北京地铁6号线浅埋暗挖法车站施工地表沉降规律研究

Study on ground settlement regularity induced by station construction with NATM( New Austrian Tunnelling Method) for line No. 6 of Beijing metro

对北京地铁6号线浅埋暗挖法车站施工引起的地表沉降规律进行研究,通过其中10个车站的地表沉降监测数据,分析地表沉降与车站埋深、开挖面积等影响因素的相关关系。研究结果表明:车站埋深与地表沉降不成反比;开挖面积相近时,东四站及其以东的暗挖车站地表沉降值明显大于其以西的暗挖车站;地表沉降区间频率曲线服从正态分布,地表沉降-40^-60 mm出现的频率最大;暗挖车站主体小导洞及桩柱体系、初支扣拱、二衬扣拱3个主要施工阶段引起的地表沉降比值为38∶14∶5;沉降槽反弯点与隧道中线的距离为10~14 m,地层损失率为0.3%~0.7%。研究结论可为类似车站周边环境风险评估及北京规划远期地铁线路起到指导作用。

This paper studied the ground surface settlement law caused by Beijing metro line 6 stations construction with shallow depth subsurface excavation method and analyzed the correlationship between the ground surface settlement and its influencing factors such as station buried depth and excavation area through gathering the surface settlement monitoring data of ten metro stations. The results shows that the station buried depth is not inversely proportional to the surface settlement;the ground surface settlement value of subsurface excavation station to the east of the Dongsi station( including) is larger than the one to the west of the Dongsi station when the excavation areas are similar; the surface settlement interval frequency curve obeys the normal distribution and the most frequently occurred values of the ground surface settlement are in 40 ~60 mm; the ratio of the surface settlement caused by the three major construction stage of subsurface excavation station including subject heading,initial supporting arch and second lining arch is 38∶14∶5;the distance between the contraflexure point of the settling tank and the midline of the tunnel is 10 ~14 meters and the ground loss ratio is about 0. 3% ~0. 7%. The results provide a reference for risk assessment of the metro stations with similar environmental conditions and for long term planning of Beijing metro line.