越江盾构隧道密封垫长期防水性能模拟研究

Numerical Simulation Study on Long⁃term Waterproof Performance of Sealing Gasket for Cross⁃river Shield Tunnel

越江盾构隧道承受水压大,对密封垫的防水性能要求较高,对内外道密封垫长期防水性能进行研究,基于材料黏弹性理论,采用数值模拟方法分析越江隧道内外道密封垫的应力松弛现象。首先不考虑密封垫应力松弛系数,进行首次数值模拟,在上述结果的基础上,考虑应力松弛系数进行第2次数值模拟,橡胶设置为黏弹性材料,使用Maxwell模型描述其松弛行为,并使用预先拟合得到的模型参数进行黏弹性分析。得到密封垫的压缩曲线及平均接触应力随时间变化曲线,通过分析,得出内外道密封垫在接缝张开量8mm、错台量6mm的情况下,使用100年后,最终应力松弛系数分别为0.75,0.61。

The shield cross-river tunnel bears large water pressure has high requirements for waterproof performance of gasket.In this paper,the long-term waterproof performance of the inner and outer gaskets is studied.The finite element software is used to simulate the compression deformation of inner and outer gaskets of cross-river tunnel.The calculation and analysis are divided into two steps,the first step is large deformation compression calculation of gasket without considering stress relaxation of rubber material,and the second step is calculation of stress relaxation of gasket.Considering that the rubber is set as viscoelastic material,the viscoelastic analysis is carried out by the model parameters fitted by Maxwell model.The compression curve of the gasket and the curve of average contact stress with time are obtained.Through analysis,it is concluded that the final stress relaxation coefficients of the inner and outer seal gaskets after 100 years of use are 075 and 061 respectively when the joint opening is 8mm and the dislocation is 6mm.