Application and research of dry-type filtration dust collection technology in large tunnel construction

Large amounts of rock dust are produced in the process of constructing large tunnels. It then accumulates in the tunnel where, because it is difficult to disperse, it is a serious threat to workers' health; more than 90% of dust is respirable. Traditional methods to reduce rock dust concentrations, such as a water spray, ventilation, and foam are not effective. Therefore, a new dry-type filtration dust collection method is put forward to use in the construction of large tunnels, and a dry-type filtration dust collection device is designed. Experiments and field application of the dry-type filtration dust collection device were carried out. Experimental results showed that the total dust suppression efficiency reached 98.41% and the leakage rate was 7.86% with the dry-type filtration dust collector. The field application in the Chaoyang tunnel indicated that the efficiency of the dry-type dust collector in suppressing total and respirable dust was 98.13% and 97.86%, respectively. During lining trolley shotcreting operations, the total dust concentration decreased from 253.41 mg/m(3) to 29.97 mg/m(3) and the respirable dust concentration dropped from 226.73 mg/m(3) to 28.85 mg/m(3). The dust collection system also reached the optimal dust removal efficiency in two other tunnel construction operations and made an obvious improvement in the environment behind the dust collection system in the large tunnel. The dry-type filtration dust collector effectively improves the rock dust collection efficiency and makes up for the problem of inadequate treatment of respirable dust by the traditional methods. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.