$9-25$ A $1-$m$-$wide surface$-$supported strip footing carries a loading ofper meter of wall length. Determine the total vertical stress acting at a depth ofbelow the center of the foundation width $($note that the total stress will be the sum of the original vertical stress due to the soil mass plus the increase due to the foundation loading$).$ Assume the Boussinesq conditions apply. Use a soil unit weight equal to $.$