St. Petersburg Metro's Flooded Secret: A 1970s Engineering Disaster

Flooded St. Petersburg Metro Tunnel: A Historical Perspective On April 8, 1974, during the construction of the St. Petersburg metro, a significant incident occurred. A section of the tunnel between Lesnaya and Ploshchad Muzhestva stations flooded. This wasn't a simple mishap; it was the result of a challenge faced by Soviet engineers: a large underground river running approximately 100 meters below the surface. The video by PRO МЕТРО (laveromna) details the innovative ground freezing method employed. "The ground was pre-frozen using special boreholes filled with freon," explains the author. This process aimed to solidify the earth, allowing for safe tunnel construction. However, despite these precautions, water breached the frozen ground, leading to the flooding. The video includes archival photographs showing the construction process and the subsequent flood. These visuals, coupled with the author's clear explanation, make this a compelling story of engineering challenges and unforeseen circumstances. The incident serves as a reminder of the complexities involved in large-scale infrastructure projects, even with advanced techniques.