【摘要】 青岛地铁1号线某暗挖地铁车站跨度22 m。拱顶覆岩以厚度较大的强风化火山角砾岩为主,总体呈现覆岩强度差,洞室埋深浅且围岩强度上软下硬的特点,围岩级别为Ⅳ-Ⅴ级。中隔壁法、双侧壁导坑法为拟采用的施工工法。为确定合理开挖工法,采用Flac有限差分法分析开挖时的围岩位移,应力及塑性区的分布。得出Ⅳ级围岩时,拱顶围岩基本稳定,可采用中隔壁法开挖;Ⅴ级围岩时,双侧壁导坑时围岩自稳性较好,开挖中间岩柱时围岩自稳性差,如无支护措施不当,拱顶可坍塌至地面。更多还原

【Abstract】 One metro station with span of 22 meters belongs to Qingdao Metro Line 1 is constructed by mining method. The overburden of roof is dominated by strong weathered volcanic breccia. The surrounding rock grade is between Ⅳ and V. CD method and double-sided drift method are probably adopted. In order to determine the reasonable excavation method,Flac with finite difference method is used to analyze the distribution of displacement,stress and plastic zone of surrounding rock during excavation. It is concluded that the surrounding rock is basically stable and can be excavated by CD method when surrounding rock belongs to the Ⅳ grade; the surrounding rock of the V grade shows self-stability when the double-sided pits are excavated. The surrounding rock should collapse to the ground when the intermediate rock pillar is excavated and the proper supporting measures haven’t been done.更多还原