摘要
中隔墙作为连拱隧道最主要的受力结构,其稳定性既关系到施工期间的结构安全,还直接影响后期隧道的运营安全。如何确保中隔墙的稳定是软弱地层双连拱隧道设计施工的关键难题之一,而不同结构型式的中隔墙对双连拱隧道整体结构和中隔墙稳定性影响较大。文中以南山路双连拱隧道为背景,从中隔墙受力机理入手,通过理论分析、三维数值模拟并结合现场实测,分析对称和不对称型式中隔墙的受力特点及稳定性。结果表明:(1)非对称式中隔墙在地表偏压区适应性更强,比对称式中隔墙有明显的优势;(2)在双连拱隧道开挖过程中,中隔墙始终有向先行洞一侧偏转的趋势;(3)双连拱隧道开挖过程中,中隔墙应力变化复杂,墙顶处偏压明显,在后行洞上台阶开挖时其偏压最大;开挖结束后,中隔墙仍存在局部偏压。因此,为防止中隔墙倾覆,建议先行主洞施工时要在中隔墙另一侧施加横撑或回填片石作为临时支撑。
The mid-partition wall is the main structure of the double arch tunnel. Its stability is not only related to the structural safety but also affects the later operation safety. How to ensure its stability is a key problem,however,the different structural type of mid-partition wall has a great influence on the stability of the wall and the whole tunnel structure. In this paper,based on the Nanshan Road tunnel,the load carrying characteristics and stability of symmetry and asymmetric type of mid-partition wall are analyzed by theoretical analysis,three-dimensional simulation and field measurement. The results show:( 1) the asymmetric mid-partition wall has more advantages than the symmetrical midpartition wall in the zone with unsymmetrical pressure.( 2) The middle wall always has the tendency to deflect toward the first excavated hole during excavation.( 3) The top of the mid-partition wall carries obvious unsymmetrical pressure in the whole construction process,the maximum value appears at upper bench excavation of the following hole. In order to prevent overturn of the mid-partition wall,lateral bracing or backfill concrete should be added on the opposite side of the first excavated hole before the first main tunnel excavation.
出处
《土木工程学报》
EI
CSCD
北大核心
2017年第S2期236-242,共7页
China Civil Engineering Journal
关键词
双连拱隧道
中隔墙
结构选型
稳定性研究
double-arch tunnel
mid-partition wall
selection of structural type selection
stability analysis
