Author Topic: pit progression with time  (Read 810 times)

nrinaldi

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pit progression with time
« on: June 04, 2014, 12:11:41 am »
it will be good if feflow has capability in modeling the pit progression with time as input mesh during a run. Elevation of the pit will be seepage boundaries that changing with time during the run and recollected their flow as potential seepage to the pit.
nr

Carlos Rivera

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Re: pit progression with time
« Reply #1 on: June 04, 2014, 08:17:38 pm »
Have you tried the element deactivation available in FEFLOW 6.2?  You can define pit stages (e.g. polygons) already in the supermesh. In the FEM file later, elements can be selected to become deactivated over time. This is handled as material property. At the same time you can impose seepage nodes. Recharge is automatically passed to next active elements in the vertical direction for 3D models.
Dr. Carlos A. Rivera Villarreyes
Director Sales Service & Support
DHI WASY

nrinaldi

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Re: pit progression with time
« Reply #2 on: June 05, 2014, 01:20:29 am »
Hi Carlos, thanks for the reply, unfortunately I use 6.0.
I work to model a large open pit and underground mines mainly dewatered by gravity drain, I see there are options now for temporary element deactivation and BC on and off in 6.2 that will be very helpfull for my case here. I use to work with transient BC by constraining them in 5.0 to 5.3 and still do the same in 6.0.
nr

Blair

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Re: pit progression with time
« Reply #3 on: June 05, 2014, 03:54:24 am »
Have you tried the element deactivation available in FEFLOW 6.2?  You can define pit stages (e.g. polygons) already in the supermesh. In the FEM file later, elements can be selected to become deactivated over time. This is handled as material property. At the same time you can impose seepage nodes. Recharge is automatically passed to next active elements in the vertical direction for 3D models.

Hi Carlos,

Just a thought - does this new feature provide an alternative to the BASD approach currently used in 3D models with a free and movable top surface? Could elements above the water table be deactivated instead of being redistributed within the layers below? A suggestion for future development perhaps...

Carlos Rivera

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Re: pit progression with time
« Reply #4 on: June 05, 2014, 10:04:49 am »
Hi Blair,

No, this is not alternative to BASD technique.
The element deactivation can be understood as "delete mesh" operation. However, element deactivation can be done at any time and any location of the model domain. It is very good to simulate impermeable barrier (e.g. sheet piles) or geomorphological changes of the mesh. At the moment, element deactivation is not supported for models using free-and-movable approach. This is to "prevent" a situation of material averaging between an active element and deactivated element.
To keep things organized in the forum and on this Suggestion section, if you have further questions/discussions, I would suggest to open a new post on the standard FEFLOW board. Thanks!

Cheers,

Carlos
Dr. Carlos A. Rivera Villarreyes
Director Sales Service & Support
DHI WASY