Abstract: Mechanical excavation methods are particularly suitable for the construction of high-level radioactive waste repository pits owing to their high circularity of tunnel formation and minimal surrounding rock damage. Among these methods, efficient muck removal constitutes the core operational challenge. Given the water scarcity at the Beishan project site, this study adopts a vacuum-based muck removal scheme. Utilizing a self-developed full-scale vacuum muck removal test platform, experiments were conducted to investigate the influence of system parameters on the airflow fields at the shaft bottom and within muck-transporting pipes under both dual-pipe and single-pipe removal configurations. Based on airflow field analysis results, optimization strategies for different removal configurations were developed, and high-efficiency muck removal measures were proposed. This research aims to inform the design optimization of muck discharge systems for small-diameter blind shaft boring machines.