考虑公轨合建型内部结构的盾构隧道纵向力学性能研究

Study on Longitudinal Mechanical Properties of Shield Road-Metro Tunnel Internal Structure

盾构隧道朝着超大断面发展,其内部结构形式愈加复杂多样化,内部结构对盾构隧道纵向力学性能的影响值得探讨。为研究考虑公轨合建型内部结构的盾构隧道纵向力学性能,以济南黄河隧道为工程背景,建立31环考虑公轨合建型内部结构的盾构隧道三维有限元实体模型,以集中力的形式作用在第16环管片环进行加载。结果表明:盾构隧道考虑内部结构后,通缝拼装隧道和错缝拼装隧道纵向刚度有效率分别提高21.4%~61.9%和14.3%~35.3%,说明内部结构能够有效提高盾构隧道的纵向刚度;通缝拼装隧道和错缝拼装隧道加载环最大Mises应力分别减小61.3%和69.2%,说明内部结构能够起到承载作用;隧道管片与内部结构会发生应力集中现象;错缝拼装形式有利于减小内部结构在纵向上的位移变形,同时内部结构的侧墙在施工时应尽可能保证混凝土的密实。

With the development of large cross-section shield tunnel, its internal structure is becoming more and more complex and diversified. The influence of the internal structure on longitudinal mechanical properties of the shield tunnel is worth exploring. Taking the Yellow River tunnel in Ji’nan as the engineering background, a 31-ring three-dimensional finite element solid model for road-metro shield tunnel internal structure is built. In order to explore the longitudinal mechanical properties of the shield tunnel, a concentrated force is exerted on the 16 th ring. The results show that after considering the internal structure of the shield tunnel, the longitudinal stiffness efficiencies of the straight-jointed tunnel and the stagger-jointed tunnel are increased by 21.4%~61.9% and 14.3%~35.3% respectively, which shows that the internal structure can effectively improve the longitudinal stiffness of the shield tunnel;the maximum Mises stresses of the load rings of the straight-jointed tunnel and the stagger-jointed tunnel are decreased by 61.3% and 69.2%, respectively, indicating that the internal structure is capable of bearing the load;stress concentration tends to occur in the connected areas of internal structure and segments;the stagger-jointed assembly is helpful to reduce the longitudinal displacement of the internal structure;while, the concrete of the internal structure’s side wall should be as dense as possible.