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Convergence Issues with semi-permeable interface in dam 2d seepage analysis using PlaxFlow

Mauricio Carcamo — Tue, 11 Feb 2020 20:35:15 GMT

Dear all,

I'm performing a 2D seepage analysis of a tailings dam using the 'PlaxFlow' module. Our design includes a geomembrane in the upstream face of the dam, we are currently modelling it as as an impervious interface element for. As a part of a sensibility analysis, I'm trying to model the geomembrane as low hydraulic conductivity interface (k = 1E-8 cm/s) but the model does not converge, It actually diverges, with flow error achieving several orders of magnitude before aborting by itself.

The interface properties that I'm using are:
Cross permeability: Semi permeable
Hydraulin resistance, d/k : 20E6
Drainage conductivity: dk [m3/s/m]: 0

The material adjacent to the interface have the following hydraulic conductivities:
Tailings (dam pond): 3E-5 cm/s
Core: 1E-5 cm/s

Thanks for your help.

Mauricio.

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Wed, 09 Oct 2019 02:33:23 GMT

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Plaxis2D Max Step

Mauricio Carcamo — Wed, 09 Oct 2019 21:34:26 GMT

Hello,

I'm currently working with Plaxis2D V20, in particular with the 'PlaxFlow' module, to perform a steady state seepage analysis for a tailings dam, without deformation analysis (Calculation type 'flow only').

The dam has a low permeability clay core, and a high permeability chimney drain, the contrast in the permeabilty makes the converge of the model difficult. I tried increasing the model max number of steps, but there this number can't be higher than 10.000, is there a way to bypass this restriction?

Any other tip related to facilitating convergence is appreciated.

Thanks beforehand,

Regards,

Mauricio.