DENSITOMETRY FOR SUSPENDED SPRAYED CONCRETE DUST FOR TUNNEL CONSTRUCTION BY DIGITAL CAMERA

Abstract

  The guideline of dust control for tunnel construction works, published by the Ministry of Health, Labor and Welfare of Japan, dictates that the employer has a management duty to control the suspended dust density for the safety of workers in the tunnel construction work. The "Digital dust Indicator"(DDI) is the most accurate instrument for dust density measurements. However, DDI is also expensive.
  In this paper, the authors propose a dust density measuring method which measures the dust density from the digital image which carried out the flash photography. The feasibility test of real tunnel construction site, there was the high correlation in this study and DDI, and the effectiveness of this new method was confirmed.