Airflow-Dust Migration Law and Control Technology Under the Simultaneous Operations of Shotcreting and Drilling in Roadways

Abstract

The simultaneous operations of drilling (cutting rock) and shotcreting are occasionally carried out in order to advance the tunneling speed in underground roadways. Under these circumstances, the dust pollution from multiple dust sources is serious, especially threatening worker health. In this paper, the main dust sources were divided; a new ventilation system under the simultaneous operations was proposed by adding one turbulator (T) and the second exhaust air outlet (SEAO). The airflow-dust migration law after improving ventilation system was analyzed to determine the optimum combination and corresponding working parameters of T and SEAO based on computational fluid dynamics. Results showed that the combinatorial arrangements of A-3 pattern, T installed upstream while SEAO laid downstream of shotcreting area, were the best ventilation pattern in terms of dust suppression. The more air volume from SEAO is, the smaller the diffusion distance of high concentration dust is. The dust concentration at the interface between cutting rock and shotcrete declined and then increased with increasing total forced air volume. The bigger the forced-exhaust air ratio is, the larger the dust concentration at interface is. According to the on-site test, the new method prevented the high concentration dust from diffusing at tunneling district and reduces the dust concentration at shotcreting district.