Dear Hamed,

I suggest you refer to ALA Guidelines for the Design of Buried Steel Pipe (2001) Section B.1 Page 68. It is related to modeling of axial soil spring, in which an interface angle of friction is defined (μ=tan(fφ)). It is uded for soil-pipe interaction, but I am sure it can be well used for defining the interface friction angle of soil-pile system. Some references suggest μ=tan(2/3φ).

Also as you will see in the guideline, a term related to cohesion is defined. I suggest for  φ=0 you define α (defined in the same section of the guideline) as your friction coefficient. 

Regards,

Himan

Dear Hamed,

I suggest you refer to ALA Guidelines for the Design of Buried Steel Pipe (2001) Section B.1 Page 68. It is related to modeling of axial soil spring, in which an interface angle of friction is defined (μ=tan(fφ)). It is uded for soil-pipe interaction, but I am sure it can be well used for defining the interface friction angle of soil-pile system. Some references suggest μ=tan(2/3φ).

Also as you will see in the guideline, a term related to cohesion is defined. I suggest for  φ=0 you define α (defined in the same section of the guideline) as your friction coefficient. 

Regards,

Himan

Dear Himan

I read the manual but it seems to me it is not clear and I am not sure there is a direct relationship between cohesion and friction coefficient. are you sure about that?can you explain more?

Regards

Hamed

Thanks, Himan.

"Some references suggest μ=tan(2/3φ)." Can you please tell me what's these references are?

Best regards,

Zhigen

Dear Zhigen,

If I recall correctly, it should be Yimsiri et al. (2004). You can find it fully cited in one of my papers.

Bests,

Himan