BAM and Van Oord were constructing a new deep water berth at Bootle Docks in Liverpool for Peel Ports. This required the reclamation of land from the tidal River Mersey. Following the placement and compaction of sand (dredged from the River Mersey) behind the new quay wall, Van Oord identified a layer of silt up to 1.5 m thick at the base of the dredged fill, which created a potential stability issue for the quay wall and rear crane rail for the 92 m high dock cranes.
The soils comprised of 18 m of fine to medium grained dredged sands which had been compacted by a vibratory lance. Below the dredged sands was a layer of estuarine silt up to 1.5 m thick. The silt layer/dredged sand was underlain by up to 10 m of very stiff clay/dense sands over sandstone.