UDEC v7 - Strain-softening model - elements instantly reach failure after excavation

Hi There,

When I use strain-softening model in UDEC 7, the element instantly reach failure after tunnel excavation. I am modeling block as a CWFS material to simulate brittle behavior of Sandstone under high stress.
A similar model parameters that I used in 3DEC did work as expected and failure zone appeared around opening where stress reached spalling limit. Please see the attached screenshots and command files for your reference.

I have used both small strain and large strain in the model and this procedure did not help at all.

Please advise what I am missing here to simulate Strain Softening model in UDEC 7.

Many thanks
02_initial_SSII.dat (3.6 KB)

I would send all of the data files to udecsupport@itascacg.com

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Thanks. I have sent all files to the support team and am waiting their response.

Make sure the stresses are applied correctly.
If you have very small blocks, keep them rigid.
Or consider the elastic behavioral model of small groups.

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Thanks and the UDEC support team has fixed the issue in my commands as I was using a same table number for input and result and when the program runs, input table overwrites by result table.