KNOWS TO THE GROUND

The 1.8 km long dual carriageway Limehouse Link road in London's dockland has attracted much publicity mainly due to its location, cost and scheduling. The article describes the complex geotechnics of the scheme which includes an underground junction designed to take traffic from dockland office and residential complex to the main road network. Most of the road will pass through a cut and cover tunnel built top down, except for a section through the Limehouse basin where conventional methods are used within a cofferdam. Very detailed site investigation was carried out because of the difficult nature of the variable clays, silts and sands found along the route. Old documents, ground radar and probing were used to locate obstructions which might have delayed the rigs of the diaphragm walling contractor. Ground movement is being closely monitored because of possible effects on the Docklands Light Railway and adjacent buildings. Dewatering is an important factor as the road is situated close to the river Thames. An extensive network of sandwicks has been installed to transfer water to the deeper levels of sand. A specially built dock has been constructed to receive large quantities of material delivered by barge; much of the spoil is also being removed by barge.