关键词: 三连拱隧道, 施工工法, 变形控制, 设计优化

Abstract: Based on the project between Jiuquhe East Station and Chongguang stations of Chongqing Urban Rail Express Line No. 15, this paper studies the applicability of different excavation methods in the construction of a continuous three-arch tunnel by using numerical calculation methods. The results indicated that the construction of the continuous three-arch tunnel in this project using methods of side tunnel, middle tunnel, and pilot tunnel resulted in a maximum surface settlement of no more than 5.56mm. The control effect of the surface settlement during the construction of this project is the best using the pilot tunnel method, followed by the side tunnel method, and the worst using the middle tunnel method. The plastic zone of the surrounding rock during the tunnel construction in this project is mainly distributed on the outer side of the side tunnel arch wall, as well as in the middle tunnel arch shoulder and arch foot area. The anchor rods of the arch shoulder system penetrate the main plastic strain area and have a good anchoring effect. The design of the anchor rods of the arch crown system can be appropriately optimized. By comprehensively comparing the advantages and disadvantages of four excavation methods in terms of strata deformation control, material consumption, and construction difficulty, and considering the actual situation, it is recommended to use the side tunnel method for the construction of the continuous triple arch tunnel in this project. The research methods and conclusions of this paper can provide a reference and the guidance for the similar engineering design and construction.

Key words: Continuous Three-Arch Tunnel, Construction Technique, Deformation Control, Design Optimization