Abstract
The “Guideline for the measures against dust generated in the tunnel construction” set out by the Health, Labor and Welfare Ministry, in December 2000, the target control level of the dust was for the first time dearly set at 3mg/m3. Therefore, the authors carried out several tests and obtained dust reduction effect quantitatively by introducing different dust reduction measures such as use of dust preventing agent, large volume dust collector, and liquid accelerator. This report covers the results of the tests carried out in Nezarne Tunnel, Nagano Prefecture, Japan, and also comments on the ideal future tunnel excavation method.
