考虑密封垫表面工作状态的盾构隧道接缝防水能力数值模拟研究

针对目前施工中盾构隧道防水密封垫经常出现粘贴不牢、沾水、不涂抹润滑剂等情况，构建了密封垫防水能力数值计算模型，将数值方法计算结果与常规计算结果进行对比，并对密封垫在底部与管片槽口粘贴、密封垫顶部涂抹润滑剂及沾水等多种工作状态下的防水能力进行研究。结果表明： 1）计算时是否考虑密封垫表面工作状态导致的闭合压缩力、平均接触应力结果差异分别为3.3%、23.9%，因此考虑表面工作状态的密封垫防水能力评估较为合理； 2）由于粘贴效应约束了密封垫底部的横向变形，其因此闭合压缩力及平均接触应力均大于不考虑底部粘贴效应的计算结果，影响值范围分别为31%~199%、0~245%； 3）密封垫顶部涂抹润滑剂能够减小闭合压缩力、增加接触面平均接触应力，影响值范围分别为4.7%~19.9%、6.5%~111%； 4）密封垫沾水时，闭合压缩力降低29.1%, 接触面平均接触应力降低8.7%； 5）在长期工作情况下，由于密封垫表面接触状态的变化，其平均接触应力整体呈下降趋势，最终下降约23.9%。

Numerical Simulation on Waterproof Capacity of Shield Tunnel Joints Considering Working State of Sealing Gasket Surface

In shield tunnel construction, the problems that the sealing gasket of shield tunnel joints not sticking well, being wet, and not being painted with lubricant are common. As a result, a numerical calculation method for waterproof capacity of the sealing gasket is constructed. The calculation results of the model are compared with conventional calculation results, and the waterproof capacity of the sealing gasket under the conditions such as the bottom of gasket being pasted to the notch of segment, the top of gasket being painted with lubricant, and being wet is studied. The results show that: (1) The difference of closed compression force and average contact stress between the calculation results with and without consideration of the working conditions of gasket surface are 4.2% and 8.1%, respectively, which indicates that it is necessary to evaluate the waterproof capacity of the sealing gasket with consideration of gasket surface condition. (2) The lateral deformation at the bottom of liner is constrained by sticking effect, hence, both closed compression force and the average contact stress are larger than those without consideration of bottom sticking effect, and the influencing ranges are 3.1%~19.9% and 0~24.5% respectively. (3) By painting the top of gasket with lubricant, the closed compression force can be reduced and the average contact stress can be increased, and the influencing ranges are 4.7%~19.9% and 6.5%~11.1%, respectively. (4) If the sealing gaskets are wet, the closed compression force and the average contact stress will be reduced by 29.1% and 8.7%, respectively. (5) Under long term working condition, the average contact stress of the gasket decreases due to the contact state variation of sealing gasket surface, which is decreased by 23.9% at last.