Slurry overflow prevention tool for shield construction in high-cold ultra-shallow earthing area

The utility model belongs to the technical field of civil engineering construction, and relates to an alpine ultra-shallow earthing area shield construction grout overflow prevention tool which comprises a monitoring rod embedded in a monitoring point hole site and a protective cover arranged above the monitoring rod, and a sandy soil layer is arranged on the outer portion of the monitoring rod inthe monitoring point hole site in a surrounding mode. The monitoring rod is a hollow rod, an inflatable air bag is arranged in an inner cavity of the monitoring rod, an inflation pipe is arranged onthe air bag and extends to the outer side of the top of the monitoring rod, and a plurality of openings capable of enabling the air bag to be extruded out after being inflated are formed in the side wall of the monitoring rod. The ratio of the thickness of the sandy soil layer in the monitoring point hole site to the diameter of the monitoring rod is 1: 3-6. And the openings are vertically and circumferentially distributed