Sub Surface Barriers
The creation of sub-surface barriers to inhibit the transmission of water and pollutants or to stabilise soil against erosion can be divided into those used in rock and those used in soil, whilst acknowledging some degree of overlap.
One method of barrier creation involves filling and hence sealing voids within the host material and is generally more common for barriers in rock. Menard Bachy, from its inception, has been involved in rock grouting; frequently this has been permeation “curtain” grouting of the foundation rock below dams.
A second method relies on the removal of transmissive in-situ material and replacing it with a relatively impermeable backfill material; installation usually takes the form of excavating a trench through a supporting fluid, over the depth designed for the barrier. The supporting fluid may be replaced in the backfilling operation, as with bentonite or polymer, or may be self hardening, eliminating the need for backfilling but requiring the removal of excavated material, as with bentonite cement. Frequently, this method is used as a water barrier but it also has environmental applications in the containment and control of contaminants and pollutants.
A third method involving interlocking Jet Grouted Columns is particularly suited to the elimination of erosion of soils in tidal situations.
The range of methods offered by Menard Bachy:
- Permeation grouting of rock or soil
- Slurry cut-off barriers
- Diaphragm walls
- Continuous Jet Grout barriers
- Freyssipile (Pile and Jet Grout Column) walls
Objectives:
- To reduce water flow within soil or rock
- To inhibit the transmission of contaminants
- To contain and capture contaminants
- To eliminate erosion arising from water transmission
