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Urban development

Tunnel design

Since approximately 70% of the land in Japan is mountainous, tunnels are essential structures for road building in mountainous areas, in order to achieve excellent road linearity and to avoid natural disasters on steep slopes. Since a wide variety of tunnel-related technologies are constantly being developed, it is important to select those that suit the society’s current situation.

As a general construction consultancy firm, Kokusai Kogyo possesses many technologies related to traffic planning, road design, bridge design, tunnel design, and road construction, and also offers services related to surveys, investigations, analyses, construction project management, and tunnel maintenance and management. As a result, we possess the broader perspective for overseeing an entire project and can apply the latest-tunnel-related technologies exactly where they are needed.

Service Features
  • We create basic (preliminary) designs as well as implementation (detailed) designs for road tunnels on high-standard highways and general roads, as well as aqueducts.
  • We carry out FEM analyses (2D and 3D) to determine how mountains will behave during tunnel construction.
  • We carry out various types of surveys for maintaining and managing tunnels, such as regularly scheduled inspections of existing tunnels and damage surveys. We have developed our own high-definition imaging system and a maintenance and management system based on a simple GIS.
  • We create repair designs for maintaining the functions of road tunnels in service.
  • We develop construction plans and tunnel entrance excavation designs that are considerate of the environment and surrounding scenery.