Based on the Coulomb's earth pressure theory hypothesis that active earth pressure against the back of retaining wall is due to thrust force 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 formula of active earth pressure is proposed

which considers the cohesion force on the sliding plane

the adhesive force between soil and the retaining wall

tension crack appears on the surface of cohesive soil

the strip surcharge; and the explicit solutions of critical rupture angle are given. When continuous uniform load acts on the back of the wall or without considering the situation that tension crack appears on the surface of cohesive soil

it can be solved by the same method with zeroing the distance from the strip surcharge to the coping and that the calculation of crack depth. Studies have shown that the calculation result of earth pressure based on specification is small

as the influence of strip surcharge on critical angle of rupture doesn’t count. The formula has a wide range of application

especially for the case that the strip surcharge acts on arbitrary position behind the wall. It has a certain practical value for the design and calculation of retaining wall in practical projects.