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foundations / retaining walls

Retaining wall stability screen.

Screen overturning, sliding, resultant location, and linear base contact pressure for a simple trapezoidal gravity-wall body under dry active earth pressure.

read the result

Keep the wall body and lateral load visible.

This screen treats the wall as a trapezoidal gravity-wall body per metre run. The wall weight provides resistance, while Rankine active pressure and surcharge provide the horizontal load and overturning moment.

Governing relationships

Wall area is A = H(B + T)/2 and wall weight is W = gammacA. For soil friction angle phi, Ka = (1 - sin(phi))/(1 + sin(phi)).

The lateral thrust is Pa = 0.5Ka gamma H2 + KaqH. Soil self-weight acts at H/3 and surcharge thrust at H/2. The screen reports FSOT = W xg/M and FSS = muW/Pa.

Read the base result with the resultant.

The vertical resultant is located from the toe using the net moment divided by W. Its eccentricity from the base centre gives a linear toe/heel pressure estimate. A negative pressure indicates that the simple full-contact assumption has broken down and uplift or a different model needs review.

This is a preliminary screen.

  • The wall is a trapezoid with a vertical front face and no separate base slab.
  • Heel fill, passive resistance, groundwater, drainage, cohesion, compaction loads, seismic effects, surcharge position, and foundation settlement are excluded.
  • Use project-specific code factors, geotechnical parameters, load combinations, drainage details, reinforcement, and a qualified design review for the final wall.