The role of wall slip and temperature in shield tail seal performance: A novel modeling approach

Abstract

The increasing number of tunnel construction projects utilizing shield machines has led to frequent occurrences of tail seal failure. Current models for predicting shield tail sealing performance often neglect crucial factors such as wall slip and temperature-dependent grease properties, leading to inaccurate predictions and suboptimal designs. This study presents a novel computational model that incorporates both wall slip and temperature effects to accurately predict the performance of seals. The model utilizes a finite element method approach with a non-Newtonian fluid model to capture the complex rheological behavior of the sealing material. The simulation results reveal that neglecting wall slip can lead to an underestimation of grease leakage amount and the water pressure resistance of the tail seal system, highlighting the critical importance of incorporating this effect in seal design. When the wall slip effect is considered, the breaking water pressure of the tail seal brush is 0.45 MPa, while the breaking water pressure is only 0.34 MPa when the wall is considered to be non-slip. Furthermore, it was demonstrated that temperature variations significantly influence the pressure distribution within the seal. When the temperature is 10 °C, the breakdown water pressure is 0.88 MPa, while when the temperature rises to 60 °C, the breakdown water pressure is only 0.07 MPa. This study provides a significant advancement in seal design by offering a more accurate and comprehensive model that incorporates both wall slip and temperature-dependent material properties. The model can facilitate the design of more reliable and efficient shield tail sealing systems.