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

UDEC
1

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.

3D02_initial_SSII.dat|attachment (3.6 KB)EC - model
3D02_initial_SSII.dat|attachment (3.6 KB)EC - model1289×683 133 KB

UDEC model
UDEC model1452×810 104 KB

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
Thiru
02_initial_SSII.dat (3.6 KB)

2

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

1 Like
3

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

4

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.

1 Like
5

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.