Lifting Grouting Technology for Settlement Control of Existing Operating Subway Tunnels

This paper focuses on the settlement issues of existing operating subway tunnels, delving into their causes, the principles of lifting grouting technology, and construction techniques. Settlement causes are analyzed from four aspects: construction quality, geological conditions, subway operations, and surrounding environment. Lifting grouting technology addresses settlements through filling, reinforcement, and lifting. The construction technique covers preparation, hole layout, grouting procedures, and monitoring. This research offers a technical foundation and practical guidance for controlling settlement in operating subway tunnels.