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Peaty, clayey and sometimes even silty soils are characterized by a high-water content, very low permeability and a low strength. When loads are applied to these soils, excess pore water pressure develops as the soil cannot adjust to the new load due to the very low permeability and slow dissipation of the excess pore water. With the dissipation of the excess pore pressures the soil adjusts to the new load. This often results in long periods (years) with high consolidation settlements and a low to insufficient safety factor on the stability of the embankment. With the application of low cost prefabricated vertical drains (PVD) a considerable reduction of the consolidation / settlement time, from years to months, and a major improvement in the stability of the embankment can be achieved. When surcharge is used, residual settlements can be controlled. The use of PVD with surcharge is therefore one of the most commonly used techniques and often the cheapest method to prepare soft compressible subsoil for future construction activities. Cofra has several consolidation systems within its portfolio. Find out more by using the links in the overview below. 

Website Diagram Consolidation Wide
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Our solutions

Cofra has the following consolidation solutions within it's portfolio

Offshore vertical drain installation

A selection of our consolidation projects

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PVD installation for A6 Randalstown diversion, UK

Cofra Ltd installed 450,000m1 for this road embankment in 2018.


PVD installation for Newton farm housing development, UK

Cofra Ltd installed 126,000m1 of vertical drains for this housing development in 2018.


PVD installation for Doncaster iPort warehouse development, UK

Cofra Ltd installed 257,000m1 of vertical drains for the development of a new warehouse in Doncaster in 2018.


PVD installation for housing development Centenary Quay, UK

Cofra Ltd installed 35,000m1 for this housing development in 2018.


PVD for tailing pond remediation, France

Cofra has installed vertical drains for the remediation of a tailing pond in 2019.