Technologies and Solutions

Mechanical Sheet Laying Construction Method

In creation of reclaimed land, it is necessary to spread a sand-proof sheet on the rubble mound in order to prevent earth and sand from being washed out through crevices in the rubble by waves and tidal currents.

Conventionally, sand prevention sheet laying work had depended on the manpower of divers. However, because work efficiency and safety were issues when this work was performed in deep water, application in deep water had been considered impossible.

Toyo Construction developed a sheet laying machine and realized mechanization of sheet laying work in the “Mechanical Sheet Laying Construction Method.” Furthermore, a high elasticity sheet that can flexibly follow the irregularities in a rubble mound was also developed, eliminating the need for rubble mound leveling work and enabling construction in large water depths of 20m. 

Sheet laying control is performed by a construction management system which combines a GPS crane ship positioning system and a laying machine underwater position detector utilizing an ultrasonic range finder. This information is displayed on a CRT screen which is monitored during sheet laying. The condition of sheet payout and the width of overlap on the adjoining sheet can also be confirmed by an underwater video camera.

Mechanical Sheet Laying Construction Method


  • Realizes mechanized sheet laying from deep waters to shallow waters.
  • The high elasticity feature of the sheet eliminates the need for rubble mound leveling work, and thus can shorten the construction period.
  • Because diving work is greatly reduced, a large improvement in safety is possible.
  • Construction is also possible on steep slopes.
  • Extremely accurate construction management is possible thanks to Toyo Construction’s leading-edge construction management system.