Experimental investigation and field application of pulse-jet cartridge filter in TBM tunneling construction of Qingdao Metro Line 8 subsea tunnel

Abstract

In the process of large-scale urbanization, the increase of traffic flow has led to severe traffic jam in large and medium-sized cities. The metro can effectively relieve this problem, but large amounts of dust, which affects human health and safe production, will be generated during metro tunneling construction. While traditional methods such as water spray, ventilation and foam dedusting have some shortcomings, cartridge filters boast high dust collection efficiency, zero water consumption and no secondary pollution. Cartridge filters are suitable for the construction of subsea tunnels with water inrush problems. In order to solve the dust pollution during tunnel boring machine (TBM) tunneling in the Qingdao Metro Line 8 subsea tunnel, a cartridge filter was designed independently in this study. The optimization-factors were adopted to improve the uniformity of pulse-jet cleaning among filter cartridges. The optimized injection pipe was adopted in the design of pulse-jet cleaning system. Before the dust collection system in the TBM tunneling face was renovated, the dust concentration increased with the increase of running time. The total dust and respirable dust collection efficiencies of three measuring points were all lower than 70% when the axial flow fan ran for about 1 h and lower than 55% when it ran for about 4 h. After the renovation, the total dust and respirable dust collection efficiencies of three measuring points became higher than 92%, and the concentrations of total dust and respirable dust 20 m away from the cutterhead-changing platform were lower than 2 mg/m3. This indicates that the renovated cartridge filter effectively reduced the dust concentration and improved the working environment.