# Time-dependent jointed rock response
**URL:** https://forum.itascainternational.com/t/time-dependent-jointed-rock-response/927
**Category:** 3DEC
**Created:** [February 16, 2023, 10:18am UTC](https://forum.itascainternational.com/t/time-dependent-jointed-rock-response/927 "2023-02-16T10:18:03Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@VijayKiranKota](https://forum.itascainternational.com/u/VijayKiranKota)
#### Post date: [February 16, 2023, 10:18am UTC](https://forum.itascainternational.com/t/time-dependent-jointed-rock-response/927/1 "2023-02-16T10:18:03Z")
Hi,
Can I use a time-dependent (Burgers/CVISC/WIPP) creep model for zones and a non-time-dependent (Elastic/MC-slip/CY) model for joints? What result would such a combination have in simulating a jointed rockmass?
Let me know your thoughts.
Thanks,
Vijay
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### Author:  [@Theophile](https://forum.itascainternational.com/u/Theophile)
#### Post date: [February 17, 2023, 2:17pm UTC](https://forum.itascainternational.com/t/time-dependent-jointed-rock-response/927/2 "2023-02-17T14:17:12Z")
Hi!
I’m no expert in dynamic models, here, so I’m just sharing my thoughts.
To me, there is no reason why you could _not_ do so: a time-dependent matrix versus a static joint mostly implies that the joint response is immediate (or at least, way faster than the matrix’s).
However, I am not sure that _any_ models combination would be relevant.
Indeed, if we consider that a joint results from the rupture of its host rock, I would expect the joint to inherit its properties (or at least some of them) from the nature of its host rock. For example, a rigid and/or brittle rock would _a priori_ create a brittle joint, and a ductile rock would create a ductile joint. This question becomes even more complex if you consider that joints infills can alter their initial properties (_e.g._, calcareous deposits would bring a more fragile joint, and argillaceous would bring a more ductile one). And obviously, dynamic models give additional complexity.
Maybe you can start off with simple models and do step-by-step evolutions:
- elastic matrix / elastic joint
- viscous matrix /elastic joint
- elastic matrix / Mohr-Coulomb joint
- viscous matrix / Mohr-Coulomb joint
- …
After a (very) brief check on the literature, I could not find publications regarding this subject.
Hope you can get some interesting results!
Regards,
Théophile