Example $10\mathrm{.}8$: A rectangular foundation, $2m4m,$ transmits a uniform pressure of $450k\frac{N}{m^2}$

to the underlying soil. Determine the vertical stress at a depth of $1$ metre below the foundation

at a point within the loaded area, $1$ metre away from a short edge and $0\mathrm{.}5$ metre away from a

long edge. Use Boussinesq's theory.