Abstract: As an auxiliary facility of railway construction, spoil disposal sites play a critical role in ensuring the safe operation of railway lines. This study examines the Zhangjiaying No. 2 spoil disposal site along the Pumei Railway. Through field investigation, topographic surveying, and UAV oblique photogrammetry, the current conditions of the site were characterized, and the spoil volume and maximum pile height were obtained using a DEM-based modeling approach. The SLOPE/W and SEEP/W modules of GeoStudio were employed to evaluate site stability, overall and local stability of the spoil mass, and retaining-wall stability under both natural and heavy-rainfall conditions, using the Ordinary method, the Morgenstern-Price method, and the unbalanced force method. The results indicate that all stability factors satisfy the required criteria under natural conditions. Under heavy-rainfall conditions, the overall stability of the spoil mass and the retaining-wall stability remain acceptable; however, certain local areas exhibit marginal stability. To mitigate potential instability, it is recommended to flatten the slope, improve the drainage system, and enhance surface vegetation to prevent sliding or collapse of the spoil mass.

Key words: Spoil Sites, Railway Engineering, Geo Studio, Sliding, Stability