Herein, a shield tail seal test platform modeling tail
shield with an inner diameter of 2 000 mm is designed to conduct a test on the sealing performance of
shield tail under ultra-high water pressure up to 2 000 kPa.
Shield tail sealing principles are analyzed, revealing the primary operations
guaranteeing its performance, which is maintaining the maximum grease pressure
higher than the external environmental mud and water pressure to ensure that
the grease fully fills the tail seal gap and effectively resists the intrusion
of external mud and water. Based on this instruction, targeted improvements are
made to the tail seal system and pressure monitoring control system of the test
platform. This platform adopts six tail brushes which can effectively transmit
environmental pressure under high-pressure conditions
while ensuring the safety of the tail brush steel plates. Additionally, 10
pressure monitoring points are arranged circumferentially in the grease
chamber, enabling realtime monitoring and feedback of internal pressure
changes. By establishing a pressure-increasing test
scheme and using a pressure fluctuation within the grease chamber not exceeding
100 kPa as the evaluation criterion for sealing performance, a sealing test
under 2 000 kPa water pressure is successfully completed, and the effectiveness
of the test platform is verified. The experimental results show that by
monitoring and adjusting the grease chamber pressure in real time and
maintaining the maximum grease chamber pressure of 50 kPa higher than the
external water pressure can achieve effective sealing performance of the tail
seal system under the 2 000 kPa ultra-high water
pressure environment. Furthermore, based on the analysis of experimental data
and phenomena, a numerical calculation model is established, focusing on the
influence of the number of grease injection ports and injection pressure on the
grease chamber pressure. Multiple sets of empirical formulas are derived, which
can be used to evaluate the time required for the grease chamber pressure to
stabilize from the start of grease injection and the pressure drop of the
stable pressure relative to the injection pressure.
GAO Wenliang
,
WU Hao
,
YAN Yang
,
ZHANG Lin
,
HU Jianli
.
Sealing Performance Test and Numerical Calculation of
Shield Tail Under Ultra-High
Water Pressure
[J]. Tunnel Construction, 2025
, 45(S1)
: 61
-70
.
DOI: 10.3973/j.issn.2096-4498.2025.S1.007
