This paper constructs a three-dimensional numerical calculation model based on the project of Lanzhou NO.1 metro line,and researches the laws in the surrounding rock deformation and surface subsidence of shallow excavation metro tunnel construction in loess area to provide the technical basis for metro tunnel in loess area in the future.Conclusions are drawn as follows: In the construction of two side-wall pilot tunnel method, most of the surrounding rock displacement and the surface subsidence are caused by the first pilot tunnel excavation, the upper tunnel excavation should be a key factor to control the surrounding rock displacement and the surface settlement in the construction process;In large tunnel construction, the range of influence caused by excavation face is 1~1.5 times the hole diameter, and the maximum settlement of the surface is 21.68 mm, which is less than the warning value of 30 mm and can meet the construction requirements.%依托兰州地铁一号线,尝试构建三维数值计算模型,对黄土地区浅埋暗挖地铁隧道的围岩变形、地表沉降规律进行研究,以期能够为未来黄土地区地铁区间隧道的施工建设提供技术依据.主要得出以下结论:双侧壁导坑法施工时,围岩变形、地表沉降的大部分由先行导洞的掘进引起,因此在隧道施工过程中,应该对上部导洞的施工进行重点监测,控制;大断面浅埋黄土隧道的拱顶位移、地表沉降,受开挖面影响的范围为1~1.5倍洞径,地表最大沉降量为21.68 mm,小于地表沉降警戒值30 mm,满足施工要求.
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