为对盾构隧道密封垫长期防水性能进行预测，通过总结以往的密封垫性能预测方法与老化试验方法及成果，参考以往研究将老化试验温度控制在90 ℃以内、老化时长控制在168 h以内，开展哑铃Ⅰ型三元乙丙橡胶（ethylene propylene diene monomer，EPDM）热氧老化试验，分析EPDM试件拉断伸长率、拉伸强度和拉断永久变形率的变化规律，给出化学层面的解析，并与以往EPDM密封垫老化试验结果进行对比。根据试验结果认为： EPDM拉断伸长率和拉断永久变形率的衰减是EPDM密封垫防水能力下降的原因之一，EPDM拉伸强度对EPDM密封垫防水能力影响较小，采用EPDM单个拉伸性能指标老化规律预测密封垫长期防水能力不可靠。最后，基于阿伦尼乌斯方程的动力学曲线直化法，预测EPDM拉断伸长率100年后的老化系数约为37%。
To explore the prediction
method for long-term waterproof performance of
sealing gaskets, the previous methods for predicting and fitting the
performance of sealing gaskets in shield tunnels, as well as the aging test
methods and results are summarized. On the basis of previous research, the aging
test temperature is controlled within 90 ℃ and the
aging duration is controlled within 168 h. The thermal oxygen aging test of
dumbbell type I ethylene propylene diene monomer(EPDM) is conducted, the
variation patterns of the elongation at break, tensile strength, and permanent
deformation rate at break of EPDM are analyzed, and a chemical analysis is
provided. According to the experimental results, the attenuation of EPDM
elongation at break and permanent deformation at break is one of the reasons
for the decrease in the waterproof performance of EPDM sealing gaskets. The
tensile strength of EPDM has a small impact on the waterproof performance of
EPDM sealing gaskets, and predicting the long-term
waterproof performance of sealing gaskets using a certain index′s attenuation pattern is not reliable. The kinetic curve
straightness method based on the Arrhenius equation predicts that the
attenuation coefficient of EPDM elongation at break after 100 years is 37%.
