Distribution of earth pressure on a retaining wall

On the basis of Coulomb's concept that the earth pressure against the back of a retaining wall is due to the thrust exerted by a sliding wedge of soil between the back of the wall and a plane which passes through the bottom edge of the wall and has an inclination of θ, a differential equation of first order is set up by considering the equilibrium of the forces on an element of the wedge. A theoretical result for the unit earth pressure on a retaining wall is obtained. A comparison is made between Coulomb's formula and the formula presented here, and the earth pressure calculated by the formula presented here is also compared with experimental observations.