大连地铁盾构开挖地层移动规律的模型试验研究

Study of strata movement law through similar model test in the Dalian city subway shield tunnelling

以大连市地铁2号线202标段工程为研究对象,通过相似材料模型试验绘制不同地层随时间沉降曲线,即同一时刻不同地层沉降槽曲线和不同地层水平位移曲线,得到盾构隧道施工地层移动规律。试验结果表明,不同地层各测点的垂直位移随时间的变化可用以时间为自变量的负指数函数表示;先行隧道施工对地层产生扰动,引起地层软化,导致两条隧道之间地表沉降明显叠加,沉降较大;隧道开挖时,若存在地下结构或管线,其将受到附加剪切作用,易出现裂缝,在施工中必须做好切实可行的防护措施。

It is obtained the strata movement law under shield tunnelling construction engineering through similar material model test to monitor the curves over time that the different strata settlement trough and horizontal displacement at the same time taking the No.202 tender of No.2 line in Dalian city subway project as the studying object.The results show that the vertical displacement change of the monitoring points for the different strata can be fitted negative with exponential function.The ground strata disturbance has been produced because the first constructing tunnel and resulting as the ground softening;and the surface settlement of the two tunnels is obviously superimposed larger settlement.The existed underground structures or pipelines will prone to cracks subjected additional shearing when tunnel excavating,so that must taking effective protective measures.