Tunnel modeling with FLAC 7.0

[amin6]

How can we model tunnel face that the entire face is under the groundwater level?
2 approach we can use, like configure ground-flow or use pore pressure on the boundary of tunnel.
which way is perfect?? and why?? please let me know your reasons.

 

[miningman]

After 40 years working in the underground environment. I've not once had to model a tunnel, nor to the best of my knowledge , have any of my consulting engineers done so. That should tell you something. Perhaps you need to focus on the likely geotechnical parameters . Is this in hard rock or incompetant soils??? Kinda makes a major difference snd if you haven't yet identified these paramewter, you need to go back to basics. Tunnel size ??? RQD??? In situ sresses?? Geological discontinuities??

 

[BUGGAR]

I conclude from your post that your tunnel face is a concrete structure cast against the tunnel opening to hold rock and debris from falling and blocking the opening? And it is going to be cast underwater? Where are you getting your flow? Is this an intake structure? Or outflow? Are you concerned with hydraulic pressure between the concrete and rock?
Perhaps a better definition of "modeling" would help. I will interpret your word "model" to mean "understand".

I worked on dam where the Geo Engineer modeled the rock foundation as a "semi-infinite solid". I suppose he got a semi-infinite fee for this.

 

[amin6]

Dear minigman
In this case we have all parameters like Tunnel size, RQD, In situ sresses and Geological discontinuities. also, path of tunnel in soils environment. But the problem is the entire of tunnel located under the ground water level of the soils environment.
Here we want to simulate this tunnel with FLAC 2d program. At first we should define the material and boundary for modeling but we have 2 approach in this case:
1) we can configure ground-flow to FLAC program in first of simulate before any command.
2) we can configure basic model like mohr-coulomb and after that we can use pore pressure command to apply water pressure to boundary of tunnel.
which approach do you think is perfect and why????

 

[amin6]

Dear BUGGAR
thanks for your attention.
we use FLAC 2d program to simulate stresses and displacements happened around the boundary of the tunnel.
but the entire of tunnel located under the ground water level of the soils environment.
now just we just boring the tunnel face and we don't using any concrete structure.
but to simulate this problem which approach is perfect and why??
1) we can configure ground-flow to FLAC program in first of simulate before any command.
2) we can configure basic model like mohr-coulomb and after that we can use pore pressure command to apply water pressure to boundary of tunnel.