地铁暗挖隧道邻近既有运营盾构区间施工变形影响研究

Deformation Characteristics of Operating Shield Section Influenced by Subway Bored Tunnel Construction

为提升地铁盾构隧道的防灾减灾能力,以太原某地铁暗挖隧道邻近既有运营盾构区间施工为例,应用数值模拟与现场监测相结合的方法,研究地铁暗挖隧道施工过程中,盾构区间隧道结构及轨道结构的变形特征。研究结果表明:地铁暗挖通道上方地表沉降呈非对称“U型”分布,影响范围约为1倍埋深,影响角约45°。随着地铁暗挖隧道施工的进行,盾构区间及轨道结构的竖向位移及水平位移逐步累加,最终呈“弓”型对称分布,最大竖向位移及水平位移均出现在盾构区间中部位置,靠近暗挖隧道一侧轨道结构上浮量较大,远离暗挖隧道一侧轨道结构上浮量较小。盾构区间除发生常规竖向位移及水平位移外,还会产生一定量的扭转变形。现场监测结果表明,注浆加固作业施工过程中,盾构区间的变形剧烈,随着注浆压力的消散,盾构区间的已发生变形会逐步恢复,此过程中,要密切关注管片接缝位置漏浆、道床表面开裂等情况。

In order to improve disaster prevention and reduction of subway shield tunnels,taking the construction of existing operating shield section adjacent to a subway bored tunnel in Taiyuan as an example,we studied the deformation characteristics of both tunnel structure and track structure in the shield section influenced by the construction of subway bored tunnel by using the methods of numerical simulation and field monitoring.The results show that the distribution of the surface settlement above the subway bored tunnel shows an asymmetric U-shaped,and the influence range of it is approximately equal to the buried depth,and the influence angle of it is about 45°.During the construction of subway bored tunnel,the vertical and horizontal displacements of both shield section and track structure gradually accumulate,and finally present a bow-like symmetrical way.The maximum vertical and horizontal displacements occur in the middle of the shield section,and the floating amount of the track structure on the side close to the underground tunnel is large,and that on the side away from the underground tunnel is small.In addition to the vertical and horizontal displacements,a certain amount of torsional deformation also occurs in shield section.The field monitoring results show that during the grouting reinforcement process,the deformation of the shield section is severe,and then gradually recovers with the dissipation of grouting pressure.In this process,it is necessary to pay close attention to the mortar leakage at the segment joint position and the cracking of the track bed surface.