Saemankeum Comprehensive Tideland Reclamation Project

Saemankeum Comprehensive Tideland Reclamation Project: Feasibility Study on Hydraulic Filling of Seadikes

Anonymous, A

NEDECO

Saemankeum Comprehensive Tideland Reclamation

1989-11

The Saemankeum Comprehensive Tideland Reclamation Project has as objective the reclamation of the extensive tidal flats in the estuaries of Dongjin river and Mankyung river for, among others, agricultural, urban and industrial use. The project includes the construction of a number of closure dams with a total length of some 34 km. Due to the large scale and unfavourable site conditions the Agricultural Development Corporation (ADC) commissioned the Korean Research Institute for Reclamation (KRIR) to study seadike construction and related aspects. The scope is formulated as: - Conceptual design of the cross section of the hydraulic fill of the closure dam, placed behind the quarry stone embankment; - Assessment of operational criteria for sea borne dredging equipment and evaluation of construction methods required for the application of the hydraulic fill. Given the natural boundary conditions of the site (mainly tidal boundary conditions) and the natural properties of the available sand it can be concluded that the under water slopes of the hydraulically filled sand body will be in the order of 1:15 and that the relative density of the under water part is expected to be between 35% and 45%. The expected density indicates that the sand body might be subject to liquefaction during earthquakes with a ground surface acceleration of 0.10 g. It is therefor recommended: - to apply gentle side slopes for the underwater part of the sand body. A slope inclination of approximately 1:15 is preferred both for stability and execution reasons. - to include appropriate in-situ quality control procedures during the construction. For the construction methods the following conclusions have been drawn: - The medium size, high output, cutter suction dredge is the most attractive dredging equipment. - Hydraulic transport by means of pipelines is both economical and technical the most attractive option. The expected losses of sand vary between 15% and 25%, depending on the different stages of fill operations. To minimise additional losses a number of recommendations have been made for the filling process: - Spreading the sand-water mixture over the full width of the disposal area; - the use of several discharge pipes, alternating in use depending on the stage of the tide; - the use of dry-earth moving equipment such as bulldozers to guide the filling process and to improve densification of the fill. The hydraulic fill operations have been described in three stages: - Direct filling with an underwater discharge pontoon in an open fill up to MSL -6.0 m; - Direct filling with the discharge pipes just above the water in an open fill between MSL -6.0 m up to MSL +3.5m, by optimising the use of three discharge pipes during the various tidal stages; - Direct filling with two discharge pipes at the required height in a bunded area.

hydraulic filling
land reclamation
construction methods
dredging
sea dike
Saemankeum
Dongjin
Mankyung

TCS200500
TPN100100

http://resolver.tudelft.nl/uuid:46c85eea-ba75-4038-8897-d8ce7c746489

Korean Research Institute for Reclamation (KRIR)

35.849398, 126.665177

Hydraulic Engineering Reports

report

(c) 1989 NEDECO