Terraforce 4x4 Multi

Design table - Terraforce 4x4

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 horizontal
		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

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