Simulation of screening characterization of double-deck vibrating screen of slurry TBM tunnelling using integrated CFD-DEM-FEM

Abstract

To evaluate and optimize the screening characterization of double-deck vibrating screen of slurry TBM tunnelling, a three-dimensional (3D) coupled model of vibrating screen was established based on an integrated CFD-DEM-FEM method in this paper. The transport characteristics of particles and the fluidity of slurry were revealed, and the kinetic response of the screen surfaces was comprehensively analyzed. The results indicated that the particles were evenly distributed on the screen surface, and the velocity of the particles shows a trend of a steady increase in velocity from 0 m/s to 5 m/s. The coarse screen experienced impact forces up to 90 times greater than those on the fine screen, influenced by particle bed formation and collision dynamics, which reduced direct loads on the screen surface. Screening efficiencies of coarse and fine screens stabilized at approximately 61 % and 73 %, with coarse screens exhibiting greater efficiency fluctuations due to the particle size distribution and collisions. The stress and deformation primairly concentrate in the middle position of the screen surface near the feed and discharge ends, highlighting the need for structural reinforcements to enhance strength and stiffness. Lastly, the optimization schemes for each parameters were proposed, and applied to the slurry TBM tunnelling of Qingdao Jiaozhou Bay Second Undersea Tunnel. The findings in this work provide references and suggestions on the efficient operation of double-deck vibrating screen for slurry TBM tunnelling.