Deep Trenching-bentonite

Deep Trenching - Bentonite


Bentonite is a natural clay which consists mainly of montmorillonite. This material derives its capacity to swell from the fact that it can absorb water up to five times its own mass, increasing its volume by up to fifteen times the original. The addition of cement causes the bentonite water mixture to form a stable mass, the specific mass of which can be increased considerably by the addition of various fillers.
The dry substances are often mixed in advance, so only water needs to be added on site. The composition of the mixture can be adjusted depending on whether it is permanent or temporary in nature. Because all the materials used are natural in origin, no environmental pollution results either on installation or on possible later removal of a bentonite-cement wall.
Slurry walls are often used in dykes and dams to restrict seeping water to a minimum. Slurry walls are also used to achieve the various water levels in building excavations where lowering of the groundwater level is necessary. Bentonite-cement walls are a very good application in the layout of new landfill sites. Retaining walls are also an excellent solution for isolating contaminated ground sites and preventing the spreading of percolating water at existing landfill sites. Using the impermeable strata present in the soil a trough is formed together with a retaining wall, within which the water level can be controlled and through which contamination cannot spread any further into the surroundings.

Depending on the depth of the natural impermeable stratum, walls are dug or cut with trenching machines. During trenching the slurry is pumped into the dosing box. This produces a wall formed in the ground which is built up to the working level / ground level. The depth of the wall is determined extremely accurately by the laser control. The slurry is mixed on site in a special mixing unit.