WORK ON the Amsterdam Metro is benefiting from high capacity Colcrete Eurodrill batching units built to mix and pump huge amounts of bentonite at Stratford International station on the Channel Tunnel Rail Link.
Cementation Foundations Skanska used the two containerised units to batch bentonite slurry for the diaphragm walls and piling for the 1km long Stratford Box on CTRL Contract 230.
Cementation also wanted both units to be able to mix and pump grout so they could be used on other projects, such as the Amsterdam Metro, where the firm is in a joint venture with Franki Geotechnics to install diaphragm walls for three underground stations across the city centre (GE November 03).
'This posed a design problem because different volumes of water are required for mixing bentonite and grout, ' said Colcrete Eurodrill general manager Mark Rex. 'We had to find a way to provide this dual system with limited space.'
This was achieved by assembling the units in a virtual environment on Colcrete's CAD system and getting Cementation's approval approval before the real units were built.
The two batching plants are based on Colcrete's Comixter CP mixers.The paddle-assisted colloidal grout mixer units are able to mix up to 30m 3an hour.The units can store grout, using the paddles to agitate it. Colcrete says weighing facilities and control systems can be added to make the plants automatic.