foundations / retaining walls

Rankine active earth pressure calculator.

Estimate the lateral soil thrust, base pressure, resultant height, and overturning moment for a simple dry, level-backfill retaining-wall load case.

read the result

Make the pressure diagram explicit.

For the stated Rankine active case, soil self-weight produces a triangular lateral-pressure distribution and a uniform surcharge produces a rectangular component. The tool reports both components so the resultant and its height above the base remain inspectable.

Governing equation

Ka = (1 − sin φ)/(1 + sin φ). The soil thrust is = ½KaγH², the surcharge thrust is Pq = KaqH, and the total thrust is Pa = Pγ + Pq.

The relationship is consistent with the Rankine active coefficient and horizontal stress form shown in FHWA guidance.

Keep stability wider than the thrust.

  • Check wall self-weight, base width, eccentricity, bearing, sliding, overturning, drainage, uplift, and structural reinforcement separately.
  • Include groundwater, hydrostatic pressure, seepage, sloping backfill, layered soil, cohesion, wall friction, seismic effects, and compaction where relevant.
  • Confirm whether active pressure is justified; rigid or restrained walls may require at-rest or another project-specific pressure model.