盾构隧道管片接缝三元乙丙橡胶密封垫力学性能影响因素敏感度分析

为研究盾构隧道管片接缝三元乙丙橡胶密封垫力学性能的影响因素,首先,以实际工程为背景,采用自主设计的试验系统进行试验,并以此验证数值模型的可靠性; 然后,利用数值模型,采用正交分析方法,对密封垫断面参数(开孔形状、断面开槽数量、断面开孔率)、密封垫橡胶材料硬度、密封垫拼装姿态(张开量、错位量)进行六因素三水平的密封垫力学性能影响因素的敏感度分析; 最后,结合力学性能研究与防水性能预测需求,提出以闭合压缩力、密封垫接触应力分布作为分析指标。研究结果表明: 1)针对密封垫装配时所需的闭合压缩力,其影响因素主次顺序为张开量、断面开孔率、橡胶硬度、开槽数量、开孔形状、其他因素以及错位量; 2)密封垫接触应力分布的影响因素主次顺序为开孔形状、断面开孔率、错位量、其他因素、张开量、橡胶硬度、开槽数量。根据研究结果选取对密封垫力学性能影响较为显著的因素进行单因素分析,然后根据分析结果及橡胶垫密封垫防水性能预测方法, 提出背景工程管片接缝密封垫的优化方案。

Sensitivity Analysis of Influencing Factors on Mechanical Properties of EPDM Sealing Gasket of Segment Joint of Shield Tunnel

The study on influencing factors on mechanical properties of ethylene-propylene-diene monomer(EPDM) sealing gasket of segment joint of shield tunnel is of great significance. Hence, a testing system is developed, and the feasibility of the system is verified by case study. And then the 6-factor-and-3-level sensitivity analysis is carried out on influencing factors of mechanical properties of sealing gasket, such as cross-section parameters of sealing gasket(hole shape, groove number and holing rate), hardness of sealing gasket material and assembly posture of sealing gasket (opening and dislocation amount), by numerical model and orthogonal analysis method. Finally, the closed compressive force and contact stress distribution of sealing gasket are regarded as analytical indices considering the requirement of mechanical properties and waterproofing properties of sealing gasket. The results show that: (1) The influencing degree of joint opening amount on the closed compressive force is the greatest, followed by those of cross-section holing rate, rubber hardness, grooving number, hole shape and other factors, and that of dislocation amount is the smallest. (2) The influencing degree of hole shape on contact stress distribution is the greatest, followed by those of cross-section holing rate, dislocation amount, other factors, opening amount and rubber hardness, and that of the grooving number is the smallest. Single factor analysis is carried out on factors that affecting the mechanical properties of sealing gasket greatly to provide optimization scheme for sealing gasket based on analytical results and water-proof property prediction method.