Minimum depth of foundation calculated by Rankine's formula for the design of retaining wall is ________.
Where,
q0 = safe bearing capacity of soil
γ = Density of soil,
ϕ = Angle of repose
1
\(\frac{\gamma }{{{q_0}}}{\left( {\frac{{1 - \sin \phi }}{{1 + \sin \phi }}} \right)^2}\)
2
\(\frac{q_0 }{{{\gamma }}}{\left( {\frac{{1 - \sin \phi }}{{1 + \sin \phi }}} \right)^2}\)
3
\(\frac{\gamma }{{{q_0}}}{\left( {\frac{{1 + \sin \phi }}{{1 - \sin \phi }}} \right)^2}\)
4
\(\frac{q_0 }{{{\gamma }}}{\left( {\frac{{1 + \sin \phi }}{{1 - \sin \phi }}} \right)^2}\)