LECA & Hillsides

LECA & Hillsides Basic principle of problem Hillsides are generally stable in themselves! That we see during all “dry” seasons of the year – anywhere.

But when added with great amounts of water – normally by rainfall – this water is partially absorbed by the sub-soil substances – that is the multiple miniature voids between those substances, whether it is clay, gravel or even loose rock sub-soil.

So – when water comes, these voids in the sub-soil substances will start to saturate with water through the filling up/absorption into these voids. This makes the entire “mass” partially liquidified.

More rain cannot be absorbed any longer, and although excess water would be partially running off the surface ground, such excess water creates added pressure onto the saturated sub-soil.

The saturation in itself virtually becomes comparable with a water “column” – mixed with other substances – which anyone will know means great pressure – particularly the higher such water “column” becomes.

The loads/weights of structures (f.ex. houses) on top of such semi-liquidified sub-soil mass add to the pressure. A normal double-storey house can easily weigh a total of about 100 tons – or about 1 ton per square meter.

The total combined weight of structures + sub-soil + water exerts very substantial pressure onto the retaining wall, and even if this wall has been “anchored” into the sub-soil behind, the liquifidication of this sub-soil has no more anchorage ability. Hence the retaining wall will collapse, with everything else on top and behind “running off” the hillside.

Solution Remove the water/rain – and do it fast! And make sure that the sub-terrainean substances do not get saturated and/or liquidified – meaning remain stable.

LECA granules (immediately) behind retaining hillside walls drains all water very fast – both from direct absorption from above, and also from the sub-soils “behind” it. This ensures that the mass does not become saturated, even behind the front LECA granule mass, as the LECA will accommodate – absorb and drain (dispose off) - the water from the sub-soils behind it in the hillside mass.

Another important aspect is that LECA granules themselves have a very low density (weight) – at about 300 kilos per M3 only, and therefore exert a substantially reduced load/weight/pressure themselves.

Many technical tests have proven that the inherited abilities of the LECA granules remove minimum 75% of the back pressure onto the back of the retaining wall – in any conditions – compared to any traditional alternative materials.