盾构及明挖隧道平行下穿机场跑道沉降分析与实测

Analysis and Measurement of Settlement of Airport Runway Traversed by Parallel Shield and Open⁃cut Tunnels

上海浦东国际机场三期扩建工程中,既有航站楼(T1)与新建卫星厅(S1)之间的暗挖捷运隧道和明挖行李地道长距离近接平行施工,且同时穿越机场停机坪和滑行道。为了研究盾构及明挖隧道平行下穿越施工引起的机场道面沉降变形规律,首先建立数值模型,对两隧道同期施工时引起的地表沉降叠加影响进行了模拟分析,然后结合现场实测,分别分析了地表纵向沉降分布、地表横向沉降分布和地表沉降时程变化规律。结果表明:明暗双通道同时施工引起的地表沉降分布相比单独施工叠加得到的地表沉降分布存在明显差异,地表沉降曲线整体向隧道一侧偏移;地表纵向沉降分布上呈现出明显的不均匀性,地表横向沉降分布上越接近隧道轴线沉降或隆起越大,沿两侧逐渐减小,沉降分布不对称;盾构机接近指定环断面前地表发生沉降,到达并穿越断面时地表隆起,穿越后地表沉降渐趋稳定。

In the third phase expansion project of Shanghai Pudong International Airport,the excavated MRT tunnel and the open-cut baggage underpass between the terminal(T1)and the newly built satellite(S1)are constructed in adjacent parallel for a long distance,and simultaneously traverse underneath the airport apron.In order to study the rule of airport ground settlement caused by the construction of the adjacent parallel tunnels,this paper first establishes a two-dimensional numerical model to analyze the distribution rule of ground settlement during the simultaneous construction of open-cut and excavated tunnels,and then analyzes the rule of longitudinal settlement distribution,latitudinal settlement distribution and change in ground settlement with time,combined with the field monitoring data.The results show that,there is a significant difference in the surface settlement distribution caused by the simultaneous construction of open-cut and excavated underpasses,compared with the superimposition of settlement distribution caused by single construction,and the settlement curve deviates to the tunnel side.The longitudinal settlement distribution shows obvious unevenness,the latitudinal settlement distribution shows that the closer to the tunnel axis,the larger of the settlement or uplift,along both sides the settlement decreases,and the settlement distribution is asymmetric.The ground surface subsides when the shield machine approaches the designated section,and it rises when crossing,and after crossing,the ground settlement tends to be stable.