CONSTRUCTION OF NAGOYA STORM-TIDE-PREVENTING BREAKWATER

The Nagoya Storm-Tide-Preventing Breakwater is a large-scale Breakwater built as a link in the general Ise Bay Storm-Tide-Prevention Project. The entire length of this breakwater is about 8,250 meters, which extends from the mouth of the Nabeta River, transversing the northern part of Ise Bay, to the Chita town. (Pig. 4) The greater half of this breakwater was built on an extremely unstable foundation, the nature of ground being of soft clay stratum with a thickness of 10 m - JO m. The sand-drain method was adopted for improving the ground on which caissons were laid, forming a composite type section. For this reason, during the process of construction a close work control was maintained constantly by applying boring, observation on the sinking, pore water pressure and other conditions to ascertain whether the sinking by consolidation took place according to the calculations laid in the design specification. Based on the date obtained in this manner the speed of the work was regulated and the work was conducted under strict control of soil mechanics. The required volume of materials for the construction of the breakwater was so immense that a special care had to be given to ensure their smooth and efficient supply. And to speed up the work with a view to reducing the effects of wind and waves to a minimum, large machinery were employed. The present paper describes the engineering features of this great 8,250-meters breakwater project which was completed in a short period of 2 years and 8 months at a cost of 30 million dollars after overcoming numerous obstacles.