Optimization Design of Rockfall Box in Mud-water Shield Based on CFD-DEM
Currently,the rockfall box used in the slurry shield has the problems of a high slag removal frequency and low screening efficiency.Taking the rockfall box used in Luoyang Metro Line 2 as an example,the CFD-DEM fluid-solid coupling simulation technology was used to clarify the movement law of pebbles in the rockfall box pipeline,explain the causes of the current rockfall box problem,and optimize the structure.Meanwhile,the influence of the inclination angle of the grille and the distance from the rockfall mouth on the screening efficiency of the rockfall box is studied.The results show that when the inclination angle of the grille is greater than 10°,the screening efficiency gradually decreases with the increase in the inclination angle.As the distance between the grille and the rockfall mouth increases,the screening efficiency gradually increases.However,when the distance is 80mm,there appears to be a phenomenon of large particle-size slag blocking the grille.Therefore,it is recommended that the inclination angle of the grille be set to 0～10°and the distance between the grille and the rockfall be 50～70mm.
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