Geotechnical Engineering
Lateral Earth Pressure Calculator
Estimate active, at-rest, or passive lateral earth pressure for simple drained backfill cases.
Parameter sketch
Wall pressure diagram
Labels update with the current input values so the formula symbols stay tied to the geometry.
Result
Total lateral force: 2833.33 force/length
Ka
0.333
K0
0.5
Kp
3
Selected K
0.333
Base pressure
400
Total force
2833.33
Resultant above base
3.33
Step-by-step calculation
- Compute pressure coefficients for phi=30 deg.
- Select K=0.333 for active wall condition.
- Soil force = 0.5 x 0.333 x 120 x 10^2 = 2000.
- Surcharge force = 0.333 x 250 x 10 = 833.33.
What this means
Higher wall movement restraint increases pressure; passive pressure should be used cautiously with deformation compatibility.
Formula Used
Pa = 0.5 K gamma H^2 + KqH
Step-by-Step Example
A 10 ft wall with gamma=120 pcf, phi=30 deg, and 250 psf surcharge gives about 2,217 lb/ft active force.
Engineering Notes
Check units, assumptions, boundary conditions, groundwater, drainage, and whether the simplified method is appropriate before using a result in any project decision.
FAQ
What is K0?
K0 is at-rest pressure used when the wall cannot move enough to mobilize active conditions.