Multi-objective optimization of parameters of slurry shield slag agitating and discharging system

Abstract

Slurry shield is an indispensable and important excavation equipment in today's cross-river and cross-sea tunnel projects. Among them, mixing and slag discharge system is an important component to ensure the safe and efficient excavation of the shield. In this paper, the CFD-DEM coupling method is used to simulate the high water pressure environment of the seabed and solve the slag movement trajectory of the slag agitating and discharging system, and multi-objective optimization was carried out on four parameters of slag diameter, blade rotating speed, slurry velocity at outlet and slurry density, with slurry mean flow rate, slag discharge capacity and power loss as evaluation indicators. The results demonstrate that the affecting significance of four factors on the evaluation index of flow velocity and blade power loss are both ranked as: rotating speed > slurry density > slag diameter > slurry velocity at outlet. While for the evaluation index of slag discharging capacity, the affecting significance is ranked as: slag diameter > slurry velocity at outlet > slurry density > rotating speed. Besides, the parameters of the best performance of the slag agitating and discharging system are calculated as: the slag diameter of 10 mm, the rotating speed of 40 rpm, the slurry velocity at outlet of 4.0 m/s and the slurry density of 1.3 g/cm3.

Keywords

• Slurry shied
• Slag agitating and discharging system
• CFD-DEM coupling method
• Agitating parameters
• Multi-objective optimization