剖析双层盾构隧道预制内部结构拆分设计技术

Analysis on Split Design Technology of Prefabricated Internal Structure of Double-layer Shield Tunnels

摘要:

相较于地面结构，盾构隧道内部双层车道结构预制装配化具有如下特征：首先受制于洞内空间限制，预制构件需小型化、轻量化。其次，隧道为纵向延续，具备模数化、标准化条件，适合预制装配化。最后，上海软土易变形，叠加盾构掘进偏差，与预制高精度相驳。因此，基于上海诸光路通道，针对上述特征剖析双层盾构隧道预制内部结构拆分设计技术，形成如下结论：预制立柱拆分点宜为柱底和梁底，其高度由吊装作业空间、吊具高度、接头高度和施工容差共同确定。立柱横向净距受制于车道宽度，而纵向净距随隧道延续不受限制。因此，纵梁长度短，宜与车道板合并预制，形成n形结构，可减少一道拼装工序和后浇接头数量。

Abstract:

Compared with the ground structure, the prefabrication and assembly of the double-layer lane structure inside the shield tunnel have the following characteristics. Firstly, due to the space limitations inside the tunnel, the prefabricated components need to be miniaturized and lightweight. Secondly, the tunnel is longitudinally continuous and has the conditions for modularization and standardization, making it suitable for prefabrication and assembly. Finally, the soft soil in Shanghai is prone to deformation, and when combined with the deviation of shield tunneling, it conflicts with the precast high precision. Therefore, based on the Zhuguang Road Tunnel in Shanghai and aiming at the the above characteristics, the internal structure split design technology of double-layer shield tunnel prefabrication is analyzed, and the following conclusions are that the split points of prefabricated columns should preferably be the bottom of the column and the bottom of the beam. Its height is jointly determined by the hoisting operation space, the height of the lifting gear, the height of the joint and the construction tolerance. The transverse clear distance between the columns is restricted by the width of the lane, while the longitudinal clear distance is not restricted as the tunnel continues. Therefore, the longitudinal beam is short in length and is advisable to be prefabricated in combination with the lane slab to form an n-shaped structure, which can reduce one assembly process and the number of post-poured joints