Which of the following assumptions is NOT true per Terzaghi's bearing capacity theory?

Explanation:

Terzaghi's Bearing Capacity Theory:

Bearing capacity of soil: 

\({q_u} = C{N_c} + γ {D_f}{N_q} + 0.5γ B{N_γ }\)

Where,

C = Cohesion, D_f = Depth of footing, B = Width of footing, γ = unit weight of footing, N_c, N_q, N_γ = Bearing capacity factors

Assumptions:

1. The soil is homogeneous and isotropic and its shear strength is represented by Coulomb's equation.
2. The strip footing has a rough base, and the problem is essentially two-dimensional.
3. The elastic zone has straight boundaries inclined at ψ = ϕ to the horizontal, and the plastic zones fully develop.,
4. Pp consists of three components, which can be calculated separately and added, although the critical surface for these components is not identical.
5. Failure zones do not extend above the horizontal plane through the base of the footing, i.e. the shear resistance of soil above the base is neglected and the effect of soil around the footing is considered equivalent to a surcharge σ = γ × D [γ = unit weight of soil, D = Depth of foundation