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Design table - Terraforce S Block

Maximum wall heights (in block height, metres, feet) for a single skin, mass gravity, block retaining wall system - without additional interlocking keys, reinforcements or backfill stabilizing.

Retained Soil Backslope above crest
of retaining wall
Wall inclination from horizonta
  
60° 65° 70° 75° 80° 85° 90° inclination
144.3 116.6 91.0 67.0 44.1 21.9 0 mm setback
5.7 4.6 3.6 2.6 1.7 0.9 0 " setback
Firm clay
&
compact silt
0
 19.6 16.0 12.8 10.5 8.4 6.6 4.9 S block
4.9 4.0 3.2 2.6 2.1 1.6 1.2 meters
16.09 13.15 10.47 8.6 6.91 5.39 4.05 feet
10°
 15.5 13.0 10.6 8.5 6.6 5.5 4.4 S block
3.9 3.2 2.7 2.2 1.7 1.4 1.1 meters
12.74 10.65 8.73 6.99 5.43 4.49 3.64 feet
22°
 13.1 9.9 7.1 5.2 4.2 3.3 2.5 S block
3.3 2.5 1.8 1.3 1.1 0.8 0.6 meters
10.73 8.14 5.82 4.30 3.45 2.69 2.02 feet
Silty sand
&
sand
0°
 30.2 23.7 18.4 14.4 11.4 9.3 7.4 S block
7.6 5.9 4.6 3.6 2.9 2.3 1.9 meters
24.81 19.41 15.13 11.83 9.37 7.63 6.07 feet
10°
 27.0 20.6 15.6 11.8 9.6 7.7 5.9 S block
6.7 5.2 3.9 2.9 2.4 1.9 1.5 meters
22.13 16.91 12.80 9.68 7.89 6.29 4.86 feet
22°
 22.9 16.0 12.1 9.2 7.2 5.5 4.4 S block
5.7 4.0 3.0 2.3 1.8 1.4 1.1 meters
18.77 13.15 9.89 7.53 5.92 4.49 3.64 feet

  1. Wall height measured from top of foundation / levelling pad.
  2. Top of foundation / levelling pad a minimum of 150mm / 0.5 ft below ground level
  3. No allowance made for surcharge above wall
  4. Angle of internal friction used in calculations: P(firm clay)>26°,P(silty sand)>32°.
  5. Compaction effort at optimum moisture content to ensure maximum density achievable.
  6. Provided that groundwater conditions are controlled, a wide variety of soil types can be used for infill soil.
  7. Subsoil drainage is essential to intercept groundwater. Build-up of hydrostatic pressure and seepage forces minimised.
  8. Surface water run-off should be directed away from the wall