Research on the Application of Rapid Closure Construction Technology in Pit Excavation

Due to the wet and rainy climate of the Pearl River Delta region, constructing open-pit underground works has long been a challenge in the construction of the Guangzhou Metro. To address the issue of the pit in deep foundation excavations not being closed promptly after excavation, leading to washing by rain and soaking by groundwater, which can cause instability and landslides, this research innovatively proposes rapid sealing construction technology for the excavation of pits in sandy viscous soil layers, tailored to the specific application scenarios. In this method, U-shaped groove members, prefabricated in blocks on the ground according to the size requirements of the pit's main structure, are hoisted to the quick-sealing base within the pit, replacing the original cast-in-place cushion or masonry retaining wall process. The practical research shows that rapid closure technology avoids repeated disturbances to the foundation and reduces safety and quality control risks associated with the long-term exposure of soil in the pit, thereby mitigating the risk of soil instability and landslides on the pit's sides due to the failure to seal the foundation promptly after excavation. The research findings can provide valuable insights for similar construction projects in challenging geological conditions.