Abstract: Water leakage in railway tunnels signifies a decline in the performance of tunnel waterproofing and drainage systems, which compromises their safe operation. To mitigate such water leakage issues, the authors identify existing challenges in tunnel waterproofing and drainage systems at various stages through a literature review, on-site investigations, model testing, and field testing. Subsequently, measures to ensure effective waterproofing and drainage are discussed, including design optimization, construction quality control, material performance specifications, and drainage system maintenance. The research findings are summarized as follows: (1) During the design phase, measures such as constructing waterproof drainage boards, drainage-type self-adhesive back-adhesive waterstops, and inverted arch drainage systems enhance drainage capacity and prevent the lining from being compromised by buried waterstops. (2) During the construction phase, promoting the adhesive laying and hanging process minimizes the risk of hot welding penetration of waterproof boards. Additionally, implementing precise construction practices, such as strengthening drainage system joints and securely fixing waterstop clamps, improves the overall construction quality of waterproofing and drainage systems. (3) During the material stage, distinctly outlining key performance requirements, including flame retardancy of waterproof boards, anti-degradation properties of geotextiles, anti-crystallization properties of drainage blind pipes, and high-temperature resistance, helps meet the demands of complex tunnel engineering environments. (4) During the operational phase, using U-shaped anti-crystallization seals and micro-mechanical dredging equipment helps maintain smooth and functional drainage systems.

Key words: railway tunnel, waterproofing and drainage system, design optimization, construction quality control, material properties, drainage system dredging