An introduction to the construction processes of the land reclamation works of Yangshan deepwater port Phase-I project
Type:
Presented during:
WODCON XVII: "Dredging in a Sensitive Environment" - 2004, Hamburg, Germany
Authors:
Liu Reyuan, Liu Huafeng, Tao Runli, Shi Feng
Abstract: Yangshan Deepwater Port, located between Da Yangshan and Xiao Yangshan Islands, Shengsi of Zhejiang Province, is being built by phases. The Phase-I project is between Xiao Yangshan and Huo Gai Tang Islands, 5 container berths totaling 1600m in length will be constructed. The Phase-I harbor district will mainly comprise the wharf and the rear storage yard, the latter will chiefly be reclaimed by hydraulic fill.
About 1.30 million m2 of back-up area needs to be reclaimed in the phase I, which requires 25.00 million m3 of sandfill to be dumped. Where the project is located, the deepest depth reaches up to 40m or so and the biggest current velocity up to 2.6m/s. In order to ensure the project to be completed on time and in high quality, we adopt a special working process of dumping in combination with discharge through floating pipes, i.e., different equipment and different working process will be employed at different depths and in different construction stages: where the depth is below -8m, TSHD Xin Hai Long and other large trailing suction hopper dredges, assisted by various types of bottom hopper barge, are used to dump mixture; where the depth is above -8m, reclamation dredges are used to discharge sand through pipelines.
There originally was a N-S passage for water to pass between Xiao Yangshan and Huo Gai Tang. The reclamation of the Phase-I back-up area separately relies on Huo Gai Tang, Xiao Yangshan and the wharf as its eastern, western, and southern boundaries, but its north side is open to the ocean. Therefore, a retaining structure North Dike has to be built on its north side to ensure the smooth reclamation of the Phase-I area.
The structure of the North Dike, 1200m long in total, is: geo-containers as core, mattresses with rib-like sand-filled bags fixed on them for bottom stabilization, special-shaped blocks as armoring. It is the first time for the engineering and construction circles at home and abroad to use such a structure in such deep waters. Little experience could be used for reference. So the building of the North Dike is actually a pilot project in the fields of engineering research and study, design and construction. We must face many challenges such as laying mattress and filter in deep water, placing geo-containers in deep water and have to find suitable solutions to them. A package of construction processes that is technically feasible, economical, safe and reliable is developed finally through painstaking studies, tests and practice.
Keywords: Yangshan deepwater port, reclamation project, port construction, technology