Hello, everyone

I am an abaqus user and developer. Recently, I want to simulating the liquefaction phenomenon with abaqus/standard or abaqus/explicit. As I know, this cannot be realized using the internal program because solution of the u-p formulation is not supported. Does that mean I have to write an UEL or VUEL program to solve it ? As the postprocessing of UEL/VUEL is unconvenient, is there other simple way to solve this problem? like using umat or vumat subroutine. Any advice would be greatly appreciated.

1. Hans Henning Stutz 5 years ago

Dear Ruibin,

I did not have much experience with this kind of problems, but so far as I know. You have to code your own element formulation u-p or u-p-u.
An example of such an approach can be found in:
J. Machaček, Th. Triantafyllidis and P. Staubach, Fully coupled simulation of an opencast mine subjected to earthquake loading, Soil Dynamics and Earthquake Engineering, 115:853-867, 2018
https://www.sciencedirect.com/science/article/pii/S0267726118304718

Best regards,
Hans Henning

2. Ruibin Hou 5 years ago

Dear Hans,
Thanks for your reply. It seems uel is necessary to solve this problem. However, the following paper shows a simple method which simulating soil as a two phase material in dynamic analysis. https://onlinelibrary.wiley.com/doi/abs/10.1002/gete.201200018 Unfortunately, I still cannot figure it out at this time.

• Ahmed Mahir 5 years ago

iam working on same target can you help me

• Kassem Dib 2 years ago

Hello, i am facing today the same problem, I think I found the solution using SaniSand constitutive model by defining the mechanical constant number 17 in abaqus (pore water bulk modulus) that is null in case of drained conditions, liquefaction can not be then modeled explicitly, but liquefied area will be distinguished by the excess pore pressure.
you might be model the process easily also using PLAXIS 3D or 2D, the built-in constitutive models that visualize liquefaction process , like UBCSAND and PS4Sand are very suitable for your purpose.

• Kassem Dib 2 years ago

Dear Ahmed how did you solve your old problem?

3. Kassem Dib 2 years ago

sorry it was PM4Sand not PS4Sand

4. Kassem Dib 1 year ago

This is what Eng Arie Koot informed about analogy between temperature -and pore pressure in Abaqus, you should define Specific heat and Heat conductivity:
QT=(T1-T2)*A*ktemp/L*dt [J]
ΔT=Q/VRCtemp

Qw= ΔhxAxkw/L*dt = (P1-P2)/9810xAxkw/L*dt [m3]
kw=m/s
ΔP=Qw/VxEwbulk

=> ktemp=conductility=Kw/9810
=> Ctemp=specified heat= 1/Ewbulk/R