为研究2 000 kPa超高水压环境下盾构盾尾密封性能的关键影响因素及评价标准，设计一套模拟尾盾内径2 000 mm的盾尾密封试验台，并开展最高2 000 kPa的超高水压密封性能试验。通过分析盾尾密封原理，确定影响其性能的关键因素：
保持最大油脂压力高于外部环境泥水压力，确保油脂充分填充盾尾间隙并有效抵抗外部泥水侵入。基于此，对试验台的盾尾密封系统和压力监测控制系统进行针对性改进。试验台采用6道尾刷设计，可在高压环境下有效传递环境压力并保障尾刷钢板的安全性；同时，在油脂腔圆周方向设置10个压力监测点，实现对油脂腔内部压力变化的实时监测与反馈。通过建立压力递增的试验方案，以油脂腔内部压力波动不超过100 kPa为密封性能达标的评价标准，成功完成了2 000 kPa超高水压密封试验，验证了试验台设计的有效性。试验结果表明：
通过实时监测油脂腔各监测点压力变化并实时调节油脂腔压力，保持最大油脂腔压力高于外部水压50 kPa，可实现盾尾密封系统在2 000 kPa 超高水压环境下的有效密封。此外，基于对试验数据和试验现象的分析，建立数值计算模型，重点研究注脂口数量和注脂压力对油脂腔压力的影响，推导出多组经验公式，可用于评估油脂腔从注脂开始到压力稳定所需时间，以及稳定压力相对注脂压力的压降值。
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.
