The Slurry Wall can be executed using several different technique’s dependant on the design depth of the wall. Long boom excavators can be used for trenches with a depth of up to 20 meters where high production rates (about 200 m² per shift) can be achieved as the excavation of the trench is performed using backhoes. For depths exceeding 20 meters equipment such as grabs can be used where depths of up to 45m can be reached.
Whilst the trench is excavated a bentonite slurry is introduced to stabilise the side walls. Soil, bentonite, water, cement (if required) are mixed on site using a bulldozer in a designated area or on the ground to obtain an impervious mixture. After blending, the trench is backfilled through gravity flow with the soil bentonite slurry which replaces the bentonite slurry used to stabilize the trench. The backfilling is performed in phases with a slope of roughly 6H:1V. The length of excavation is therefore 6 times longer than the depth of the slurry wall.
Thanks to the re-use of excavated materials for the wall slurry, very little spoils are generated, which considerably reduces the requirement for disposal of spoils.