Example $13\mathrm{.}16$: A retaining wall is battered away from the fill from bottom to top at an angle

of $15$ with the vertical. Height of the wall is $6$ m $.$ The fill slopes upwards at an angle $15$ away

from the rest of the wall. The friction angle is $30$ and wall friction angle is $15.$ Using Cou$-$

lomb's wedge theory, determined the total active and passive thrusts on the wall, per lineal

metre assuming $=20k\frac{N}{m^3}.$