Lateral earth passive pressure (Rankine theory for horizontal backfill)


Lateral earth pressure is the pressure that soil exerts in the horizontal direction. Rankine’s theory, is a stress field solution that predicts active and passive earth pressure. It assumes that the soil is cohesionless, the wall is frictionless, the soil-wall interface is vertical, the failure surface on which the soil moves is planar, and the resultant force is angled parallel to the backfill surface. The passive state occurs when a soil mass is externally forced laterally and inward (towards the soil mass) to the point of mobilizing its available full shear resistance in trying to resist further lateral deformation. When the backfill is not inclined to the horizontal the passive lateral coefficient is depended on the angle of shearing resistance.

Related formulas


KpPassive lateral earth pressure coefficient (dimensionless)
ϕAngle of shearing resistance (radians)