首都国际机场西区L滑行道下管棚–箱涵顶进工程是当前首例在机场滑行道下不停航施工规模最大的顶进隧道,地表沉降控制要求严格,施工风险高。为研究施工工法的可行性,针对超长管棚施作、开挖导洞布设下滑道、长大箱涵顶进等主要工况进行数值模拟,重点对典型施工工况引起滑行道地表沉降变形特征和规律进行分析研究。计算结果表明,在理想状态下施工引起的地表沉降最大值约为24mm,能控制在允许范围内,而工程实施过程中地表最大沉降基本控制在30mm之内,可满足飞机运行安全,表明计算模型和结果是有效的,工程采用超长管棚–箱涵顶进工法施工是合理可行的。
The vehicle tunnels adopt box culvert advancing scheme under overlength pipe shed, which is the first case to underpass the west L-taxiway of Beijing Capital International Airport without suspending air service during construction in China. The ground settlement should be strictly controlled. For the case of safety, the numerical simulation of construction has been carried out. The characteristics of ground settlement have been analyzed according to the construction of long pipe shed, excavation of pilot drift and the advancing of box culvert. The simulation result shows that the maximum ground settlement is 24 mm at normal condition. In actual practice, the settlement has been well controlled within 30 mm, which meets the limitation of allowable value. It indicates that the simulation models and results are effective and rational; and the box culvert advancing scheme under overlength pipe shed is feasible.