Analysis of muck migration behavior and suction port extending forward performance in the working chamber of the slurry shield machine under clay stratum

Abstract

This study aimed to solve the problem of clogging in the working chamber of a large-diameter slurry shield passing through the clay stratum. Numerical simulation and experimental methods were employed to investigate the migration behavior of the muck in the original working chamber structure. The impact of increasing the percentage of scouring flow and implementing the suction port extending forward method on the muck discharge performance was also investigated. The results indicated that raising the scouring flow percentage could not improve the muck discharge performance under the original structure. However, extending the suction port to 500 mm from the slurry gate resulted in a 75.19% increase in the muck discharge rate and an 84.70% reduction in muck accumulation at the bottom of the chamber. Moreover, closing the scouring pipelines V25 and V7 after extending the suction port forward allowed for more efficient use of the limited slurry flow. Finally, an optimized suction port extending forward method was proposed and successfully applied to alleviate the clogging issue.