Does anyone know how to determine the width (in the figure, BE) of the failure wedge?

[ripongeo]

For my research, it is necessary to find the width (in the figure, BE) of the failure wedge in Terzaghi, Vesic, or Prandtl bearing capacity theories for shallow foundations. I searched the literature but could not find any equations or calculations. I tried the trigonometric method, but the resulting value was too large compared to real-world observations. Does anyone know how to determine BE from the figure? Thanks!

N.B: in my calculation, I found BE= 2.2 m (Terzaghi), 2.70(Prandtl) for 200mm diameter, Angle of Internal Friction 45-degree, foundation (physical Model).

 

[HTURKAK]

Arc CD or CF , Log spiral Line and defined by the equation;



ro= BC=AC Notice that r=ro if ϕ=0

Angle theta is angle of CBD =135 – ϕ/2

( E.G . For ϕ=30 degr , then theta =135 – ϕ/2 =120 degr= 2.094 rad. if ro=1.0 m , r=3.35 m )

I will suggest you to look ; Shallow Foundations Bearing Capacity and Settlement (by Braja.M. DAS )