上软下硬复合地层中拱盖法单拱大跨地铁车站的埋深影响研究

以大连地铁兴工街站为例,结合车站范围内上软下硬复合地层的特点,以及采用双层初支拱盖法施工的单拱无柱大跨的特殊结构形式,通过数值方法对不同埋深条件下的开挖环境变形效应、围岩稳定性及支护结构安全性进行分析研究,并对合理埋深进行判定。研究结果表明:采用拱部双层初支形式的拱盖法能较好地适用于上软下硬复合地层,形成的单拱大跨结构能够维持稳定;双层初支拱盖结构的第一道初支起主要的支护作用,且埋深越大,发挥的支护作用愈加明显,而第二道初支主要起维持拱部稳定和安全储备的作用;从结构及地层变形、围岩稳定性、支护结构受力等角度出发,提出车站合理埋深,为类似地层工程建设提供有益的理论和技术支撑。

Impacts of Depths on the Large-span and Single-arch Subway Station with Arch Cover Method in Hard-soft Heterogeneous stratum

Taking the Xinggongjie Station of Dalian Metro as an example to solve this problem ,combined with the char-acteristics of the hard-soft heterogeneous stratum and the special structure of large-span and single-arch with arch cover method ,the deformation caused by excavation environment , the stability of excavation and the security of supporting structure was studied by using numerical simulation method ,and the reasonable depth has been determined .The results show that:the arch cover method with double primary support can be preferably applied to the hard-soft heterogeneous stratum ,and eventually forms the large-span and single-arch subway station;the early primary support of the arch cover with double primary support plays a major supporting role which is more obvious as the depth increases ,however ,the lat-er primary support plays the role of maintaining the stability of arch and ensuring safety ;considering the deformation of tunnel and stratum ,the stability of surrounding rock and the force of supporting structure ,the reasonable depth was pro-posed ,which provides useful theoretical and technical support for the construction in similar stratum .