地铁区间重叠隧道近接施工数值分析

城市隧道建设中，由交叉重叠的隧道施工引起对周围环境的多次干扰通常是不可避免的，这将对地面结构和既有地下工程产生负面影响。如何控制盾构隧道施工引起的沉降和隧道变形，确保隧道及邻近建筑物的安全，是设计和施工过程中必须考虑的问题。对此，依托某地铁隧道工程，运用有限差分软件FLAC3D模拟先下洞后上洞的开挖施工条件，计算上下洞盾构掘进引起的地表沉降、既有隧道连续墙侧移和下洞隧道断面收敛，分析总结了重叠隧道下穿既有隧道引起周围环境变形的规律。

Numerical Analysis on Approaching Construction of Overlapping Tunnel in Metro Sections

In the construction of urban tunnel, the repeated disturbances caused by the overlapping tunnel construction are usually unavoidable and it has a series of negative effects on the ground construction and existing underground works. The ways to control the ground movement and tunnel deformation caused by shield tunneling and ensure the safety of the surroundings and adjacent buildings are the main issues that must be considered in the design and construction process. Based on a subway tunnel project, the finite difference software FLAC3D is used to simulate the construction conditions (lower hole digs firstly). Then the surface subsidence, horizontal lateral movement of underground continuous wall and tunnel section converges caused by the excavation of the upper and lower holes are calculated and the deformation rules of the overlapping tunnel underpass existing tunnel are summarized and analyzed.