Abstract:

To conduct an indepth investigation of the sealing performance of the shield tail under ultrahigh water pressure in principle, a test bed is developed based on mechanical, electrical, and hydraulic control technologies. The key design elements are as follows: (1) attitude design: The test bed can achieve axial movement, radial movement, and steering deflection by the expansion and contraction of oil cylinders, which can simulate the posture changes during the shield tunneling process; (2) oil supply design: Five shield tail brushes form four grease cavities for simulating the shield tail under ultrahigh water pressure; (3) design of an ultrahigh water pressure supply: A mudwater circulation pressuremaintaining system is designed for simulating ultrahigh water pressure outside the shield, which is safe, reliable, and can withstand a pressure reaching 2.5 MPa. Factors such as the mudwater pressure, number of grease cavities, shield tail grease and brush quality, shield tunneling attitudes, and segment dislocation, that affect the static and dynamic shield tail sealing performance under ultrahigh water pressure, are determined by subsequent tests.

Key words: shield tail, ultrahigh water pressure, sealing performance, segment attitude, test bed design