THE INDIAN Navy is consolidating by moving from bases in the commercial ports of Mumbai, Kochi and Visakhapatnam on India's east coast, to a colossal new deep water harbour at Karwar, on the west coast.
The 4,000ha, $7.48bn Seabird facility will be enclosed by three new breakwaters up to 3.1km long and will occupy some 28 km of coastline. It will be the biggest naval base in Asia.
As part of the mammoth construction project, UK marine contracting specialist Seacore is installing piled foundations for a 15,000t capacity ship lift that will be used to remove vessels from the water and transport them horizontally into a dry working area for repair and maintenance. Seacore's work involves installing large diameter rock-socketed tubular steel raking piles into the sea bed.
Working in 13m to 17m of water, 860mm diameter piles are pitched at a 1:5 rake and initially driven by a hammer through overburden to toe into the underlying bedrock. The hammer is then removed and a reverse circulation pile top drill mounted on top of the pile.
This is used to drill out the overburden from inside the tube and on, past the pile toe, to create an open blind socket into the broken basalt bedrock to depths of 5m-13m. Main civils contractor Skanska Cementation India then follows on to place reinforcement cages and pump in tremie concrete, finishing the pile.