A typical crew requirement for building Reinforced Earth TerraTrel walls would consist of a ganger, 3 general labourers and a machine operator. Production rates depend largely on the quantity of structural fill placed each day and the reinforcing strip length. As a guide, under normal working conditions, a 4 man gang could build 30m² per day given the wall height was up to 7m and 330 tonnes of fill was placed and compacted. Large wall areas have more scope for utilising plant and labour more efficiently, and as such daily construction rates of over 30m² are achievable.

Firstly, a level, compacted formation is prepared for placing elements on. Then the initial course of TerraTrel elements can be placed directly onto the levelled ground. The structure is built by placing one element directly above another, this way the structure is self supporting as it is like building 0.5m high walls on top of each other. 

The reinforcing strip is connected to the TerraTrel facing elements by means of a bolt passing through ‘C’ shaped steel tie strips on the front of the elements and 13mm diameter holes punched through the strips.

Prior to backfilling the panels, the rear face is covered with a geotextile lining cloth to prevent loss of fine backfill particles, whilst still allowing water to drain through.

Acceptable fill material for Highways structures is 6I or 6J frictional fill as described in the Manual for Construction of Highways Works, or frictional fill as described in BBA certificate No. 99/R106 (click here to download a copy)

The construction technique allows the main building activities to be carried out from the backfill side of the wall, as such the structure is stable during construction, allowing equipment to operate on top of any layer.