Investigation on Double-Deck Vibratory Screening of Shield Muck in Moderately Weathered Strata Using EDEM Simulation and Multi-Factor Analysis

The shield tunneling method is widely used for underground space development in the world, where vibratory screening is a critical pretreatment stage for resource utilization of shield muck. However, existing parameters for vibrating screens are mainly based on soft soil and sandy cobblestone strata. Research regarding shield muck from moderately weathered strata remains scarce, leading to poor equipment adaptability and low efficiency. This study focuses on a dry granular system of typical shield muck from moderately weathered strata after washing, drying, and homogenization. By combining laboratory standard sieve tests with EDEM discrete element simulations, a DEM numerical model of double-deck vibratory screening was established. Using single-factor controlled variables and orthogonal experimental designs, the comprehensive influences of vibration frequency, amplitude, and screen inclination angle on a double-deck screen were systematically investigated. Within the investigated parameter ranges, the screen inclination angle produced a relatively large variation in screening efficiency. Based on the preliminary evaluation using the numerical model developed in this study, a vibration frequency of 15 Hz, an amplitude of 2.0 mm, and a screen inclination angle of 12° exhibited favorable overall screening performance among the investigated parameter combinations, yielding upper- and lower-deck screening efficiencies of 95.16% and 82.96%, respectively. The results indicate that changes in the feed state of the lower deck induced by upper-deck pre-classification may be associated with the differentiated responses of the two screen decks to operating parameters, providing a reference for multi-stage screening analysis and parameter selection for shield muck from moderately weathered strata.