Cohesionless soil
Cohesionless soil
(OP)
I am analysing a soil which has a cohesion value of 0Kn/m2. The soil is a granular material. I am trying to analyse the foundation in sliding.
When calculating sliding the formula is
Rv tan angle of friction/Rh
If you take out the angle of friction the formula becomes
Rv/Rh
This results in no internal friction in the soil. The factor of safety will be bigger than soils with a angle of friction say 10 degrees which can not be true. As the 10 degrees soil has internal friction and the so of zero angle hasnt.
What would the formula be for a soil with no internal friction.
When calculating sliding the formula is
Rv tan angle of friction/Rh
If you take out the angle of friction the formula becomes
Rv/Rh
This results in no internal friction in the soil. The factor of safety will be bigger than soils with a angle of friction say 10 degrees which can not be true. As the 10 degrees soil has internal friction and the so of zero angle hasnt.
What would the formula be for a soil with no internal friction.





RE: Cohesionless soil
I think you have something backwards...usually as cohesion increases, the angle of internal friction decreases.
RE: Cohesionless soil
RE: Cohesionless soil
RE: Cohesionless soil
A more general formulation is:
[(Rv * tan phi') + B*c + Pp] / [Rh]
B = ftg width
Pp = passive pressure from embedment
Note that even this is simplified somewhat.
Your formula has been simplified for a footing on a cohesionless soil (i.e., c=0) and with no embedment (i.e., Pp = 0)