A question about coupling TOUGH2 and FLAC3D

titanium_boat
2 yrs ago
9replies

I have read many articles about coupling TOUGH2 and FLAC3D, most of them said FLAC can calculation the effective stress and strain after reading the data from TOUGH such as pore-pressure. But when I go on it I find that the effective stress have been calculated but without the corresponding strain. So I test some examples in which pore-pressure defined by "initialize gridpoint" command, but no strain generated as well.

Can anybody help me solve this problem?

- kenny
- 2 yrs ago
- Reported - view
This seems a question for 'FLAC3D', not for TOUGH
- Keurfon_Luu
- 2 yrs ago
- Reported - view
Are you solving the mechanical equilibrium once you imported the pore pressure?
- titanium_boat
  
  2 yrs ago
  
  Reported - view
  Keurfon Luu Yes, I did.
- titanium_boat
  
  2 yrs ago
  
  Reported - view
  Keurfon Luu I assumed that you have worked with TOUGH and FLAC3D according to your history. Can you guide me please?
- Keurfon_Luu
  
  2 yrs ago
  
  Reported - view
  cocogoat I can try, although I haven't coupled TOUGH with FLAC that way.
  
  But we cannot help you without a MRE (minimal reproducible example). Please provide much more details when describing your bug.
- titanium_boat
  
  2 yrs ago
  
  Reported - view
  Keurfon Luu Thanks a lot. I use a coupling method which is called fixed-stress split in related articles. I generate a initial state by TOUGH2, and import data to FLAC3D to calculate the effective stress and strain increment in this time step. As a minimal test, I only consider the pore-pressure, but ignore the thermal effect. I think I should keep the pore-pressure constant while calculating the stress and strain, so I don't configure fluid mode in FLAC3D. But the strain generated is too small so I consider it is zero. As I import the pore-pressure from TOUGH2's mesh to FLAC3D's mesh, the data has transferred from mesh's middle position to gridpoint. And I can give the gridpoint pore-pressure in FLAC3D some value to carry on a test. So I don't use the data from TOUGH2 but define the pore-pressure in FLAC3D by myself and try again. The result is same, I can't generate the strain. Is my learning wrong? I attach a simple example just made by FLAC3D. It generate a simple cube, give a normal stress, and then define the pore-pressure, to test the strain increment, assuming the pore-pressure is exported from TOUGH2. But whatever the pore-pressure defined, the strain increment seems to be zero... By the way, I have read the manual, it says the pore-pressure distribution corresponds to an initial state for which there is no strain in fixed pore-pressure mode(I have attached this part). So I wonder how to complete the couple. Please help me.
  
  test3.f3dat
- titanium_boat
  
  2 yrs ago
  
  Reported - view
  Keurfon Luu Hello, I have send you the whole code by email as it's a little big. I am waiting for your reply sincerely. Thanks a lot.
- titanium_boat
- 2 yrs ago
- Reported - view
Maybe it seems a question concentrate on "FLAC3D", but there is no related topic on the FLAC3D forum. As this question emerges in the coupling process, I want to find some help here.
- zhao_feng
  
  2 yrs ago
  
  Reported - view
  cocogoat I think the reason of no strain increment is that you didn't configure fluid mode in FLAC3D. Maybe you could set ''model configure fluid'' and set the fluid modulus/Biot modulus to zero to prevent additional pore pressure generation. You could set ''model fluid active off mechanical on'' & ''model solve'' and see if there will be any strain increment.