关键词: 地铁车站, 浅埋, 超大断面, 拱盖支柱法, 数值模拟, 施工力学, 现场监测

Abstract: The study aims to investigate the mechanical behavior of the cover arch pillar method in the construction of metro stations, with a focus on the Beijinglu station of Guiyang metro line 3 in China. Numerical simulation and onsite monitoring methods are used to examine the deformation of the surrounding rock and surface settlement and the stress of supporting structures during the construction of the metro station. The results reveal the following: (1) The cover arch pillar method flexibly uses the construction concept of pilebeamarch method and centerdrift method to form the top support structure. The cover arch pillar method also makes full use of the bearing function of the lower hard rock to effectively control surface settlement and surrounding rock deformation. (2) The excavation of the upper middle pilot tunnel leads to the maximum settlement of the crown and surface, while the excavation of the upper side pilot tunnel leads to the maximum stress change of the support structure. (3) The construction of the top support structure results in small deformations of surrounding rock and surface and small stress change of the support structure, indicating that the top support structure plays an important role. The trend of numerical results with respect to the change in the construction process is in good agreement with the trend of onsite monitoring.

Key words: metro station, shallow cover, superlarge crosssection, cover arch pillar method, numerical simulation, construction mechanics, onsite monitoring