Example $10\mathrm{.}1$: A concentrated load of $22\mathrm{.}5$ kN acts on the surface of a homogeneous soil mass

of large extent. Find the stress intensity at a depth of $15$ meters and $($i$)$ directly under the load,

and $($ii$)$ at a horizontal distance of $7\mathrm{.}5$ metres. Use Boussinesq's equations.