IMASS Tension Cutoff

FLAC3D
1

Hello,

I am using the IMASS model for brittle rock modeling. I want to set my tensile strength cutoff to 10 MPa. The software documentation says that you can set the tensile strength with

“the input tensile strength, either by a scalar value (calc_stren_tension), or by a table-like property (in_weak_tabletension)” (IMASS Model ** — Itasca Software 9.0 documentation)

However, when I do

zone prop calc_stren_tension 10e6.

An error saying that calc_stren_tension is a read-only property appears. This makes sense as the manual later states it. Is there a way to set the tensile cutoff with a single value? Is inputting tension as a strain-dependent table the only option?

2

Hello @lfgomezdea,
The IMASS property calc_stren_tension is a calculated property defined as
image
where s is the Hoek-Brown parameter (defined in eq 3 in the IMASS doc), sig_ci is the uniaxial compressive strength of intact rock and m_b is the intial Hoek-Brown parameter (see eq 2).

3

Yes, with the properties I am using I get a tension of 90 MPa and I want to modify it to 10 MPa without using the in_weak_tabletension property. Is this possible?

4

If “emer_stren_tension” is input a value less than “s*\sigma_{ci}/m_b”, the smaller one will be the tension strength. So the answer is just

zone property emer_stren_tension 10e6

1 Like
5

Thank you @cheng.

Maybe the manual should be changed to reflect that?

Something like:
“the input tensile strength, either by a scalar value (emer_stren_tension ), or by a table-like property (in_weak_tabletension )”

6

Sure, we will update. Thanks.