双孔平行隧道施工对地表沉降影响的数值分析

准确而又方便地确定双孔平行地铁隧道施工引起的地表沉降是工程实践中经常遇到的问题。以城市地铁区间隧道施工为工程背景，运用FLAC3D数值模拟，并结合现场实测数据，探讨了双孔平行地铁隧道开挖对地表沉降的影响。研究结果表明:地表沉降变形趋于稳定后，地表总沉降值等于开挖左线隧道和开挖右线隧道沉降变形稳定后所引起的地表沉降值之和；后行开挖隧道所引起的地表沉降值大于先行开挖隧道所引起的地表沉降值；当双线隧道间距较小时，沉降槽曲线为“单峰”形态，而双线隧道间距较大时，会呈现“双峰”特征。

Numerical Analysis on Effect of Double-tube Parallel Tunnel Construction on Ground Surface Subsidence

How to correctly and simply confirm the ground surface subsidence caused by double-tube parallel tunnel construction is often encountered in engineering practice. Taking interval tunnel construction of a city subway project as the background, by means of FLAC3D numerical simulation, the effect of double-tube parallel tunneling on ground surface subsidence was discussed with the measured data. The result shows that, after the ground surface deformation becomes stable, the total settlement is equal to the sum of subsidence caused thereby when the deformation from the left and right tunneling is steady; the ground surface subsidence caused by later tunneling is larger than that caused by first tunneling; when the spacing between the two tubes is small, the settlement trough has a profile of ‘single peak’, when the spacing is large, the trough has a profile of ‘double peak’.