Seal performance test of shield tail under high water pressure

Shield method has been used for more tunnels projects due to its safety and high efficiency. However, the shield method is facing more unprecedented technical challenges because of the increasingly complex conditions such as high water pressure and mixed ground formation. Shield tail seal plays an important role in the tunneling process, which is greatly affected by high water pressure, soil pressure or other factors that might endanger the construction safety. The injection of grease is of fundamental importance for shield tail seal, which can prevent water and soil from flowing into the shield machine. As a result, the sealed grease must be studied in details. This paper introduces an experiment on shield tail grease used in tunneling. The experiment includes testing in static pressure and propelling state, which can fully reflect the performance of shield tail grease in shield tunneling. The pressure change of grease during pipeline transportation and in the shield tail gap are both studied in this paper. The research results of this paper provide the technical reference for the safety control of shield tail seal during the tunneling process.