1. Always use free draining gravel or sand and gravel backfill to allow drainage. Where high groundwater conditions occur in the native ground , chimney or blanket drains may be required.

2. Coulomb (sliding wedges) or Rankine (earth pressure) analysis can be used to determine adequate resitance to sliding and overturning of the clocks.

3. Analysis must include additional loading effects of sloping backfill.

4. Additional transient or permanent loads behind the wall.

5. bearing capacity of foundations including additional loads from backfill on wall should be considered.

6. Prevent migration of fines through wall by use of filter material.

7. Prevent migration of subgrade into backfill.

8. Consider overall stability of retaining wall, backfill, and subgrade.

Excavate to suitable sub-grade and prepare a well compacted granular base.

A vertical or near vertical wall is possible is a soil reinforcing geo-grid is added to the backfill at every row of blocks. Very high loads can be supported with this typ of construction.

The greater the batter into the fill, the higher the wall can be built without the need to increase the width of the base or adding reinforcing geo-grid to the backfill.