地铁车站开挖项目面临复杂多变的地质条件,采用何种开挖方法是目前关注的重点。常规开挖方式中,明挖法占用大量土地,产生噪声污染;双侧壁导坑法强度过度储备;拱盖法对上软下硬地层有很好的适应性,但存在施工缝渗水问题。青岛市位于上软下硬的特殊地质环境中,地铁车站多在花岗岩层建设,以上几种施工方法在地下水资源丰富的青岛并不十分适用。为了研究初支拱盖法在该类地层地铁车站的适用性,本文运用Midas GTS NX软件,对青岛地铁一号线某车站建模并仿真计算,结合实时监测数据分析了拱顶沉降、洞内净空收敛和地表沉降规律。结果表明:初支拱盖法在该类上软下硬地层中能有效保障施工安全,其中关键施工环节为凿除初支和开挖核心土体;及时支护对维持洞室稳定和防止地表沉陷至关重要。

The subway station excavation project faces complex and variable geological conditions, and the choice of excavation method is currently a focus of attention. In conventional excavation methods, the cut-and-cover method occupies a large amount of land and generates noise pollution; the double-side wall pilot tunnel method has excessive strength reserves; the arch cover method has good adaptability to the upper soft and lower hard strata, but there is a problem with water seepage at construction joints. Qingdao City is located in a special geological environment of upper soft and lower hard strata, and most subway stations are built in the granite layer. The above construction methods are not very suitable for Qingdao, which has abundant groundwater resources. In order to study the applicability of the initial support arch cover method in subway stations in such strata, this paper uses midas GTS NX software to model and simulate a station on Qingdao metro line 1, and analyzes the laws of arch crown settlement, tunnel internal net convergence, and ground surface settlement combined with real-time monitoring data analysis. The results show that the initial support arch cover method can effectively ensure construction safety in such upper soft and lower hard strata, with the key construction link being the removal of the initial support and the excavation of the core soil. Timely support is crucial for maintaining the stability of the chamber and preventing ground subsidence.