Field note / retaining-wall screening
Start with a clear geometry.
The calculator represents the wall body as a trapezoid with base width B, top width T, and retained height H. Its weight is calculated per metre run using the entered wall unit weight. The centroid location is kept visible because it controls the resisting moment.
Use the same pressure model as the load screen.
Dry level cohesionless backfill is represented with the Rankine active coefficient. Soil self-weight creates a triangular thrust acting at H/3, while a uniform surcharge creates a rectangular thrust acting at H/2. Their moments are added before the overturning factor is calculated.
Four outputs make the first pass inspectable.
- Overturning factor of safety compares wall resisting moment with lateral overturning moment.
- Sliding factor of safety compares frictional base resistance with total horizontal thrust.
- Resultant location and eccentricity show where the vertical load falls relative to the base centre.
- Toe and heel pressure use a linear contact distribution and expose negative-pressure uplift.
What remains outside this screen
A final retaining-wall design still needs groundwater and drainage, water pressure, surcharge location, compaction effects, passive resistance, seismic conditions, bearing capacity, settlement, global stability, structural design of the stem and base, reinforcement, joints, and project-specific load combinations. The target factors and allowable pressure in the tool are user inputs for a screening comparison, not universal code requirements.