• Registered: 2013-07-23
  • Posts: 6

Topic: Fig. 2-38: Typical interface model behavior in shear (a)

Hi there,

I am examining Fig. 2-38(a) in the ATENA theory manual. It is depicted on the y-axis that shear stress = cohesion - (normal stress x friction angle). Shouldn't this formula read: shear stress = cohesion + (normal stress x friction angle)?

Also why is the residual surface corresponding to dry friction set to a negative value? It is depicted as - (normal stress x friction angle). This also does not make sense. Can you please correct or clarify?

Thanks

Robin

Quote Post 1

  • Registered: 2013-07-23
  • Posts: 6

Re: Fig. 2-38: Typical interface model behavior in shear (a)

Hi there,

Bumping up this topic...

I need to include a modified form of this figure in a journal paper that is being reviewed and awaiting resubmission. I really need a response as soon as possible. Please confirm that figure 2-38 shown in the ATENA Theory manual is correct. Please clarify the points raised.

Thanks

Robin

Quote Post 2

  • Tii
  • Member
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  • Registered: 2013-04-15
  • Posts: 14

Re: Fig. 2-38: Typical interface model behavior in shear (a)

Hi,

I am also just an ATENA user but I had make research work on interface failure too.

I think the figure is right. You have to consider the algebraic sign of the normal stress. In ATENA the normal stress pointing on the interface is negative so the formula is right: shear stress=cohesion-(-normal stress)*friction angle
See also formula 2.113 in the theory manual.

At first I was confused too because the Mohr-Coulomb criteria is normally written with a "+" but then, like I mentioned, the normal stress pointing on the interface is positive.

Quote Post 3

  • Registered: 2013-07-23
  • Posts: 6

Re: Fig. 2-38: Typical interface model behavior in shear (a)

Thankyou for sharing Tii. This makes sense now. All the Best.
Robin

Quote Post 4