As specialists in tunnel construction, we provide a range of services, including the planning of new roads for local and regional government and expressway operators, and the planning of new line and line extensions for railway operators. For example, if a tunnel is to run from point A to point B, we plan the necessary size, route, depth, and structure. We also design tunnels to be safe, secure, and long-lasting, taking into account a range of conditions, including the ground where the tunnel is to be excavated and existing underground and aboveground structures around the proposed route.

Our involvement from the design phase as consultants specializing in tunnel design allows the realization of attractive cities that are more convenient to live in.

The area underneath a city is an intricate and inexhaustible web of underground structures of all kinds. Advanced underground technologies and, above all, extensive design experience are indispensable in constructing new railroad tunnels in such environments. We specialize in tunnel design and construction, skilled in the knowledge of designing new tunnels under complex cities for new rail line and extension projects.

In a lot of areas Japan’s transportation infrastructure requires tunnels to fill in the missing links in transportation networks. We have expertise in shield tunnel technology, a technology we have continued to develop since our founding, and in numerous other tunnel design methods, including mountain tunneling, open-cut tunneling, in which the ground is excavated from the surface, and underwater tunnel construction, where the tunnel is embedded in the sea bed. These technologies are being used to design tunnels to enhance Japan’s transportation network.

In recent years, there has been an urgent need for “utility tunnels” that combine telephone, electricity, gas, water, sewage, and other infrastructure that we use in our day-to-day lives into a single tunnel, and “telecommunications tunnels” that rid the aboveground landscape of telephone poles. Utility tunnels are resilient against natural disasters such as earthquakes and typhoons, and also have the advantage of being very easy to manage. Another major benefit is the improvement of the aboveground landscape by eliminating power poles. In our role as specialists in tunnel design and construction, we also help to develop and maintain such important lifelines.

Shield tunnels are built using the shield tunneling method, in which a machine called a shield machine is used to dig through the ground. This makes it possible to build tunnels without disturbing life above ground, and it has proven its value in a variety of infrastructure projects in urban areas. Since our founding, we have accumulated expertise in shield tunneling design, and we are one of the leading firms in Japan in terms of both the number of projects and the content of our work.

We have a long history of designing underground structures of all kinds, including tunnels for flood control and water utilization, as well as railroads and roads. Before a tunnel is completed, there are often a range of unexpected challenges. Having an organizational structure that boasts engineers with the know-how and knowledge backed by extensive experience is essential to overcome seemingly insurmountable challenges. Our strength lies in the experience we have accumulated over many years in overcoming myriad challenges.