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Research and Development
At Nishimatsu Construction, we develop technologies to raise the quality and efficiency of the construction process, as well as environment-related technologies. We also place priority on the development of renovation technologies for the refurbishment of social infrastructure. To respond to diverse needs, we actively undertake joint research with other technical laboratories, including the research institutions of universities, companies in both our and other industries, as well as public institutions and research laboratories.
Air Cleaning System for Tunnels and Busy Arterial Roads
The Nishimatsu Method of Air Cleaning System employs electric dust extractors together with newly developed denitration equipment. The electric dust extractors are capable of removing more than 90% of suspended particulate matter (SPM), while the denitration equipment can absorb more than 90% of the nitrous dioxides (NO2) contained in the air before treatment. By adding an oxidation device, it is also possible to eliminate nitrous oxides (NOx).This system has been installed at the ventilation station in the Shinjuku Line Tunnel of the Central Circular Route of the Metropolitan Expressway. This is the first instance in Japan of the installation of a system of this kind in the ventilation structure of a road tunnel. The system is also being used to purify the air in the semi-enclosed portion of the elevated section (overpass) of the Tokyo No. 8 Ring Road. The system is effective for mitigating air pollution caused by vehicle exhaust emissions, which is a concern of people living in the vicinity of trunk roads passing through cities.
In response to a request from the municipal government of Shanghai, we have installed this system in the tunnel ventilation station already in service to carry out an onsite test run. Test data showed that our system was highly effective in removing harmful substances contained in the exhaust gases.
| Ventilation system: How it works | |
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Polypropylene Fiber Lining Method
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| Tunnel lining process |
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This technology prevents the generation of spall fragments so common in aging concrete structures, and offers superior workability compared with existing fibers, thanks to the highly dispersive feature of the fiber. In addition, polypropylene fiber allows for the same level of durability as concrete without fiber. Also, rusting is not a problem, as it would be in the case of steel fibers.
This method is effective for large-scale tunnels with a cross-sectional area of 100m2 or more, such as tunnels which constitute part of an expressway, and in places where there is a low overburden surcharge or where the ground is soft. As of March 2009, Nishimatsu had used this polypropylene fiber lining method in more than 10 tunnel construction projects, and has received approval for the technology’s use in the tunnel ordered by NEXCO (Nippon Expressway Company).