Location: Sri Lanka

Construction Period: July 2011 – April 2013

Project Profile:
The Puttalam Coal Power Plant Phase II - Water Intake Construction Project contains two major sections, i.e., onshore section and offshore section. The offshore section includes water intake culverts and water intake heads. The offshore intake section of Phase I is 295.2m long, while the offshore intake section of Phase II is about 300m long, consists of two water intake heads and the water intake culverts. The design diameter of each water intake head is 12.2m.
Innovations:
(1) Successful offshore seabed excavation was carried out in the hard and solid sand rock layer. With reference to the limited geotechnical data, the SPT “N” value of this sand rock layer is greater than 50, which indicates this layer is very hard. The average thickness of this layer ranges from 1.5m to 2.5m. To carry out the offshore excavation, our project management office decided to transform the barge “Zhong Ren 101” into a cutter suction dredger, and also equipped a high strength rock breaker to this barge which aimed to deal with the hard sand rock layer.
(2) By pulling the precast concrete culverts to sea via the launch way, and creatively using the “underwater pulling air tubes”, the cost had been greatly reduced. During arrangement of the “underwater pulling air tubes”, the operation was highly affected by the plunging wave of Indian Ocean. By design and installation of wave wall, the arrangement progress of the air tubes had been accelerated effectively and safely.