Passive Earth Pressure Calculator
Compute the Rankine passive earth pressure coefficient (Kp), total lateral passive pressure, and resultant force on a retaining wall from soil friction angle, unit weight, wall height, and surcharge.
Soil & Wall Parameters
Typical range: 28° – 42° for granular soils.
Typical: 17–21 kN/m³ (108–133 pcf).
Uniform load on the passive soil surface (e.g. fill, slab).
Passive Pressure Diagram
| Depth | Soil Pressure | Surcharge Press. | Total Pressure |
|---|
Force Breakdown (per unit width)
Kp vs Ka Comparison
Passive pressure is always larger than active pressure for the same soil. The ratio Kp/Ka illustrates the difference in resistance vs. driving force.
Enter soil parameters and click Calculate.
Kp and the passive pressure diagram will appear here.
Summary
Compute the Rankine passive earth pressure coefficient (Kp), total lateral passive pressure, and resultant force on a retaining wall from soil friction angle, unit weight, wall height, and surcharge.
How it works
- Enter the soil internal friction angle (φ) in degrees.
- Enter the soil unit weight (γ) in kN/m³ or pcf.
- Enter the embedded wall height (H) in meters or feet.
- Optionally enter a uniform surcharge load (q) acting on the soil surface.
- The calculator applies Kp = tan²(45° + φ/2) (Rankine passive theory).
- Results show Kp, the pressure diagram, and total horizontal passive resultant force per unit width.
Use cases
- Checking passive resistance for retaining wall sliding stability.
- Designing sheet pile walls and calculating toe resistance.
- Geotechnical coursework and exam problems.
- Comparing Rankine Kp with active Ka to assess overall wall equilibrium.
- Estimating passive resistance behind deadman anchors.
- Quick sanity checks before running full numerical models.