中文摘要：

重庆市轨道交通三号线红旗河沟车站,开挖断面面积达760 m2,具有超浅埋、覆跨比小（仅0.4）的特点,属特大断面城市地下暗挖车站,且位于城区中心,地表环境复杂。通过方案比选,在施工中提出并实施预留十字岩梁岩柱的隧道施工新方法。通过数值分析优化施工参数,确定中间岩柱宽度为8 m,岩柱开挖步距为1 m,对隧道修建引起的地表沉降、断面净空位移进行现场监测,确保围岩稳定性,并分析施工过程中围岩变形规律。预留十字岩梁岩柱开挖可为供同类工程提供经验。

英文摘要：

The largest cross-sectional area of Hongqihegou Station in Chongqing Metro third line has reached 760 m2. The shallow station tunnel is located in urban area, the engineering condition is very complex. The tunnel is shallow buried and the ratio of depth to span is small（only 0.4）. By comparing different methods, a new excavation method named reserved cross rock beam-pillar is proposed; and the parameters are optimized with numerical analysis. The rock pillar is 8 m of width and the rock pillars excavation is 1 m of length. The surface subsidence and section convergence are monitored which are caused by the tunnel construction. The surrounding rock is stable during excavation, which proves that the proposed method is feasible in practice. Through the monitoring, the displacements law caused by construction process is researched. The result can provide experience to similar projects.