20Model%20-%20Formulation%20and%20Verfication.pdf
Regards,
What version of Plaxis did you use? Here is my e-mail account [email protected] . Can I have yours?
I have the last version of plaxis, PLAXIS 2D 2015. Off course, my e-mail is [email protected]. Feel free asking me anything.
FOR SURE dilatation angle affects the results, especially in PLANE STRAIN analysis. In this cases, for certain values of dilatation angle, you will never reach the collapse.
You can find a lot of informations in my paper
A. Panteghini, R. Lagioia. The influence of plastic potential on plain strain failure. Int J Numer Anal Met, Vol. 38(8), 2014, 844-862. DOI: 10.1002/nag.2236
Good Luck!
A
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