高水压盾构隧道管片T型缝处防水性能研究

Study on Waterproofing Performance of T-joint of Shield Tunnel Segment with High Water Pressure

为降低隧道内渗漏水风险、保障运营期间隧道安全,依托上元门越江隧道工程防水设计方案,利用ABAQUS有限元软件建立了密封垫-管片沟槽三维精细化模型,研究了高水压盾构隧道管片T型缝处不同张开量下不同截面形式密封垫的防水特性。结果表明:T型缝处两个L型密封垫角部刚度较大,管片压缩后密封垫与角部接触部分变形较大;环缝和纵缝交点附近的平均接触应力最大,随着与交点的距离逐渐增大,接缝上平均接触应力急剧减小,在距交点10~25 mm范围内存在有应力谷;纵缝上靠近密封垫角部的应力谷位置是T型缝处最容易发生渗漏水的部位;同一张开量下,圆形开孔密封垫防水能力优于三角形开孔密封垫与无开放孔密封垫,建议在高水压盾构隧道管片T型缝处选用圆形开孔密封垫。

In order to reduce the risk of water leakage in the tunnel and ensure the safety of the tunnel during operation, with the reference of the waterproofing design scheme of Shangyuanmen river crossing tunnel project, a three-dimensional refined model of gasket segment groove is established by using ABAQUS finite element software. With this software, the article studies the waterproofing characteristics of the sealing gaskets of different section forms at different openings for the T-joints of high water pressure shield tunnel segment. The results show that the corner stiffness of the two L-shaped gaskets of the T-joint is larger, and the deformation of the contact part between the gasket and the corner is large after the segment is compressed. The average contact stress near the intersection of circumferential and longitudinal joints is the largest. With the gradual increase of the distance from the intersection, the average contact stress on the joint decreases sharply, and there is a stress valley within10 ~ 25 mm from the intersection. The stress valley area near the corner of the sealing gasket on the longitudinal joint is the most prone part of the T-joint to water leakage. Under the same opening degree, the waterproofing performance of circular opening gasket is better than that of triangular opening gasket and non-opening gasket. It is recommended to select circular opening gasket for the T-joint of high water pressure shield tunnel section.